DEPARTMENT OF GEOSCIENCES                   NAME ________________________

San Francisco State University                                                                 Spring 2011

 

Metr 415/715

Quiz 3

Open Book/Notes

150 pts. (60 minutes)

 

At the rear of the quiz are provided the following KBMX (Birmingham, Alabama) Level

II-derived products for ~2129 UTC  4/27/2011, including the following Level III- equivalent plots: reflectivity plots N0R,  N3R and NCR;  storm  relative velocity plot N0S;  VAD profile NVW and the Storm Attribute Table.  The radar side is located due east of the radar echoes and slightly east of the right margin of the plots.

 

1.    Identification (you donÕt need complete sentences here) (5 pts each for a total of 50 points):

a.     Which Volume Control Pattern (VCP) was in use at the times shown for Fig. 1 and Fig. 2? 

b.    How often was the radar information updated for Fig. 1 and Fig. 2?

c.     What was the elevation angle depicted on Fig. 1?

d.    What was the elevation angle depicted on Fig. 2?

e.     What was the maximum echo strength value on Fig. 1?

f.      What is the red circle labeled Q0 on Figs. 2 and 4?

g.     On Fig. 4, the light green pixels (or gates or bins) next to the light red pixels (or gates or bins) indicate a general area of rotation called what?

h.    The label Q0 indicates what?

i.      Figure 5 (NVW) is called what?

j.      ND is indicated for many of the levels shown in in Fig. 5.  What does ND mean?


2.    Short Essay (Answer two of the three) (30 points each for a total of 60 points)

 

a.     Figs. 1, 2 and 3 together indicate the presence of a Bounded Weak Echo Region.  Briefly discuss.

b.    Fig. 4 indicates that the thunderstormÕs updraft was rotating.   Briefly discuss.

c.     The Volume Control Pattern in use by the radar is used as a special strategy during times of intense convection.  This strategy is designed to eliminate accuracy issues with the reflectivity and velocity data. Briefly describe the issue and the basic strategy this VCP uses to address that.




 

 

3.    Short Answer (Answer Both).   (20 points each for a total of 40 points)

a.     The information on the storm relative velocity plot shows that there was 64 knots of inbound velocity and 50 knots of outbound velocity.  Based upon the information in the storm attributes table and mesocyclone recognition guidelines, what was the strength of the mesocyclone? (Please show details of any calculation you did). (20 points)

















b.    The radar makes judgments about future positions of the radar signatures based upon current motion and characteristics of the storm and echoes. What was the direction and speed of the storm and how large was the hail that was associated with it? (20 pts)



 

Figure 1.  KBMX Level III Reflectivity Plot, N0R, 2120 UTC, 4/27/2011

 

Figure 2.  KBMX Level III Reflectivity Plot, N03, 2120 UTC, 4/27/2011

 

Figure 3.  KBMX Level III Reflectivity Plot, NCR, 2120 UTC, 4/27/2011

 

 

Figure 4.  KBMX Level III Storm Relative Velocity Plot, N0S, 2129 UTC, 4/27/2011

 

 

Figure 5.  KBMX Level III Plot, NVW, 2101 UTC, 4/27/2011

 

Figure 6.  KBMX Storm Attributes Table, 2129 UTC, 4/27/2011