DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 171652
SWODY2
SPC AC 171651

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1051 AM CST THU FEB 17 2011

VALID 181200Z - 191200Z

...NO SVR TSTM AREAS FORECAST...

...SRN CA COAST...

LATEST SHORT RANGE MODEL GUIDANCE SUGGEST A STRONG MID LEVEL SPEED
MAX WILL ADVECT ACROSS THE NRN BAJA PENINSULA LATE IN THE PERIOD
ENSURING A FOCUSED ZONE OF ASCENT OVERSPREADS SRN CA WITHIN THE EXIT
REGION. LAPSE RATES WILL STEEPEN CONSIDERABLY ACROSS THE L.A. BASIN
WITH FORECAST SOUNDINGS EXHIBITING SUFFICIENT INSTABILITY FOR
NEAR-SFC BASED CONVECTION ALONG ADVANCING COLD FRONT. IN
FACT...DEEP LAYER SHEAR IS MORE THAN ADEQUATE FOR SUSTAINING
ROTATING UPDRAFTS AS SFC-6KM VALUES...ROUGHLY THE CLOUD BEARING
LAYER...IS EXPECTED TO BE ON THE ORDER OF 60KT. IT APPEARS
CONVECTION WILL EVOLVE AROUND 03Z-06Z TIME FRAME BEFORE SPREADING
INLAND WHERE THE LACK OF MARINE BOUNDARY LAYER WILL LIMIT UPDRAFT
INTENSITY. AT THIS TIME WILL NOT INTRODUCE SEVERE PROBS TO SRN CA
COAST...HOWEVER THERE IS AN OUTSIDE CHANCE THAT AN ISOLATED
SUPERCELL COULD DEVELOP ALONG ADVANCING FRONTAL ZONE. THIS REGION
WILL BE MONITORED FOR POSSIBLE UPGRADE IN LATER OUTLOOKS.

DOWNSTREAM ACROSS THE SRN ROCKIES...STEEP LAPSE RATES MAY ENHANCE
THE PROSPECT FOR WEAK CONVECTION ACROSS ERN AZ INTO CNTRL NM.
ALTHOUGH AN ISOLATED LIGHTNING STRIKE MAY BE OBSERVED ACROSS THIS
REGION IT APPEARS ACTIVITY WILL BE TOO SPARSE TO WARRANT A THUNDER
FORECAST.

..SRN MO/NRN AR...

SUBSTANTIAL BOUNDARY LAYER MOISTENING HAS OCCURRED ACROSS THE SRN
PLAINS/LOWER-MID MS VALLEY REGION WHERE SFC DEW POINTS HAVE RISEN
INTO THE 50S. FURTHER ADVECTIVE PROCESSES WILL CONTRIBUTE TO
GRADUAL DESTABILIZATION ACROSS SRN MO/NRN AR WITHIN AN OTHERWISE
NON-DESCRIPT ENVIRONMENT FOR CONVECTIVE DEVELOPMENT. LATEST
FORECAST SOUNDINGS FROM THE NAM SUGGEST ANY PARCELS LIFTED NEAR
850MB ACROSS THIS REGION WILL BE WEAKLY INHIBITED WITH MUCAPE IN
EXCESS OF 400 J/KG POSSIBLE. IF SUFFICIENT ASCENT CAN INSTIGATE AN
UPDRAFT ACROSS THIS REGION NEAR 12Z THEN A FEW THUNDERSTORMS COULD
EVOLVE.

..DARROW.. 02/17/2011

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