predecessor rain events ahead of tc ike and tc lowell on 11–14 september 2008 lance f. bosart,...

Predecessor Rain Events Ahead of TC Ike and TC Lowell on 11–14 September 2008

Lance F. Bosart, Thomas J. Galarneau, Jr., Jason M. Cordeira, and Benjamin J. Moore

Department of Atmospheric and Environmental SciencesUniversity at Albany, SUNY

Albany, NY 12222

11th Annual Northeast Regional Operational WorkshopAlbany, NY

4–5 November 2009

Motivation• Predecessor Rain Events (PREs) are high-impact

weather events that can result in significant inland flooding

• High-impact PREs occurred with TS Erin (18–19 Aug 2007), TC Ike (12–13 Sep 2008), and TC Rita (24–26 Sep 2005)

• PREs represent a big forecast challenge for models and humans alike

• Dynamics and thermodynamics governing PREs need to be better understood

TS Erin PRE 18–19 Aug 2007Example of High-Impact Nature of PREs

Photo from Minneapolis Star Tribune Photo from NWS La Crosse, WI

Outline• Brief synopsis of PRE/TC relationships• Synoptic overview of Lowell/Ike PREs

– Rainfall and satellite signatures– Upper-air analyses– Precipitable water (PW) and sounding analysis

• Regional perspective– Ike moisture, PRE, and downstream jet– Trajectory analysis– Cross section analysis

• Summary

Predecessor Rain Events (PREs)• Coherent area of rain displaced poleward of TC• Moisture transport from TC toward PRE• Event duration ~ 12 h• Maximum rainfall rates typically ≥ 100 mm (24 h)1

• Time lag between PRE and TC passage ~ 36 h

~100

0 km

Bosart and Carr (1978) conceptualmodel of antecedent rainfallfor TC Agnes (1972)

Detailed study of PREs in Cote (2007) andGalarneau et al. (2009, submitted to MWR)

200 hPa h mean (dam) and anomaly (σ), mean wind (kt), and TC tracks

1110

9 8 7

78

910111213

14

15

TC IkeTS Lowell

= 00Z position

8–14 September 2008

Data: 2.5 NCEP–NCAR Reanalysis

72-h Quantitative Precipitation Estimates (inches)

Ending 1200 UTC 14 Sep 2008 http://nmq.ou.edu/

- 1. Lubbock, TX (LBB), 11 Sept, 198.1 mm- broke all-time 24-h rainfall record of 147.8 mm set on 18–19 Oct 1983

- 2. Wichita, KS (ICT), 12 Sept, 261.9 mm- broke all-time 24-h rainfall record of 165.6 mm set on 8 Jun 1923

- 3. Chicago, IL (ORD), 13 Sept, 168.7 mm- broke all-time daily rainfall record of 164.8 mm set on 14 Aug 1987

1

2

3

00Z/13

06Z/13

12Z/13

18Z/13

ORD rainfall in 6-h periods:00–06 UTC 13 5.1 mm06–12 UTC 13 75.4 mm12–18 UTC 13 72.6 mm18–00 UTC 13 19.8 mm

PREPRE

PRE

Ike

IkeIke

Ike

Ike tropical moisturearrives by 06 UTC

L L

LL

WSR-88D base reflectivity mosaic

Source: NCAR case-selection archive

ORD

06Z/14

12Z/14

15Z/14

18Z/14

ORD rainfall in 6-h periods:00–06 UTC 14 1.3 mm06–12 UTC 14 5.6 mm12–18 UTC 14 25.7 mm18–00 UTC 14 5.3 mm

Ike

Ike

Ike

Ike

ORD

WSR-88D base reflectivity mosaic

Source: NCAR case-selection archive

1200 UTC 9 September 2008 1200 UTC 10 September 2008

Infrared Satellite Imagery

source: http://adds.aviationweather.gov

L LI I

L = TC LowellI = TC IKE




LI I

L = TC LowellI = TC IKE




I

I

I = TC IKE

SLP, 1000–500 hPa Thickness, 250 hPa Wind

1200 UTC 8 September 1200 UTC 9 September

SLP (solid contours every 2 hPa), 1000–500 hPa thickness (red dashed contours every 3 dam)and 250 hPa wind speed (shaded in m s−1)

L LI I

I = TC IkeL = TC Lowell




L LI I





I I





II


DT Analysis and Low-Level FrontogenesisDT pressure (shaded in hPa), DT–850 hPa wind shear (barbs in kt),925–850 hPa ζ (contours every 2.0×10−5 s−1)

1200 UTC 12 September 2008

850 hPa h (solid contours every 2 dam)wind (barbs in kt), θ (dashed contours every 2 K),frontogenesis [shaded in K (100 km)−1 (3 h)−1]

II

I = TC Ike




II

I = TC Ike




I I

I = TC Ike

1200 UTC 11 Sep 2008

PW (shaded; mm), 250-hPa HGHT (black; dam), 700-hPa WND (kt), and 925–850-hPa REL VOR (magenta;

every 0.5 x 10-4 s-1)

PW above 700 hPa only Total PW

9−10 Sep 11−12 Sep 13−14 Sep

8 24 40 56 7216 32 48 64 80 mm m s−1

Total Precipitable Water Flux [mm m s−1]

Data: 0.5 NCEP–GFS analyses

50 mm m s−1

Source: http://weather.uwyo.edu/upperair/sounding.html

EPZ Santa Teresa DRT Del Rio

MAF Midland

12Z 10 Sep

00Z 11 Sep 12Z 10 Sep

TOP Topeka DVN Davenport

ILX Lincoln

12Z 13 Sep

12Z 12 Sep 12Z 13 Sep

Source: http://weather.uwyo.edu/upperair/sounding.html


925 hPa h (dam)925 hPa e (K)

200 hPa wind speed (m s1)


250 hPa h (dam), 700 hPa (105 s1)precipitable water (mm), 850–500 hPa mean wind (m s1)

LL

Ike

Ike

PRE

56 mm

56 mm



700 hPa h (dam), 700 hPa wind (m s1)700 hPa ascent (103 hPa s1)

900–400 hPa relative humidity (%)

925 hPa h (dam), 925 hPa wind (m s1)925 hPa e (K)

200 hPa wind speed (m s1)

Ike Ike

PRE

H H


http://www.atmos.albany.edu/student/cordeira/WEB/GFS_ARCHIVE/

Surface Observations and Base Reflectivity (dBZ)

0002 UTC 13 Sep 2008 0600 UTC 13 Sep 2008

NE

SDMN

WI

IL

IA

KSMO

NE

SDMN

WI

IL

IA

KSMO

72-h Backward Air Parcel Trajectories

LBB: 00Z / 12 Sep ICT: 12Z / 12 Sep

hPa10 3020 40 dBZ

Backward trajectories released from latitude and longitude of station every 100 hPaCircles represent 00Z locations

t − 72h position of IKE

t − 72h position of LOWELL


72-h Backward Air Parcel Trajectories

TOP: 18Z / 12 Sep CHI: 12Z / 13 Sep

hPa10 3020 40 dBZ

Backward trajectories released from latitude and longitude of station every 100 hPaCircles represent 00Z locations

t − 72h position of IKE

t − 72h position of LOWELL


Potential vorticity (PVU), θ (K), wind (kt) Relative humidity (%), θ (K), andupward vertical motion (10−3 hPa s−1)

A

B

A B A B

69

0600 UTC 12 September

Data: 0.5 NCEP–GFS analysesSource: NCAR case-selection archive

Potential vorticity (PVU), θ (K), wind (kt)

A

B

Frontogenesis [K (100 km)−1 (3 h)−1], θ (K), andupward vertical motion (10−3 hPa s−1)

A B A B

69Source:NCAR case-selection archive

1200 UTC 12 September


Cross Section Analysis1200 UTC 13 Sep

Potential vorticity (PVU), tangential circulation vectors, potential temperature (K)

PVUC D

C

D

0.5°x0.5° NCEP GFS analysis

Pres

sure

(hPa

)

10 m s−1

10 cm s−1


Potential vorticity (PVU), tangential circulation vectors, potential temperature (K)

PVUC D

C

D


Pres

sure

(hPa

)

10 m s−1

10 cm s−1


Mixing ratio (g kg−1), wind speed (kts), tangential circulation vectors, potential temperature (K)

g kg−1C Dkts

C

D


Pres

sure

(hPa

)

10 m s−1

10 cm s−1


K (100 km)−1 (3 h)−1C D

C

D


Pres

sure

(hPa

)Petterssen frontogenesis (K (100 km)−1 (3 h)−1), upward vertical

velocity (μb s−1), potential temperature (K)


Petterssen frontogenesis (K (100 km)−1 (3 h)−1), upward vertical velocity (μb s−1), potential temperature (K)

K (100 km)−1 (3 h)−1C D

C

D


Pres

sure

(hPa

)

Summary of TC Ike/Lowell PREs

• PREs fed off deep moisture from Ike and middle- and upper-level moisture from Lowell

• PREs occurred along low-level baroclinic zones well poleward of Ike and Lowell

• PREs were best defined where intense frontogenetical forcing was concentrated

• PREs were driven by deep ascent in equatorward jet-entrance regions

• Downstream jet strengthened considerably due to PRE- and Ike-driven diabatic heating

predecessor rain events ahead of tc ike and tc lowell on 11–14 september 2008 lance f. bosart,...

Documents

wi slide

mwr slide

h rainfall record

tc lowell

h periods

tc agnes

tc ike ts lowell

tc passage