SWODY1
SPC AC 121255
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 AM CDT FRI SEP 12 2008
VALID 121300Z - 131200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE WRN AND NRN GULF CST
REGION...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF KS AND MO...
...SYNOPSIS...
HRCN IKE IN THE NWRN GULF OF MEXICO WILL BE THE MAIN SVR WEATHER
MAKER THIS PERIOD AS UPR RIDGE PERSISTS OVER THE TN VLY. TPC
EXPECTS IKE TO CURVE NWWD LATER TODAY...AND THEN TURN MORE NNW AS IT
CROSSES THE UPR TX CST EARLY SATURDAY. IN THE MEANTIME...UPR LOW
NOW OVER UT/WY SHOULD EJECT E/NE INTO WRN NEB/SD AS UPSTREAM NRN
BRANCH IMPULSE NOW OVER BC MOVES SE INTO CNTRL MT.
...WRN/NRN GULF CST...
HRCN IKE WILL REMAIN WELL OFFSHORE TODAY...AND NO LOW LVL BAROCLINIC
ZONE IS APPARENT TO ITS N TO ENHANCE LOW LVL ASCENT/SHEAR.
NEVERTHELESS...THE HRCN'S LARGE/STRONG CIRCULATION WILL MAINTAIN
KINEMATIC FIELD FAVORABLE FOR LOW LVL UPDRAFT ROTATION WELL N ACROSS
PORTIONS OF THE GULF CST REGION TODAY. SATELLITE LOOPS SUGGEST
POTENTIAL FOR CORRIDORS OF MODERATE SFC HEATING ON NRN FRINGE OF
IKE...WHERE PERSISTENT ESELY SFC FLOW WILL ALLOW DEWPOINTS TO RISE
INTO THE MID TO UPR 70S F. COUPLED WITH 50+ KT SSELY 850 MB JET AND
SLOW WNW MOTION OF HRCN...SETUP COULD YIELD MULTIPLE BANDS OF
SEMI-DISCRETE SHOWERS/STORMS WITH OCCASIONAL TORNADOES/WATERSPOUTS
ACROSS FAR SRN MS AND ABOUT THE SRN THIRD OF LA. THIS THREAT LIKELY
WILL SPREAD W/NW INTO SW LA AND SE TX LATER TODAY/TONIGHT.
...KS/MO/IL...
DEEP FRONTAL ZONE WILL REMAIN NEARLY STNRY THIS PERIOD ALONG AN ARC
FROM THE SRN HI PLNS ACROSS NRN KS INTO THE MID MS VLY. A WEAK
IMPULSE WITHIN THIS FEATURE APPEARS TO BE MOVING ENE ACROSS KS/NEB
ATTM...WHILE JET ENTRANCE REGION OF DOWNSTREAM SPEED MAX OVER THE
GRT LKS LIKELY WILL CONTINUE TO ENHANCE ASCENT/UPR DIVERGENCE OVER
MO/IL/IND. MEANWHILE...SINKING MOTION ON OUTER FRINGE OF IKE SHOULD
ALLOW FOR SUBSTANTIAL SFC HEATING S/E OF FRONT OVER PARTS OF
OK/AR/SE KS AND SRN MO.
DIFFERENTIAL HEATING LIKELY WILL LEAD TO DEVELOPMENT OF A WEAK SFC
WAVE LATER TODAY OVER SERN KS. THIS WAVE SHOULD MOVE NE INTO IA
EARLY SATURDAY AS UT/WY UPR IMPULSE EDGES CLOSER TO REGION.
COMBINATION OF ENHANCED LOW LVL WAA WITH WAVE...SFC HEATING...AND
PERSISTENT JET ENTRANCE REGION ASCENT EXPECTED TO SUPPORT
INTENSIFICATION OF EXISTING BAND OF STORMS FROM NRN OK ENE INTO
PARTS OF SE KS AND CNTRL MO. IF HEATING IS SUFFICIENT...SCTD
ADDITIONAL STORMS COULD FORM SE OF THE FRONT FROM NE OK INTO SRN
MO.
MID LVL LAPSE RATES WILL REMAIN WEAK. BUT VERY MOIST...MODERATELY
SHEARED ENVIRONMENT COULD YIELD A FEW SUPERCELLS...AND THESE COULD
PRODUCE A FEW BRIEF/WEAK TORNADOES...SIMILAR TO YESTERDAY'S
SITUATION IN SRN MO.
...SWRN U.S...
UPR LOW OVER NRN BAJA CA WILL BEGIN TO MOVE E ALONG THE
U.S./MEXICAN BORDER TODAY. THIS WILL MAINTAIN STEEP MID LVL LAPSE
RATES OVER REGION...WHILE LOW LVL LAPSE RATES STEEPEN WITH AFTN
HEATING. SFC TEMPERATURES IN THE 90S F SHOULD ONCE AGAIN ALOW
STRONG STORMS TO FORM OVER THE HIGHER TERRAIN...ESPECIALLY IN SE AZ.
A FEW OF THESE MAY PRODUCE GUSTY SFC WINDS GIVEN THE 40-50 F SFC
TEMP/DEW POINT SPREADS.
..CORFIDI/HURLBUT.. 09/12/2008
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