May 22, 2005 1300 UTC Day 1 Convective Outlook Updated: Sun May 22 12:46:11 UTC 2005
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SPC AC 221242 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0742 AM CDT SUN MAY 22 2005 VALID 221300Z - 231200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 70 WNW ANJ PLN DTW CMH HTS JKL LOZ BNA MEM HOT 40 S MLC FSI CSM GAG P28 25 NNW JLN TBN BLV MTO LAF SBN MKG MQT. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 S SAV 40 SSE CSG 45 NW JAN 40 NNW MWL 15 N BGS INK 65 SSW MRF ...CONT... 20 NW ELP 15 SW 4CR 10 N ABQ 30 SSE GUC 25 WSW 4FC 40 SW LAR 15 NE DGW 50 WNW CDR 25 SW CDR 25 NNW SNY 10 NW GLD 55 NW GCK 15 ESE SLN 25 ENE SZL 45 WNW STL 20 W SPI 25 E PIA 10 WSW JVL 30 NNE RHI 40 W CMX 80 NNW CMX ...CONT... 50 ESE MTC 15 SW CAK 45 E LYH 10 E ORF. GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM SRQ 30 S AGR MIA. ...THERE IS A SLGT RISK OF SVR TSTMS FROM MI AND THE LWR OH VLY SW INTO THE OZARKS/SRN PLNS... ...SYNOPSIS... POTENT UPPER IMPULSE WHICH CRESTED SWRN STATES RIDGE YESTERDAY IS NOW CENTERED NEAR INL. SYSTEM HAS LIKELY REACHED MAXIMUM INTENSITY AND SHOULD DEAMPLIFY AS IT SHEARS SE ACROSS THE WI LATER TODAY IN RESPONSE TO CONTINUING PRESENCE OF NRN QUEBEC BLOCK. FARTHER W... STRONG UPSTREAM SYSTEM NOW NEARING VANCOUVER ISLAND SHOULD CONTINUE E INTO AB/SASK...SERVING TO FURTHER FLATTEN SWRN RIDGE. AT LWR LEVELS...COLD/OCCLUDED FRONT NOW CROSSING THE UPR GRT LKS SHOULD WEAKEN AS IT CONTINUES SE ACROSS THE OH VLY. SWRN PART OF SAME BOUNDARY SHOULD DECELERATE AND BECOME NEARLY STATIONARY OVER SRN PARTS OF AR AND OK BY 12Z MONDAY. ...SRN PLNS/OZARKS... TSTMS NOW OVER SRN MO/NRN AR ARE ASSOCIATED WITH A NARROWING ZONE OF WARM ADVECTION ASSOCIATED WITH WLY BRANCH OF LLJ. THIS ACTIVITY SHOULD DISSIPATE AS THE JET WEAKENS A BIT LATER THIS MORNING. IN WAKE OF MORNING STORMS...CONSIDERABLE INSTABILITY /AVERAGE MLCAPE TO 2500 J PER KG/ WILL DEVELOP INVOF WEAKENING FRONT SETTLING S INTO THE SRN PLNS AND NRN OZARKS THIS AFTERNOON. SATELLITE LOOPS SHOW NO APPARENT SMALL SCALE IMPULSE UPSTREAM TO ENHANCE FORCING FOR ASCENT. BUT COMBINATION OF HEATING AND FRONTAL CONVERGENCE SHOULD BE SUFFICIENT TO BREAK STRONG CAP AND INITIATE A FEW SURFACE-BASED STORMS OVER NRN OK...NRN AR AND SW MO LATE THIS AFTERNOON. ADDITIONAL STORMS MAY FORM ALONG STORM GUST FRONTS AS THE BOUNDARIES MOVE GENERALLY S/SE INTO TONIGHT. WHILE MID LEVEL NNW FLOW WILL BE MODEST ON EDGE OF STRONG UPPER RIDGE ...AMPLE /30-35 KT/ DEEP SHEAR SHOULD BE PRESENT FOR SUSTAINED SUPERCELLS...ESPECIALLY IN AR/MO. STEEP BOUNDARY LAYER LAPSE RATES AND FAIRLY LARGE TEMPERATURE/DEW POINT SPREADS SHOULD SUPPORT OUTFLOW-DOMINANT STORMS WITH HIGH WIND AND LARGE HAIL. THE ACTIVITY MAY MERGE INTO ONE OR TWO MCSS THIS EVENING. LOW LEVEL INFLOW INTO THE CONVECTIVE SYSTEMS WILL REMAIN MODEST...BUT WILL PROBABLY BE SUFFICIENT TO EXTEND A LIMITED THREAT FOR HIGH WIND/HAIL SE ALONG PERIPHERY OF CAP INTO NRN MS BY EARLY MONDAY. ...GRT LKS/LWR OH VLY INTO SE MO... MORE MODEST INSTABILITY WILL DEVELOP THIS AFTERNOON AHEAD OF FRONT CROSSING MI IL/IND AND WRN KY. AFTERNOON MLCAPE VALUES SHOULD RANGE FROM AROUND 500 J/KG IN MI TO AROUND I500 J/KG IN SRN IL/WRN IND. THESE VALUES ARE CERTAINLY SUPPORTIVE OF SEVERE STORMS GIVEN A SUFFICIENT DEGREE OF UPLIFT. CONSIDERABLE UNCERTAINTY EXISTS REGARDING THE LATTER POINT. WITH THE COLD/OCCLUDED FRONT CROSSING THE REGION LIKELY TO WEAKEN THROUGH THE DAY...THE MAIN SOURCE OF FORCING FOR ASCENT WILL BE LOBE OF VORTICITY WELL DEPICTED IN SATELLITE IMAGERY ATTM CROSSING CNTRL WI. EXTRAPOLATION OF CURRENT SATELLITE TRENDS...AND GFS GUIDANCE...SUGGEST THAT STRONGEST DCVA WILL REMAIN CONFINED TO MI AND NRN IND. POINTS FARTHER SW SHOULD REMAIN ON ANTICYCLONIC SIDE OF UPPER JET...ALTHOUGH UPPER FLOW WILL BE SOMEWHAT DIFFLUENT. SHEAR PROFILES WILL BE FAVORABLE FOR DISCRETE SUPERCELLS THROUGHOUT THE REGION...ESPECIALLY FROM SRN MI INTO SRN IL/IND/SE MO...WHERE 40-50 KT DEEP NWLY SHEAR WILL BE ORIENTED PERPENDICULAR TO SURFACE FRONT. WEAK LARGE SCALE FORCING FOR ASCENT AND CLOUDINESS MAY LIMIT CONVECTIVE COVERAGE. BUT OVERALL SETUP SUPPORTS FORECAST OF AT LEAST A CONDITIONAL THREAT FOR SUSTAINED SEVERE THIS AFTERNOON INTO EARLY TONIGHT. ...FRONT RANGE... WIDELY SCATTERED STORMS SHOULD FORM LATE THIS AFTERNOON THROUGH THIS EVENING IN ZONE OF OROGRAPHIC UPLIFT/STRONG HEATING ALONG THE FRONT RANGE OF THE CNTRL RCKYS. DEEP SHEAR WILL DECREASE FROM SRN WY INTO SRN CO/NRN NM...BUT SHOULD BE SUFFICIENT THROUGHOUT REGION FOR ORGANIZED ACTIVITY INCLUDING A FEW SUPERCELLS. ACTIVITY WILL LIKELY BE HIGH BASED...PROMOTING A FEW STRONG TO SEVERE GUSTS AND PERHAPS MARGINALLY SEVERE HAIL. ...N GA/WRN CAROLINAS... A FEW STRONG STORMS MAY FORM LATE THIS AFTERNOON INTO THIS EVENING IN UNCAPPED...WEAKLY CONFLUENT ENVIRONMENT OVER THE SRN APLCNS. 30-40 KT DEEP NWLY SHEAR WILL BE FAVORABLE FOR SUSTAINED ACTIVITY...BUT SPARSE MOISTURE WILL LIMIT DEGREE OF INSTABILITY AND SHOULD MITIGATE ANY SEVERE THREAT. WELL-MIXED SUB CLOUD LAYERS MAY YIELD A FEW STRONG DOWNDRAFTS WITH SOME STORMS. ..CORFIDI/JEWELL.. 05/22/2005 ...NOTICE... THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1... WUUS02 PTSDY2...WUUS03 PTSDY3. THE INCLUSION OF POINTS IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005 CONVECTIVE SEASON. A PUBLIC NOTIFICATION STATEMENT (PNS) WILL PROVIDE DETAILS ON THE TRANSITION. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |