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DECEMBER 2001 3057A N N U A L S U M M A R Y

Atlantic Hurricane Season of 1999

MILES B. LAWRENCE, LIXION A. AVILA, JACK L. BEVEN, JAMES L. FRANKLIN, JOHN L. GUINEY, AND

RICHARD J. PASCH

National Hurricane Center, Tropical Prediction Center, NOAA/NWS, Miami, Florida

(Manuscript received 30 January 2001, in final form 24 May 2001)

ABSTRACT

The 1999 Atlantic basin hurricane season produced 4 tropical storms and 8 hurricanes for a total of 12 namedtropical cyclones. Seven of these affected land. Hurricane Floyd—the deadliest U.S. hurricane since Agnes in1972—caused a disastrous flood event over the U.S. mid-Atlantic and northeastern coastal states, resulting in56 U.S. deaths and 1 death in the Bahamas. Heavy rain from a tropical depression contributed to some 400inland flood deaths in Mexico.

1. Introduction

There were 12 named tropical cyclones in the AtlanticOcean, the Caribbean Sea, and the Gulf of Mexico dur-ing 1999. These cyclones are listed in Table 1, alongwith their dates, maximum 1-min surface wind speed,minimum central surface pressure, U.S. damage, anddirectly attributable deaths. Four of the tropical cycloneswere tropical storms and eight reached hurricane inten-sity. The four tropical storms were at the 1950–99 av-erage of 4.0, and the eight hurricanes were above theaverage of 5.9. In addition, there were four tropicaldepressions that did not reach tropical storm intensity.Five hurricanes attained category 4 intensity on the Saf-fir–Simpson hurricane scale (Simpson 1974). This is themost category 4 hurricanes in a single season since1886.

After each cyclone has dissipated, a ‘‘best track’’ isdetermined, using all available data. The best track con-sists of 6-hourly center positions, maximum 1-min windspeed, and minimum central surface pressure. A recordof Atlantic basin best tracks (Jarvinen et al. 1984) ismaintained at the National Hurricane Center for tropicalstorms and hurricanes. Figure 1 is a map showing thebest track positions of this year’s named storms alongwith an indication of depression, storm, or hurricanestage.

Many of the tropical cyclones affected land. Bret,Floyd, and Irene made U.S. hurricane landfalls in Texas,North Carolina, and Florida, respectively. Floyd also hit

Corresponding author address: Dr. Miles B. Lawrence, TropicalPrediction Center, National Hurricane Center, NWS/NOAA, 11619SW 17th Street, Miami, FL 33165-2149.E-mail: [email protected]

the Bahamas as a hurricane. Dennis was nearly a hur-ricane at landfall in North Carolina. Tropical Storm Har-vey went across Florida, Hurricane Jose hit the northernLeeward Islands, and Tropical Storm Katrina movedinland over Nicaragua. Lenny moved eastward over thenorthern Leeward Islands as a hurricane and its exten-sive rain and ocean swells affected much of the southernand eastern Caribbean.

Flooding from Floyd caused a disaster in the easternUnited States and particularly in North Carolina. TheU.S. death toll of 56 from Floyd was the highest sinceHurricane Agnes of 1972 (122 deaths). The deadliesttropical cyclone of the season was a tropical depression,whose heavy rain and flooding caused 400 deaths inMexico.

Between May and November, 59 tropical wavesmoved westward across Dakar, Senegal’s longitude.Many were tracked all the way across Central Americato the eastern North Pacific basin. The origins of 11 ofthis season’s 12 named tropical cyclones, or 92%, wereassociated with these waves. This compares to the 1967–99 average of 62% of the named tropical cyclones thatoriginated from tropical waves. So, there are normallymore systems originating from upper-tropospheric coldlows or along frontal zones than was observed during1999.

2. Description of tropical storms and hurricanes

a. Tropical Storm Arlene, 11–18 June

Arlene remained at sea. The storm passed about 100n mi east of Bermuda, but tropical storm force windsremained offshore.

On 8 June, water vapor imagery first showed the cir-

3058V

OL

UM

E129

MO

NT

HL

YW

EA

TH

ER

RE

VI

EW

FIG. 1. Tracks of tropical storms and hurricanes in the Atlantic basin during 1999.


culation of an upper low located a few hundred milesnorth of Puerto Rico. Simultaneously, a large-amplitudetropical wave passed through the tail end of a frontalzone southeast of the upper low and a low-level cloudswirl became visible near 228N, 618W, close to the waveaxis and southeast of the upper low. The low-level cloudswirl then moved slowly northwestward for 2 days withdevelopment inhibited by westerly shear from the upperlow.

Meanwhile, steady convection had been maintainedin the diffluence region to the east of the upper low. By10 June, the low-level circulation moved underneath thecold low, near 248N, 638W. Shortly thereafter, the upperlow moved eastward into the convective area. As theupper low accelerated northeastward late on 10 June,satellite microwave imagery revealed the developmentof a new circulation in the convection. During the morn-ing of 11 June, the convection developed a well-definedbanding pattern, and it is estimated that a tropical de-pression formed from this activity at 1800 UTC 11 June,about 465 n mi southeast of Bermuda.

Soon after reaching depression status, the cycloneslowed and drifted northward for 24 h. By 1200 UTC12 June, satellite classifications (Dvorak 1984) indicatedthat tropical storm strength had been attained. Arleneintensified for 12 h until westerly shear began to exposethe low-level circulation center. The maximum intensitywas reached at 0000 UTC 13 June, when the winds wereestimated to be 50 kt and the minimum central pressurewas estimated to be 1006 mb. From 13 to 15 June,Arlene moved generally west-northwestward whileweakening slightly under the westerly shear.

Steering currents became poorly defined and Arlenemoved little on 15 June. The best track indicates thatArlene executed a small cyclonic loop, although thisapparent motion may have been due to a reformationof the center closer to the convection on the east sideof the cyclone. A northwestward motion resumed lateon 15 June, followed by a gradual turn to the north andthen northeast over the next 3 days as Arlene movedaround the western periphery of the Atlantic subtropicalridge. Convection began to diminish on 16 June whenthe environmental vertical wind shear changed to north-easterly and Arlene moved over cooler waters. Arlene’sclosest approach to land was on 17 June, when it passedabout 100 n mi to the east of Bermuda. The storm weak-ened to a depression on 17 June, and dissipated aheadof an approaching frontal zone on 18 June.

The maximum wind speed of 50 kt on 13 June isbased on Dvorak satellite estimates. There was U.S. AirForce Reserve Hurricane Hunter aircraft reconnaissanceon 15 and 16 June, but the estimated maximum windshad decreased slightly to 45 kt by this time.

Arlene’s center passed about 100 n mi to the east ofBermuda and no significant weather occurred there.

b. Hurricane Bret, 18–25 AugustBret was a small hurricane that made landfall along

a sparsely populated section of the south Texas coast

with maximum sustained winds of 100 kt. Bret was thefirst hurricane to strike Texas since Hurricane Jerry inOctober 1989 and was the strongest Texas hurricanesince Hurricane Alicia in 1983.

1) SYNOPTIC HISTORY

A tropical wave moved from Africa to the tropicalAtlantic Ocean on 5 August. On 18 August, continuityand soundings from Merida, Mexico, place this weaktropical wave in the vicinity of the Yucatan Peninsula.Also, a weak surface low-formed over the peninsula.This low originated from a thunderstorm complex as-sociated with a westward moving upper-level cycloniccirculation.

Later on 18 August the surface low moved over theBay of Campeche. Early morning visible satellite im-agery showed a low-level cloud circulation center and,a few hours later, a Hurricane Hunter reconnaissancemission confirmed the existence of a closed circulation.With some deep convection and banding present, thesystem became a tropical depression at 1800 UTC on18 August over the Bay of Campeche.

The depression did not strengthen right away due tovertical wind shear caused by an upper-level trough overthe extreme western Gulf of Mexico. However, thetrough moved away and the depression became TropicalStorm Bret late on 19 August while beginning to moveslowly northward. Bret steadily strengthened. On themorning of 22 August, it reached 125 kt (a category 4hurricane on the Saffir–Simpson hurricane scale) justoffshore from Brownsville, Texas. Figure 2 is a visiblesatellite image of Bret on the morning of 22 August.Responding to the presence of a weak midtroposphericridge over the northwest Gulf of Mexico and to a mid-tropospheric cyclonic circulation over the Rio Grandevalley, Bret turned northwestward and its forward speedslowed from near 10 kt to about 5 kt.

Bret’s center crossed the Texas coast midway betweenBrownsville and Corpus Christi and near the middle ofPadre Island at 0000 UTC 23 August. By the time oflandfall, it had weakened to a category 3 hurricane with100-kt winds and a pressure of 951 mb. After movinginland, Bret’s movement became more westward. Bretcontinued to weaken while it moved across south Texasand into the high terrain of north-central Mexico, whereit dissipated on 25 August.

2) METEOROLOGICAL STATISTICS

The maximum 1-min surface wind speed of 125 ktearly on 22 August is based on a reconnaissance aircraftGlobal Positioning System (GPS) dropwindsonde ver-tical wind speed profile (Hock and Franklin 1999). Pro-files from Bret’s eyewall show that winds reached near150 kt within 300 m above the surface and were about125 kt near the surface.

Bret’s pressure dropped 35 mb to 944 mb in the 24

3060 VOLUME 129M O N T H L Y W E A T H E R R E V I E W

FIG. 2. GOES-8 visible satellite image of Hurricane Bret at 1345 UTC 22 Aug 1999, near the time of 125-ktmaximum wind speed. (Courtesy of Naval Research Laboratory, Monterey, CA.)

h ending at 1200 UTC 22 August and dropped 21 mbduring the 6 h ending at 0000 UTC of the same day.This episode of intensification coincides with the hur-ricane’s track over a maximum in the sea surface tem-perature (SST) field over the west-central Gulf of Mex-ico. Analyses from Applied Physics Laboratory, TheJohns Hopkins University, shows 318C SST valuesalong Bret’s track during the intensification. In addition,values of the upper oceanic heat content (described byShay et al. 2000) under portions of the hurricane’s cir-culation in the western Gulf of Mexico were high.

Bret was a small hurricane. At its peak, hurricaneforce winds were confined to a radius of 30–40 n mifrom the center in the north semicircle and only 10–20n mi in the south semicircle. Thus only a small segmentof the Texas coast was affected by the core of the hur-ricane. Kennedy County received most of the hurricaneforce winds, which were as high as 100 kt over a small

portion of the coast of Padre Island. With the centermoving inland over a sparsely populated area, few sur-face reports were available substantiating strong winds.Table 2 lists a selection of surface observations. Thehighest reported sustained wind is 63 kt at Rincon delSan Jose on Padre Island. That instrument failed at 2230UTC on 22 August just before the center passed nearby.The Port Aransas Coastal Marine Automated Network(C-MAN) station reported maximum sustained winds of41 kt as the center of the hurricane passed about 60 n mito the south.

Bret was slow moving and radar estimates suggestmaximum storm total rainfall of over 760 mm in Ken-nedy County. None of the observed rainfall totals inTable 2 come close to that value. Aransas Pass is northof the area of peak rainfall and reported a storm totalof 320 mm. The heavy rains accompanying the weak-ening tropical cyclone caused notable river flooding in


TABLE 1. 1999 Atlantic hurricane season statistics.

No. Name Class* Dates**

Maximum1-min

wind (kt)

Minimum sealevel pressure

(mb)U.S. damage($ millions) Direct deaths

123456

ArleneBretCindyDennisEmilyFloyd

THHHTH

11– 18 Jun18–25 Aug19–31 Aug24 Aug–07 Sep24–28 Aug07–17 Sep

50125120

9045

135

1006944944962

1004921

60

157

4500

4

57789

101112

GertHarveyIreneJoseKatrinaLenny

HTHHTH

11–23 Sep19–22 Sep13–19 Oct17–25 Oct28 Oct–01 Nov13–23 Nov

13050958535

135

930994958979999933

15800

330

2

2

17

* T 5 tropical storm wind speed 34–63 kt; H 5 hurricane wind speed 64 kt or higher.** Dates begin at 0000 UTC and include tropical depression stage (wing speed ,34 kt).

the Rio Grande Valley. The Rio Grande River at Laredoand the Aransas River near Skidmore and at Oso Creekcrested slightly above flood stage. A 24-h rainfall totalof over 350 mm was reported from the Mexican stateof Nuevo Leon. The state of Tamaulipas is believed tohave received similar amounts.

The Sea, Lake, and Overland Surges from Hurricanes(SLOSH) storm surge model suggested that a narrowregion along central and north Padre Island experienceda storm surge of 2.5–3 m. A report from Port MansfieldPass suggests that 1–1.5 m of water inundated this coast-al location. Several cuts were observed in the dunessurrounding Padre Island. The largest of these, near milemarker 50 near the eye’s passage, was mistaken as theMansfield Pass by aircrews inspecting the damage. Oth-er substantial beach erosion was reported near PortMansfield.

In Aransas County around 2145 UTC 22 August, atornado reportedly uprooted trees, destroyed a recrea-tional vehicle, a barn, and a shed. Other reports indicatethat a tornado touched down in Kingsville around 2245UTC on 22 August and a tornado was reported in Alice,but the time was not known. Neither led to reporteddamage.

3) CASUALTY AND DAMAGE STATISTICS

Despite Bret’s intensity, damage was fairly light.Much of this is due to its landfall over a sparsely pop-ulated region in south Texas and the hurricane’s smallsize. The nearest population centers to the south andnorth of landfall were Brownsville and Corpus Christi.These cities are about 100 n mi apart and were bothspared the brunt of the hurricane’s core. Brownsville’smaximum reported sustained wind was only 29 kt andCorpus Christi’s maximum was only 39 kt (see Table2). There were no deaths.

Property insurance damage claims total $30 millionas reported by the Property Claims Services Divisionof the Insurance Services Office. A standard practice of

multiplying by a factor of 2.0 gives an estimated damagetotal of $60 million. This is a conservative multiplier,based on a sample of past landfall damage estimates.

c. Hurricane Cindy, 19–31 August

Cindy had a long track across the Atlantic, but withno direct impact on land.

The origin of Cindy was a tropical wave that crossedthe west coast of Africa early on 18 August. It wasaccompanied by 4.5-mb, 24-h surface pressure falls anda 50-kt, 700-mb wind speed maximum, as indicated inDakar, Senegal, rawinsonde data. Shortly after movingover the eastern tropical Atlantic, deep convection be-came better organized. By the evening of 18 August,thunderstorm activity consolidated near the center of abroad circulation and it is estimated that a tropical de-pression formed early on 19 August, centered about 250n mi east-southeast of the Cape Verde Islands.

Persistent 20–30-kt easterly vertical shear, as depictedin analyses (not shown) from the Cooperative Institutefor Meteorological Satellite Studies, University of Wis-consin, prevented the system from becoming signifi-cantly better organized during the next 36 h. By theafternoon of 20 August, the shear relaxed and convec-tion appeared at the center of the depression. The systemis estimated to have become Tropical Storm Cindy atthis time. Cindy’s track followed the western peripheryof the Atlantic subtropical ridge during its existence.

Cindy continued to become better organized on 21August as banding features developed and a centraldense overcast formed over the center. Cindy reachedhurricane strength early on 22 August, about 400 n miwest of the Cape Verde Islands. Then easterly shearbecame more pronounced and Cindy weakened to atropical storm later that day. By the afternoon of 25August, the easterly shear again slackened and Cindyrestrengthened to a hurricane about 1100 n mi southeastof Bermuda. Cindy continued to intensify during thenext several days as indicated by more prominent band-


TABLE 2. Selected surface observations for Hurricane Bret, 18–25 Aug 1999.

Location


Day/time,(UTC)

Pressure(mb)

Maximum surfacewind speed

Day/time,(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Storm tide(m)d

Total rain(mm)

TexasBrownsville AirportCameron City AirportHarlingen AirportPort Isabel

22/213122/203522/2310

1002.4999.7999.0

22/183022/184122/2208

293638

474648

0.3

518965

McAllen AirportSouth Padre IslandArroyo ColoradoPort MansfieldRincon del San Jose

23/002322/1815

22/2000

1003.1998.6

985.4

22/220922/191522/190022/220022/2230

2838434263e

3748576678e

7499

Falfurrias AirportEdinburgEl SauzFalconGarciasville

22/0330 976.6 23/0330 85e

87513069

HarlingenHebbronvilleLaguna AtascosaLa JoyaLos Fresnos

75116106118

65McAllenMercedesMonte AltoRancho ViejoRaymondville

7926

1033778

RinconRio Grande CitySanta Ana National Wildlife RefugeSanta RosaWeslaco

46105

9790

174ZapataBob Hall PierCorpus ChristiKingsville Naval Air Station (NAS)Rockport

23/0322

22/2228

1002.41001.71006.4

23/032622/184323/1506

393534

484441

0.8

0.6

630

1327858

VictoriaAliceCotullaMcMullen TargetAransas Pass

23/090023/121723/1753

1008.8998.3

1006.4

24/181123/174823/233222/212423/2115

22393338

284840

57

18101108

320FreerBenavidesCallihamConcepcionFowlerton

68130

51187103

George WestPoint ComfortPortlandRobstownSinton

1355

202136139

Tilden 9 STilden 4 SSEVictoria CP&LAliceTilden 9 S

8115137681

Tilden 4 SSEFreeportGalvestonAngleton/Lake JacksonPalacios

23/042523/060223/0353

1010.51010.21008.5

23/1032

22/1012

19

23

22

27

0.715

17

11NOAA Buoys and C-MAN stations

Buoy 42019Buoy 42020

22/220022/1900

1007982.9

23/160022/1900

3758 73


TABLE 2. (Continued)

Location


Day/time,(UTC)

Pressure(mb)


Day/time,(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Storm tide(m)d

Total rain(mm)

Port Aransas C-Man 23/2200 41

a Day/time is for sustained wind when both sustained and gust are listed.b Standard National Weather Service (NWS) Automated Surface Observing System (ASOS) and C-MAN on-hour averaging periods are 2

min; buoys are 8 min.c Storm surge is water height above normal astronomical tide level.d Storm tide is water height above National Geodetic Vertical Datum (NGVD) or 1919 above mean sea level.e Equipment failed or power outage experienced.

ing features and improved upper-tropospheric outflow.A ragged eye first appeared in visible satellite imageryon the morning of 27 August and, by that afternoon, a25 n mi diameter banding-type eye became evident. Thehurricane continued to strengthen and reached its esti-mated peak intensity of 120 kt about 375 n mi east-southeast of Bermuda on 28 August. Figure 3 shows avisible satellite image of Cindy near its time of peakintensity.

On 29 and 30 August, Cindy began to weaken inresponse to increasing westerly, then southwesterly,shear. The overall cloud pattern gradually degenerated,the eye became indiscernible, the cloud tops warmed,and the deep convection became displaced north andthen east of the center. Cindy reached its westernmostlongitude, about 58.58W, on the afternoon of 28 August.The system turned northeastward on the next day fol-lowed by acceleration late on 30 August. Cindy’s closestapproach to Bermuda, about 325 n mi, occurred earlyon 29 August.

Cindy was downgraded to a tropical storm early on31 August as it accelerated northeastward over pro-gressively cooler waters. By that afternoon, Cindy’s cir-culation became indistinct in satellite imagery when itmerged with a large extratropical cyclone over the NorthAtlantic about 850 n mi west of the Azores.

Satellite-based intensity estimates on 28 August arethe basis for the best-track maximum sustained windspeed of 120 kt and the minimum central pressure of942 mb at 1200 UTC 28 August. The highest windreported by a ship was a sustained 62 kt, from the Min-eral Colombia located about 120 n mi east-northeast ofthe hurricane’s center.

d. Hurricane Dennis, 24 August–7 September

Although Dennis never made landfall as a hurricane,it affected the North Carolina coast with hurricane forcewinds, heavy rains, prolonged high surf, and beach ero-sion. Its rain was particularly important in North Car-olina as it saturated the ground and set the stage for thesevere inland flooding from Hurricane Floyd. Dennisalso produced tropical storm force winds over portionsof the Bahamas.

1) SYNOPTIC HISTORY

Dennis originated from a tropical wave that crossedthe coast of Africa on 17 August. The system movedwestward with little significant weather until 21 August,when its shower activity increased a few hundred milesnortheast of the Leeward Islands. A low-level circula-tion developed over the next 2 days and the convectionbecame better organized. A reconnaissance flight on 23August failed to find a surface circulation, but aircraftdata indicated a circulation was present aloft at 850 mb.Later, surface observations showed a closed circulation,and it is estimated that Tropical Depression 5 formedearly on 24 August about 190 n mi east of Turks Island.Reconnaissance data and ship reports indicated furtherintensification, and the depression became TropicalStorm Dennis later that day, and a hurricane early on26 August.

Dennis initially moved at 9–12 kt, but slowed to anerratic 3 kt on 25 August when steering currents weak-ened due to the passage of a midlatitude trough to thenorth. Once Dennis reached hurricane strength, it begana more steady northwestward motion near the easternBahamas. This motion continued into 28 August.

Westerly shear persisted, preventing additional sig-nificant strengthening until late on 27 August. After theshear decreased, Dennis reached a peak intensity of 90kt on 28 August and maintained that speed until earlyon 30 August. Even at peak intensity, Dennis was nota tightly wound hurricane. The eye was 30–40 n miwide and, on several center fixes, the Hurricane Hunteraircraft did not report an eye. The radius of maximumwinds was, at times, as large as 70–85 n mi.

A second midlatitude trough caused Dennis to turngradually northward on 28–29 August, and accelerateeast-northeastward on 30–31 August. This turn kept thecenter about 60 mi south of the North Carolina coast.The east-northeast motion continued until the troughpassed Dennis on 31 August. Then steering currentscollapsed and the cyclone slowed to an erratic drift about110 n mi east of Cape Hatteras, North Carolina. Thiserratic drift lasted into 2 September.

During this time, Dennis was affected by the coldfront associated with the midlatitude trough. A com-


TABLE 3. Selected surface observations for Hurricane Dennis, 24 Aug–7 Sep 1999.

Location


Days/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Total rain(mm)

BahamasCat Island

North CarolinaAlligator Bridgee

Atlantic (9.1-m tower) 30/1351 992.630/110030/1532

4848

5675

102

BeaufortBeaufort (10.1-m tower)Blockade RunnerBrunswick County AirportBrunswick Power Plant

04/204930/1302

984.8992.8

04/182330/1103

30/081030/0456

3352

50f

45757261

CalabashCarolina BeachCastle Hayne (Oxychem)Castle Hayne (SW)Cherry Point Marine Corps Air Station

(MCAS)04/2355 986.5

30/071030/110030/090004/2005

3541

3566546753

40

235

DelcoEast WaccamawElizabeth CityElizabethtownFlemington

04/2313 1003.8

30/120030/110030/1654

30/0900

28

34

39

5734453768

25178

GreenvilleHarkers Island BridgeHatteras InletHatteras VillageJacksonville 05/0235 994.2

05/014030/123030/193030/151530/0835

50g

4376648541

KingstonKure BeachKure Beach (Federal Point)ManteoNew Bern 05/0000 986.8

04/225030/074030/053030/163530/1056 35

3758715246 85

New RiverNewportNorth Topsail BeachOak IslandOcean Isle

04/212604/2115

993.9985.1

30/095630/120430/124030/080030/0559

33

44g

46

5054656249

146251

Ocean Isle (Tubbs Inlet)Ocracoke Islande

Oregon InletOrientalSt. James

31/0740 995.130/075331/022030/2030

35g

53g

465877

2.4

486

152ShallotteShallotte InletSouthport (elementary)Southport (marina)Southport (pilot boat dispatch)

30/070030/0730

30/0743

606049

60

229343

WhitevilleWilmington AirportWilmington (Battleship, NC)Wilmington (College Rd)Wilmington (Corning)

30/0953 996.1 30/060730/0530

30/1200

423753664660

50120170222

Wilmington (Eastwood Rd)Wilmington (Masonboro Loop)Wilmington (New Hanover EOC)Wilmington (WECT-TV)Wrightsville Beach

30/0650

30/0800

30/0444

51

4437764696

168

129

Wrightsville Beach Fire Dept.South Carolina

Charleston HarborCharleston Weather Forecast Office (WFO)Murrells Inlet

30/0630

29/2050 29

73

400.6

3173

Myrtle Beach (Pavilion)N. Myrtle Beach

VirginiaJohn Kerr Dam

30/060030/0732 29

4542 42

86



Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Total rain(mm)

Norfolk Airport 05/0551 1006.1 30/1651 37 46 84Langely Air Force Base (AFB)Newport NewsNorfolk NASOceana NASPortsmouth

1007.11006.51006.51006.5

04/233204/2332

4528

6639 84

7274

146RichmondRoanoke RapidsSewells PointWakefieldWallops Island

05/0754 1006.530/1214

30/1717

27

33

35

40

0.9

55

117

NOAA buoys and C-MAN stations41001410024100441008

31/040030/110030/030029/2000

976.0997.6990.5

1003.9

30/2300

30/033029/1700

48g

43g

54g

31

63597243

41009e

4101044014Drifting buoy 41650e

Drifting buoy 41651e

29/090029/075030/200027/000025/2100

1001.3980.2

1002.31009.81010.8

29/070029/050030/210027/120025/2100

2957434542

377253

Cape Lookout, NC (CKLN7)Chesapeake Bay, VA (CHLv2)Duck, NC (DUCN7)Folly Beach, SC (FBIS1)

04/200005/060004/230030/0100

986.51006.21005.61001.6

30/140030/210030/200030/0000

6049g

5624

79566535

Frying Pan Shoals, NC (FPSN7)Settlement Point, Bahamas (SPGF1)St. Augustine, FL (SAUF1)

30/090028/220029/1100

977.21002.61004.9

30/094529/003029/1355

81g

34g

27

974641

a Day/time is sustained wind when both sustained and gust are listed.b Standard NWS ASOS and C-MAN on-hour averaging periods are 2 min; buoys are 8 min.c Storm surge is water height above normal astronomical tide level.d Storm tide is water height above NGVD.e Incomplete record.f 100-ft tower, 15-min average.g 10-min average.

bination of vertical shear and entrainment of cool dryair into the circulation decreased the convection andcaused weakening. Dennis weakened to a tropical stormon 1 September, and on 1 and 2 September may have,in fact, been as much subtropical or extratropical astropical. Despite the lack of convection, surface obser-vations indicate maximum sustained winds were near45 kt on 2 September, some of which were due to thepressure gradient between Dennis and a strong surfaceridge north of the front. Winds in excess of 34 kt orgreater were observed as far north as New Jersey.

A large high pressure cell over the eastern UnitedStates forced Dennis southward late on 2 September.This motion over warmer water probably helped initiatea deep convective burst on the next day. Then, Dennisturned northwestward toward the North Carolina coastas the ridge moved east into the Atlantic. This motioncontinued on 4 September along with reintensification.Dennis was just below hurricane strength when it madelandfall at the Cape Lookout National Seashore just eastof Harkers Island, North Carolina, on 4 September. Den-

nis continued inland and weakened to a depression overcentral North Carolina. Even in dissipation, Dennis con-tinued to move erratically along a zigzag northwardcourse. Dennis became extratropical on 7 September andwas absorbed into a larger extratropical low on 9 Sep-tember.


Dennis’s path brought it near the eastern Bahamas on27–28 August. The only official report of tropical stormforce winds in the Bahamas was from a C-MAN stationat Settlement Point, Grand Bahama, which reported 34-kt sustained winds with gusts to 46 kt on 29 August. Aselection of surface observations is listed in Table 3.Also, unofficial reports from amateur radio operatorsindicated sustained winds of up to 55 kt with gusts to65 kt in the Abaco Islands.

Aircraft reconnaissance data suggest that Dennismaintained 90-kt surface wind speeds for 36 h from 28to 30 August. Just before landfall on 4 September, an


TABLE 4. Selected surface observations for Hurricane Floyd, 7–17 Sep 1999.

Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Totalrain

(mm)

BahamasGrand Bahama IslandLittle Harbor AbacosNassau

Florida

15/010014/1910

983.0929.0

14/2000 52

55

65

68

1.6237

Craig FieldDaytona BeachFowey RocksFort Lauderdale Executive AirportFort Lauderdale International Airport

15/165315/135314/230014/2253214/2253

994.6991.8995.5994.9994.6

15/192915/105314/160015/065314/2201

3736362325

60443336

31

03

Fort PierceGainesvilleJacksonville International AirportLake Worth PierLeesburg

15/073515/165315/165614/220015/1053

989.5994.6995.3993.4996.4

15/073615/140715/090714/170015/1153

2933403220

43

4927

Melbourne AirportMelbourne WFOMiamiOcalaOrlando

15/0900

14/225615/103515/0853

989.1

995.8998.0993.8

15/050115/065515/032215/153515/0853

4532192824

595229

42

34

1

32Patrick AFBSanfordTamiami AirportWest Palm Beach

Georgia

14/225315/0453

996.4992.9

15/082014/202414/195314/1941

49252127

57373138

81

10

AlmaBrookletDoverLudowiciNewington

15/950 999.7 15/1746 2810101322

Rocky FordSavannah AirportSt. Simon’s Island

South CarolinaAllendale

15/1804 993.215/181015/1804

3540

465

17BeaufortCharleston City OfficeCharleston HarborCharleston International AirportEdisto Beach State Park

15/0052 989.5

16/0150

16/004616/0029

50

4433

74

5847

3.1

46101

99

Florence AirportFolly BeachGrand StrandLadson OakbrookMyrtle Beach Airport

16/0655

16/0553

16/0553

991.2

977.0

979.7

16/015815/230016/0523

16/0455

3647

546257

103

109408

RidgevilleSt. GeorgeWalterboroWilliams

North Carolina

91486461

BeaufortCastle Hayne 2ECastle Hayne 3SWCherry Point MCASElizabeth City

16/0409

16/055516/1418

976.0

961.4968.5

16/040516/071516/084516/040516/1346

42

5634

5881

1047156

141

8367

Federal PointFlemingtonFriscoGreenvilleHolden Beach

16/0740 983.8

16/062016/062516/080516/080016/0820

51

42

9780615164

9

ManteoMasonboro IslandMount OliveMyrtle Grove

16/1000

16/052016/0540

53

6589

3.1



Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Totalrain

(mm)

Newport 16/0454 58New BernNew RiverOak IslandPleasure IslandRocky Mount/Wilson

16/054316/0426

961.1959.0

16/050116/055616/0820

394452

586869 3.1

3.1

109210

385Seymour Johnson AFBSouth RiverWashingtonWilmington AirportWilmington Corning

16/0955

16/0755

983.0

959.7

16/1055

16/080016/085516/0700

45

54

60

417589

89

484

Wilmington Emergency Operations Center (EOC)Wrightsville Beach

VirginiaFort EustisGlouchester

16/1455 985.2

16/0845

16/1640 25

104120

37286

HamptonJames City CountyLangley AFBLower James CityNewport News 16/1558 983.4

16/1355

16/1623

40

33

55

44

191363

326421

Norfolk AirportNorfolk NASOceana NASPortsmouthRichmondSmithfield

16/155116/155516/155616/160016/1640

977.1979.1975.7978.3991.9

16/130316/160916/165616/161416/1405

2738353029

4048

5244

257166318

Wakefield WFOWeemsYorktown

MarylandAnnapolis

323275

295CambridgeChestertownLewisettaMartin State AirportMid-Bay buoy

989.016/1710 60

0.8

1.1356

Ocean CityPatuxent NASSalisburySolomon’s IslandSt. Inigoes

16/1853

16/1851

976.8991.0980.4

987.6

16/165316/155516/2150

313028

453642

0.9

43

129

Tall TimbersThomas Point Light

DelawareCape HenlopenGreenwood

16/204016/1300

16/PM

436249

56

282

269LewesVermonWilmington

New JerseyAmerican Corners

16/2106 986.0 16/2214 32 40

0.8 2.1 0314

259Atlantic CityCaldwellCape MayDoylestownFederalsburg

16/205416/2353

980.2987.8

16/234516/2353

23 3438

0.6

0.8

1.9

2.2259

256284

NeshanicNewark International AirportPequannockSandy HookSomerville

16/2351

16/2306

985.1

981.0

16/2351

17/0024

38

34

46

45 0.6 2.0

256158280

339Teterboro AirportWayne/Iflows

16/2351 985.0 16/2351 24 38 217310



Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Totalrain

(mm)

White HousePennsylvania

Philadelphia 16/2136 985.0 16/2136 32 42 0.9 2.8

330

New YorkCentral ParkFarmingdale AirportIslip/MacArthur AirportJFK International AirportLaGuardia Airport

16/225016/235317/015616/235116/2351

983.8981.6983.4982.5983.7

16/145016/205316/235617/005117/0051

2523273030

3637374141

12880

83125

Montgomery AirportMontauk Point AirportNewburgh/StewartUpton NWSWesthampton Airport

17/025417/0045

17/0153

986.9992.6

984.8

16/203917/045416/2245

17/0153

292234

28

443754

4389

White Plains AirportMassachusetts

BeverlyBlue Hill ConservatoryBoston

17/0050 985.8 16/2350 25 42

3140

3.3

159

Boston/Logan AirportBrewsterBuzzards BayFox Point barrierHadley

17/054517/0300 47

386357

1.3244

HyannisLawrenceMartha’s VineyardNantucketNew Bedford barrier 17/0600

6232343264 0.8

0.4

NorwoodOrangePlymouthSouthwickTaunton

272933

38233

WestfieldWorcester

Rhode IslandBlock IslandNewport

3730

3935 0.8

ProvidenceWesterly

ConnecticutBridgeport AirportBristol

17/0154 981.8 16/2254 29

3531

39

1.8

274BurlingtonDanbury AirportGroton/New LondonHartford AirportMeriden

17/015317/014517/025317/0156

987.1986.8985.4984.5

17/015317/0045

1530

2143

240

Meridan Markham AirportNew Haven AirportSouthingtonWillimanticWindsor Locks

17/015517/0145

17/0352

986.4983.8

985.8

17/0155 2033

34

3137

232

New HampshireManchester 28

NOAA buoys and C-MAN stations41004410094100841010

15/0900

15/09001

980.9

939.6

16/020015/100015/210015/0700

54522472

72703191

440094401444025

16/190016/160017/0000

976.0981.4980.0

16/180016/161517/0600

395033

526643



Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Totalrain

(mm)

BUZM3CLKN7 16/0500 974.9

17/030016/0450

4763

5779

DSLN7DUCN7FPSN7SAUF1

16/073016/090016/060015/1200

985.8977.0958.7992.9

16/075016/085016/051215/1200

69678658

828397

a Day/time is for sustained wind when both sustained and gust are listed.b Standard NWS ASOS and C-MAN averaging periods are 2 min; buoys are 8 min.c Storm surge is water height above normal astronomical tide level.d Storm tide is water height above NGVD.

FIG. 3. GOES-8 visible satellite image of Hurricane Cindy at 1115 UTC 28 Aug 1999, near the time of 120-ktmaximum wind speed. (Courtesy of Naval Research Laboratory, Monterey, CA.)


FIG. 4. NOAA-12 visible satellite image of Hurricane Floyd at 2148 UTC 12 Sep 1999, several hours prior to the135-kt maximum wind speed. (Courtesy Space Science and Engineering Center, University of Wisconsin—Madison.)

aircraft measured 71-kt wind at 850 mb and a 984-mbpressure. Vertical wind profiles from several hundredGPS dropwindsondes (Franklin et al. 2000) indicate thatthe average ratio between surface and 700-mb flight-level winds is about 0.90 and the ratio between surfaceand 850-mb winds is about 0.80. Thus, Dennis is es-timated to be a 60-kt tropical storm at landfall.

Dennis tracked parallel to the Florida and Georgiacoasts, with tropical storm force winds near the coasts.A 41-kt gust was reported from the St. Augustine, Flor-ida, C-MAN station. On 29 August, the core of Dennispassed just east of National Oceanic and AtmosphericAdministration (NOAA) buoy 41010, which reported a57-kt sustained wind with a gust to 72 kt and a minimumpressure of 980.2 mb.

Dennis’s first pass near the mid-Atlantic coast on 30August caused sustained tropical storm force winds withgusts to hurricane force in coastal North Carolina and

gusts to tropical storm force in coastal South Carolinafrom Charleston northward. The maximum reported sus-tained winds were 53 kt with gusts to 77 kt at OregonInlet. Gusts to 96 kt at Wrightsville Beach and 85 kt atHatteras Village suggest that sustained hurricane forcewinds may have occurred along the coasts of New Han-over and Dare Counties. Sustained hurricane forcewinds of 81 kt with gusts to 97 kt were measured at theFrying Pan Shoals C-MAN station (145-ft elevation)with a minimum pressure of 977.2 mb.

The landfall of Dennis on 4 September produced trop-ical storm force winds over portions of eastern NorthCarolina and coastal southeastern Virginia. The largecirculation of Dennis also affected shipping over thewestern Atlantic. On 30 August, the ship Zim U.S.A.reported a sustained wind speed of 65 kt while locatedabout 120 n mi east-southeast of the center of the then90-kt tropical cyclone.


FIG. 5. Airborne radar reflectivity from NOAA WP-3D aircraft: (a)2342 UTC 13 Sep 1999 and (b) 2028 UTC 14 Sep 1999. (Courtesyof M. Black, Hurricane Research Division, NOAA, Miami, FL.)

Few detailed observations of storm surge are avail-able from areas affected by Dennis. Storm tides up to1.5 m above normal were reported along much of theNorth Carolina coast on both 30 August and 4 Septem-ber. Areas along the Neuse River reported tides 3 mabove normal tide level on 30 August, while areas alongthe Pamlico River reported similar heights on 4 Sep-tember. Portions of the South Carolina and southeasternVirginia coasts experienced tides about 1 m above nor-mal. Amateur radio reports from the Bahamas indicatesimilar tide heights as the eye passed over the Abacos.

Because Dennis meandered off the North Carolina coastfor several days, the above normal tides were prolonged.This led to extensive beach erosion along portions ofthe North Carolina and southeastern Virginia coasts.

Dennis affected the mid-Atlantic states twice withina week, and other weather systems affected the regionduring the same period. The maximum reported rainfallwas 486 mm at Ocracoke, North Carolina, with 150–250 mm reported elsewhere over portions of easternNorth Carolina. Amounts of 75–150 mm occurred else-where over eastern North Carolina, extreme easternSouth Carolina, and over portions of southeastern Vir-ginia. Rainfalls were generally 75 mm or less elsewhereover eastern South Carolina and less than 25 mm inFlorida and Georgia.

Dennis significantly contributed to saturating theground of the mid-Atlantic coastal states and this setthe stage for the severe flooding caused by HurricaneFloyd 2 weeks later. Rainfall data from the Bahamasindicates a maximum total of 102 mm at Cat Island.Heavier amounts likely occurred on Eleuthera and inthe Abaco group near the eye of Dennis.

One tornado was reported with Dennis on 4 Septem-ber. This F2 tornado in Hampton, Virginia, caused 15injuries, 6 of them serious.


Four deaths reported in Florida were related to highsurf spawned by the hurricane. No deaths are knowndue to winds, rains, storm tides, or tornadoes associatedwith Dennis.

The Property Claims Services Division of the Insur-ance Services Office reports insured losses due to Den-nis totaled $60 million in North Carolina and Virginia.As in Bret, a two-to-one ratio was applied to the insuredlosses, giving $120 million total property damage. Pressreports indicate that agricultural losses in North Carolinaand Virginia were $37 million, making a total estimateddamage from Dennis of $157 million.

e. Tropical Storm Emily, 24–28 August

A tropical depression formed from a tropical waveearly on 24 August about 360 n mi east of the WindwardIslands. A reconnaissance aircraft reached the area laterthat day and found a small circulation with a 1004-mbcentral pressure and 55-kt flight level winds. The 45-ktsurface winds estimated for that time represent Emily’speak intensity.

Emily was in a strong shearing environment becausethe circulation of the much larger Cindy was graduallyapproaching from the east. This shearing limited Emily’sdevelopment by displacing the sporadic deep convectionfrom the circulation center. Cindy also affected Emily’smotion by disrupting the easterly trade wind flow suchthat Emily moved slowly toward the northwest, and thennorth. Emily was absorbed by the much larger circu-


TABLE 5. Selected surface observations for Hurricane Irene, 13–19 Oct 1999.

Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Total rain(mm)

CubaHavana CasablancaPlaya GironTopes de CollantesJuguey Grande

14/2020 68122272221221180

JovellanosMelena del SurUnion de ReyesBatabanoGuines

183180163157140

CienfuegosNueva GeronaColon

FloridaBig Pine Key 15/0000 69 89

137122

Key West International AirportMarathon AirportKey WestVaca KeyTavernier

15/1010 987.6989.6

15/0518

15/163015/0800

38

38

47

47 0.50.6

182

249

Miami BeachTamiami AirportHomestead AFBMiami International AirportPompano Beach Airport

15/235315/225715/225616/0253

990.9990.9990.1991.0

15/195015/213015/180915/200815/2202

5245424140

60746150

279

Fort Lauderdale Executive AirportFort Lauderdale International AirportOpalocka AirportWest Palm Beach AirportNorth Perry Airport

16/015316/012316/005316/045315/2029

909.5990.9989.9990.9

15/2048

15/225716/021115/2029

40

393737

50

495350

340

276

Winter HeavenFort Myers Page AirportFort Myers Regional AirportBunnel (X47)St. Augustine Airport

16/192715/232816/0017

17/—-

1003.11000.11000.0

997.7

15/203316/022815/230516/222217/0020

4238383847

5241

Mayport Navy BaseCraig FieldOrlando International Airport

17/0820

16/2053

996.8

1000.2

17/030217/031116/1553 33

483842

744398

Melbourne AirportPatrick AFB unofficialVero Beach AirportFort PierceBunnell X47

16/1053 989.1

16/105016/104816/091016/075316/2222

40503937

5859624538 63

Flagler Beach Volunteer Fire DepartmentGeorgia

St. Simons IslandFernandina Beach

South Carolina

16/unkn

17/0907

998.7

997.3 17/0303 47 0.60.9

Charleston International AirportJohns IslandCharleston City Office

North CarolinaFrisco 18/0139 986.0 17/2215 33 41

158107

80BeaufortCherry PointWilmington AirportCape FearElizabethtown

18/0202 994.6

18/032618/0210

3539

11973

140170162

New BernSnowhillErnul

VirginiaNorfolk 18/0552 997.3 18/1152 35

140279

186190



Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Total rain(mm)

Oceana NASNewport News AirportWallops IslandCheasepeakePortsmouth

18/075618/065418/0754

996.6998.6998.5

18/105618/105418/0754

423434 305

2553

NOAA Buoys and C-MAN stationsBuoy 41009Gray Reef buoy (41008)Sombrero Key C-MANMolasses Reef C-MAN

15/0900

15/170015/2100

984.8

990.5991.5

16/110017/080015/153015/2020

45

5753

60516964

78

Long Key C-MANSand Key C-MANDry Tortugas C-MANFowey Rock Light C-MANLake Worth C-MAN

15/200015/1200

15/230016/0300

988.7987.0

991.9

15/200015/061015/085015/220016/0300

5043415744

6157517353

225241370

Frying Pan Shoals towerDiamond Shoals (DSLN7)Cape Lookout (CLKN7)Duck Pier (DUCN7}

18/0200218/010018/0700

983.0989.0994.0

17/225017/225018/030317/0300

4945

40

61494049 90

NWS COOP observer rainfallFort LauderdaleHollywoodHomestead General AirportNorth Dade County

340334306212

NWS unofficialCooper CityWest Pembroke PinesSaga BaySouth Miami

392377353343443

Boyton BeachPlantationTamiami Trail/Krome Ave.Everglades/U.S.27Lauderdale Lakes

297295264247242

El PortalPompano BeachLake WorthBiscayne Bay/320 St.Weston

44 53

237233227223210

North Miami BeachWest Boca RatonOpa-LockaSaw Grass MillsNorth Palm Beach

198193188192180

Leisure CityJupiter

South Florida Water Management DistrictBelle Glade20–25 mi SW of Clewinston

16/230315/2226

8179

164

Lake Ockeechobee (middle)25 mi west of Palm Beachwest of Lake Ockeechobee35 mi west of Boca Raton

16/052215/005515/223915/2314

70595650

Krome Ave (near Homestead)La BelleKissimee

15/200315/171216/1510

504340

a Day/time is for sustained wind when both sustained and gust are listed.b Standard NWS ASOS and C-MAN averaging periods are 2 min; buoys are 8 min.c Storm surge is water height above normal astronomical tide level.


lation of Cindy on 28 August several hundred nauticalmiles northeast of the Leeward Islands.

f. Hurricane Floyd, 7–17 September

Floyd was a large and intense Cape Verde hurricanethat pounded the central and northern Bahama Islands,threatened the southeast U.S. coast from Florida throughSouth Carolina, finally struck the coast of North Car-olina, and moved along the U.S. east coast into NewEngland. It neared the lower threshold of category 5intensity as it approached the Bahamas, and produceda flood disaster of immense proportions in the easternUnited States, particularly in North Carolina.

1) SYNOPTIC HISTORY

Floyd can be traced to a tropical wave that emergedfrom western Africa on 2 September. The wave pro-ceeded westward across the eastern tropical Atlantic atabout 15 kt, with little change in structure. On 6 Sep-tember, a curved band of deep convection began to de-velop and Tropical Depression 8 formed on 7 Septemberabout 1000 mi east of the Lesser Antilles.

A deep-layer ridge prevailed to the north of the cy-clone such that the associated steering current was west-northwestward at 12–15 kt for 2 days. The cloud patternbecame sufficiently well organized for the system tobecome Tropical Storm Floyd early on 8 September andabout 750 n mi east of the Leeward Islands. Floyd slow-ly strengthened and became a hurricane on 10 Septem-ber about 200 n mi east-northeast of the northern Lee-ward Islands.

As Floyd was nearing hurricane status, a midtropos-pheric trough near 608–658W caused a slowing of theforward speed, and a turn toward the northwest. Thismotion continued until 11 September, keeping the hur-ricane well to the northeast of the Leeward Islands. On11 September, Floyd’s upper-level outflow was dis-rupted over the southern semicircle by the above-men-tioned trough and by an anticyclone over the easternCaribbean Sea. Consequently, after strengthening to 95kt early on 11 September, the hurricane weakened to 85kt by 12 September. Early on 12 September, rising mid-to upper-tropospheric heights to the north of Floydforced the hurricane to turn toward the west. Maximumsustained winds increased to 135 kt and the central pres-sure fell about 40 mb by early on 13 September. Figure4 is a visible satellite image of Floyd about 8 h priorto the maximum wind speed reaching 135 kt.

A possible contributor to the significant strengtheningof Floyd was the presence of enhanced upper oceanicheat content along its track. Analyses from the PhysicalOceanography Division, Atlantic Oceanographic andMeteorological Laboratory (AOML), NOAA, showedrelatively high values of heat content just to the east ofthe Bahamas a day or two before Floyd passed throughthe area.

Floyd moved toward the central Bahamas until lateon 13 September when it turned west-northwestward.The eye passed just 20–30 n mi northeast and north ofSan Salvador and Cat Islands on the night of 13 Sep-tember. Floyd’s eyewall passed over central and north-ern Eleuthera on the morning of 14 September, and afterturning toward the northwest, Floyd struck Abaco Islandon the afternoon of 14 September. By the time the hur-ricane hit Abaco, it had weakened somewhat from itspeak, but Floyd was still a borderline category 3/4 hur-ricane.

A mid- to upper-tropospheric trough over the easternUnited States eroded the subtropical ridge over the ex-treme western Atlantic and Floyd continued to turngradually to the right. The center of the hurricane par-alleled the central Florida coast, passing about 95 n mieast of Cape Canaveral on 15 September. By later thatafternoon, Floyd was east of the Florida–Georgia borderand headed northward toward the Carolinas.

Although there was a fluctuation in intensity, causedby an eyewall replacement event discussed in the nextsection, overall, the intensity of Floyd diminished from13 to 15 September. Two large-scale factors probablycontributed to the weakening: the entrainment of drierair at low levels from the northwest, and increasingsouth-southwesterly vertical shear.

After turning toward the north-northeast with its for-ward speed increasing to near 15 kt, Hurricane Floydmade landfall near Cape Fear, North Carolina, early on16 September as a category 2 hurricane, with estimatedmaximum winds near 90 kt. Floyd was losing its eyewallstructure as it made landfall. Continuing to acceleratenorth-northeastward, Floyd’s center passed over ex-treme eastern North Carolina on the morning of 16 Sep-tember and over the greater Norfolk, Virginia, area alittle later. Floyd then weakened to a tropical storm andmoved swiftly along the coasts of the Delmarva Pen-insula and New Jersey later on. By the time it reachedLong Island on 17 September, its forward speed hadincreased to near 29 kt. The system decelerated as itmoved into New England.

By late on 16 September and early on 17 September,Floyd merged with a frontal zone along the Atlanticseaboard. Floyd took the form of a frontal low andbecame extratropical by the time it reached the coast ofMaine on the morning of 17 September. The cycloneturned toward the northeast and then east-northeast,moving over the coast of New Brunswick late on 17September, Prince Edward Island early on 18 September,and Newfoundland late on 18 September and early on19 September. Floyd’s extratropical remnant mergedwith a large extratropical low over the North Atlanticand was no longer a distinct entity by later on 19 Sep-tember.


The peak intensity of Floyd, 135 kt, is based uponan estimate of 90% of the highest aircraft reconnaissance


TABLE 6. Selected surface observations for Hurricane Lenny, 13–23 Nov 1999.

Location


Day/time(UTC)

Pressure(mb)


Day/time(UTC)a

Sustained(kt)b

Gust(kt)

Stormsurge(m)c

Stormtide(m)d

Totalrain

(mm)

St. MaartenPhilipsburg Meteorological OfficeMet. Office FMC8 Rain Gauge

AntiguaV.C. Bird International Airport

19/0200

20/0100

972.1

994.5

19/1730

19/2046

73

35

90

50

474700

465English Harbour

U.S. Virgin IslandsSt. CroixHamilton AirportMaria Hill@

981.7969.9

19/XXXX

17/203517/1836

6072

69

8097

204

USDA Met Station FrederkstadLime Tree Bay National Ocean Service (NOS) gaugeSt. ThomasCyril E. King Airport 993.2 18/0417 46 61

0.971

110USGS/National Park ServiceCharlotte Amalie/NOS gaugeSt. JohnHealth Center/NWS SensorUSGS/Meteorological station Lind Point

17/XXXX 80

0.587

87

75Coral Bay/COOP observer

Puerto RicoLuis Munoz Marin International AirportLa Puntilla, San Juan/NOS gaugeCeiba/Roosevelt Roads

17/1900

17/1355

986.7

1000.0

1001.0

17/1710

17/1423

17/1345

29

29

65

34

420.5

61

64

108Magueyes Island, Lajas/NOS gauge

Puerto Rico NWS COOP observer rainfallToro Negro OrocovisPico Del EsteJayuya

0.3 239

315298290

Rio De La PlataAibonitoVillalba 3NERio Blanco NaguaboMaunabo

267251215202189

Rio OrocovisGurabo Agricultural Expt StationCayey 1ELago De MatrullasRio Fajardo, near Fajardo

177170168168165

Lago El GuineoPueblo Del Rio GuraboCerro La Punta/JayuyaJuncos 1NNE

161153151133

La Plaza 7S CaguasRio Cerrillos PonceRio Maunabo

131130127

Barrio Beatriz/CaguasMontones Las PiedrasBisley Station El YunqueBairro Arriba/Caquas

114112108

76

a Day/time is for sustained wind when both sustained and gust are listed.b Standard NWS ASOS and C-MAN on-hour averaging periods are 2 min; buoys are 8 min.c Storm surge is water height above normal astronomical tide level.d Storm tide is water height above NGVD.

flight-level (700 mb) winds of 149 kt on 13 September.The minimum dropsonde-measured central pressure was921 mb on the same day.

Floyd is estimated to have been a 90-kt hurricane atlandfall in North Carolina, based on a 10-m anemometermeasurement of sustained winds of 83 kt on 16 Sep-

tember near Topsail Beach, North Carolina. There werealso unofficial reports of peak wind gusts to 120 kt (ateight stories elevation) at Wrightsville Beach and 104kt at the Wilmington Emergency Operations Center.

Table 4 lists a selection of surface observations fromland stations and data buoys. Floyd’s eye passed over


FIG. 6. GOES-8 visible satellite image of Hurricane Gert at 2015 UTC 15 Sep 1999, near the time of 130-ktmaximum wind speed. (Courtesy of Naval Research Laboratory, Monterey, CA.)

NOAA data buoy 41010, located about 105 n mi east-northeast of Cape Canaveral on 15 September. Thatbuoy reported maximum 8-min averaged winds of 72kt at an anemometer height of 5 m. At least two factorswould imply a higher value for the 1-min, 10-m windspeed: 1) extrapolating upward from 5- to 10-m ele-vation, and 2) the presence of waves above 15 m inheight. The best track intensity of Floyd when it passedover the buoy was 100 kt, as indicated by dropsondeand aircraft flight level wind data. The center of thehurricane passed about 25 n mi west of the Frying PanShoals C-MAN station located about 30 n mi southeastof Cape Fear on 16 September. This station reportedwinds sustained at 86 kt for a 20-min period at an an-emometer height of 44 m.

On 13 September, just after Floyd reached its maxi-mum strength, a sequence of microwave satellite images(not shown), as well as aircraft radar, gave evidence of

a concentric eyewall replacement cycle. Willoughby andBlack (1996) describe Hurricane Andrew’s concentriceyewalls. First, during the deepening phase, there wasa dominant inner eyewall with an eye diameter of 20–25 n mi. Later on, after peak intensity was reached,there was an indication of concentric eyewalls. Figure5a shows a radar image from a NOAA WP-3D researchaircraft late on 13 September that shows the inner andouter eyewalls. Then, there was an apparent eyewallreplacement, as suggested by measured vertical windprofiles and radar imagery from a NOAA WP-3D re-search aircraft as well as by the microwave images. Theinner eyewall was dissipating while Floyd was centerednear Eleuthera. This corresponded to a weakening ofthe hurricane to near 105 kt. The outer convective ringbecame the new eyewall by the time Floyd was centeredover Abaco with a 50 n mi eye. This is shown in Fig.5b, an aircraft radar image at 2028 UTC on 14 Septem-


ber. Afterward, the new eye failed to contract signifi-cantly, while Floyd restrengthened just slightly as itreached Abaco. After the disintegration of the inner eye-wall, the large-scale environment, as noted previously,became less favorable. Consequently, after leaving theBahamas, Floyd never regained its former intensity.

Heavy rainfall preceded Floyd over the mid-Atlanticstates due to a preexisting frontal zone and the asso-ciated overrunning. Hence, even though the tropical cy-clone moved fairly quickly, precipitation amounts werevery large. Myrtle Beach, South Carolina, recorded 408mm. At Wilmington, North Carolina, the storm total of484 mm included a 24-h record of 383 mm. NewportNews, Virginia, also reported over 400 mm and amountsover 300 mm were reported in Maryland, Delaware, andNew Jersey. Rainfall totals in the 200–250-mm rangeextended across southern New York and into New Eng-land. Storm surge values up to 3.1 m were reportedalong the North Carolina coast.

A number of tornadoes were sighted in eastern NorthCarolina. There was a confirmed tornado in BertieCounty and another in Perquimans County. The lattertornado destroyed two houses and damaged three or fourothers. At least 10 tornadoes were reported by spottersin the Newport/Morehead City County Warning area,and these apparently caused some structural damage.Four tornadoes or funnel clouds were seen in the Wil-mington area, but no damage was apparent.


There were 57 deaths directly attributable to Floyd,56 in the United States and 1 on Grand Bahama Island.The death toll by state is as follows: North Carolina,35; Pennsylvania, 6; New Jersey, 6; Virginia, 3; Dela-ware, 2; New York, 2; Connecticut, 1; and Vermont, 1.Most of these deaths were due to drowning in freshwaterflooding. Floyd was the deadliest hurricane in the UnitedStates since Agnes of 1972.

In the United States, the Property Claims ServicesDivision of the Insurance Services Office reports thatinsured losses due to Floyd totaled $1.325 billion. Incomparison to most hurricane landfalls, Floyd causedan inordinately large amount of freshwater flood dam-age, which probably alters the two to one damage ratio.The damage estimate is $4.5 billion.

4) WARNINGS

It is notable that hurricane warnings were issued forthe U.S. east coast from south Florida northward toPlymouth, Massachusetts. The last time such an eventoccurred was during Hurricane Donna of 1960. Ac-cording to information provided to the Federal Emer-gency Management Agency, over two million peoplewere evacuated for Floyd in the United States. This isreported to be the largest evacuation in U.S. history.

g. Hurricane Gert, 11–23 September

Gert was a 130-kt hurricane that moved across thecentral North Atlantic Ocean. It briefly produced hur-ricane force winds at Bermuda and high waves alongthe southeast coast of Newfoundland.

1) SYNOPTIC HISTORY

A tropical wave moved from west Africa to the At-lantic on 10 September, accompanied by convectivebanding and some evidence of a low-level cloud cir-culation. The developing tropical cyclone’s track wassouth of the Atlantic subtropical ridge and toward thewest-northwest from 10–16 September. The best trackstarts on 11 September, south of the Cape Verde Islands,when the system became a tropical depression. Itreached tropical storm strength on 12 September andbecame a hurricane on 13 September. Gert continued tostrengthen to 130 kt by 16 September. Figure 6 is avisible satellite image of Gert near the time of 130-ktwind speed.

There was a weakness in the ridge ahead of Gert andalong Floyd’s track. While intensifying, Gert respondedto this weakness and slowly turned north and then north-northeastward during 16–21 September. Its center camewithin about 300 n mi to the northeast of the LeewardIslands during this turn. With some fluctuations in in-tensity, winds remained near 115 kt through 19 Sep-tember, after which weakening commenced. Gert weak-ened to 60 kt by 23 September, having moved to nearsoutheastern Newfoundland. It then became extratrop-ical and merged with another extratropical low pressuresystem.


Dvorak satellite wind speed estimates place the timeof Gert’s peak intensity of 130 kt near 0000 UTC on16 September. Nearly 24 h of reconnaissance data, start-ing about 0800 UTC on 16 September, indicated thatthe wind speed weakened to 120 kt and then reached125 kt early on 17 September.

The center of Gert passed about 115 n mi east ofBermuda on 21 September. The maximum 10-min windspeed reported from the airport was 39 kt with a peakgust to 64 kt. A gust to 76 kt was reported from anexposed coastal location. There were three instances of1-min mean winds speeds between 66 and 70 kt froma harbor location during the morning of 21 September.A rainfall total of 13 mm was reported from Bermuda.Gale conditions were also experienced on the AvalonPeninsula on southeast Newfoundland.

3) CASUALTIES AND DAMAGES

Bermuda experience some coastal erosion along itseast and south sides.


Two persons drowned on 20 September, when a largeand unexpected wave swept them out to sea. They hadbeen standing at the water’s edge at Schoodic Point inAcadia National Park, Maine. The local marine patroldescribed the wave as a ‘‘rogue wave.’’ This event isbelieved to be related to large swells generated by Gert,even though the hurricane was located more than 1000n mi south-southeast of Maine at the time. There werealso news reports of 8-m-high waves sweeping over thecoast of the southeast tip of Newfoundland. Three per-sons were swept into the water while trying to securetheir boat. All were rescued.

h. Tropical Storm Harvey, 19–22 September

Tropical Storm Harvey formed in the eastern Gulf ofMexico and moved across southern Florida. It producedheavy rainfall over portions of southwest Florida.

1) SYNOPTIC HISTORY

The tropical wave that produced Harvey moved offthe west coast of Africa late on 4 September. From 4to 14 September, the wave’s trek across the tropicalAtlantic into the eastern Caribbean Sea was uneventful,due, in part, to the disruptive effects of the upper-leveloutflow from Hurricane Floyd. By 16 September, con-vective activity began to increase over the western Ca-ribbean Sea and a broad area of low pressure formed.Upper-air observations from the northwest Caribbeanshowed an associated midlevel circulation near the Cay-man Islands. The broad area of low pressure driftednorthwestward into the Gulf of Mexico over the nextfew days. Early on 19 September, satellite imageryshowed increasing deep convection near and east of thecirculation center and a tropical depression formedabout 350 n mi west-southwest of St. Petersburg, Flor-ida.

Upper-level outflow around the depression improved.By early on 20 September, surface winds were near 40kt and the system became Tropical Storm Harvey, about300 n mi west-southwest of St. Petersburg. Over thenext 24 h, Harvey’s central pressure dropped a modest7 mb and the storm is estimated to have reached a peakintensity of 50 kt on 20 and 21 September. Satelliteimages showed that the system did not become betterorganized during this period because of westerly verticalwind shear. Data from a NOAA Gulfstream IV high-altitude aircraft on the afternoon of 20 Septembershowed 25–35-kt westerly upper-level winds over thecyclone. This contributed to the displacement of Har-vey’s center to the northwest edge of the deep convec-tion and restricted the outflow over the western semi-circle. Satellite imagery also suggested that dry air wasbeing entrained into the circulation from the northwest.

After turning from a north to a northeast heading onthe afternoon of 19 September, Harvey moved slowlyeastward on 20 September. By early on 21 September,

the system turned southeastward and the forward speedincreased to 9 kt in response to midlevel northwesterlyflow. Harvey’s track bent back to the east by midmorn-ing of 21 September and the cyclone accelerated in ad-vance of a midlatitude trough approaching from thewest. Harvey made landfall near Everglades City, Flor-ida, around 1700 UTC on 21 September with maximumsustained winds of 50 kt and a minimum central pressureof 999 mb. It crossed Florida and moved offshore overthe Atlantic near Fort Lauderdale. Later that afternoon,Harvey was absorbed by a developing extratropical cy-clone centered just off the coast of South Carolina. Thisextratropical cyclone then moved over portions of theCanadian Maritime Provinces, causing heavy rainfall.Several weather stations along the Fundy coast of NewBrunswick received over 200 mm, and up to 302 mmfell in northern Nova Scotia, making for the worst flood-ing in 30 years. Between 50 and 100 mm of rain fellin Labrador.


Harvey’s maximum sustained winds of 50 kt arebased on a reconnaissance aircraft wind speed of 58 ktat a flight level of 457 m. The ship Liberty Sun reported47 kt on 20 September. The Molasses Reef C-MANrecorded a sustained wind of 47 kt, with a gust to 59kt, and Fowey Rocks Light reported 45-kt sustainedwinds with a gust to 51 kt.

The highest official sustained surface wind observedover land was 32 kt at the Key West Airport on 21September. The Turkey Point Nuclear Power Plant re-corded a 10-min, 46-kt wind, at a 9-m elevation, whilethe highest gust, 48 kt, was recorded at Tenraw in theEverglades (25.68N, 81.98W). The lowest pressure ob-served in south Florida was 999.4 mb at the Fort Lau-derdale Airport, also on 21 September.

The highest storm-total rainfall recorded in Harveywas 255 mm at the Naples Conservancy in CollierCounty. Naples Lakewood measured about 250 mm ofrain as did Naples/Collier County Emergency Manage-ment at their operations center. Substantial street flood-ing was reported in portions of Collier and Lee Counties.Rainfall totals of 140 and 171 mm were observed atImmokalee and Everglades City, respectively. Storm to-tal rainfall across Miami-Dade, Broward, and PalmBeach Counties ranged from 19 mm (West Palm BeachAirport) to 72 mm (Coral Springs).

The maximum recorded storm surge was 0.7 m atFort Myers with estimates from 0.5 to 1.0 m elsewherein Charlotte County. Storm surge up to 0.6 m occurredelsewhere in southwest Florida and in the Florida Keys.Tidal flooding was reported in Everglades City includ-ing the county airport where a portion of the runwaywas flooded, resulting in the closure of the airport. Mi-nor coastal flooding was reported along the south-facingportions of the Florida Keys and the west-facing shoresof Florida Bay. Sections of Highway A1A in the Keys


were closed due to the flooding. The combined effectof wave action and the storm surge resulted in minorbeach erosion in Sarasota County, along the south-fac-ing shores of the Keys, and in the backcountry of Ev-erglades National Park.

There were two tornadoes. An F0 touched down brief-ly in Collier County near Paradise Point taking the roofoff one house, while the other touched down in DadeCounty with no reported damage.

The Canadian Hurricane Centre reported that someareas of southeastern New Brunswick and northernNova Scotia received over 250 mm of rain over a 30-h period from Harvey’s extratropical remnants. Oxford,Nova Scotia, reported 302 mm and 50–100 mm fell inLabrador.


There are no known casualties. Property damage es-timates supplied by the Property Claims Services Di-vision of the Insurance Services Office, indicate thatHarvey caused about $7.5 million in insured losses insouthern Florida. The total estimated damage from Har-vey is $15 million.

i. Hurricane Irene, 13–19 October

Irene was a wet October tropical cyclone that movedover the Florida Keys and southeast Florida. It dumpednearly 400 mm of rain and resulted in severe floodingconditions.

1) SYNOPTIC HISTORY

A broad area of low pressure accompanied by dis-organized clouds and thunderstorms prevailed over thesouthwestern Caribbean Sea from 8 to 10 October. Thissystem did not show signs of tropical cyclone devel-opment until a tropical wave reached the western Ca-ribbean Sea on 11 October. On 12 October a U.S. AirForce Reserve reconnaissance plane found an incipientlow-level circulation and a broad low pressure area of1006 mb just to the northeast of the coast of Honduras.However, the circulation was too ill-defined to be clas-sified as a tropical depression. Satellite imagery duringthe night showed that the thunderstorms increased andbanding features and upper-level outflow became quitedistinct. Surface and upper-air data from Grand Cayman,and satellite intensity estimates, indicate that a tropicaldepression formed in the northwestern Caribbean Seaearly on 13 October and reached tropical storm status6 h later. Irene moved on a general northward track,then slowed before curving to the north-northeast justto the southwest of the Isle of Youth, Cuba, where itmade its first landfall on 14 October. Radars from Cubaand Key West showed the center of Irene moving on anorth-northeast track over western Cuba. The center ofthe tropical cyclone then crossed the Havana and Ciudad

Havana provinces late on 14 October. Irene reached hur-ricane status over the Florida Straits and the calm ofthe center moved over Key West near midday on 15October. Most of the hurricane force winds were con-fined to the east of Irene’s center over the lower tomiddle Florida Keys. Irene made its fourth landfall nearCape Sable, Florida, and then moved across southeastFlorida bringing tropical storm conditions and 250–500mm of rain. During the period while Irene was crossingFlorida, sustained hurricane force winds appeared to belimited to squalls offshore of the east coast of Florida,as reported by reconnaissance aircraft and indicated bysurface observations and Doppler radar.

Irene moved back over water in northern Palm BeachCounty near Jupiter a little after 0000 UTC on 16 Oc-tober. It retained hurricane strength and moved on ageneral northward track paralleling the Florida eastcoast heading for the Carolinas. An upper-level trough,sweeping eastward across the eastern United States,forced Irene on a fast northeastward track. The core ofIrene missed the mainland Carolinas but produced veryheavy rains inland. It then brushed North Carolina’sOuter Banks before moving out to sea.

During a 12-h period beginning on the evening of 18October, Irene’s central pressure dropped from 978 to958 mb and the winds increased from 70 to 95 kt. Thismay be attributable to a combination of a trough inter-action and the tropical cyclone moving over the warmwaters of the Gulf Stream. Thereafter, Irene continuedto accelerate and, on 19 October, was absorbed by amuch larger extratropical low near Newfoundland. Theresultant system became an intense extratropical stormover the North Atlantic.


Irene was monitored by three Cuban weather radarslocated at Havana, Isle of Youth, and Pinar del Rio.Operationally, Irene was upgraded to hurricane statusjust before landfall over the Isle of Youth. However,numerous observations from Cuba and a postanalysisof satellite imagery indicate that Irene was most likelya tropical storm while crossing Cuba. Peak wind gustsreported from Cuba were 68 kt at the Havana forecastoffice.

A selection of surface observations is given in Table5. The highest sustained wind observed was 69 kt atBig Pine Key in the Florida Keys. Observations fromthe South Florida Water Management District indicatethat gusts to hurricane force were experienced near LakeOkeechobee. Based on the Miami Weather SurveillanceRadar-1988 Doppler signatures, these gusts were likelyproduced by small-scale mesocyclone-induced down-bursts. Four weak tornadoes occurred in Broward andPalm Beach counties.

There was serious urban flooding in southeast Floridawith a maximum rainfall amount reported in south Flor-ida of 443 mm in South Miami. Coastal sections of


FIG. 7. GOES-8 visible satellite image of Hurricane Lenny at 1445 UTC 17 Nov 1999, several hours prior to the135-kt maximum wind speed. (Courtesy of Naval Research Laboratory, Monterey, CA.)

North Carolina and Virginia also recorded amounts inthe 200–300-mm range, with lesser amounts in Georgiaand South Carolina.

The rapid intensification of Irene on 18 October offthe North Carolina coast was documented by a recon-naissance plane investigating the hurricane during thatperiod. Their report indicated a very small closed eye-wall of about 3 n mi in diameter and 114 kt winds ata flight level of 850 mb.


There were eight deaths indirectly caused by Irene.Five people were electrocuted (four in Broward Countyand one in Miami-Dade County) when they walked intopuddles that concealed downed power lines. There werethree drownings when vehicles were driven into canalsobscured by flooding (one in Palm Beach County and

two in Broward County). In addition, there were threepersons injured by tornadoes in Broward County.

Irene caused considerable damage due to flooding insouth Florida. In some residential areas, flooding lastedfor a week, displacing several hundred people and iso-lating thousands more. The total losses (agricultural andproperty) were estimated near $600 million mostly inDade, Broward, and Palm Beach Counties. Additionallosses to near $200 million occurred in the rest of Flor-ida. An estimated 700 000 customers lost electricity.

j. Hurricane Jose, 17–25 October

1) SYNOPTIC HISTORY

Jose originated from a tropical wave that moved offthe west coast of Africa on 8 October. The wave movedslowly westward across the tropical Atlantic for several


days. By 15 October, when the system was located aboutmidway between Africa and the Lesser Antilles, showeractivity became better organized. The disturbance be-came a tropical depression on 17 October, about 550n mi east of the southern Windward Islands. There waswell-defined upper-tropospheric outflow over the de-pression. Moving west-northwestward, the depressionstrengthened into Tropical Storm Jose on 18 October.

Jose turned northward when a mid- to upper-tropo-spheric trough produced a weakness in the Atlantic sub-tropical ridge. Jose became a hurricane late on 19 Oc-tober about 100 n mi east of the Leeward Islands. Asit neared these islands, Jose reached its peak intensityof 85 kt at 1200 UTC 20 October. Turning back to awest-northwest heading, Hurricane Jose struck thenorthern Leeward Islands, passing over Antigua aroundmidday on 20 October. The eye then moved near St.Barthelemy and St. Martin early on 21 October.

Southwesterly vertical shear caused weakening, asJose moved over the northern Leeward Islands. Joseweakened to a tropical storm by the time it reachedTortola in the British Virgin Islands, on the morning of21 October. A little later on 21 October, the cycloneturned back toward the northwest and the center passedabout 40 n mi northeast of the eastern tip of PuertoRico. With a large mid- to upper-tropospheric troughpositioned over the western North Atlantic, Jose turnednorthward, then north-northeastward on 22 October. Thestorm continued north-northeastward at a faster forwardspeed on 23 October. Its structure was still disrupted bysouthwesterly shear. Early on 24 October, however, mi-crowave satellite data indicated that the deep convectionagain was over the low-level center and Jose regainedhurricane strength. The hurricane passed about 250 nmi east of Bermuda around midday on 24 October, andthe forward speed increased markedly. The rejuvenationof the tropical cyclone was short lived and Jose weak-ened back to a tropical storm by 25 October. It continuedto accelerate into the North Atlantic, losing tropicalcharacteristics later that day. It then merged with a largermidlatitude low and associated front.


The estimate of a peak intensity of 85 kt is based ona wind of that speed measured at 10 m by a reconnais-sance aircraft GPS dropwindsonde. The highest mea-sured wind speed from a surface reporting station was70 kt with a gust to 89 kt at Antigua. Sustained windsof 65 kt were measured at St. Maarten. The highestsustained wind reported from the Virgin Islands was 52kt with a gust to 60 kt at St. John. Higher wind speedslikely occurred over portions of the British Virgin Is-lands. In Puerto Rico, winds were mostly below tropicalstorm force. There was an unofficial measurement ofsustained winds of 30–39 kt with a gust to 48 kt fromCosta Azul Beach in Luquillo.

Very heavy rain fell well after the passage of the

center over the northern Leeward Islands, in associationwith bands of thunderstorms extending east and south-east of the center. Rainfall totals were as high as 350mm over portions of the islands.


Two deaths were caused by Jose, one in Antigua andone in St. Maarten. Damage in Antigua was character-ized as ‘‘minor.’’ In St. Maarten, the heavy rains causedextensive flooding and mud slides that damaged roadsand homes, especially in low-lying areas. United States(Puerto Rico and the U.S. Virgin Islands) damage totalswere less than $5 million.

k. Tropical Storm Katrina, 28 October–1 November

Katrina was briefly a 35-kt tropical storm while mov-ing onshore on the Caribbean coast of Nicaragua.

1) SYNOPTIC HISTORY

Satellite imagery shows that the remnants of a coldfront moved slowly southward across the western Ca-ribbean Sea beginning on 22 October. A broad area oflow pressure gradually formed over much of the Carib-bean during this time and cloudiness and thunderstormsbecame concentrated over the southwestern CaribbeanSea on 26 October. On the next day, low-level cloudlines began to show a closed circulation just north ofPanama. On 28 October, a reconnaissance aircraft re-ported a well-defined low-level closed circulation about150 n mi east of Bluefields, Nicaragua, indicating thata tropical depression had formed.

Katrina was a tropical storm for about 6 h late on 30October, while making landfall on the coast of Nica-ragua just south of Puerto Cabezas. For the rest of its4 days, Katrina was a tropical depression that movedon a mostly northwestward track across Nicaragua andHonduras, back over the waters of the northwest Ca-ribbean, and then across northern Belize and the YucatanPeninsula. The depression dissipated on 1 Novemberjust north of the Yucatan Peninsula when it was ab-sorbed by a cold front.


The system was monitored by reconnaissance aircrafton 28 and 29 October while located in the southwesternCaribbean Sea. The basis for naming Katrina a tropicalstorm was a 43-kt flight-level wind observation on 29October. Satellite-based rainfall estimates suggest that250–375 mm of rain may have occurred over portionsof Nicaragua and Honduras, with lesser amounts for theYucatan Peninsula. San Andres, Colombia, an islandabout 100 n mi east of Nicaragua, reported 91 mm ofrain in 6 h on 28 October.


3) CASUALTIES AND DAMAGES

It is possible that the rainfall described above causedsome flash flooding over mountainous terrain over Cen-tral America. No reports of damages or casualties werereceived.

l. Hurricane Lenny, 13–23 November

Hurricane Lenny was the fifth category 4 hurricaneof the 1999 season. This hurricane had a major impactaround the Caribbean Sea. Moreover, Lenny is the firststorm to have an extended west-to-east track across thecentral and eastern Caribbean Sea in the roughly 150-yr record of Atlantic tropical cyclones.

1) SYNOPTIC HISTORY

A broad area of low pressure was first identified inthe southwest Caribbean Sea early on 8 November. Al-though thunderstorm activity remained poorly orga-nized, locally heavy rains and strong gusty winds oc-curred over the northwestern Caribbean Sea and adja-cent Central America and Mexico for several days. Earlyon 13 November, satellite imagery showed that the sys-tem was gradually becoming better organized. Based on30-kt surface winds and a 1003-mb central pressurefrom aircraft reconnaissance that afternoon, a tropicaldepression formed about 150 n mi south of the CaymanIslands. By mid morning of 14 November, the overallorganization of the depression was improving and thedepression became a tropical storm on the morning of14 November.

Later that day, a reconnaissance mission found max-imum flight-level winds of 84 kt and a central pressureof 988 mb. Lenny became a hurricane about 150 misouthwest of Kingston, Jamaica. Satellite imageryshowed a banding-type eye, 15–20 n mi in diameter.

Lenny’s extended west-to-east motion across the Ca-ribbean is unprecedented. For its first 48 h, Lennymoved on an east to east-southeastward course. Thismotion was induced by the flow around the southernportion of a deep-layer trough located over the westernAtlantic. Several short-wave troughs helped to amplifythe mean western Atlantic trough through the period,increasing the westerly steering flow. From 1200 UTC15 November to 1800 UTC 16 November, Lenny’s meanforward speed was 14 kt toward the east. The unusualnature of this steering pattern is illustrated by an anom-aly chart of November mean 500-mb heights. This chart(not shown) shows a very large negative anomaly (min-imum height of 260 m) centered a few hundred nauticalmiles north of Puerto Rico.

During a 24-h period beginning midday on 16 No-vember, the central pressure dropped 34 mb. Lenny’smaximum sustained surface winds of 135 kt and min-imum central pressure (933 mb) occurred at 1800 UTC17 November when the hurricane was centered about

20 n mi south of St. Croix in the U.S. Virgin Islands.However, the 135-kt winds were confined to the south-east quadrant of the hurricane over water. Figure 7 is avisible satellite image of Lenny just before reaching135-kt wind speed.

Lenny moved into a col between two midlevel ridgeslate on 17 November and its forward motion slowed.The hurricane drifted east-northeastward before turningsoutheastward early on 19 November. Despite what ap-peared in satellite imagery as a favorable upper-leveloutflow pattern, Lenny weakened, perhaps due to oce-anic upwelling. Lenny was gradually weakening whenits center passed very slowly over St. Maarten duringthe afternoon of 18 November, over Anguilla later thatevening, and over St. Barthelemy early on 19 November.Lenny weakened to a tropical storm on 19 Novemberjust south of St. Barthelemy. It made its final landfallin Antigua late on 19 November.

Lenny continued to move southeastward and the for-ward motion increased to near 8 kt. The motion turnedagain toward the northeast as Lenny weakened to a de-pression on 21 November. The depression turned backto the east early on 21 November and dissipated on themorning of 23 November about 600 n mi east of theLeeward Islands.


The estimated peak intensity of Lenny, 135 kt, isbased on 90% of the 149-kt flight-level (700 mb) windspeed reported at 1702 UTC 17 November. A GPS drop-windsonde measured 183 kt at 891 mb, a record drop-windsonde wind speed in a hurricane. The lowest pres-sure recorded by the aircraft was 934 mb at 1929 UTC17 November. However, the minimum central pressureof 933 mb was assigned based on the lower 700-mbheight from the 1702 UTC fix.

Table 6 lists a selection of surface observations fromland stations. The highest official sustained surface windspeed observed over land was 73 kt at the St. MaartenMeteorological Office in Philipsburg on 19 November.However, the meteorological antenna fell down duringthe strongest winds. Hamilton Airport on St. Croix re-corded sustained 1-min winds of 60 kt, with a gust to80 kt. The lowest official pressure observed in the north-ern Leeward Islands was 972.1 mb at the St. MaartenMeteorological Office.

The maximum sustained surface wind speed reportedvia amateur radio operators was 81 kt on St. John inthe U.S. Virgin Islands on 17 November. During thepeak of the hurricane, Saba recorded a gust of 145 kt(792-m elevation) before the anemometer blew away.The highest measured gust of 97 kt on St. Croix co-incides with Lenny’s closest approach. The minimumcentral pressure at St. Croix, 980 mb, was also recordedat this time.

Lenny’s slow drift across the northern Leeward Is-lands resulted in very large rainfall amounts over a 36-


h period. For many locations, heavy rain over severaldays was the primary impact of Lenny. Portions ofFrench St. Martin, St. Barthelemy, and Guadeloupe re-ceived record rains. The highest rainfall total in DutchSt. Maarten was 700 mm, recorded at the meteorologicaloffice in Philipsburg. Even higher amounts are likely tohave occurred in French St. Martin. V. C. Bird Inter-national Airport in Antigua reported 465 mm.

Rainfall totals up to 200 mm occurred across the U.S.and British Virgin Islands and resulted in widespreadflooding. The largest official rainfall total in Puerto Ricowas 239 mm on Magueyes Island, Lajas.

Fredericksted in St. Croix was inundated by an es-timated 4–6-m storm surge. The maximum reportedstorm tide was 0.9 m at the NOAA National OceanService gauge in Lime Tree Bay on St. Croix.

Lenny’s approach from the west produced unprece-dented wave and storm surge impact on westward-fac-ing coasts and harbors. The meteorological service inDutch St. Maarten reported that southern and westerncoastal areas were significantly impacted by wave ac-tion. The Meteo-France meteorological station in Gus-tavia on St. Barthelemy estimated waves up to 4.9 min the harbor on 17 November. A platform near La De-sirade, just east of Grande-Terre, Guadeloupe, recordeda significant wave height of 3.0 m at 2300 UTC 20November and estimates range up to 4 m in the harbor.

Lenny generated large waves and swells that propa-gated across much of the southern and eastern Carib-bean, affecting the Guajira Peninsula of Colombia, Aru-ba, Bonaire, Curacao, and much of the remainder of theLeeward and Windward Islands.


Lenny was responsible for 17 direct deaths: 3 inDutch St. Maarten, 2 in Colombia, 5 in Guadeloupe, 1in Martinique, and 6 offshore. Two of the deaths in St.Maarten were caused by flying debris while the otherwas the result of a collapsed roadway. The remainderof the onshore fatalities, based on media reports, arepresumed to be due to freshwater flooding. Two of theoffshore deaths occurred when the sailing yacht Vdarwas lost somewhere in the southern Caribbean Sea.

Lenny’s heavy rain, and wave and storm surge pro-duced considerable damage on many of the islands inthe northeast Caribbean. St. Croix sustained moderatedamage. Many boats were washed ashore along thenorth coast of the island. Several boats sank In Chris-tiansted Harbor and structures in the south and east por-tions of the island suffered roof damage. Lenny alsoimpacted the agricultural areas of the island. Both theDutch and French portions of St. Maarten/Martin wereseverely impacted with many buildings damaged andboats damaged or lost. In St. Lucia, at least 70 homeswere reported damaged. In Saba, the airport tower andseveral other buildings were severely damaged. Gua-deloupe sustained a large amount of damage along the

west coast due to the wave action, and inland due toheavy rains. In Grenada, 10 homes were destroyed and21 small boats were lost. There were also reports ofdamage in St. Vincent and the Grenadines, and Mont-serrat.

Insured losses of $165 million have been reportedfrom Puerto Rico and the U.S. Virgin Islands. Using afactor of 2.0, the total U.S. damages from Lenny isestimated at $330 million.

3. Tropical Depression 11

Four tropical depressions that did not strengthen totropical storms were tracked. Tropical Depressions 2, 7,and 11 occurred over the southwest Gulf of Mexico, inearly July, early September, and early October, respec-tively. Depression 12 was over the tropical Atlantic, eastof the Lesser Antilles in early October. Only TropicalDepression 11 had a significant impact on land.

Tropical Depression 11 caused heavy rains and a highdeath toll in Mexico. Its origin can be traced to a tropicalwave that moved westward from the west coast of Africaon 22 September. Little development occurred until thewave reached the western Caribbean on 30 September,when a broad low pressure area developed. Further de-velopment was slow while the system moved across theYucatan Peninsula into the Gulf of Mexico, and it wasnot until 4 October that the system became a tropicaldepression about 125 n mi east-northeast of Veracruz,Mexico.

Steering currents were weak, and the depression me-andered erratically over the Bay of Campeche through-out its lifetime. There was one notable reformation ofthe center early on 6 October, based on reconnaissanceaircraft data. A broad surface trough dominated the cen-tral and eastern Gulf of Mexico, and the depressionmerged with this trough about 130 n mi northeast ofVeracruz on 6 October. While ship reports and recon-naissance aircraft data indicate that tropical storm forcewinds were present as the cyclone dissipated, these ap-pear to have been associated with a wind surge movingsouthward over the western Gulf and not with the trop-ical cyclone.

Although the depression was poorly organized, it con-tributed to widespread and prolonged heavy rains overthe states of Puebla, Tabasco, and Veracruz, Mexico.Press reports indicate the resulting severe flooding wasresponsible for an estimated 400 deaths.

4. Verification

The National Hurricane Center issues a 72-h trackand intensity forecast, every 6 h, for all tropical cyclonesin the Atlantic basin. These forecasts are verified bycomparison with the best tracks described in section 1.This season’s average official track and absolute inten-sity forecast errors are given in Table 7, along with theprevious 10-yr averages. Absolute intensity errors are


TABLE 7a. National Hurricane Center Atlantic basin average trackforecast error (n mi).

Forecast period (h)

12 24 36 48 72

1999 official1999 CLIPER model1999 no. of cases1989–98 official1989–98 CLIPER model

37.347.0

28847.655.4

70.397.1

26688.7

113.2

106.4153.3244127.1174.8

139.9207.1222163.9253.3

211.4306.8181242.2341.9

TABLE 7b. National Hurricane Center Atlantic basin averageabsolute intensity forecast errors (kt).

Forecast period (h)

12 24 36 48 72

1999 official1999 SHIFOR model1999 no. of cases1989–98 official1989–98 SHIFOR

7.49.0

2866.88.5

11.613.9

26410.412.0

14.417.3

24313.314.6

16.320.4

22116.017.1

18.623.0

18019.519.8

errors without regard to sign that measure the magnitudeof the errors and not the bias. Errors of the simple cli-matology and persistence (CLIPER) and statistical hur-ricane intensity forecast (SHIFOR) statistical models arealso listed, as a basis for comparison.

The official track errors for 1999 were lower thantheir previous 10-yr averages and were also lower thanthe corresponding CLIPER model errors for a homo-geneous set of cases. In contrast, the official 1999 ab-solute intensity errors were slightly larger than theirprevious 10-yr average, except at 72 h, where they wereslightly smaller. As did the official track errors, the 1999official intensity errors demonstrated skill over the sta-tistical model.

Acknowledgments. We thank Stephen R. Baig for pre-paring Fig. 1 and James Gross for the forecast verifi-cation statistics. The Geostationary Operational Envi-ronmental Satellite-8 (GOES-8) images in Figs. 2, 3, 6,and 7 are from the Naval Research Laboratory Internetsite. The NOAA-12 image in Fig. 4 is from the SpaceScience and Engineering Center, University of Wiscon-

sin—Madison, Internet site. The aircraft radar imagesin Fig. 5 are courtesy of Michael Black, Hurricane Re-search Division, NOAA.

REFERENCES

Dvorak, V. F., 1984: Tropical cyclone intensity analysis using satellitedata. NOAA Tech. Rep. NESDIS 11, 47 pp.

Franklin, M. L., M. L. Black, and K. Valde, 2000: Eyewall windprofiles in hurricanes determined by GPS dropwindsondes. Pre-prints, 24th Conf. on Hurricanes and Tropical Meteorology, Ft.Lauderdale, FL, Amer. Meteor. Soc., 446–447.

Hock, T. F., and J. L. Franklin, 1999: The NCAR GPS dropwindsonde.Bull. Amer. Meteor. Soc., 80, 407–420.

Jarvinen, B. R., C. J. Neumann, and M. A. S. Davis, 1984: A tropicalcyclone data tape for the North Atlantic Basin, 1886–1983: Con-tents, limitations, and uses. NOAA Tech. Memo. NWS/NHC 22,Coral Gables, FL, 21 pp.

Shay, L. K., G. J. Gustavo, J. Goni, and P. G. Black, 2000: Effectsof a warm oceanic feature on Hurricane Opal. Mon. Wea. Rev.,128, 1366–1383.

Simpson, R. H., 1974: The hurricane disaster potential scale. Weath-erwise, 27, 169, 186.

Willoughby, H. E., and P. G. Black, 1996: Hurricane Andrew inFlorida: Dynamics of a disaster. Bull. Amer. Meteor. Soc., 77,543–549.

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