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Name: ANSWERSAlso write your name on the back of your completed assignment!This is how it will be returned to you.

Severe and UnusualWeather - Fall 2007Homework #2

Due Wednesday 7 March 2007

Before you begin: 1) Your completed assignment must be your own work. Recall that the syllabus statesthat if your answers are the same as someone else's, you will share the credit for the answer. 2) You mustshow all your work to receive full credit. 3) If you don't want everyone else to see your grade, pleasewrite your name at the top left corner on the back of your assignment.When you're done: Please date and sign the last page.

1/Decode the follo'_ling surface observation. As always, include the correct units (e.g., °F, mb,

kts,etc.).P:3 r.._'L ,vx.a...0.-_,-e_,r_82 992 _1 ff-_OD

26

/Temperature: 82°F Wind Direction: south

Dew Point Temperature: 26°F Wind Speed: 15 kts

Cloud Cover: overcast Pressure: 999.2 mb

Significant Weather: fog__

2_ Since that was so fun, let's do another one!I

98 003 < 500 ,_Lc:_,_g | O _ oq¢__c-'_

64

Temperature: 98°F Wind Direction: southeast

Dew Point Temperature: 64o[ :_ Wind Speed: _35 kts

Cloud Cover: mostly cloudy or 6/8 coverage Pressure: 1000.3 mb

Significant Weather: thunderstorm

3. Convert the following times into Central Daylight/Standard Time and UTC. Be sure to usea.m./p.m, time for Central times, and leave UTC in 24-hr time.

a. 7 a.m. CST Monday 1300 UTC Monday

b. 8 p.m. CDT Friday 0100 UTC Saturdav

c. 1:45 am. CDT Wcdnesda.y.v 0645 UTC Wednesday

d. _ CST Saturdav 0330 UTC Sunday

4. What are the three types of satellite images available from a geostationary satellite? Explainwhat we see in each image.

Visible: What we would see ifwe were looking down fi'om spaceWhite areas = clouds or snowDark areas = ground or water

Infrared: A measurement of cloud top temperaluresColder = higher cloudsWarmer = lower clouds

Water Vapor: Amount of water vapor in the upper-atmosphere

5. Explain the Doppler shift. Compared with conventional weather radars, what new informationcan we measure with Doppler radars that is helpful in severe weather situations?

The I)opplcr shift refers to frequency shifts of acoustic and electromagnetic waves becauseof relalive motion between the source and the observer. While older, conventional radars callmeasure only the returned power reflected from a distant object (reflectivity), Doppler radars canalso measure the speed of the object along the radial direction (velocity). This allows the radarto detect rotation in thunderstorms.

6.' What is the frequency of an electromagnetic wave with a wavelength of 2.944 meters? Thespeed of light, c = 3.0 x 10s m/s, and a Megahertz (MHz) is equal to Ix 106sn. Give your answer

in MHz. Is it possible to tune your car radio to this frequency? C0_Xre-¢ 5] 0"el"7,

The equation is c = t_., where c is the speed of light, fis the frequency and L is the wavelength.The units must match! Solving for the fi'equency.

f =__c=2300000000m/s2.944meters 1'019 x10s" s-' = (1.019x 10s s")Tii x!_l) =101"910s" MtlzYes, you can tune your car radio to this station. Try it...it's the Twister!!

2

7. The sun is classified as a G2 main sequence star with an effective surface temperature of5770K. Now you can impress your friends with this bit of trivia and the fact that the sun's peakemission wavelength corresponds with the color green! Compute the peak emission wavelengthof the brightest star in our sky, Sirius, an AI star with a surface temperature of 9230K.

2897 p.mK 2897 p_mKUse Wien's Law: )_ma.x = -- = =0.314 p.m. This is within the spectrum ofT 9230Kultraviolet B radiation. That's the stuffthat burns your skin at the beach!

8. How far away is a radar target (an object that reflects radiation) if a pulse of radiation isreceived by a NEXRAD radar 600/.ts (6 x l0_ s) after it is sent? The speed of light is 3 x l0 sm/s.

h , 7. _ • CIUsing t e equauon g_ven m class, d = (/2), we can compute the distance:d = (3 x 10sin/s)*(6 x 10.7 s)/2 = 90000 m = 90 km

9. / How could increased cloud cover cause an increase in the average surface temperature.'? Howcould increased cloudiness cause a decrease in the average surface temperature?

Water vapor is a greenhouse gas. An increase in water vapor, indicated by increased cloudcovet', would cause terrestrial radiation to be sent back to earth, warming the lower atmosphere.On the other hand, increased cloud cover would resull in increased albedo, reducing the totalshortwave radiation received from the sun, ultimately cooling the earth.

3

10. The environmental lapse rate is 8.5°C/km. A parcel starts at the surface where thetemperature is 27°C and is forced upward dry adiabatically to the LCL at I km above the surface.The parcel continues to rise moist adiabatically until it reaches 2 km above the surface.Calculate the temperature of this lifted air parcel at 2 km above the surface. Will the parcelcontinue to rise or sink downward? Is this an absolutely stable, absolutely unstable orconditionally unstable atmosphere?

Temperature at 2 kin: I 1.2°C

Rise or sink? rise

Stability: _conditionally unstable

The environmental temperature at 2 km above the surface is 27°C - (2 km)*(8.5°C/km) = 27°C -17°C = I 0°C. The air p:_r(:elrises dry adiabatically to I kin, where its temperature is reduced to27°C - (I km)*(9.8°C/km) = 17.2°C. At the LCL, the air becomes saturated, so as the parcelcontinues to rise fi'om I km to 2 kin, it does so while cooling at the moist adiabatic lapse rate.Theretbrc the new temperature of the parcel at 2 krn is 17.2°C - (I krn)*(6.0°C/km) = 17.2°C -6.0°C = I 1.2°C. Since the air parcel is warmer than the environment at this height, the parcelwill continue to rise. The environmental lapse rate lies between the values tbr the moistadiabatic lapse rate and the dry adiabatic lapse rate (6.0°C/kin < 8.5°C/kin < 9.8°C/kin).Therelbre, this is a conditionally unstable atmosphere.

I I. A saturated air parcel from the surface, where the temperature is 26°C, gets caught in theupdraft of a strong thunderstorm and is lifted moist adiabatically inside the cloud to the top of thethunderstorm at 12 km above the surface. What is the new temperature of the air parcel when itreaches the anvil of this storm?

Calculate the reduction in temperature from the stn'face to 12 km above the surihce as the parcelis lilied moist adiabatically.26°C - (12 km)*(6.0°C/km) = 26°C - 72°C = - 46°CBrrrr!!!

12.' Different types of force balances drive atmospheric motion.a. What forces constitute the geostrophic wind balance?pressure gradient and Coriolis PGF + Coriolis = geostrophic wind

b. What forces constitute the gradient wind balance?pressure gradient, Coriolis, and centripetal PGF + Coriolis + centripetal = gradient wind

c. What makes the wind motion around upper-level systems different from the wind motion "41around surface pressure systems?Friction

4

13. On the 500-mb map below, the contours indicate lines of constant height and the arrowsindicate the approximate speed and direction of the geostrophic wind.

Using the letters A, B, C, and D, identify the letter closest to the:

a. troughaxis B -fiv ,wsvw' Iocout/V_o.t_va._s I_ Vvllv_tavva Vt_ltae_ wtrl0_rt _, -Iqr°_-_ _

b. region of maximum upper divergence associated with the trough C

c. region of maximum upper convergence associated with the trough AV_t__- iva 74. try/

d. ridgeaxis D "- lick-t O.t_ VV'VI_Clc, __._ l_,v-.<,sv_'__ IOc_t_l_

14. Two mid-latitude cyclones are tracking simultaneously across the United States. Onecyclone (cyclone A) is over Colorado and the other (cyclone B) is over Vermont. Cyclone A hasa pressure gradient of 1 mb per 100 km and cyclone B has a pressure gradient of 4 mb per 100kin. Which cyclone is likely to produce the strongest winds? Why?

The cyclone with the strongest pressure gradient would produce the strongest winds, that is.

cyeloneBoverVermont. L.) _ov, Lw,.t_-J-IV-_'¢_c_¢" _v_°F° _ r, _Y-_vc

Severe and Unusual WeatherMeteorology 2603, Section 001

First Examination

February 26, 2007

NAME: ANSWERS

You have 50 minutes to complete this examination. To receiveproper credit, please write all of your multiple choice answerson the answer sheet provided. For multiple choice questions,choose the best answer. Please write your responses to theshort answer section directly on the exam. Please write clearly.If I can't read your answer, it is wrong. Useful equations arelisted on the back page. Solutions will be available on the classWeb site soon. Good luck!

20070226vB

Part OneMultiple Choice(1.4 points each)

1. If the radio announces that it is 305 outside on a warm summer day, they are probablyusing the temperature scale.

a. Celsiusb. Fahrenheitc. Kelvind. Oklahoma summer

2. The processes of condensation and freezinga. both release heat to the environment.b. both absorb heat from the environment.c. do not affect the temperature of their surroundings.d. do not involve energy transport.

3. The ideal gas law says that air pressure depends upona. temperature and densityb. gravity and temperaturec. wind speed and Coriolisd. the level in the atmosphere

4. If an air parcel is given a small push upward and it falls back down to its originalposition, the atmosphere is said to be

a. adiabaticb. stablec. unstabled. isothermale. neutral

5. Water vapora. is invisibleb. is only in cloudsc. makes clouds whited. is very small drops of liquid watere. both a. and d.

6. At 40°F, the atmosphere is saturated with water vapor. If the air temperature increasesto 60°F, with no addition or removal of water vapor, one may conclude that the dewpointis

a. 20°Fb. 40°Fc. 60°Fd. impossible to determine with this information

Use the following table to answer questions 7-10.City Air Temperature Dewpoint

(°F) Temperature (°F)a) Key West, Florida 79 66b) Norman, Oklahoma 85 52c) Juneau, Alaska 1I 6d) Ithaca, New York 21 2 I

7. Which city has the highest relative humidity? d

8. Which city has the least amount of water vapor in the air? c

9. Which city has the greatest amount of water vapor in the air? a

I0. Which city has the highest saturation vapor pressure? b

I I. Which of the following is the best indicator of the actual amount of water vapor inthe air?

a. air temperatureb. saturation vapor pressurec. dewpoint temperatured. relative humidity

12. The most abundant permanent gas in the atmosphere isa. Argonb. Nitrogenc. Neutrogenad. Oxygene. Ozone

13. The science of meteorology studies which part of the planet'?.a. cryosphereb. atmospherec. lithosphered. hydrospheree. biosphere

14. The is the ratio of the mass of water vapor in a given parcel of air to themass of the remaining dry air.

a. absolute humidityb. mixing ratioc. relative humidityd. dewpoint

15. Millibars are commonly used units ofa. massb. atmospheric pressurec. altituded. humidity

16. When the air temperature decreases, the saturation vapor pressure willa. increaseb. decreasec. remain the samed. become saturated

17. A radar beam in elevation with increasing range due to the curvatureof the earth.

a. rotatesb. decreasesc. increasesd. remains constant

18. Particles that serve as surfaces on which water vapor may condense are called

a. hydrophobic nucleib. nacreous nucleiC. scud

d. condensation nuclei

19. The amount of force exerted over a surface area is calleda. densityb. weightc. temperatured. pressure

20• The earth's atmosphere is divided into layers based on changes in the vertical profileof

a. air temperatureb. air pressurec. air densityd. wind speede. height

21. The order of the layers of the atmosphere from lowest to highest isa. stratosphere, tropoSphere, mesosphere, thermosphereb. stratosphere, troposphere, thermosphere, mesospherec. troposphere, stratosphere, mesosphere, thermosphered. thermosphere, stratosphere, mesosphere, tropospheree. troposphere, tropopause, thermosphere, mesosphere

22. The atmospheric greenhouse effect is produced mainly by thea. absorption and re-emission of visible light by the atmosphereb. absorption and re-emission of ultraviolet radiation by the atmospherec. absorption and re-emission of infrared radiation by the atmosphered. absorption and re-emission of visible light by cloudse. absorption and re-emission of visible light by the ground

23. The number of molecules in a given space or volume is calleda. densityb. weightc. temperatured. pressure

24. This process causes descending air to warm:a. evaporationb. condensationc. expansiond. compression

25. Which of the following weather elements always decreases as we climb upward inthe atmosphere?

a. windb. temperaturec. pressured. moisturee. all of the above

26. Which of the following can we observe with a Doppler radar?a. temperature and radial wind speedb. reflectivity and temperaturec. reflectivity and radial wind speedd. pressure and reflectivity

27. The earth's radiation is often referred to as radiation, while the sun'sradiation is often referred to as radiation.

a. Iongwave, shortwaveb. shortwave, Iongwavec. terrestrial, Iongwaved. shortwave, solar

28. If the average temperature of the sun increased, the wavelength of peak solar J

emission would 11a. shift to a shorter wavelengthb. shift to a longer wavelengthc. remain the samed. uh...impossible to tell from given information

29. The combined albedo of the earth and the atmosphere is approximatelya. 4%b. I0%c. 30%d. 50%e. 70%f. 90%

30. The earth is closest to the sun ina. Januaryb. Marchc. Julyd. September

3 I. The vernal equinox this year will occur less than a month from now on Tuesday, 20March 2007 at 7:07 p.m. Central Daylight Time. At this time,

a. the sun will be directly overheadb. astronomical autumn will begin in the Southern Ilemispherec. Daylight Savings Time will stopd. the Earth will be farthest from the sun

32. At solar noon on the summer solstice (21 June 2007 at 4:18 p.m. Central DaylightTime), the sun will be directly overhead at the

a. Tropic of Equilibriumb. Tropic of Capricornc. Tropic of Cancerd. Horse Latitudese. Equator

33. The sun is directly overhead at Harare, Zimbabwe (latitude 17.8°S)a. once a yearb. twice a yearc. four times a yeard. never

34. The base of a cloud is at thea. lifting condensation level (LCL)b. level of free convection (LFC)c. level of rising parcels (LRP)d. moist adiabatic level (MAL)

35. Contour lines connecting points of equal pressure are calleda. millibarsb. isothermsc. isopressesd. isobars

Refer to the following surface station plot to answer questions 36-41:91 985

62

/36. The observed air temperature is

a. 91°Cb. 91°Fc. 62°Cd. 62°Fe. 98.5°F

37. The observed dewpoint temperature isa. 91°Cb. 91°Fc. 62°Cd. 62°Fe. 98.5°F

38. The observed wind speed and direction isa. from the south at 10 knotsb. from the north at 15 knotsc. from the south at 30 knotsd. from the north at 25 knotse. from tile south at 15 knots

39. The observed fractional cloud cover isa. 0/8- clear skiesb. 2/8 - 25% cloud coverc. 4/8- 50% cloud coverd. 8/8- overcast

40. The observed mean sea level pressure (MSLP) isa. 985.0 mbb. 998.5 mbc. 1013.25 mbd. 1098.5 mb

41. The current weather is

a. fog qllb. a thunderstormc. raind. snowe. haze

42. Which of the following would cause relative humidity to decrease?a. warming the airb. cooling the airc. increasing the actual water vapor pressured. decreasing the saturation vapor pressure

43. An unsaturated air parcel would rise and cool at thea. moist adiabatic lapse rateb. environmental lapse ratec. relapse rated. dry adiabatic lapse ratee. aerodynamic lapse rate

44. A rawinsode measures which of the following lapse rates?a. moist adiabatic lapse rateb. environmental lapse ratec. relapse rated. dry adiabatic lapse ratee. aerodynamic lapse rate

45. The rate at which temperature decreases with increasing altitude is known as the

a. temperature slopeb. soundingc. lapse rated. thermocline

46. Sea-level pressure values generally fall in the rangea. 950to 1050robb. 500 to 1500 mbc. 750 to 950 mbd. 100tol000mb

47. The pressure gradient force is directed from areas of higher pressure toward areas oflower pressure

a. only at the equator.b. at all places on earth except for the equator.c. only in the Northern Hemisphere.d. only in the Southern Hemisphere.e. at all places on Earth.

48. The wind direction isa. the direction l?om which tile wind is blowingb. the direction to which the wind is blowingc. always directly from high toward low pressured. always directly from low toward high pressure

Use the following figure to answer questions 49-51 and indicate the radiation lawthat applies to the various portions of the diagram. Your choices are:

a. Wien's Lawb. Kirchhoff's Lawc. Planck's Lawd. Stefan-Boltzmann Lawe. Inverse Square Law

On your answer sheet, j ust write the letter of the corresponding law.49. applies to A a. Wien's Law50. applies to B d. STethn-Boltzmann Law51. applies to C c. Planck's Law

A

_.__PC(peak)

c_'_1 / __._(Sle curve)

iI _ (area undBercurve) _r I I I I

Frequency

52. Your NOAA weather radio announces that the current temperature at Will RogersAirport is 95°F and the relative humidity is 80%. With your incredible memory about allthe exciting things you learned in meteorology class, you recall that the saturation vaporpressure at this temperature is 56.3 mb. You determine that the actual vapor pressure is

a. "80%b. 11.3 mbc. 45.0 mb g[d. 70.4 mbe. 76.0 mbf. 80°F

53. Which of the following instruments measures pressure?a. anemometerb. thermometerc. barometerd. radiometere. pressiometer

54. The is an apparent force that makes winds curve to the left of motion inthe Southern Hemisphere.

a. Coriolis forceb. centripetal forcec. gravitational forced. pressure gradient force

55. Which of the following is not a primary channel used to create a satellite image?

a. ultravioletb. infraredc. water vapord. visible

Almost there...just five more questions to go!

Part TwoShort Answer - Please show all of your work

I. (4 points) Convert the following temperatures into Fahrenheit, Celsius° and Kelvin.Round your answer to the nearest tenth of a degree. (Hint: Temperature conversions arelisted on the last page.)

-12.0 °F = -24.4 °C= 248.7 K

96.9 OF = 36.1 °C = 309.2 K

2. (7 points) Complete the following table by filling in the new parcel temperatures anddewpoint temperatures after an air parcel is lifted from near the surface. Then indicatewhether the parcel is stable or unstable by circling the appropriate answer. Rememberthat the dewpoint temperature cannot be higher than the temperature!

Parcel DewParcel Point Environmental

Height Temperature Temperature Temperature(kin) (*C) (°C) (°C)

2.5 9 9 14

2.0 12 12 15

1.5 15 15 17

1.0 20 15 20

STABLE UNSTABLE

3. (4 points) The vertical pressure gradient at the surface of the Earth is approximately120 mb/km. Given that a typical horizontal pressure gradient at the surface is usuallybetween 0.01 and 0.10 mb/km, what keeps the atmosphere from suddenly and violentlyblowing out into space? A one- or two-word answer will suffice.

GraviD' or Hydrostatic Equilibrinm

4. (4 points) The pressure difference between station A and station B is 8 mb and thedistance between each station is 200 kin. What is the magnitude (that's just the numberwith no direction attached to it) of the pressure gradient between these two stations? Besure to include your units!

PG = 8 mb/200 km = 4 rob/100 km = 0.04 mb/km

5. (4 points) You're sitting on a small deserted island directly on the equator. You glanceup to see your single palm tree swaying in the wind and estimate that the wind speed is15 meters per second. Since you have nothing else to do, you calculate that the Coriolisacceleration (or force per unit mass) is

ZERO m s-2.

There is no Coriolis acceleration at the Equator!

Potentially useful equations:

2897/._nKC = 2f_vsin _ p = pRdT c = f2 2m__ --

T(K)

KE = l-mv 2 O= gAz F = ma E = mc 22

oC=5(OF_32) OF=9oc+32 K =oc + 273.159 5

Dry adiabatic lapse rate = 10°C/kmMoist adiabatic lapse rate -_ 6°C/km

Severe and Unusual WeatherMeteorology 2603, Section 001

Second Examination

11 April, 2007

NAME: ANSWERS

You have 50 minutes to complete this examination. To receiveproper credit, please write all of your multiple choice answerson the answer sheet provided. For multiple choice questions,choose the best answer. Please write your responses to theshort answer section directly on the exam. Please write clearly.If I can't read your answer, it is wrong. Useful equations arelisted on the back page. Solutions will be available on the classWeb site soon. Good luck!

20070411vB

Part OneMultiple Choice(1.25 points each except where noted)

I. Some scales of atmospheric motion from smallest to largest area. global scale, mesoscale, synoptic scale, microsealeb. microscale, mesoscale, global scale, synoptic scalec. synoptic scale, mesoscale, global scale, microscaled. microscale, mesoscale, synoptic scale, global scale

2. The wind direction isa. the direction to which the wind is blowingb. always directly from high toward low pressurec. the direction from which the wind is blowingd. always directly from low toward high pressure

3. Heat lightning isa. false lightningb. caused by excessive temperatures during summerc. too thr away to hear the thunderd. very frequent in mountainous regions

4. A tornado watch is issued for a portion of the Texas Gulf Coast to address the concernfor tornadoes from isolated supercells. Who issued the watch?

a. The National Weather Service forecast office in Norman, Oklahomab. The Storm Prediction Center in Norman, Oklahomac. The Storm Prediction Center in Houston, Texasd. The National Hurricane Center in Miami, Floridae. The National Weather Service forecast office in Houston, Texas

5. What does the tornado watch mean?a. the risk of tornadoes has increased significantly but their occurrence, location.

and/or timing.is still uncertainb. actual or expected tornadoes do not constitute a serious hazard but may cause

inconvenience or concernc. a tornado is occurring, is imminent, or has a very high probability of occurringd. a tornado may interest a number of peoplee. tornadoes may occur within the next few days

6. A tornado warning is issued within the watch area in southern Texas. Who issued thewarning?

a. The National Weather Service forecast office in Norman, Oklahomab. The Storm Prediction Center in Norman, Oklahomac. The Storm Prediction Center in Houston, Texasd. The National Hurricane Center in Miami, Floridae. The National Weather Service forecast office in Houston, Texas

7. In cloud-to-ground lightning, the stepped leader travels and the returnstroke travels

a. upward, upwardb. upward, downwardc. downward, upwardd. downward, downward

8. The top of a thunderstorm is normally charged, and the middle and lowerparts are charged.

a. negatively, negativelyb. negatively, positivelyc. positively, positivelyd. positively, negatively

9. You are generally safe inside an automobile during a lightning storm because

a. the car's radio antenna will act as a lightning rodb. the rubber tires insulate you from the groundc. metal cars do not become electrically chargedd. the metal cat" body will carry the lightning current around thc passengers

inside (it's a Faraday cage)

I0. Thunder is caused bya. air masses collidingb. the collision between two thunderstorms with opposite electrical chargec. the rapid heating of air snrrotmding a lightning channeld. the explosion that occurs when positive and negative charges collide and

neutralize each othere. Zeus' anger

I 1. Which small-scale vortex is not necessarily associated with either clouds orthunderstorms?

a. tornadob. gustnadoc. landspoutd. dust devile. waterspout

12. What does the layered structure of many hailstones result from?a. recycling, i.e., a looping trajectoryb. varying concentrations of pollutants in the air

_. c. val3'ing rates of accretion of supercooled water (i.e., wet vs. dr)' growth)d. lightning strikes that occur in the portion of the cloud where the hailstones

grow

13. What does the tornado warning mean?a. the risk of tornadoes has increased significantly but their occurrence, location,

and/or timing is still uncertainb. actual or expected tornadoes do not constitute a serious hazard but may cause

inconvenience or concernc. a tornado is occurring, is imminent, or has a very high probability of occurringd. a tornado may interest a number of peoplee. tornadoes may occur within the next few days

14. The cloud that forms along the leading edge of a gust front is calleda. an anvil cloudb. a 1"ollcloudc. a mammatus cloudd. a wedge cloud

15. A circulation that may develop along the leading edge of a gust front, but is notassociated with a mesocyclone, is called a

a. dirt devilb. dust devilc. gustnadod. tornado

16. Which two processes cause air to descend in a downburst?a. Surface heating and frontal liftingb. Condensational heating and expansionc. Surface heating and evaporational coolingd. Evaporational cooling and the drag force due to falling precipitatione. Condensational heating and the drag force due to falling precipitation

17. A relatively narrow downburst, less than 4 km wide, is called aa. nlicl'oburstb. funnel cloudc. rain shaftd. narrow burste. mesocyclone

18. The vernal equinox occurred on Wednesday, March 2 I, 2007 at 0007 UTC. Note thatthis date is after the change to daylight saving time this year. What time was the vernalequinox in Norman, Oklahoma?

a. 5:06 a.m. Wednesday, March 21b. 6:06 a.m. Wednesday, March 21c. 6:06 p.m. Tuesday, March 20d. 7:07 p.m. Tuesday, March 20e. 12:07 a.m. Wednesday, March 21

19. In the Southern Hemisphere, winds flow around low pressure systems.a. cyclonicallyb. anticyclonicallyc. to the left of motiond. against the pressure gradient

20. In the Southern Hemisphere, winds flow around high pressure systems.a. clockwiseb. counterclockwisec. geostrophicallyd. faster

21. Air in surface low pressure systems and in surface high pressuresystems.

a. sinks and converges, diverges and risesb. converges and rises, sinks and divergesc. sinks and diverges, converges and risesd. diverges and rises, converges and sinks

22. A low pressure system is generally associated witha. clear skiesb. anticyclonic flowc. clouds and precipitationd. colder temperatures

23. Your best source of information and warnings during severe weather isa. a televisionb. a local radio stationc. tornado sirensd. a weather radio with SAME technologye. the sound of a freight train

24. The Fujita scale is based on tornadoa. wind speedb. damagec. angular momentumd. size

25. Which of the following methods oftornadogenesis will most likely produce amultiple vortex tornado?

a. dynamic pipe effectb. tiltingc. vortex breakdownd. tilting of the horizontal circulation along the forward flank gust front as it

moves under the updraft (the bottom-up process)e. vortex stretching

26. Wind blowing at a constant speed parallel to straight isobars with the pressuregradient force (PGF) and the Coriolis force in balance is called a

a. gradient windb. meridional windc. gcostrophic windd. cyclostrophic winde. zonal windf, cross-isobaric wind

27. A wind that blows at aconstant speed parallel to curved isobars is called aa. cyclostrophic windb. gradient windc. geostrophic windd. cyclonic winde. convergent wind

28. Which atmospheric force is the only force responsible for causing wind?a. Coriolis forceb. centripetal forcec. frictiond. pressure gradient forcee. baked beans

29. Buys-Ballot's law states that, "In the Northern Hemisphere if you stand with yourback to the surface wind, and then turn clockwise about 30 °, lower pressure will be

.,,a. to your rightb. to your leftc. behind youd. in frontofyou

30. You see lighting in the distance and count 15 seconds until you hear the thunder.How far away is the thunderstorm?

a. I mileb. 1.5 milesc. 3 milesd. 7.5 milese. 15 milesf. uh...not enough information

31. If there is weak convergence at the surface and strong divergence aloft, what kind ofpressure system will form at the surface? q

a. high pressureb. low pressurec. no pressure system will formd. a ridge

32. You are driving your car westward on 1-40 near Cordell, OK and you hear a tornadowarning on the radio. Because you were so focused on driving, you didn't notice thesmall tornado moving quickly toward you from the west. You look around and see afield full of cows (projectiles), a highway overpass, and a ditch, but no sturdy buildings(see the picture displayed on the screen). You should

a. keep driving and try to outrun the tornadob. stop the car and run into the field, avoiding the cowsc. stop and seek shelter under the overpassd. stop the car on the side of the road, get as far away fi'om it as possible, and lie

in the ditch with your hands covering your head

33. Which of the following is not correct concerning a cold front?a. it often marks the position of a trough of low pressureb. it often marks a zone of shifting windsc. it is colored purple on a weather mapd. it has cold air behind it

34. The diagram to the right represents avertical cross section of aoccluded front with the coldest air locatedat position . "_ A B

a. cold-typel B _"b. warm-type, Bc. cold-type, Ad. warm-type, A

35. An occluded front forms when a overtakes aa. cold front, dry lineb. dry line, warm frontc. warm front, cold frontd. cold front, warm front

36. The figure to the right is a pressure _ .i._ .__trace (pressure vs. time) for a singlestation. It is characteristic of what typeof occurrence? _-

a. Warm frontal passage

b. Cold frontal passage >c. Stationary frontal passage Timed. Occluded frontal passage

37. A dry line separates , generally with little change in "_a. cold air from warm air, dewpointb. warm air from cold air, pressurec. dry air from moist air, temperatured. hot air from dry air, wind direction

38. Match each feature with the most appropriate name below (½ point each).40 kilometers

4North

E B

c\lD

a) rear flank gust front D

b) bounded weak echo region E

c) main updraft G

d) forward flankdowndraft A

e) forward flank gust front B

f) V-notch 1

g) radar echo outline F

h) inflow from the surface C

i) rear flank downdraft H

NOTE: G is for the lightly shaded region and E indicates the region inside the circle butoutside the medium gray line that surrounds the storm.

39. Squall lines most often form ahead of aa. cold frontb. warm frontc. cold-type occluded frontd. warm-type occluded fronte. stationary front

40. A mesoscale convective complex (MCC) isa. the same as a multicell thunderstormb. a huge, long-lasting systera of thunderstormsc. a dryline, cold front, and warm front intersectiond. a mental disorder suffered by severe weather enthusiastse. a squall line

41. The development or strengthening of a mid-latitude cyclone is calleda. frontogenesisb. cyclogenesisc. tornadogenesisd. hurricogenesise. convergiogenesis

42. Windows break when a house gets hit by a tornado becausea. the pressure inside a tornado is lower than inside a house and the house

explodes.b. small objects become deadly projectiles and can easily break glassc. somebody forgot to open themd. people panic and jump through them

43. In reference to NOAA weather radios, what does the acronym SAME stand for?

a. Severe Alerts in Meteorological Emergenciesb. Specific Advisories and Messages in Emergenciesc. Specific Area Message Encodcrd. S-adenosyl-methioninee. Soap and water, Alcohol-based hand rub, Moisturization, and Education

44. You're driving northwestward through the Southern Plains underneath beautifulmammatus clouds when you see a thunderstorm ahead of you. You can clearly see a darkprecipitation shaft to your right, a white hail shaft directly in front of you, and a tornadonear the rain-free base to your left. What kind of storm is this?

a. an LP supercell (low precipitation)b. an HP supercell (high precipitation) 'ic. an ordinary supercelld. a classic supercelle. an ordinary thunderstorm

Questions 45 through 53 refer to the surface map below. Each letter may be usedmore than once. Choose the best option. "H" and "L" are not correct answers tothe i uestions below.

H

45. Which letter best identifies the occluded front? C

46. Which letter best identifies the warm front? B

47. Which letter best identifies the cold front? A

48. Which letter best identifies maritime tropical (mT) air? D

49. Which letter best identifies continental polar (cP) air? A

50. Which letter best identifies the warm sector of a mid-latitude cyclone? D

51. (1.25 points each) The anticyclones on the map are over the state of Utah andthe Atlantic Ocean.

52. (1.25 points each) Name two states through which the occluded front clearly passes.a) Minnesota b) Wisconsin

l

53. The air at point D is most likely than air at point A.a. warmer and the dewpoint is lowerb. warmer and the dewpoint is higherc. cooler and the dewpoint is lowerd. cooler and the dewpoint is higher

54. What stages constitute the development cycle of a typical ordinary thunderstorm?

a. embryo, development, and dying stagesb. young, mature, and old stagesc. cumulus, mature, and dissipation stagesd. small, big, and large stagese. developing cumulus, downdraft, and anvil stages

55. Which of the following is a rotating thunderstorm?a. a tornadob. a supercellc. a multicelld. an ordinary thunderstorme. a squall linef. both (a) and (b)

56. According to the National Weather Service, a severe thunderstorm exists

a. only when surface wind speeds exceed or equal 50 ktsb. when surface wind speeds exceed or equal 50 kts, hail has a diameter of at

leas! _A", or there is a tornadoc. only when there is a tornadod. when surface wind speeds exceed or equal 50 kts, hail has a diameter of at

least W', or there is a tornadoe. only for supercell thunderstorms

57. lfa tornado is heading toward your home, you shoulda. get to the bascment or a windowless interior roomb. open all the windowsc. go outside and watchd. panic and hide under the bed

58. Which environmental lapse rate is most likely to produce a strong downburst?a. 4°C/kmb. 6°C/kmc. 8°C/kmd. I0°C/km

59. If all other conditions for thunderstorm formation exist but there is no windshear,what would be the most likely mode of convection (kind of storm) to develop in theatmosphere?

a. an MCVb. supercell thunderstormsc. multicell thunderstormsd. ordinary thtmderstorms

Questions 60 through 62 refer to the 500 mb map below. Solid lines are heightcontours, dashed lines are isotherms, and the flags are wind barbs indicating winddirection and speed. Each letter may be used only once.

60. Which letter best identifies the trough axis? B

61. Which letter best identifies gradient wind flow? D

62. Which letter best identifies geostrophic wind flow? A

63. Which of the following ingredients is absolutely essential for supercells to form, butnot necessary for ordinary thunderstorms to form?

a. a source of liftb. a source of moisturec. strong wind sheard. chaser convergencee. a conditionally unstable atmosphere

64. The Enhanced Fujita scale accounts fora. construction variabilityPb. stronger tornadoesc. tornadoes from squall linesd. straight-line wind damage

65. produce no measurable precipitation and are difficult to detect visually.a. Burst swathsb. Dry microburstsc. LP supercellsd. HP supercellse. Wet microbursts

Part TwoShort Answer- Please show all of your work directly on this exam

1. The figure below depicts isobars of mean sea-level pressure (in millibars) at thesurface of the earth in the Northern Hemisphere.

a. (2 points) Points A and B are 500 km apart. Compute the magnitude of thepressure gradient between points A and B. Be sure to include your units!

PG = (change in pressure/change in distance) = (I 000 mb- 992 rob)/(500 kin)

PG = 8 nab/500 km = 0.016 mb/km

b. (1 point) Toward which compass direction will a stationary air parcel at pointB want to move solely due to the pressure gradient force?

West

c. (2 points) Beginning from each of the four 'x' marks, draw arrows clearlyindicating the direction of surface air flow at only these four points on thediagram. The direction and curvature (or lack thereof) of your arrows mustshow your knowledge of the flow field.

Tg

L A 8

.

a. (4 points) A mesocyclone with a radius of 2.5 km (2500 m) rotates with atangential velocity of 3 m s_. This vortex stretches into a tornado with a radius of100 m. If angular momentum is conserved, how fast are the winds rotating at theedge of the tornado?

Vlrl = V2r2 "-) (3 m s'1)*(2500 m) = V2*(100 m) -'-) V2 = 75 m s"l (168 m.p.h.)

b. (4 points) The tornado travels at 25 m s"_toward the east. What is the wind speed,relative to the ground, on the north, south, east, and west sides of the tornado? Besure to include units!

North: 50 m s-_

South: 100 m s-I

East: 75 m s"_

West: 75 m s-I

BONUS (4 points; all or nothing): What does the acronym NOAA stand for?

__ National Oceanic and Atmospheric Administration

BONUS (2 points each): NOAA is an organization within the United States Department

of Commerce, which is an agency within the Executive

Branch of the U.S. government.

Some potentially useful equations and constants:

F = ma 2897 _tmK_'m_, = T in KelvinT

0p-- = -pgOz E = _o'T 4

dT 2d = ctdz

Fd = 9.8°C/kmp = pR_T

Fm _ 6.0°C/kmpot = RdT

_ =5.67x10_ s WC = 2_vsin_ m z K4

019 = fT. p_/ c = 2.9979 x 10s __m0t s

KE = / mv 2 RH = e/es2

J

O=gAz cp =1004 kgK

°C= "F-32 °) So =1367m_

K=oc + 273°F = 9°C + 32

5c=f_

f_ = 7.292x10 -5 s-IZ = 300R 1.4

O=T V,_,=V_