DEPARTMENT OF GEOSCIENCES Spring 2005

San Francisco State University Metr. 201

Synoptic Metr Quiz #2

100 pts.

(Test will be collected at 9:45 AM)

1. Radar. (10 points each for a total of 50 points in this section).

Figure 1: Radar Analysis for 1749 UTC 11 February 2005

1. Convert the time and date to PST: 9:49 AM PST or 0949 PST 11 February 2005

2. The white areas on the map of the United States indicate what?

The white regions are areas with radar coverage by the National Weather Service's Doppler Radar network.

3. Why is there a grey area shown in eastern California extending into central Nevada?

This is a region without radar coverage, mostly because of high mountains blocking radar beams.

4. What do the areas colored in primary pigments (dark blue, light blue, dark green, yellow etc.) represent?

The colored areas represent areas of active precipitation at the time of the radar analysis, with the colors representing precipitation intensity (heaviness).

5. Based upon your consideration of Fig. 1, Los Angeles was experiencing what kind of weather at the time of the chart? Rain

B. Satellite (50 pts)

Figure 2: Visible Satellite Image, 1730 UTC 11 February 2005

Examine Figures 2 and 3, and note the locations shown at A, B and C on both images.

1. Which of the three locations has the clouds that are most likely be towering the highest in the troposphere and why? (20 pts)

The clouds at location B have the coldest tops (as indicated by the blue colors on the infrared imagery). We make the assumption that these clouds are towering from the ground to the level in the atmosphere at which the temperatures are very cold, which is almost always at high elevation. Also, the visible image shows the brightest white in this area, suggesting thick clouds reflecting much of the incident solar radiation.

2. Here are the three cloud types that are occurring at either location A, B and C: stratus, altocumulus, and cumulonimbus. Insert these cloud names at their most likely location. You may only use the cloud type once: (15 pts)

Location A __stratus

Location B __cumulonimbus

Location C _altocumulus_

3. The temperature of the cloud tops at location B is (15 pts)

(a) 10C

(b) 20C

(c) -10C

(d) -55C

(e) 0C

Figure 3: Enhanced Infrared Satellite Image, 1730 UTC 11 February 2005