Saturday, October 4, 2008

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 040549
SWODY2
SPC AC 040546

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1246 AM CDT SAT OCT 04 2008

VALID 051200Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE SRN HIGH PLAINS...

...SYNOPSIS...

BROAD UPPER TROUGH CURRENTLY MOVING INTO THE WRN U.S. WILL CONTINUE
TO AMPLIFY SEWD...BEFORE ADVANCING INTO THE HIGH PLAINS BY SUNDAY. A
STRONG UPPER JET WILL ROTATE THROUGH THE WRN AND SRN PART OF THE
UPPER TROUGH...REACHING THE SRN HIGH PLAINS SATURDAY. A LEE TROUGH
WILL PERSIST ACROSS THE CNTRL AND SRN HIGH PLAINS BEFORE BEING
OVERTAKEN BY A COLD FRONT SUNDAY NIGHT.

...SRN HIGH PLAINS AREA...

ENELY TRAJECTORIES ALONG SRN PERIPHERY OF ERN U.S. SURFACE RIDGE HAS
LIMITED BOUNDARY LAYER MODIFICATION ALONG THE NRN GULF. FRIDAY
EVENING RAOBS INDICATED MODEST BOUNDARY LAYER MOISTURE WITH LOW 60S
DEWPOINTS OVER S TX. STRONG SLY GRADIENT FLOW EAST OF LEE TROUGH
WILL CONTRIBUTE TO NWD ADVECTION OF MODIFIED CP AIR THROUGH SRN
PLAINS WARM SECTOR WITH DEWPOINTS GENERALLY IN THE MID TO UPPER 50S.


CURRENT INDICATIONS ARE THAT CONVECTION MAY START EARLY SUNDAY FROM
NM THROUGH NRN PARTS OF W TX WITHIN REGION OF LIFT ASSOCIATED WITH
APPROACHING UPPER JET EXIT REGION. MODEST BOUNDARY LAYER MOISTURE
AND EXPECTED AREAS OF CLOUDS AND ONGOING PRECIPITATION WILL LIKELY
MITIGATE DESTABILIZATION POTENTIAL AND SERVE AS A LIMITING FACTOR
FOR A MORE ROBUST SEVERE THREAT. HOWEVER...SOME BREAKS MAY DEVELOP
OVER CNTRL AND SRN PARTS OF WRN TX AND CLOUDS MAY MIX FROM THE SW AS
THE BOUNDARY LAYER FLOW VEERS TO SWLY WEST OF TROUGH AXIS. STEEPER
MID LEVEL LAPSE RATES AND COOLER TEMPERATURES ALOFT ARE EXPECTED TO
SPREAD OVER MOIST AXIS LATER IN THE DAY...AND THIS WILL CONTRIBUTE
TO AT LEAST MARGINAL INSTABILITY WITH MLCAPE NEAR 500 J/KG POSSIBLE.


POTENTIAL WILL EXIST FOR STORMS TO INTENSIFY DURING THE DAY OVER WRN
TX AS THE ATMOSPHERE GRADUALLY DESTABILIZES. THE AGEOSTROPHIC
CIRCULATION WITHIN UPPER JET EXIT REGION WILL LIKELY MAINTAIN A
30-40 KT SLY LOW LEVEL JET OVER THE SRN AND CNTRL PLAINS. COUPLED
JET STRUCTURE WILL RESULT IN VERTICAL SHEAR PROFILES SUFFICIENT FOR
ORGANIZED STORMS. SEVERE THREAT SHOULD DIMINISH OVERNIGHT AS STORMS
CONSOLIDATE INTO AN MCS AND CONTINUE EAST THROUGH N TX AND OK.

..DIAL.. 10/04/2008

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