SWODY1
SPC AC 011253
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0653 AM CST SUN FEB 01 2009
VALID 011300Z - 021200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
NRN BRANCH OF EXISTING SPLIT FLOW PATTERN WILL AMPLIFY THIS PERIOD
AS JET STREAK NOW OVER AB/MT CONTINUES SE INTO THE NRN PLNS/UPR MS
VLY. IN THE SRN STREAM...A SERIES OF WEAK IMPULSES WILL CONTINUE
GENERALLY E FROM NRN MEXICO ACROSS THE WRN/NRN GULF CST.
AT LWR LEVELS...COLD FRONT ASSOCIATED WITH NRN STREAM TROUGH WILL
SURGE S ACROSS THE SRN HI PLNS...AND MOVE SOMEWHAT MORE SLOWLY SE
ACROSS THE OZARKS/MID MS VLY. BY EARLY EVENING THE BOUNDARY SHOULD
EXTEND FROM THE LWR GRT LKS THROUGH CNTRL AR AND NE TX TO THE TX BIG
BEND. THE FRONT WILL CONTINUE SE INTO THE NWRN GULF OF MEXICO
OVERNIGHT AS A WEAKLY-ORGANIZED SFC LOW EVOLVES S OF LA.
...E TX TO LWR MS VLY...
MODEST /20-30 KT/ SWLY LLJ WILL GRADUALLY DEVELOP NEWD AWAY FROM E
TX AND THE LWR MS VLY TODAY IN RESPONSE TO STRONGER HEIGHT FALLS
OVER THE MID MS/OH VLYS. PERSISTENT SLY/SWLY FLOW WILL NEVERTHELESS
SUPPORT A GRADUAL INCREASE IN BOUNDARY LAYER MOISTURE...WITH
DEWPOINTS INCREASING INTO THE LOW TO MID 50S. THIS
MOISTURE...COUPLED WITH DAYTIME HEATING AND 7 DEG C PER KM MID LVL
LAPSE RATES ON N SIDE SRN STREAM JET WILL YIELD A WEAKLY UNSTABLE
AIR MASS...WITH OVERLAND MLCAPE GENERALLY AOB 500 J/KG.
SHOWERS AND TSTMS ARE EXPECTED TO SLOWLY INCREASE IN COVERAGE
TODAY OVER THE NWRN GULF...INVOF DEVELOPING SFC WAVE. SOME OF THIS
ACTIVITY MAY EXPAND NW INTO THE UPR TX GULF CSTL PLN...AND N INTO
SW/SRN LA. 30+ KT DEEP WLY SHEAR WITH MODEST LOW-LVL HODOGRAPH
CURVATURE SUGGEST POTENTIAL FOR MULTICELL OR MARGINAL SUPERCELL
STRUCTURES...GIVEN A SUSTAINED UPDRAFT. ALTHOUGH A LOW PROBABILITY
WILL EXIST FOR LOCALLY SVR WIND/HAIL AND POSSIBLY A BRIEF
TORNADO...WEAK INSTABILITY/LOW LVL CONVERGENCE WILL LIMIT
STRENGTH/DURATION OF ANY SUCH THREAT.
FARTHER NW...OTHER TSTMS EXPECTED TO FORM ALONG COLD FRONT LATE THIS
AFTN INTO TONIGHT FROM E CNTRL/NE TX INTO SRN AR/NRN LA. THESE
STORMS MAY EVOLVE INTO A SMALL MCS ALONG THE SE-MOVING FRONT...AND
MAY YIELD A SPOT OR TWO OF HAIL AND/OR LOCALLY STRONG WINDS.
..CORFIDI.. 02/01/2009
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