805  
ACUS01 KWNS 070542  
SWODY1  
SPC AC 070540  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1140 PM CST FRI DEC 06 2019  
 
VALID 071200Z - 081200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
NORTHERN CALIFORNIA...  
   
..SUMMARY
 
 
A FEW STRONG THUNDERSTORMS ARE POSSIBLE ACROSS PORTIONS OF NORTHERN  
CALIFORNIA SATURDAY AFTERNOON.  
   
..NORTHERN CA
 
 
UPPER TROUGH OFF THE PACIFIC COAST IS FORECAST TO SHIFT EAST DURING  
THE DAY1 PERIOD. AS A RESULT, 500MB SPEED MAX WILL TRANSLATE INTO  
NORTHERN CA BY 08/00Z WHICH SHOULD ENCOURAGE SURFACE CONFLUENCE ZONE  
ACROSS THE SACRAMENTO VALLEY DURING THE AFTERNOON. WHILE THE PRIMARY  
SURFACE FRONT SHOULD HOLD OFFSHORE THROUGH SUNSET, SOME INSTABILITY  
IS EXPECTED TO MATERIALIZE ACROSS THE SACRAMENTO VALLEY DUE TO WEAK  
BOUNDARY-LAYER HEATING. LATEST RAP GUIDANCE IS MORE BUOYANT THAN THE  
NAM ACROSS THIS REGION WITH FORECAST INSTABILITY THAT COULD ALLOW A  
FEW ROBUST UPDRAFTS. RAP 23Z FORECAST SOUNDING AT BAB EXHIBITS 800+  
J/KG SBCAPE WITH DEEP-LAYER SHEAR SUPPORTIVE OF ROTATING UPDRAFTS;  
ALTHOUGH, NAM DISPLAYS CONSIDERABLY LESS INSTABILITY. IF SURFACE  
TEMPERATURES CAN WARM INTO THE UPPER 50S/NEAR 60F, CONVECTION THAT  
DEVELOPS NORTH OF THE 500MB JET WILL HAVE A TENDENCY TO ROTATE. AS A  
RESULT, A FEW WEAK SUPERCELLS MAY ULTIMATELY EVOLVE WHICH WOULD POSE  
A RISK OF PRODUCING A BRIEF WEAK TORNADO.  
 
..DARROW/SQUITIERI.. 12/07/2019  
 

 
 
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