DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1119 AM CDT TUE MAY 11 2004 VALID 111630Z - 121200Z THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 35 S HLC 45 N GCK 30 SSW GLD 40 NNW IML 50 ENE CDR 45 NE RAP 35 S Y22 40 E Y22 50 NW ABR 65 S FAR 45 ENE ATY 25 SE BKX 15 SSE GRI 35 S HLC. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 20 NNW CMX 30 SSW MCW 30 SE LNK 45 N P28 60 NW ABI 35 NNW BGS 45 WSW LBB 40 ESE LAA 35 SE SNY 30 W CDR 40 WSW REJ 45 SSW DIK 60 NNE DVL. THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 SSE ALI 20 SE COT 15 WNW SAT 60 WSW TPL 35 WNW ACT 50 ENE ACT 40 WNW LFK 15 SSE BPT. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 NNE 63S 30 E GEG 15 W MSO 35 WNW 3HT 70 NNE BIL 60 NNE GGW ...CONT... 80 SSE MRF 30 SW AKO 45 E FCL 35 NNW 4FC 35 NE GJT 30 E MLF 45 NNW TPH 20 WNW NFL 20 W BNO 30 ENE BLI. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSW WAL 45 W ORF 35 ENE FLO 25 ENE CRE. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 NNW BUF 20 W ALB 25 S PSM. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 SSE JAX 25 SSE SRQ. ...THERE IS A MDT RISK OF SVR TSTMS MUCH OF SD SWD THRU NEB INTO NWRN KS... ...THERE IS A SLGT RISK OF SVR TSTMS REMAINDER OF HIGH PLAINS NEWD INTO UPPER MS VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS CENTRAL AND SRN TX... ...SYNOPSIS... VIGOROUS UPPER TROUGH WRN U.S. WITH STRONG HEIGHT FALLS MOVING EWD ACROSS INTERMOUNTAIN REGION AT 12Z. ASSOCIATED STRONG SURFACE LOW MOVING INTO WRN SD ATTM WITH SHARP COLD FRONT EXTENDING SWWD THRU SERN WY INTO SERN UT. PRONOUNCED WARM FRONT EXTENDS EWD FROM SURFACE LOW ALONG ND/SD BORDER ACROSS CENTRAL MN AND THEN ESEWD THRU SRN LOWER MI. 50-60 KT SLY LOW LEVEL JET IS RAPIDLY INCREASING MOISTURE NWD THRU PLAINS WITH LOW/MID 60 DEWPOINTS COMMON IN WARM SECTOR NWD TO WARM FRONT. WEAK SRN BRANCH S/WV TROUGH MOVING ACROSS S TX WHERE THERE IS A VERY MOIST/UNSTABLE SLY FLOW WEAKLY CAPPED AIR MASS TX COASTAL PLAINS. ...CENTRAL/NRN PLAINS... CURRENT MODEL RUNS ALL SUGGEST THAT THE SURFACE LOW MOVING INTO WRN SD WILL EVOLVE INTO AN ELONGATED LOW WITH A SECONDARY CENTER BY LATE THIS AFTERNOON NERN CORNER CO. RESULT WILL BE A SHARP N/S DRY LINE FROM LOW IN WRN SD SWD TO ALONG CO/KS BORDER WITH AIRMASS E OF DRY LINE BECOMING VERY UNSTABLE. MLCAPES OF 2000-3000 J/KG WILL BE COMMON IN MUCH OF THE WARM SECTOR E OF DRY LINE. AS THE HEIGHT FALLS ROTATE INTO HIGH PLAINS LATE THIS AFTERNOON...CURRENT CAP WILL WEAKEN TO ALLOW RAPID DEVELOPMENT OF SEVERE THUNDERSTORMS ALONG AND JUST E OF DRY LINE AS WELL AS CONVERGENCE VICINITY OF E/W WARM FRONT. DEEP LAYER SHEAR EXPECTED TO IMPROVE CONSIDERABLY BY THIS EVENING ACROSS THE DRY LINE AS STRONGER MID LEVEL JET DEVELOPS INTO HIGH PLAINS ALONG WITH THE DIURNAL INCREASE IN LOW LEVEL JET. SHEAR AND INSTABILITY WILL SUPPORT SUPERCELLS WITH THE LARGE HAIL POTENTIAL BEING DOMINANT INITIALLY. HOWEVER AS THE SHEAR INCREASES BY THIS EVENING TORNADIC SUPERCELLS WILL BECOME MORE LIKELY ALONG WITH THE DAMAGING WINDS IN DOWNBURSTS. THERE IS THE POTENTIAL OF A STRONG TORNADO THIS EVENING IN THE MDT RISK AREA AS FAVORABLE SHEAR DEVELOPS. THERE WILL BE POTENTIAL FOR AT LEAST ISOLATED SUPERCELLS SWD VICINITY DRY LINE INTO TX PANHANDLE WHERE THE SHEAR WILL BE WEAKER BUT AIR MASS STILL VERY UNSTABLE. A SEVERE MCS IS LIKELY TO PROPAGATE EWD AFTER DARK VICINITY WARM FRONT AS S/WV TROUGH ROTATES NEWD INTO PLAINS. ...TX... REF WW 183 AND MCD 648 THE VERY MOIST AND UNSTABLE SLY FLOW IN TX IS WEAKLY CAPPED. WITH ONGOING STORMS AND 30 KT LOW LEVEL JET SUFFICIENT SHEAR IS AVAILABLE FOR SUPERCELLS AND ISOLATED TORNADOS. THIS WILL BE IN ADDITION TO DAMAGING WIND THREAT WITH BOWS/SHORT LINES SUCH AS THE CURRENT BOW MOVING EWD TOWARD THE COAST N OF CRP. ...OH VALLEY EWD TO DELMARVA NJ... REF MCD 649 AGAIN TODAY A WEAKLY CAPPED AND MODERATELY UNSTABLE AIRMASS COVERS THIS REGION TO S OF COLD FRONT CURRENTLY LOCATED FROM WRN MA WWD ALONG NY/PA BORDER TO NEAR CHI. PRIMARY CONVECTIVE MODE WILL BE PULSE SEVERE WITH SUFFICIENT MLCAPE...RANGING UPWARDS TO 2000 J/KG... ALONG WITH LAPSE RATES AROUND 7C/KM FOR A MARGINAL HAIL AND DOWNBURST THREAT. ..HALES/BANACOS.. 05/11/2004