DEPARTMENT OF GEOSCIENCES                                     Spring 2009

San Francisco State University                                               Metr. 201

 

Synoptic Metr Quiz #3

100 pts.

(Test will be collected at 9AM)

 

1.    Definitions.  Choose two of the terms below.  Provide a one sentence definition (if the term is an abbreviation, first “unabbreviate” it and then define it).  (5 points each for a total of 10 points in this section).

 

(a) Dry line

 

 

 

(b) Newton’s Second Law of Motion

 

 

 

(c) CCL

 

 

 

(e) Radar echo

 

 

 

(f)  Visible image

 

 

 

2.  Units.  Provide the units (metric) used conventionally for the following (8 pts)

        

         horizontal winds    meters per sec or m s-1 (or km h-1)    

 

        

         Coriolis acceleration                 __________________________________

 

         lifted index                              __________________________________

 

         Ĺ                                          __________________________________

 

         Convective Temperature           __________________________________

 

 

 

Part C.  Use and Interpretation of Weather Maps  (Multiple Choice and Short Answer)

 

Figure1 is the surface chart for 2100 UTC 23 April 2008.  Note the pressure systems at A and B and the frontal linesat locations a, b and c. On Fig. 1, Line b isprobably

 

      a.          an OccludedFront

 

      b.          a Stationary Front

 

      c.          a Cold Front

 

d.           a Warm Front

 

      e.          a Dry Line

 

2. On Fig. 1, Line a is probably a

 

      a.          an OccludedFront

 

      b.          a Stationary Front

 

      c.          a Cold Front

 

 d.          a Warm Front

 

      e.          a Dry Line

 

 

 

3.       Figure 2 is a chart of CAPE and CIN for 2100 UTC 23 April 2008.  Note the locations A  and B, where the CAPE values are 2500 and 3000 J/kg, respectively.   The blue areas represent areas of CIN.  Assume thunderstorms develop at both locations. At which location will the thunderstorm's updrafts be stronger and why?

 

 

 

 

 

 

 

 

 

4.   The blue areas on Fig. 2 represent areas of CIN.  These correspond to

 

      a.          Regions where the tendency forconvection is encouraged.  Ifvalues are large, thunderstorms will likely be severe.

 

      b.          Tornadoes are likely to occur.

 

      c.          Severe thunderstorms are likely tooccur.

 

      d.          Regions where surface air parcels are stable,but if such parcels are force lifted, eventually they will be unstable (inother words, there is CAPE, but forced lifting is needed to get the air parcelsto an elevation at which they will we warmer than the air surrounding them atthe same elevation)

 

      e.   Strong straight-line winds are likely tooccur.

 

5.       Figure 2 is a chart of CAPE and CINfor 2100 UTC 23 April 2008.  Notethe locations A and B, where the CAPE values are 2500 and 3000 J/kg, respectively.   The blue areas represent areas of CIN.  At which location are thunderstorms likely to develop in the short term and why?

 

 

 

 

 

 


 

6.  Figure 3 is a chart of surface dew point temperatures and isobars for 2100 UTC23 April 2008.  One can use thischart to

 

      a.   find fronts.

 

      b.   locate areas of fog formation.

 

      c.   determine the position of the jetstream.

 

      d.  findareas of high relative humidity.

 

      e.   locate the Dry Line.

 

 

 

7. Figure 4 is the Radar reflectivity, 2108 UTC 23 April 2008, Roughly Centered at Location A from Fig 2. Two thunderstorms are shown on the diagram.  Both of them provide examples of theradar signature of rotation in thunderstorm updrafts. This signature is called

 

      a.   horizontal wind shear.

 

      b.   vertical wind shear.

 

      c.   the mammatus formation.

 

      d.  a hook echo.

 

      e.   an outflow boundary.

 

8.    Figure 5 is the Probabilistic Hail Outlook for 23 April 2008.  The outlook basically shows

a.   the chances that rain will also have hail mixed with it.

b.   the probabilities that severe storms will occur.
  c.   the probabilities that hail ¾” or larger will be observed within 25 miles of a given location.
  d.   the probabilities that hail will occur at a given location.
  e.   None of the above.


9.   Figure 6 is the Convective Outlook for April 23.  The outer arrow (normally colored brown or orange) encompasses
    a.   the region that has a 10% probability that  strong and violent tornadoes will be observed within 25 miles of a given location.
  b.  the portion of the United States expected to experience general thunderstorms.
  c.   the portion of the United States expected to experience tornadoes.
  d.   the region in which severe downbursts are sure to occur.
  e.   the portion of the United States expected to have a high risk for severe   thunderstorms.


10.   The inner arrow (normally colored yellow or red) on Fig. 6 encompasses
a.   the region that has a 10% probability that  strong and violent tornadoes will be observed within 25 miles  of a given location.
b.   the portion of the United States expected to experience general thunderstorms.
c.   the portion of the United States expected to experience tornadoes.
d.   the region in which severe downbursts are sure to occur.
 e.   the portion of the United States expected to have a moderate risk for severe thunderstorms.

 

 

 

 

 

 

 

 

map

 

 

 

Figure 1:  Surface Chart, 2100 UTC 23 April 2008  

 

 

 

ap

 

 

 

Figure 2: Chart of CAPE/CIN , 2100 UTC 23 April 2008

 

 

 

 

 

  ap

 

Figure 3: Chart of dew point temperature and surface pressure, 2100 UTC 23April 2008

 

 

 

 

 

 

 

 

 

Figure 4: Radar reflectivity, 2108 UTC 23 April2008, Roughly Centered at Location A from Fig 2

 

 

 

 

 

 

Figure 5. Hail  Outlook for 23 April2008

 

 

 

 

Figure 6.  Convective Outlook for 23 April 2008