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| Probabilistic Tornado Graphic | |||||||||
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| Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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| Probabilistic Damaging Wind Graphic | |||||||||
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| Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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| Probabilistic Large Hail Graphic | |||||||||
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| Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 020556 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1256 AM CDT SUN JUN 02 2013 VALID 021200Z - 031200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NERN CONUS... ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NM AND FAR W TX... ...SYNOPSIS... UPPER-AIR PATTERN FCST TO BE RATHER PROGRESSIVE THROUGH PERIOD. STG SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER INLAND PAC NW AND BC -- IS FCST TO MOVE EWD ACROSS NWRN CONUS AND SWRN CANADA THROUGH PERIOD. WEAK/EMBEDDED 500-MB LOW MAY EVOLVE OVER CENTRAL MT BY 3/12Z. DOWNSTREAM...RIDGING WILL SHIFT EWD OVER NRN PLAINS...WHILE MID-UPPER LEVEL LOW NOW OVER EXTREME NWRN ONT PIVOTS ACROSS NRN ONT TO SRN JAMES BAY REGION. SYNOPTIC-SCALE TROUGHING THAT EXTENDS SSWWD FROM THAT LOW WILL SHIFT EWD OVER UPPER GREAT LAKES AND MS VALLEY. EMBEDDED SHORTWAVE TROUGH -- NOW LOCATED OVER IL/WRN INDIANA -- WILL EJECT NEWD AND GRADUALLY DEAMPLIFY...CROSSING WRN PORTIONS PA/NY AROUND 02/18Z...THEN WEAKENING FURTHER WHILE MOVING NEWD DOWN ST LAWRENCE RIVER AREA. AT SFC...COLD FRONT NOW EXTENDING FROM LM AREA ACROSS SRN IL...AR AND CENTRAL/SW TX SHOULD REACH NRN NY...WRN PA...CENTRAL/ERN KY...WRN/MID TN...SRN LA...AND S-CENTRAL TX. FRONT SHOULD PROCEED EWD TO NEW ENGLAND...INLAND MID-ATLC AND AL BY END OF PERIOD. ...PORTIONS NERN CONUS TO DIXIE... SCATTERED TO NUMEROUS TSTMS ARE FCST TO DEVELOP MOSTLY AHEAD OF SFC COLD FRONT...INVOF NEARLY PARALLEL PREFRONTAL SFC TROUGH AND ANY OTHER MESOSCALE BOUNDARIES THAT MAY DEVELOP. DAMAGING WIND WILL BE MAIN THREAT..WITH BOW/LEWP FORMATIONS...WITH ISOLATED HAIL POSSIBLE. TORNADO POTENTIAL IS VERY CONDITIONAL GIVEN LIKELY CONVECTIVE MODE. FLOW ALOFT WILL BEAR STRONGEST FLOW COMPONENT PARALLEL TO THESE BOUNDARIES...AND SHOULD BE CLOSE TO UNIDIRECTIONAL THROUGH DEEP LAYER. THIS WILL LIMIT DEEP SHEAR...THOUGH CINH WILL BE WEAK ENOUGH THAT EVEN WEAK-MDT CONVERGENCE SHOULD PERMIT CONSIDERABLE CONVECTIVE COVERAGE. AS SUCH...DOMINANT STORM MODE SHOULD BE QUASI-LINEAR...THOUGH AT LEAST BRIEF SUPERCELL STRUCTURES MAY OCCUR FROM ERN NY AND MA NEWD WHERE LOW-LEVEL SRH WILL BE RELATIVELY MAXIMIZED. ALTHOUGH APCHG SHORTWAVE TROUGH WILL BE DEAMPLIFYING...RELATED DCVA/ASCENT MAY CONTRIBUTE SOME ENHANCEMENT OF MIDLEVEL LAPSE RATES OVER PORTIONS NY/NEW ENGLAND. THIS WILL BE CONCURRENT WITH MORE THERMODYNAMICALLY IMPORTANT PROCESS OF DESTABILIZATION OF BOUNDARY LAYER DUE TO BOTH THETAE ADVECTION AND SFC DIABATIC HEATING. THOSE...COMBINED WITH SFC DEW POINTS MID-UPPER 60S F...SHOULD YIELD MLCAPE 1000-2000 J/KG. LOW-LEVEL SHEAR AND CONVERGENCE EACH SHOULD DECREASE WITH SWWD EXTENT DOWN CENTRAL/SRN APPALACHIANS/PIEDMONT INTO PORTIONS MS/AL...WHERE CONVECTIVE STRUCTURES SHOULD BE MORE DISORGANIZED. NONETHELESS...STG SFC HEATING AND AT LEAST SUBTLE LIFT ALONG FRONTAL/OUTFLOW BOUNDARIES SHOULD OFFER POTENTIAL FOR DOWNBURSTS AND ISOLATED LARGE HAIL OVER SERN CONUS CONVECTIVE CORRIDOR. ...PORTIONS NM AND FAR W TX... WIDELY SCATTERED TSTMS SHOULD FORM MID-LATE AFTN...ESPECIALLY INVOF ELEVATED TERRAIN NEAR AND BEHIND WRN LIMB OF LOW-LEVEL BAROCLINIC ZONE. BACKED LOW-LEVEL FLOW AND RELATED MOIST ADVECTION/TRANSPORT WILL COMBINE WITH UPSLOPE FLOW COMPONENT TO CONTRIBUTE TO CONVECTIVE DEVELOPMENT AND MAINTENANCE. STEEP DEEP-LAYER LAPSE RATES WILL CONTRIBUTE FURTHER TO MLCAPE IN 1500-2500 J/KG RANGE...OVER WELL-MIXED BOUNDARY LAYER SUITABLE FOR MAINTAINING HAIL/GUSTS TO SFC. STG DIRECTIONAL SHEAR WILL COUNTERBALANCE WEAK RELATIVELY WEAK MIDLEVEL WINDS TO YIELD 30-40 KT EFFECTIVE SHEAR MAGNITUDES IN SUPPORT OF TSTM ORGANIZATION. THREAT SHOULD LAST INTO EARLY-MID EVENING ON AT LEAST ISOLATED BASIS UNTIL COMBINATION OF OUTFLOW SPREADING AND DIABATIC COOLING REDUCE BOUNDARY-LAYER INSTABILITY. ...PORTIONS MT... ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED TO DEVELOP AND MOVE NEWD ACROSS THIS REGION DURING AFTERNOON...IN REGIME OF STRENGTHENING DEEP-LAYER SHEAR AND FAVORABLE SFC HEATING. MAIN LIMITING FACTOR WILL BE MRGL MOISTURE...WITH DEW POINTS GENERALLY 30S AND 40S F. HIGH-BASED ACTIVITY MAY PRODUCE ISOLATED SVR HAIL AND DAMAGING GUSTS. ..EDWARDS/BUNTING.. 06/02/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |