SPC AC 021618
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1018 AM CST MON MAR 02 2009
VALID 021630Z - 031200Z
...NO SVR TSTM AREAS FORECAST...
DEEP TROUGH WILL REMAIN OFF THE W COAST...HOWEVER A SIGNIFICANT JET
MAX AND S/WV TROUGH ROTATES NEWD ACROSS NRN CA/OR LATER THIS
AFTERNOON INTO NRN INTERMOUNTAIN REGION TONIGHT. MOIST ONSHORE SWLY
FLOW WILL PERSIST CENTRAL/NRN CA WITH INCREASING MID/UPPER LEVEL
MOISTURE NEWD TO NRN ROCKIES.
AS IMPULSE MOVES ONSHORE NRN CA/OR LATER THIS AFTERNOON IT WILL BE
ACCOMPANIED BY MID LEVEL COOLING AND SOME INCREASE IN INSTABILITY.
WITH LAPSE RATES GENERALLY GREATER THAN 7C/KM...COUPLED WITH THE
IMPRESSIVE WIND PROFILES...THERE WILL BE POTENTIAL FOR A FEW STRONG
THUNDERSTORMS DEVELOPING LATER THIS AFTERNOON AHEAD OF THE UPPER
WIND MAX.
...ERN OR/SWRN ID/NRN NV...
THE STRENGTH OF THE CONVECTION WILL BE HIGHLY DEPENDENT ON AMOUNT OF
SURFACE HEATING THAT OCCURS. OF THE TWO AREAS INDICATED FOR A LOW
PROBABILITY OF SEVERE IN PREVIOUS DY1...E OF ORE CASCADES INTO SWRN
ID/NRN NV WOULD SEEM TO HAVE BEST CHANCE AS SOME HEATING APPEARS
LIKELY IN THE LEE OF SIERRAS AND CASCADES. WHILE MLCAPES NO HIGHER
THAN 300 J/KG CAN BE EXPECTED...EVEN WITH SOME HEATING...THE VERY
STRONG DEEP LAYER SHEAR FROM 70-80KT COUPLED WITH STEEP LAPSE RATES
DOES RAISE SOME CONCERN FOR ROTATING LOW TOPPED THUNDERSTORMS. WILL
CONTINUE A THREAT FOR ISOLATED SEVERE INCLUDING HAIL AND WIND GUSTS
DEVELOPING BY LATER THIS AFTERNOON ERN OR/NWRN NV...SHIFTING EWD
INTO SWRN ID.
...SACRAMENTO VALLEY...
ALTHOUGH AIR MASS WILL REMAIN MOIST AND STRONGLY SHEARED IN THIS
AREA...CHANCES OF SUFFICIENT SURFACE HEATING TO DEVELOP ANY MORE
THAN VERY WEAK INSTABILITY WILL BE THE LIMITING PARAMETER FOR UP
DRAFTS STRONG ENOUGH FOR A SEVERE THREAT. WILL CONTINUE A LOW
PROBABILITY OF A LOW TOPPED SUPERCELL DEVELOPING GIVEN THE STRONG
SHEAR AND MID LEVEL LAPSE RATES THAT WILL RESIDE ACROSS THE
SACRAMENTO VALLEY THRU THE FORECAST PERIOD.
..HALES/HURLBUT.. 03/02/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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