CATEGORICAL OUTLOOK
TORNADO OUTLOOK
WIND OUTLOOK
HAIL OUTLOOK
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0751 AM CDT SAT JUN 30 2012 VALID 301300Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE OH VALLEY TO MID ATLANTIC COAST... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN/CNTRL PLAINS INTO LOWER MO VALLEY... ...SYNOPSIS... A HIGH-LATITUDE OMEGA BLOCK WILL BECOME BETTER-DEFINED WITH TIME...FEATURING AN AMPLIFYING RIDGE OVER THE CANADIAN PRAIRIE PROVINCES INTO NRN HIGH PLAINS AND EVOLVING TROUGHS OVER WRN CANADA/PACIFIC NW AND ERN CANADA/NERN U.S. WITHIN THIS BROADER-SCALE FLOW REGIME...A VORTICITY MAXIMUM OF CONVECTIVE ORIGIN OVER WRN OH WILL TRANSLATE EWD...REACHING THE MID ATLANTIC COAST BY 01/00Z...WHILE UPSTREAM A MULTI-BRANCH SERIES OF IMPULSES MOVE INTO THE NRN/CNTRL PLAINS. AT THE SURFACE...THE PRIMARY BAROCLINIC ZONE WILL EXTEND FROM A HEAT/LEE LOW OVER NERN CO/NWRN KS EWD THROUGH THE LOWER MO VALLEY TO A COMPOSITE SYNOPTIC-OUTFLOW BOUNDARY TRAILING DECAYING OH MCS. E OF THE APPALACHIANS...OUTFLOW BOUNDARY ASSOCIATED WITH THE FRIDAY EVENING/NIGHT DERECHO-PRODUCING MCS HAS SETTLED INTO THE CAROLINAS. EXPECT THIS BOUNDARY RE-DEVELOP NWD INTO THE DELMARVA TODAY WITHIN STRENGTHENING LOW-LEVEL WAA REGIME ASSOCIATED WITH APPROACHING OH VALLEY VORTICITY MAXIMUM. OVER THE NRN PLAINS...AN INVERTED TROUGH WILL SHIFT EWD ACROSS THE DAKOTAS WITH THE SRN EXTENSION OF BOUNDARY LINKING WITH LEE LOW OVER THE CNTRL HIGH PLAINS. ...OH VALLEY TO MID ATLANTIC COAST THIS AFTERNOON INTO TONIGHT... LATEST CONVECTION-ALLOWING AND MESOSCALE MODEL GUIDANCE SUGGEST THAT THE PRIMARY SEVERE WEATHER THREAT WILL BE FOCUSED ALONG OUTFLOW BOUNDARY ASSOCIATED WITH DECAYING OH MCS AS IT EMERGES FROM THE CREST OF THE APPALACHIANS LATER TODAY. HERE...UPLIFT ALONG THE RESIDUAL OUTFLOW BOUNDARY/GUST FRONT WILL COINCIDE WITH DEEPER-LAYER FORCING ASSOCIATED WITH MCV TO PROMOTE AN INCREASE IN TSTMS WITHIN A MOIST/MODERATELY UNSTABLE AIR MASS WITH MLCAPE APPROACHING 1500-3000 J/KG. KINEMATIC ENVIRONMENT WILL FEATURE A UNIDIRECTIONAL WNWLY WIND FIELD WITH 50-60 KT FLOW POSSIBLE IN THE 600-500-MB LAYER PER 12Z UPSTREAM SOUNDING AT WILMINGTON OH. AS SUCH...POTENTIAL WILL EXIST FOR THE EVOLUTION OF ANOTHER BOW ECHO SYSTEM CAPABLE OF POTENTIALLY WIDESPREAD DAMAGING WINDS ACROSS PARTS OF THE DELMARVA INTO CNTRL/ERN NC. MEANWHILE...A SMALL CLUSTER OF TSTMS HAS RECENTLY INTENSIFIED OVER SERN IA...APPARENTLY FORCED BY A WEAK SHORTWAVE TROUGH PROGRESSING SEWD THROUGH SRN MN/NRN IA. THOUGH NOT WELL RESOLVED BY THE MODELS...IT IS POSSIBLE THAT THESE STORMS COULD INTENSIFY BY LATE MORNING/EARLY AFTERNOON OVER PARTS OF E-CNTRL IL/W-CNTRL INDIANA. WHILE ENVIRONMENT IS NOT NEARLY AS UNSTABLE AS FRIDAY...12Z SOUNDINGS INDICATE THE POTENTIAL FOR MODERATE-STRONG INSTABILITY /I.E. MLCAPE VALUES OF 1500-3000 J PER KG/ IN THE PRESENCE OF MODEST VERTICAL SHEAR. AS SUCH...EVOLUTION OF AN ADDITIONAL FORWARD-PROPAGATING MCS/BOW ECHO IS POSSIBLE WITH A HEIGHTENED RISK FOR DAMAGING WINDS SPREADING EWD TOWARD THE UPPER OH VALLEY. DUE TO LOWER CONFIDENCE IN THIS SCENARIO...ONLY BASELINE SLIGHT RISK PROBABILITIES WILL BE INCLUDED IN THIS FORECAST. ...NRN/CNTRL PLAINS INTO LOWER MO VALLEY THIS AFTERNOON AND EVENING... STEEP MIDLEVEL LAPSE RATES AND BOUNDARY LAYER DEWPOINTS IN THE UPPER 50S-UPPER 60S ARE EXPECTED TO CONTRIBUTE TO A MODERATE-STRONGLY UNSTABLE ENVIRONMENT BY AFTERNOON WITH MLCAPE VALUES RANGING FROM 2000-4000+ J/KG ALONG INVERTED TROUGH AND ALONG COOL SIDE OF W-E ORIENTED QUASI-STATIONARY BOUNDARY. LOW-LEVEL CONVERGENCE/ASCENT ALONG SURFACE BOUNDARIES WILL BE AUGMENTED BY FORCING ASSOCIATED WITH MULTIPLE WEAK MIDLEVEL IMPULSES...AND STRONG BOUNDARY LAYER HEATING S OF FRONT IN KS TO FOSTER MULTIPLE CLUSTERS OF TSTMS THIS AFTERNOON INTO TONIGHT. THE STRONGEST WLY/WNWLY MIDLEVEL FLOW AND RESULTING VERTICAL SHEAR WILL RESIDE ALONG DAKOTAS SEGMENT OF INVERTED TROUGH WHERE SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE. FARTHER S...THE WEAKER VERTICAL SHEAR WILL BE COMPENSATED BY THE STRONG INSTABILITY WITH ENVIRONMENT SUPPORTIVE OF MULTICELL CLUSTERS CAPABLE OF DAMAGING WINDS AND HAIL. ...INTERIOR PACIFIC NW INTO NRN INTERMOUNTAIN REGION THIS AFTERNOON AND EVENING... LARGE-SCALE FORCING FOR ASCENT AND VERTICAL SHEAR WILL INCREASE TODAY AHEAD OF SHORTWAVE TROUGH MOVING ONSHORE. THIS WILL COINCIDE WITH STEEPENING LAPSE RATES AND CONCOMITANT INCREASE IN MOISTURE WITH ENVIRONMENT BECOMING FAVORABLE FOR ISOLATED SEVERE STORMS --INCLUDING SOME POSSIBLE SUPERCELL STRUCTURES-- WITH AN ASSOCIATED RISK FOR DAMAGING WINDS AND HAIL. ANTICIPATED LIMITED AREAL COVERAGE PRECLUDES THE ISSUANCE OF A CATEGORICAL SLIGHT RISK ATTM. ...MAINE THIS AFTERNOON... ISOLATED SEVERE STORMS WILL ONCE AGAIN BE POSSIBLE THIS AFTERNOON AS LARGE-SCALE FORCING FOR ASCENT IS ENHANCED BY SHORTWAVE TROUGH MOVING ACROSS THE REGION. THE COMBINATION OF A RELATIVELY MOIST/MODERATELY UNSTABLE AIR MASS AND 30-40 KT OF DEEP WLY SHEAR MAY PROMOTE LINE SEGMENTS OR MULTICELL CLUSTERS WITH A RISK FOR DAMAGING WINDS AND/OR HAIL. ...S TX TODAY... 12Z CRP/BRO SOUNDINGS SHOWED THE POTENTIAL FOR STRONG INSTABILITY TO DEVELOP AHEAD OF TSTMS DEVELOPING ALONG THE COAST. LOCALLY DAMAGING WINDS WILL BE POSSIBLE WITH ANY ORGANIZED CLUSTERS OWING TO COLD POOL GENERATION VIA WATER LOADING EFFECTS. ..MEAD/HURLBUT.. 06/30/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z CURRENT UTC TIME: 1345Z (8:45AM), RELOAD THIS PAGE TO UPDATE THE TIME 
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