Storm Prediction Center 1300 UTC Day 1 Convective Outlook

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK

DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWBC.

VALID 201300Z - 211200Z

THERE IS A MDT RISK OF SVR TSTMS OVER ERN OK...NERN TX...MUCH OF AR. THE MDT RISK IS TO THE RIGHT OF A LINE FROM 30 ESE TXK 35 E DAL 20 WNW ADM 35 SW TUL 30 N FYV 20 SE UNO JBR 55 WSW MEM 30 S PBF 35 ESE TXK.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 35 N HLC 35 S HSI 10 WNW CNK 20 SSW SLN 40 NE ICT 40 N CNU 15 WSW SZL 30 NNW COU 25 SSE UIN 25 ENE SPI 15 NE HUF 15 W SDF 25 NW BNA 25 WSW TUP 45 S GLH 50 ESE SHV 60 NNE CLL 10 WNW AUS 25 ESE JCT 25 NNE MWL 20 NNE SPS 30 WSW CSM 65 WSW GAG 15 SSE EHA 30 ENE LAA 30 E GLD 35 N HLC.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 85 ENE ELO 35 ENE RHI 15 NE MTW 30 N GRR 25 ESE FNT 80 NNW ERI 15 NE BUF 10 SW BGM 25 E NEL ...CONT... 40 SE JAX 15 SSW CTY ...CONT... 25 ESE 7R4 30 NNW BTR 25 WNW ESF 50 SSW LFK 55 SE AUS 30 ENE COT 30 ESE DRT 15 N JCT 25 NW BWD 55 WSW SPS 25 W CDS 15 SW PVW 15 NE HOB 25 SSE CNM 75 SW GDP ...CONT... 65 SW TUS 40 NNE TUS 40 SSE SOW 35 SSW GUP 20 WSW CEZ 30 W GJT VEL 40 N RKS 40 SSW CPR 35 W SNY 55 N IML 25 E MHN 35 NNW VTN 15 SW PHP 50 NNW PHP 40 NW MBG 30 SSW DVL 60 NNE DVL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSE SRQ 10 SSE MLB.

...SRN PLAINS/LOWER MS VALLEY...

STRONG UPPER SPEED MAX IS DIGGING SEWD ACROSS ID THIS MORNING WITH DOWNSTREAM HEIGHT FALLS SPREADING INTO THE CENTRAL ROCKIES. THIS FEATURE WILL BE RESPONSIBLE FOR KICKING POSITIVE TILT UPPER TROUGH ACROSS THE SRN HIGH PLAINS INTO THE MS VALLEY REGION LATER TONIGHT.

MODELS INSIST UPPER SPEED MAX OVER WEST TX WILL INTENSIFY AND LIFT NEWD ACROSS SERN OK INTO AR BY PEAK HEATING ENHANCING DEEP LAYER SHEAR ACROSS MODERATE RISK REGION.

ONGOING MCS OVER ERN OK IS LIFTING NEWD AT ROUGHLY 30-35 KT AND SHOULD MOVE ACROSS MUCH OF NWRN AR BY LATE MORNING. TRAILING END OF THIS CONVECTIVE COMPLEX WILL NOT AFFECT BOUNDARY LAYER AIR MASS ACROSS SERN OK/SWRN AR/NERN TX...ENSURING MDT-HIGH SFC-BASED INSTABILITY WILL DEVELOP ALONG THE RED RIVER REGION BY EARLY-MID AFTERNOON...CAPE VALUES AOA 3000 J/KG. STRONG DIURNAL HEATING WILL AID IN DRY LINE SURGE ACROSS NWRN TX BY EARLY AFTERNOON WHERE IT SHOULD INTERSECT REINFORCED OUTFLOW BOUNDARY. THIS MAY PROVE TO BE AN INITIATION ZONE FOR SUPERCELLS BY 21Z. LOW LEVEL SHEAR ALONG THE RED RIVER APPEARS FAVORABLE FOR TORNADIC DEVELOPMENT...IN ADDITION TO VERY LARGE HAIL.

DOWNSTREAM...REGENERATION OF MCS IS POSSIBLE OVER CENTRAL AR BY 18Z AS DIURNAL HEATING ALLOWS BOUNDARY LAYER TO DESTABILIZE. THERE APPEARS TO BE SUFFICIENT DEEP LAYER SHEAR OVER THIS REGION TO MAINTAIN NEWD PROPAGATION ACROSS PORTIONS OF SERN MO INTO WRN KY/TN BY EARLY EVENING. LATER TONIGHT...UPSTREAM DEVELOPMENT MAY ORGANIZE INTO MCS OVER EXTREME ERN OK/AR AS LLJ VEERS AND SHIFTS EWD. POTENTIAL TORNADIC SUPERCELLS SHOULD EVOLVE INTO LEWP WITH THREAT OF DAMAGING WINDS.

...CENTRAL TX...

12Z SOUNDINGS FROM SRN PLAINS INDICATE CAP WILL NOT BE PARTICULARLY STRONG TODAY. IT APPEARS DIURNAL HEATING AND CIRCULATION ALONG DRY LINE WILL PROVE SUFFICIENT FOR AT LEAST ISOLATED SUPERCELLS ACROSS PORTIONS OF CENTRAL TX INTO THE EDWARDS PLATEAU. LOW LEVEL SHEAR WILL LIKELY LIMIT SEVERE THREAT TO MAINLY LARGE HAIL.

..DARROW.. 05/20/01

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 1630Z


STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK

Storm Prediction Center 1630 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWBC.

VALID 201630Z - 211200Z

THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER EASTERN OK...EXTREME NORTHEAST TX...EXTREME SOUTHWEST MO...MUCH OF AR...TO THE RIGHT OF A LINE FROM 30 S PRX 40 N FTW OKC TUL UMN UNO JBR 55 WSW MEM PBF TXK 30 S PRX.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM MCK 35 S EAR SLN 40 NE ICT CNU SZL UIN BMI DNV 10 S SDF BNA TUP MLU GGG ACT 40 W AUS JCT 45 W MWL 45 NE CSM GAG DHT TAD COS GLD MCK.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 7R4 40 SE ESF 25 WNW ESF LFK CLL COT DRT SJT ABI 55 WSW SPS CDS PVW HOB 75 SW GDP ...CONT... 65 SW TUS SAD ABQ ALS ASE CAG RWL BFF LBF ANW PHP 4BQ 70 NNE BIL 75 ESE HVR 65 ENE HVR ...CONT... 35 ENE ELO EAU VOK 10 SSE MKG FNT JHW IPT ACY ...CONT... 40 SE JAX 15 SSW CTY.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM FMY VRB.

...OK/TX/MO/AR... WATER VAPOR IMAGERY SHOWS UPPER TROUGH EXTENDING FROM CENTRAL PLAINS INTO NORTHERN MEXICO...WITH LEAD SHORTWAVE TROUGH OVER EASTERN OK/AR. INCREASING MID LEVEL WINDS BEHIND THIS FEATURE...AS WELL AS APPROACH OF UPPER TROUGH NOW OVER WESTERN KS/TX PANHANDLE MAY RESULT IN A SIGNIFICANT SEVERE WEATHER EPISODE THIS AFTERNOON AND TONIGHT OVER PARTS OF OK/AR.

LATEST VAD/PROFILER DATA OVER OK/TX VERIFY THAT MID LEVEL WESTERLY WINDS HAVE INCREASED TO OVER 40 KNOTS NEAR THE RED RIVER. THESE WINDS ARE FORECAST TO CONTINUE TO INCREASE THROUGH THE DAY...WITH BAND OF 50-60 KNOT FLOW EXPECTED BY LATE AFTERNOON FROM SPS-MKO. SOUTHERLY LOW LEVEL WINDS ARE ALSO EXPECTED TO INCREASE THROUGH THE AFTERNOON PROVIDING VERY FAVORABLE LOW LEVEL AND DEEP LAYER SHEAR PROFILES FOR SUPERCELL THUNDERSTORMS.

DECAYING MCS CURRENTLY OVER WESTERN AR WILL TRACK EASTWARD ACROSS NORTHERN AR/SOUTHERN MO THROUGH THE EARLY AFTERNOON. CLOUD COVER AHEAD OF SYSTEM WILL LIMIT DESTABILIZATION. HOWEVER...MESOSCALE ORGANIZATION OF FEATURE MAY SUPPORT ISOLATED DAMAGING WINDS AND LARGE HAIL.

BEHIND THIS SYSTEM...SURFACE OUTFLOW BOUNDARY FROM MORNING CONVECTION EXTENDS FROM NORTH OF TXK-SOUTH OF ADM-LAW. THIS BOUNDARY SHOULD LIFT SLOWLY NORTHWARD DURING THE DAY WITH RAPID DESTABILIZATION ACROSS OK. SURFACE DEWPOINTS IN THE LOW 70S AND MODERATELY STEEP LAPSE RATES WILL RESULT IN AFTERNOON SBCAPE VALUES OF 3000-4000 J/KG.

PRESENT INDICATIONS ARE THAT SCATTERED THUNDERSTORMS WILL INITIATE NEAR OLD OUTFLOW BOUNDARY/SURFACE DRYLINE OVER CENTRAL/EASTERN OK OR EXTREME NORTHEAST TX THIS AFTERNOON AND TRACK EAST-NORTHEASTWARD INTO WESTERN AR THIS EVENING. STRONG UVVS ASSOCIATED WITH APPROACHING UPPER TROUGH...HIGH CAPE VALUES...AND SUFFICIENT/INCREASING VERTICAL SHEAR SUGGEST THE THREAT OF SUPERCELLS PRODUCING STRONG TORNADOES...LARGE HAIL...AND DAMAGING WINDS OVER THE MODERATE RISK AREA. WIDESPREAD NATURE OF STORMS WILL LIKELY LEAD TO FORWARD PROPAGATING MCS OVERNIGHT...POSING THREAT OF DAMAGING WINDS AND HAIL ACROSS MUCH OF AR.

RELATIVELY WEAK CAPPING INVERSION AND STRONG DAYTIME HEATING MAY ALSO BE SUFFICIENT FOR ISOLATED SEVERE STORMS EXTENDING SOUTHWARD ALONG DRYLINE INTO CENTRAL TX LATE THIS AFTERNOON/EVENING. LARGE HAIL SHOULD BE THE MAIN THREAT WITH THESE STORMS.

...CO/KS... STRONG SURFACE COLD FRONT IS FORECAST TO SURGE SOUTHWARD ALONG FRONT RANGE OF ROCKIES INTO WESTERN KS/EASTERN CO BY AFTERNOON. MODERATE INSTABILITY AND STEEP LAPSE RATES IN THIS AREA WILL AID IN THE DEVELOPMENT OF SCATTERED THUNDERSTORMS CAPABLE OF LARGE HAIL AND DAMAGING WINDS. ACTIVITY MAY SPREAD AS FAR SOUTHEAST AS NORTHWEST OK BEFORE WEAKENING.

...GA/SC... AIRMASS OVER GA/SC REMAINS QUITE MOIST/UNSTABLE TODAY. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE AFTERNOON...WITH SBCAPE VALUES RANGING FROM 2500-3000 J/KG. LOW/MID LEVEL WINDS ARE RATHER WEAK AND MID LEVEL TEMPERATURES ARE RATHER WARM. HOWEVER...POTENTIAL EXISTS FOR PULSE SEVERE STORMS PRODUCING WET MICROBURSTS OR HAIL.

..HART.. 05/20/01


Return to May 20, 2001 chase report

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 2000Z