METR 360 Fall, 2015 Final Exam

Directions: Answer all parts of all 6 questions. Use the blue books or write a text file where required. Draw on the paper copy of the exam where requested. For calculations, show all work. You may use any source, including your notes, any textbook or the Internet. You may NOT talk during the exam, except to me. Raise your hand if you have a question.

The following information may (or may not) be useful:

1. For this question, use the 500 mb map at this link. This map has been analyzed for heights in black and the 60 knot isotach in blue. Answer the following:

a. ( 6%) Data from the radiosonde released from Buffalo, NY are shown over the designation KBUF on the map. List the 500 mb temperature, dewpoint, and height above mean sea level, using the proper units.

b. ( 4%) On the paper version, where appropriate, label all Entrance and Exit regions. Note: On this map, not all jets will have both. You decide.

c. ( 4%) Again, on the paper version, for the Entrance and Exit regions draw solid black arrows to represent the ageostrophic wind directions (do not draw the geostrophic wind directions).

d. ( 4%) What will be the net effect of the ageostrophic winds on the eastern ridge only from the jet centered on Iowa? Briefly justify your answer.

2. For this question, a PowerPoint loop of surface progs has been created. The PowerPoint file allows you to see the individual frames or step through the frames to see changes. Note that the location of Green Bay, WI is marked KGRB on the first map.

( 12%) Write a forecast for KGRB that is consistent with this series of progs and the classic features of the Norwegian Model. Specifically, forecast relative temperatures (warm, hot, cool, arctic, etc), precipitation types, and the cloud types at each time shown by the progs. Use the times shown at the bottom of each prog. In the blue books or text file, list them like this:

12Z Saturday: (in the blue books or text file, write your answers on each line)

00Z Sunday:

12Z Sunday:

00Z Monday:

3. This question refers to the NAM 500 mb initialization loop starting from 12Z Nov 26, 2015 with forecast maps out to 48 hours. The wave which initially is centered on 40°N has a measured wavelength of 2277 miles which is 3.6635 x 10⁶ meters. Show your work in a logical progression and finish with the answer, including the units. If you change units, you must show how.

a. ( 6%) If we were to consider the entire wave across North America to be stationary for the 24 hours of the loop, what would be the mean west to east wind at 500 mb?

b. ( 6%) The waves are not stationary everywhere. For the latitude of 60°N (in Canada), compute the actual wave speed using the mean west to east wind you found for part a. Then do the same for a latitude of 30°N (across the southern U.S.).

c. (12%) Using the loop and your other answers for this question, portray in one line each (a total of three lines), the wave types and motions across the U.S., Canada, and the Caribbean Sea area (40°N, 60°N, 30°N in that order) for the duration of the loop using appropriate terminology for a meteorologist.

4. For this question, click the link for a Miami, FL (KMFL) sounding taken at 00Z on an unspecified day in the last four weeks.

a. ( 6%) List three separate reasons why the atmospheric conditions at 00Z are unfavorable for precipitation.

b. ( 3%) Is there anything at all on this image that tells you there is a possibility for precipitation? List just one aspect that is favorable.

5. The 500 mb map shown here is a 12Z depiction. Four vorticity centers are labeled A, B, C, and D. The labels are offset slightly from the centers so you can see the colors better. There is a zoom-in version to help you even more.

a. ( 8%) What are the maximum/minimum vorticity values at the places nearest A, B, C, and D? Use the correct units.

b. ( 4%) Based on the size of the white arrows, two jet streak locations are marked with heavy black arrows. Briefly explain why the centers A and B straddle one of those jet streaks and centers C and D straddle the other. Both answers are the same so you may write it just once.

c. ( 4%) The white arrows are almost perfectly straight between A, B, C, and D. Why are the vorticity values on the west side of the black arrows much greater than the values on the east side? There are two reasons. List them both (do no calculations).

6. Here is a series of MOS forecast data for Minneapolis, MN, based on the NAM run at 00Z on December 12, 2015

KMSP NAM MOS GUIDANCE 12/12/2015 0000 UTC

DT /DEC 12 /DEC 13 /DEC 14 /

HR 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 18 00

X/N 40 35 43 31 33

TMP 36 35 34 34 38 39 38 38 38 37 37 38 40 42 39 37 35 34 33 32 29

DPT 31 31 30 31 32 33 33 33 33 34 34 34 36 37 36 33 31 30 29 27 25

CLD OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV

WDR 03 03 03 04 04 03 04 06 04 05 03 04 02 01 36 36 35 35 34 31 31

WSP 05 04 05 06 05 07 08 07 07 09 10 10 07 11 12 12 09 13 11 09 08

P06 1 7 6 23 69 69 64 63 66 58 8

P12 13 69 75 76 58

Q06 0 0 0 0 2 3 3 3 3 2 0

Q12 0 2 4 4 2

T06 0/ 1 0/ 4 1/ 2 0/ 0 2/ 5 2/ 1 3/ 5 3/ 0 0/ 1 0/ 5

T12 0/ 4 1/ 2 2/ 5 3/ 5 6/ 3

SNW 0 0

CIG 4 4 4 3 2 3 2 3 2 2 2 2 2 2 3 2 2 2 2 2 4

VIS 7 5 5 5 5 5 5 5 3 4 4 3 3 3 3 3 3 3 4 3 7

OBV HZ BR BR BR BR BR BR BR BR BR BR BR BR BR BR BR BR BR BR BR N

a. ( 6%) What are the forecast maximum and minimum temperatures from 06Z on Dec 13 to 06Z on Dec 14?

b. ( 6%) Sometime during the entire 72 hour period of this forecast, there is a significant shift in the wind direction accompanying an air mass change. When does that happen and how do other forecast parameters change to tell you the air mass is changing? (be sure to name the parameters)

c. ( 4%) Under the time 00Z on Dec 14, the line marked Q12 has the number 4. What do Q12 and 4 mean? Please be specific.

d. ( 5%) At any time during these 72 hours, should a forecast for KMSP include the word snow? Why or why not? Base your answer on this MOS guidance, not on what actually happened.