High Latitude Type Storm Passage

1. Examine the progression and evolution of the WRF-NAM forecast soundings and hodographs for KSFO for the next 48 hours.

http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=NAM&STATIONID=KSFO

(a) What UTC time will the frontal cloud band be at KSFO?

(b) Fill in the following table.

  Mixing ratio value (g/kg Most unstable parcel CAPE (Best CAPE) (J/kg) CIN (J/kg) Lifted Index (deg K) Wind Backing or Veering 500 mb Temp (C) Sfc Temp (C) Freezing Level (mb), (ft use scale on left of sounding) 1000-500 mb Thickness (m)
Now (12 UTC)                  
Frontal Passage                  
6 h Post Frontal                  
12 h Post Frontal                  
                   

 

2. Discuss how the values above correspond to those characteristics of the High Latitude Type Storm mentioned in the handout.

3. How valuable was the Lifted Index in assessing the risk of thunderstorms?

4. Does nam_thick generally corroborate your findings of frontal passage?