DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0102 AM CDT FRI APR 09 2004 VALID 091200Z - 101200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 60 NW AUS 35 SSE GGG 20 SSW ELD 20 WNW LIT 35 SSW HRO 30 NE MKO 40 S PNC 20 NNE GAG 40 SW GAG 40 N CDS 40 SSW LTS 55 N ABI 35 NNE SJT 40 NNE JCT 60 NW AUS. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 ESE P07 50 NNE P07 MAF 30 SW HOB 30 WNW CNM 20 ESE DMN 30 NNE DUG 50 WNW GBN 10 SSW TRM 15 SSE EDW 30 NNW NID 45 S P38 25 SSE MLF 40 E DPG 30 E BYI 30 NW SUN 45 SSW S80 45 ESE 63S 80 ENE 63S 45 N FCA 50 SSE BIL 30 WSW DGW 15 NNE CYS 30 S AKO 35 NNW GCK 25 SW HUT 15 E SGF 10 ESE PAH 35 SW CKV 25 NW MSL 25 SW CBM 45 NNE HEZ 25 WNW POE 40 WSW GLS. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 60 W MIA 10 NNW VRB. ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF TX/OK INTO WRN AR... ...SYNOPSIS... THE SHORTWAVE TROUGH NOW OVER NM WILL DE-AMPLIFY AND WEAKEN AS IT MOVES EWD THROUGH OK EARLY IN THE PERIOD AND INTO THE MS VALLEY THIS EVENING. A SECONDARY WEAKER SHORTWAVE NOW OVER CNTRL CA WILL WEAKEN AND SHEAR EWD INTO THE SRN PLAINS FRIDAY NIGHT. COLD FRONT OVER THE NRN PLAINS WILL DEVELOP SWD INTO OK AND THE TX PANHANDLE BY EVENING. WEAK SURFACE FRONT CURRENTLY EXTENDS FROM THE SERN STATES WWD THROUGH NRN TX...WHERE IT INTERSECTS AN OUTFLOW BOUNDARY ASSOCIATED WITH ONGOING CONVECTION OVER W TX. CURRENT THINKING IS THAT PRECIPITATION WILL SPREAD EWD ALONG AND N OF THIS FRONT INTO WRN/CNTRL OK AND EXTREME NRN TX AS LOW LEVEL JET VEERS AND ASSOCIATED WARM ADVECTION ZONE SHIFTS EWD. ...OK/TX AREAS... THE FRONT NEAR THE RED RIVER MAY BE REINFORCED BY PRECIPITATION ASSOCIATED WITH MCS AS IT CONTINUES MAINLY THROUGH OK EARLY FRIDAY. THOUGH CLOUDS AND RAIN COOLED AIR MAY IMPEDE NWD PROGRESS OF THE BOUNDARY...IT SHOULD BEGIN TO LIFT NWD INTO AT LEAST SRN OK DURING THE DAY AS WARM ADVECTION PRECIPITATION SHIFTS EWD. MODEST LOW LEVEL MOISTURE CURRENTLY RESIDES OVER MUCH OF TX WITH DEWPOINTS GENERALLY IN THE MID TO UPPER 50S. THIS MOISTURE WILL ADVECT NWD THROUGH TX AND INTO PARTS OF SRN/CNTRL OK DURING THE DAY UNDERNEATH STEEPENING LAPSE RATES WITH MLCAPE FROM 1500 TO 2000 J/KG POSSIBLE. THE SHORTWAVE TROUGH WILL MOVE EAST OF THE AREA EARLY IN THE PERIOD...AND AS THIS OCCURS THE LOW LEVEL FLOW WILL VEER AND WEAKEN DURING THE DAY. MID LEVEL SUBSIDENCE AND WEAKENING/VEERING LOW LEVEL FLOW MAY POSE A LIMITING FACTOR...ESPECIALLY WITH REGARD TO INITIATION ALONG THE DRYLINE THAT IS EXPECTED TO DEVELOP FROM WRN OK THROUGH THE ERN PART OF W TX. THOUGH ISOLATED STORMS MAY STILL BE POSSIBLE ALONG THE DRYLINE GIVEN WEAK CAP...THERE IS A HIGHER CONFIDENCE THAT STORMS WILL REDEVELOP/INTENSIFY FARTHER NE IN WARM ADVECTION ZONE FROM N TX INTO SRN/CNTRL OK. FRONTOGENETIC FORCING WILL INCREASE ACROSS OK DURING THE EVENING AS SURFACE HIGH PRESSURE BUILDS SWD. THE SHARPENING BOUNDARY AND INCREASING SLY LOW LEVEL JET OVERNIGHT WILL ENHANCE LIFT AND SUPPORT CONTINUED DEVELOPMENT OF STORMS...POSSIBLY EVOLVING INTO AN MCS FROM SERN OK INTO THE LOWER MS VALLEY AREA. THOUGH LOW LEVEL FLOW IS EXPECTED TO REMAIN VEERED...SHEAR THROUGH A DEEPER LAYER WILL REMAIN SUFFICIENT TO SUPPORT A THREAT OF ISOLATED SUPERCELLS WITH ANY STORMS DEVELOPING ALONG THE DRYLINE OR IN WARM ADVECTION ZONE FARTHER E. LARGE HAIL WILL BE THE MAIN THREAT...THOUGH ISOLATED DAMAGING WIND WILL ALSO BE POSSIBLE... ESPECIALLY FROM SE OK/NE TX INTO WRN AR AS ACTIVITY EVOLVES INTO AN MCS. THOUGH LOW LEVEL SHEAR WILL NOT BE PARTICULARLY STRONG... AN ISOLATED TORNADO OR TWO MAY BE POSSIBLE...MAINLY WITH ANY STORM DEVELOPING ON OR INTERACTING WITH E-W BOUNDARY THAT MAY PERSIST ACROSS SRN OR CNTRL OK. ..DIAL/TAYLOR.. 04/09/2004