DEPARTMENT OF EARTH & CLIMATE SCIENCES SAN FRANCISCO STATE UNIVERSITY NAME Metr 302.02 Fall 2014 Test #1 September 30, 2014 200 pts (4 pts each answer) Part I. Surface Chart Interpretation. Questions 1 through 7 refer to the surface weather map below and the weather station data for the four weather stations shown on the map and expanded below. Figure 1. Surface Chart for 1500Z 7 September 2007 1. Pressure System A on the chart is a High Pressure area. This means (a) dew points are high. (b) the air there is cold. (c) the air there is warm (d) the atmospheric pressure (weight) is greater there than in surrounding areas. (e) the atmospheric pressure (weight) is lesser there than in surrounding areas. Page 1 of 25
2. Pressure System B on the chart is a Low Pressure area. This means (a) dew points are high. (b) the air there is cold. (c) the air there is warm (d) the atmospheric pressure (weight) is greater there than in surrounding areas. (e) the atmospheric pressure (weight) is lesser there than in surrounding areas. 3. Station 4 (see above) is reporting (a) a thunderstorm (b) heavy continuous rain (c) moderate fog. (d) heavy continuous snow. (e) haze. 4. The station(s) with a relative humidity of 100% (a) Station 1 (b) Station 2 (c) Station 3 (d) Station 4 (e) Stations 1, 2 and 3. 5. The station(s) with the lowest relative humidity (a) Station 1 (b) Station 2 (c) Station 3 (d) Station 4 (e) Stations 1, 2 and 3. 6. The pressure at Station 3 is (a) 1080 mb (b) 1010.8 mb (c) 910.8 mb (d) 520 mb (e) 1052 mb 7. The FRONT shown on the weather map is (a) a stationary front (b) a cold front (c) a warm front (d) an occluded front Part II. Satellite and Radar Interpretation from Class Weather Map Discussions. Refer to Figs. 2a and b, and 3. Questions 8 through 11 refer to these figures. Page 2 of 25
Fig. 2a. Visible Satellite Image, 1500 UTC 25 Sept 2014 Page 3 of 25
Fig. 2b. Infrared Satellite Image, 1500 UTC 25 Sept 2014 Page 4 of 25
Fig. 3. Radar Reflectivity, KMUX 1505 UTC 25 Sept 2014 8. With respect to the visible satellite image, Fig. 2a, the texture in the cloud band located over northern California is probably due to (a) different cloud colors. (b) shadows cast by towering cloud forms on the lower overcast. (c) cold temperatures at 500 mb. (d) unusually warm sea surface temperatures. (e) industrial activity in the Sacramento Valley. 9. Fig. 2a and b and Fig. 3 in combination would suggest to meteorologists that Page 5 of 25
(a) (b) (c) (d) (e) fog is present in the Sacramento Valley. severe thunderstorms are occurring off the Southern California coast. cold temperatures are over the Central Valley. dew points are very high over California. a band of moderate to heavy precipitation is moving through northern Callifornia. 10. The information in Fig. 3 suggests that the precipitation near Fairfield is associated with (a) stratus. (b) fog. (c) cumulonimbus. (d) ciirrus spissatus. (e) nimbostratus. 11. Figures 2a and b and 3 together suggest that the main immediate forecast issue over southwestern for the Southern California coastal waters would be (a) fog. (b) frost. (c) warm temperatures. (d) low dew points. (e) thunderstorms. Part III. Severe Thunderstorms Outlooks, Watches, and Warnings. Questions 12 through 20 are in this section). Page 6 of 25
Figure 4. Convective Oulook issued 1958Z 23 February 2007 12. The Convective Outlook is issued by (a) the Storm Prediction Center (b) the US Geological Survey (c) the National Thunderstorm Forecast Center (d) the National Hurricane Center (e) the local National Service Forecast Office 13. The Convective Outlook shown above (Fig. 4) indicates that (a) no severe thunderstorms were expected over the United States. (b) there is a moderate risk of thunderstorms over western Oklahoma.. (c) the highest likliehood of severe thunderstorms is over Florida (d) there is a slight chance of hurricanes forming over the Great Plains (e) thunderstorms are expected over a large portion of the central and southern Great Plains, and that there is a moderate risk that some of these thunderstorms will be severe over western Oklahoma, south central Kansas and NW Texas. 14. The following is the text of a statement issued by the Storm Prediction Center for a portion of the Great Plains. Read the text: URGENT - IMMEDIATE BROADCAST REQUESTED??????????????? NUMBER 761???????????????? NORMAN OK 210 PM CDT TUE OCT 9 2001 Page 7 of 25
THE????????????? HAS ISSUED A???????? WATCH FOR PORTIONS OF WESTERN OKLAHOMA NORTHWEST TEXAS THE EXTREME EASTERN TEXAS AND OKLAHOMA PANHANDLES EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 230 PM UNTIL 900 PM CDT. TORNADOES...ALSO HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE WATCH AREA IS ALONG AND 55 STATUTE MILES EAST AND WEST OF A LINE FROM 75 MILES SOUTH SOUTHEAST OF CHILDRESS TEXAS TO 55 MILES NORTH NORTHEAST OF GAGE OKLAHOMA. REMEMBER...A??????? WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. This text corresponds to: (a) a Tornado Warning (b) a Severe Thunderstorm Warning (c) a Hurricane Watch (d) a Tropical Storm Watch (e) a Tornado Watch 15. Which of the following is NOT included in the definition of a severe thunderstorm (a) hail 1 or larger (b) straight line winds 57 mph or greater (c) frequent cloud-to-ground lightning (d) tornadoes (e) all of the above are part of the definition of severe thunderstorms 16. The definition for a Warning is (a) the given weather event is not expected to occur. (b) the given weather event is expected to occur sometime in the future, but no one can say when. (c) the given weather event is occuring, or is observed, and is about to move into the area mentioned in the statement. Take appropriate action immediately. (d) conditions are favorable for the given weather event to occur in the time interval and for the area specificed in the statement, although the weather event has not yet formed. Persons living in the area should listen for further statements and should take precautions in case the event occurs. Page 8 of 25
(e) is an advisory statement not meant to be taken literally. 17. The definition for a Watch is (a) the given weather event is not expected to occur. (b) the given weather event is expected to occur sometime in the future, but no one can say when. (c) the given weather event is occuring, or is observed, and is about to move into the area mentioned in the statement. Take appropriate action immediately. (d) conditions are favorable for the given weather event to occur in the time interval and for the area specificed in the statement, although the weather event has not yet formed. Persons living in the area should listen for further statements and should take precautions in case the event occurs. (e) is an advisory statement not meant to be taken literally. 18. Thunderstorms are associated with (a) cirrus clouds (b) status clouds (c) nimbostratus clouds (d) cumulonimbus clouds (e) altocumulus clouds 19. Severe thunderstorm forecasters often look at surface dew point temperatures to make a first guess of the region expected to get strong to severe thunderstorms. The minimum summertime surface dew point temperature they look for is (a) 30 o F (b) 40 o F (c) 50 o F (d) 60 o F (e) 70 o F 20. Cumulonimbus clouds show up very well on infrared satellite images because (a) their tops are very cold, and usually are evidenced in the primary colors on color infrared satellite images. (b) their tops are very warm, and usually are evidenced in the primary colors on color infrared satellite images. (c) on such images rainfall is directly indicated in primary colors. (d) lightning is easily detected by the infrared satellite sensor. (e) infrared satellite images only show cumulonimbus clouds. 21. The scale used by meteorologists to rate tornadoes is known as (a) the Fujita Scale. (b) the Saffir-Simpson Scale. (c) the Dorothy Scale. Page 9 of 25
(d) (e) the Enhanced Fujita Scale. the Doppler Scale. Part IV. Scientific Method (Questions 22 through 25 are in this section). 22. The Scientific Method is (a) only used in the United States. (b) based upon a belief system. (c) varies from country to country.. (d) a series of structured steps that provide scientists with a blueprint of how to study and solve problems pf the natural world. (e) none of the above. 23. Once the observations are made, or the data is collected, and the scientist observes some sort of systematic organization or pattern to the data, he or she develops an educated explanation for the pattern. This educated explanation is known as (a) A guess (b) An opinion (c) A theory (d) A flip of the coin. (e) A hypothesis 24. Once a theory is formulated it is tested. If the theory bears out statistically, it becomes a hypothesis. (a) True (b) False 25. The example that Zebrowski and we have used (in class) to illustrate how to use a PRINCIPLE to explain a pattern of observations of wind is that gases tend to move from high to low pressure areas. (a) True (b) False Part V. Hurricanes (Questions 26 through 29 are in this section) Page 10 of 25
Figure 5: Northern Hemisphere Hurricane and Tropical Storm Frequencies per 100 Years (Source: National Hurricane Center) 26. A logical hypothesis to explain the fact that tropical cyclone frequencies increase rapidly in the spring is (as shown in Figure 5 above) (a) that sea surface temperatures in the hurricane formation areas of the Northern Hemisphere have exceeded the minimum threshold that supports such storms at that time. (b) that the polar jet stream is very active at that time. (c) that the temperatures in tropical latitudes are still cold at that time. (d) that the dew points are unusually low at that time. (e) that cold fronts are very active in tropical latitudes at that time. 27. The minimum sea surface temperature that seems to support the intensification of tropical cyclones is (a) 28F. (b) 28K. (c) 16C. (d) 61F. (e) 28C. 28. The general tracks of hurricanes in the Atlantic and in the eastern Pacific extend from east to west with most hurricanes curving northward towards the western portion of both regions.. (a) True (b) False 29. A tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) ranges from 34 kt (39 mph or 63 km/hr) to 63 kt (73 mph or 118 km/hr) and with usually associated with at least one isobar surrounding the area of lowest pressure at sealevel. (a) is the definition of a tropical low. (b) is the definition of a tropical depression. Page 11 of 25
(c) (d) (e) is the definition of a tropical storm. is the definition of an easterly wave. is the definition of a hurricane. Part VI. Radar Network Issues and Image Interpretation (Questions 30 through 41 are in this section) s Figure 6. National Weather Service Doppler Radar Sites 30. Figure 6 above shows the location of National Weather Service Forecast Offices. (a) True (b) False 31. Radar data is used (a) to show areas of precipitation (b) to infer locations of thunderstorms (c) (a) and (b) (d) to find cloudiness (e) to find areas experiencing high water vapor. 32. Radar can detect precipitation up to (a) about 1 miles from the radar site. (b) about 10 miles from the radar site. (c) about 100 miles from the radar site. (d) about 500 miles from the radar site. (e) about 1000 miles from the radar site. 33. There is dense coverage of the national radar network except Page 12 of 25
(a) (b) (c) (d) (e) in tornado alley. in the Midwest. in the coastal sections of California. in the Great Plains. in the intermountain West. Figure 7: Radar Reflectivity over Texas, 1608 UTC 9/18/2014. The black box is the approximate location of Lubbock, TX. 34. The scale at the bottom of Fig. 7 shows cloud top temperatures. (a) T (b) F 35. Figure 7. shows regions of Texas experiencing precipitation at the time of the radar plot. (a) T (b) F 36. The yellow and orange colors on Fig. 7 probably indicate the location of (a) Very heavy precipitation (b) Thunderstorms (c) (a) and (b) (d) Light winds. (e) High water vapor. 37. Fig. 7 suggests that Lubbock was experiencing (a) Heavy rain and possibly thunderstorms. (b) Fog. (c) Drizzle (d) Blowing dust. Page 13 of 25
(e) Haze. 38 The time and date of Fig. 7 is (a) 9:08 AM PDT 09/18/2014 (b) 9:08 PM PDT 09/18/2014 (c) 8:08 AM PDT 09/17/2014 (d) 9:08 AM PDT 09/19/2014 (e) 4:08 PM PDT 09/18/2014 39 The colored areas on Fig. 7 are referred to by meteorologists as radar echoes (a) T (b) F 40. Besides detecting precipitation, the radar can be used to make short term forecasts of (a) motion of rainfall/storm areas. (b) dew points. (c) relative humidity. (d) temperatures. (e) jet streams. 41. A significant problem in the western portion of the US, is that in certain storm patterns the local radar overshoots the top of the precipitation or is blocked by mountains. (a) T (b) F Part VII. 500 mb chart. (Questions 42 and 43 refer to Fig. 8 below) Page 14 of 25
Figure 8. 500 mb chart With Possible Polar Jet Stream Positions, 12 UTC 24 September 2014 42. On Fig. 8, the correct location of the Polar Jet Stream is indicated by the arrow labeled. (a) A (b) B (c) C (d) D (e) E 43. The conditions shown on Figure 8 are occurring roughly at an elevation of a. 180 feet b. 1800 feet c. 18000 feet d. 180000 feet e. 30000 feet Page 15 of 25
Part VIII. Dew Point Temperature. Questions 44, 45 and 46, refer to figure 9 below. Figure 9. (Synthesis) Dew point temperatures (in Fahrenheit) expected at 15 UTC 27 September 2014. Note the locations A, B, and C where the dew points are forecast to be 39F, 67F, and 55F, respectively. Assume that the actual temperature will be 67F everywhere. 44. Of the three locations shown on Figure 8, the place with the greatest amount of water vapor is at (a) A (b) B (c) C 45. Of the three locations shown on Figure 8, the place with the least amount of water vapor is at (a) A (b) B (c) C 46. Of the three locations shown on Figure 8, the place with 100% Relative Humidity is at (a) A (b) B (c) C 47. The dew point temperature is used by meteorologists in many ways. Which of the following is NOT one of those ways? (a) The dew point temperatures can be used as a rough indication of how much water vapor is present. Page 16 of 25
(b) (c) (d) (e) The difference between the actual temperature and the dew point temperature is related to the relative humidity. Meteorologists can use the dew point temperature to determine how much cooling is needed to produce clouds at the observation site.. Meteorologists use the dew point temperature to assess the strength of cyclones. The surface dew point temperature can be used as a very rough indicator of how prone the atmosphere is for thunderstorm formation. 48. When the temperature is cooled to the dew point temperature at the ground (a) condensation begins, often evidenced by the formation of fog. (b) there is much water vapor in the air. (c) strong winds develop. (d) evaporation begins. (e) rain occurs. 49. If cloud cover is observed at a weather station (indicated by the filled in station circle), then the relative humidity at that station instrument level must be 100% (a) T (b) F 50. The relative amount of water vapor present at a sealevel station can be estimated by the (a) temperature (b) dew point temperature (c) pressure (d) present weather symbol (e) wind speed Page 17 of 25
Figure 1. Surface Chart for 1500Z 7 September 2007 with the weather data for Stations 1 through 4 expanded out. Fig. 2a. Visible Satellite Image, 1500 UTC 25 Sept 2014 Page 18 of 25
Fig. 2b. Infrared Satellite Image, 1500 UTC 25 Sept 2014 Page 19 of 25
Fig. 3. Radar Reflectivity, KMUX 1505 UTC 25 Sept 2014 Page 20 of 25
Figure 4. Convective Oulook issued 1958Z 23 February 2007 Figure 5: Northern Hemisphere Hurricane and Tropical Storm Frequencies per 100 Years (Source: National Hurricane Center) Page 21 of 25
s Figure 6. National Weather Service Doppler Radar Sites Page 22 of 25
Figure 7: Radar Reflectivity over Texas, 1608 UTC 9/18/2014. The black box is the approximate location of Lubbock, TX. Page 23 of 25
Figure 8. 500 mb chart With Possible Polar Jet Stream Positions, 12 UTC 24 September 2014 Page 24 of 25
Figure 9. (Synthesis) Dew point temperatures (in Fahrenheit) expected at 15 UTC 27 September 2014. Note the locations A, B, and C where the dew points are forecast to be 39F, 67F, and 55F, respectively. Assume that the actual temperature will be 67F everywhere. Page 25 of 25