GRY 135 - Investigations 9A
3. Upper-air winds steer low-pressure systems as well as air masses. A surface Low centered to the east of a trough axis and west of a ridge axis will move toward the ______.
Northeast
13. One of the highest reported wind speeds plotted in Figure 9A-4 was reported at Topeka, KS (TOP) from the southwest at about ______ knots. For reference, the wind barb includes 2 flags and 1 half feather.
105
9. Surface wind speeds behind the front in Figure 9A-3 were greater than other regions of the U.S. For example, Dallas, TX reported a sustained wind speed with two long feathers and one shorter one, denoting a speed of ______ knots.
25
11. Recall that the heights radiosondes detect at 500 mb are reported in the upper right position of the station, plotted in tens of meters. Place a "0" to the right of the number for the actual height. The height of the 500-mb pressure level plotted at Topeka (TOP), in northeast Kansas, was ______ m above sea level, denoted as 553.
5530
15. Figure 9A-5 is the 300-mb constant-pressure map for 00Z 31 October 2019, the same time as Figure 9A-3 and Figure 9A-4. The 300-mb pressure level occurs in the upper troposphere and the 300-mb station heights are plotted in tens of meters. The height of the 300-mb pressure level at Little Rock, AR (LZK) was ______ m above sea level.
9500
10. Figure 9A-4 is the 500-mb constant-pressure map for 00Z 31 October 2019, the same time as the Figure 9A-3 surface map. The middle troposphere flow pattern, shown by the height contours, displayed ______.
A trough marked by a center axis from South Dakota to west Texas
16. The general 300-mb height contours at 00Z on 31 October exhibited an upper airflow with ______.
A trough marked by center axis from South Dakota to west Texas
23. For Figure 9A-5, highest wind speeds are inside the 110 kt isotach (from west Texas northeastward into the Great Lakes and Ontario). A 90 kt isotach encircles an even larger area than the 110 kt isotach. Such high wind speed regions within the overall jet stream flow are called jet streaks. Which state below is NOT under a 110-kt jet streak region?
Arizona
8. Wind directions in Figure 9A-3 near blue isobar lines across the country flowed ______. Good examples are the stations located in Wichita, KS and Oklahoma City, OK.
At angle across isobars
2. The Northern Hemisphere's upper-air westerlies flowing through troughs exhibit counterclockwise (cyclonic) curvature as seen from above. As shown in Figure 9A-1, the trough axis line divides the trough into two roughly symmetrical sectors. West of the trough axis, winds are from the northwest (a cold weather direction) and east of the trough axis, winds are from the southwest (a warm weather direction). West of a trough axis favor ______ air advection while winds east of a trough line favor warm air advection.
Cold
6. In the Northern Hemisphere, when the polar-front jet stream is south of your locality, the weather is relatively ______.
Cold
12. Compare the heights of the 500-mb constant pressure surface across the southern U.S. to the northern U.S. As latitude increases (poleward), the height of the 500-mb surface generally ______.
Decrease
17. Comparing the heights of the 300-mb pressure surface across the southern U.S. to the northern U.S., as latitude increases the height of the 300-mb surface ______. This pattern is the same as that found at 500 mb.
Decrease
21. As seen on the Figure 9A-4 and Figure 9A-5 constant-pressure maps, higher wind speeds are located where spacing of height contours are relatively ______. Furthermore, the relationship is consistent with surface weather maps between wind speeds and the spacing of isobars.
Far apart
20. Compare the wind speeds plotted on the 00Z 31 October 2019, Figure 9A-4 with Figure 9A-5. Wind speeds typically ______ as altitude increases in the troposphere.
Increase
4. When the upper-air flow pattern is zonal, the source region for much of the air over the coterminous U.S. is the Pacific Ocean. On the other hand, when the upper-air flow pattern is meridional, the source regions for air masses are Canada (with winds from the northwest) or Mexico and the Gulf of Mexico (with winds from the southwest). Hence, from west to east, temperatures are likely to be more variable with a ______ flow pattern.
Meridional
5. Fundamental to the formation of the polar-front jet stream within the westerlies is that warm air is less dense than cold air when both are at the same pressure. Air pressure drops ______ rapidly with increasing altitude in cold air than in warm air.
More
14. The 500-mb wind directions provide guidance on surface storm movements. Over much of the Ohio Valley and Northeast in Figure 9A-4, they indicate the developing cyclone center in northern Kentucky of Figure 9A-3 would move toward the ______ over the next day or so.
Northeast
22. Compare the 500-mb and 300-mb wind flows. The pattern of wind direction also shows the winds flow ______ at greater distances from the surface. This directional relationship is particularly evident at higher wind speeds.
Parallel to the contour lines
1. The Northern Hemisphere's upper-air westerlies flowing through ridges exhibit clockwise (anticyclonic) curvature as seen from above. As shown in Figure 9A-1, the ridge axis line divides the ridge into two roughly symmetrical sectors. West of the ridge axis, winds are from the southwest (a warm weather direction) and east of the ridge axis, winds are from the northwest (a cold weather direction). Winds to the west of a ridge axis favor ______ air advection while winds to the east of a ridge axis favor cold air advection.
Warm
19. Survey the Figure 9A-5 map for wind speeds of 70 knots or more (one flag and 2 long feathers). Using this wind speed threshold to define the existence of a jet stream, there ______ evidence of a jet stream curving across the U.S. on the 300-mb constant-pressure map.
Was strong
7. As a component of the planetary-scale upper-air westerlies and similar to the winds at 500 mb, the polar-front jet stream steers low pressure systems. Hence, middle latitude storms generally move from ______.
West to East
