DEPARTMENT OF EARTH & CLIMATE SCIENCES NAME SAN FRANCISCO STATE UNIVERSITY Fall 2016 Part 1. Weather Map Interpretation ERTH 365.02 FINAL EXAMINATION KEY 200 pts Questions 1 through 9 refer to Figure 1, which shows the Great Plains Thunderstorm Pattern we discussed in class. 500 mb (blue arrows with wind speeds) and surface isobars (thin solid). Lines 1, 2 and 3 refer to boundaries on the surface chart, and Lines 4 and 5 refer to features on the 500 mb chart. Locations A, B, and C refer to places where thunderstorms developed on that day. 1. On figure 1, the line labeled 2 is a a. ridge b. trough c. warm front d. cold front e. dry line 2. On figure 1, the line labeled 3 is a a. ridge b. trough c. warm front d. cold front e. dry line 3. On figure 1, the line labeled 4 is a a. ridge b. trough c. warm front d. cold front e. dry line 4. On figure 1, the line labeled 5 is a a. ridge b. trough c. warm front d. cold front e. dry line 5. On figure 1, divergence in the upper troposphere is probably occurring at 1
b. Line 1 c. Line 2 d. Line 3 e. Line 4 6. On figure 1, the green shaded area probably represents an area of a. high dew point b. CAPE c. low relative humidity d. low dew point e. (a) and (b) 7. On figure 1, the thunderstorm most likely to be a common or single cell thunderstorm 8. On figure 1, the line labeled 2 is a a. boundary between warm dry and warm moist air b. boundary between advancing cold air and warm air c. boundary between advancing warm air and cold air d. boundary between cool dry and cool moist air e. none of the above 9. On figure 1, the thunderstorm at Location A is most likely a supercell a. because divergence is occurring in the upper troposphere there b. because there is great horizontal shear at that location c. because there is great vertical shear at that location d. because there is a gust front at that location e. because a cold front is nearby. Part 2. Instability and Thunderstorms 10. Thunderstorms that develop in an unstable air mass in an environment of low or absent jet streams are known as a. Multicell Thunderstorms. b. Tornadic Thunderstorms. c. Severe Thunderstorms. d. Common or Single Cell Thunderstorms. e. Supercells. 11. The most dangerous type of lightning is a. Cloud-to-cloud lightning. b. Cloud-to-ground lightning. c. Ball lightning. 2
d. Sheet lightning. e. In-cloud lightning. 12. You notice a flash of cloud-to-ground lightning. It takes 10 seconds before you hear the thunder. The lightning struck the ground a. 1 mile away. b. 1/2 mile away. c. 2 miles away. d. 3 miles away. e. 10 miles away. 13. An air parcel rises spontaneously if a. it is warmer than the air below it b. it is cooler than the air above it c. it is cooler than the air around it at the same elevation d. it is warmer than the air around it at the same elevation e. all of the above. 14. An ice pellet that forms when a cloud droplet makes successive trips through the freezing level at the top of a growing cumulus cloud is known as a. sleet b. freezing rain c. drizzle d. hail e. snow 15. The amount of energy liberated for each gram of water condensed is known as the latent heat of condensation. a. T 16. The reason that lightning, rainfall, and downdrafts all seem to occur when a growing cumulus congestus cloud penetrates the freezing level is a. a coincidence b. that all of these phenomena can be linked to the formation of hail and frozen precipitation which occur at this stage in the development of the thunderstorm. c. related to the stronger jet stream winds at upper levels. d. dependent on the amount of hygroscopic nuclei present e. related to the amount of water vapor in the rising air. Figure 2 is the sketch of an air mass thunderstorm we discussed in class. Note the locations noted at A, B, C, D and E. Questions 17-21 refer to this figure. Locate the following: 17. Cold air downdraft location 3
18. Anvil 19. Level of maximum hail formation 20. Location outflow boundary 21. Maximum horizontal wind shear (max hazard to pilots) 22. The strength of the cold air downdraft is a. related to the sun angle b. cannot be determined c. related to the time of year d. related to the size of the cumulonimbus e. related to the strength of the updraft 23. Hail size is ultimately related to a. the type of thunderstorm. b. the length of time the updraft remains existent. c. The mammatus formation. d. the strength of the updraft. e. (b) and (d) (both). 24. Common thunderstorms have no significant threats to life and property associated with them. 4
a. T 25. Thunderstorms developing in an environment of vertical shear are longer lived than others because a. such storms usually are associated with stronger instability. b. they are less likely to be associated with large hail. c. they are prone to be associated with cloud-to-ground lightning. d. their updrafts are weaker. e. the precipitation filled downdraft does not fall into the updraft area, but downwind. 26. The radar signature of a supercell is the a. anvil. b. hook echo c. large hail d. rear flank downdraft e. TVS (tornado vortex signature) 27. Which of the following is NOT what you should do if you here a Tornado Warning? a. get into your bathtub and lie down flat. b. get into a storm shelter. c. get into an interior room of your house. d. if possible, and you can see the tornado, drive at right angles to the path of the tornado. e. hide under a freeway overpass 28. Single cell (air mass) thunderstorms quickly die upon reaching maturity because a. the dew points are too low. b. all the hail melts. c. the vertical shear is large. d. the jet stream is strong. e. the cold downdraft suppresses the updraft area of he storm. Figure 3 is the chart we looked at in class when discussing instability/stability. Questions 29 through 31 refer to this figure. 29. Which panel on this chart illustrates stability? a. A b. B 30. In the case shown by Panel B, if moisture were condensing as the air parcel lofted, its temperature at the top of the mountain would be warmer than the temperature shown. a. T 31. A direct measure of the degree to which lofted air parcels will be warmer than the surroundings at the same elevation is a. Convective Available Potential Energy b. surface dew point c. surface relative humidity 5
d. surface temperature e. surface wind speed. Part 3. Hurricanes Figure 4 shows the data recorded by a buoy that experienced the direct passage of Hurricane Rita. Questions 32 through 34 refer to this figure. 32. The data indicate that the center of the hurricane was directly over the buoy at about a. 1200 UTC on September 22 b. 0000 UTC on September 22 c. 1200 UTC on September 23 d. 0000 UTC on September 23 e. 0600 UTC on September 20 33. The data indicate that the greatest upper tropospheric divergence was directly over the buoy at about a. 1200 UTC on September 22 b. 0000 UTC on September 22 c. 1200 UTC on September 23 d. 0000 UTC on September 23 e. 0600 UTC on September 20 34. The data indicate that winds exceeded hurricane strength at around a. 1800 UTC on September 22 b. 2100 UTC on September 22 c. 1200 UTC on September 23 d. 2100 UTC on September 23 e. 1600 UTC on September 20 35. A tropical storm is a. any member of the hurricane family. b. a tropical cyclone with winds between 39 and 74 mph c. a tropical cyclone with winds between 38 mph or less. d. a storm of hurricane strength e. a typhoon 36. A tropical depression is a. a severe tropical cyclone b. a tropical cyclone with winds of 65 knots (74 mph) or greater c. a tropical cyclone with tornadic thunderstorms embedded in it d. the same as a typhoon e. b. and d. 37. The most significant source of heating leading to hurricane formation (besides warm ocean temperatures) is a. strong solar insolation b. the release of latent heat from condensing water vapor 6
c. divergence at the top of the storm d. friction e. lightning heating up the air 38. Hurricanes weaken when crossing over land because a. the increased friction causes the wind speed to decrease and to suddenly converge to the center of the low. b. the storm loses its main source of heating, access to water vapor from the oceans. c. trees take water vapor from the storm. d. there is more Coriolis Effect over the land. e. a. and b. 39. The best estimate from computer projections for the impact of Global Warming on hurricanes/typhoons is that a. such storms will be more frequent, but less intense. b. such storms will be more frequent, and more intense. c. such storms will occur in similar numbers as occur today, but will be less intense. d. such storms will occur in similar numbers as occur today, but will be more intense. e. there will be no change in frequency and intensity. 40. The best estimate from computer projections for the impact of Global Warming on the vertical change in temperature (environmental lapse rate) associated with such storms will be basically the same through the 21 st Century a. T Figure 5 is the track and intensity forecast for Hurricane Katrina. 41. Sustained winds of 135 knots with gusts to 165 knots occurred at (or were forecasted to occur at) a. 12 UTC, August 29 b. 06 UTC, August 28 c. 12 UTC, August 28 d. 12 UTC, August 30 e. 06 UTC, August 29 42. The inset box at the bottom right of Figure 5 (with place names) indicates a. places where damage was expected to take place. b. the closest passage in distance of the center Hurricane Katrina to those places c. evacuation centers. d. the location of National Weather Service Forecast offices in that area. e. the location of underground shelters. 43. The track forecast suggested that the greatest threat for a storm surge would take place a. the Gulf Coast from Mississippi east to Alabama and the Florida Panhandle. b. the Gulf Coast from Louisiana west to Texas. c. Cuba. d. South Carolina. e. the Yucatan peninsula of Mexico. 7
44. The disaster in New Orleans associated with Hurricane Katrina was primarily a failure of a. the government to respond properly to the threat. b. the National Weather Service s forecasts c. the Coast Guard to evacuate trapped individuals. d. the National Hurricane Center. e. the National Guard. 45. The natural flood control system associated with rivers that is often improved by humans is known as a levee a. T 46. Hurricane Katrina experienced rapid intensification when a. it passed over the Kuroshio Current. b. it passed over the Gulf Stream. c. it passed over the Humboldt Current d. it passed over the Loop Current. e. it passed over Florida. Part 4. Ensemble and Prediction Science Figure 6 is the actual GFS 500mb 5 th Day Forecast Valid 12 UTC 12/16/16. Figure 7 I sthe GFS Ensemble 500 mb Spaghetti Plot 5 th Day Forecast fort the same date and time. The letters A, B, and C refer to locations referred to in the questions below. 47. If Fig. 6 verifies (actually occurs on 12/16/16), one would expect a. fair weather east of A, over portions of Southern California and western Arizona. b. no jet stream will be found near A. c. a trough would be located just southwest of location C. d. ta strong jet stream would be located at B. e. Stormy weather east of A, over portions of Southern California and western Arizona. 48. Fig. 7 suggests that a. it is least likely that the 500 mb forecast in Fig. 6 would be correct at location A. b. it is most likely that the 500 mb forecast in Fig. 6 would be correct at locations A and C. c. it is least likely that the 500 mb forecast in Fig. 6 would be correct at locations A and C. d. it is most likely that the 500 mb forecast in Fig. 6 would be correct at location A. e. it is most likely that the 500 mb forecast in Fig. 6 would be correct at location B. Fig. 8 shows the Accuracy Die-off Curves for the 5 th Day Forecast GFS (black) and the GFS Ensemble Mean (blue) for 2 September 2016 through 11 December 2016. 49. One way of interpreting the meaning of Fig. 8 is that it suggests that the 5 day GFS Forecast (120 h) a. has been very inaccurate. b. capture about 90% of the actual pattern that did occur 5 days into the future. c. is not as accurate as the NAM forecast for the same day. 8
d. is inaccurate 90% of the time. e. is not good at anticipating patterns. 50. Forecasters aim to have his/her forecast statistics characterized by a. a high FAR and a low POD. b. a high FAR and a high POD. c. a low POD and a low FAR. d. a high POD and a low FAR. e. none of the above. 9