Severe Weather for Ohio River Valley
Posted by JAC on 3/23/2011, 7:39 am
 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT WED MAR 23 2011 VALID 231200Z - 241200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER ERN KY...CNTRL AND SRN OH...MUCH OF WV... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE OH VALLEY INTO THE DELMARVA... ...SYNOPSIS... A STRONG UPPER TROUGH WILL MOVE ESEWD FROM THE UPPER MS VALLEY INTO THE OH VALLEY BY LATE THUR...WITH VERY COLD TEMPERATURES ALOFT AND HEIGHT FALLS OVERSPREADING THE REGION. AT THE SURFACE...LOW PRESSURE IS FORECAST TO MOVE FROM IL INTO OH/WV BY 00Z...ALONG AND JUST S OF A STATIONARY BOUNDARY THAT WILL STRETCH EWD FROM NRN IND INTO NRN OH AND WRN PA DURING THE DAY. BY LATE IN THE DAY...A COLD FRONT WILL PUSH SEWD ACROSS IND/NWRN OH...WITH A DRYLINE EXTENDING SWWD ACROSS WRN KY/TN. BROAD SWLY FLOW ACROSS THE WARM SECTOR WILL HELP TO BRING AT LEAST MID 50S F BOUNDARY LAYER DEWPOINTS NEWD INTO THE OH VALLEY BY AFTERNOON. DAYTIME HEATING IN COMBINATION WITH RAPID COOLING ALOFT WILL RESULT IN ABNORMALLY STEEP MID TROPOSPHERIC LAPSE RATE PROFILES OVER THE REGION...SETTING THE STAGE FOR A POTENTIALLY ACTIVE SEVERE WEATHER EVENT TODAY INTO THE EARLY EVENING. ...OH VALLEY EWD INTO VA... EARLY WED...THUNDERSTORMS ARE LIKELY TO BE ONGOING FROM IND INTO OH...AND EXTENDING SWD ACROSS KY AND TN IN A BROAD ZONE OF LOW LEVEL WARM ADVECTION ASSOCIATED WITH A 50 KT WSWLY LOW LEVEL JET. SOME MARGINALLY SEVERE HAIL MAY OCCUR WITH THIS ACTIVITY OVER INDIANA AND OH WHERE LAPSE RATE PROFILES WILL BE MORE FAVORABLE FOR ELEVATED HAIL. THIS INITIAL AREA OF STORMS SHOULD MOVE RAPIDLY EWD...ALLOWING FOR AIR MASS RECOVERY AND DESTABILIZATION TO THE W. BY MID AFTERNOON...A PLUME OF STEEP LOW LEVEL LAPSE RATES WILL EXTEND NEWD ACROSS IL INTO IND...AND WILL GRADUALLY EXPAND EWD INTO OH/KY/WRN TN. STORMS ARE EXPECTED TO RE INITIATE FROM THE DRYLINE/COLD FRONT INTERSECTION NEAR THE IND/OH BORDER SWWD ALONG THE DRYLINE INTO WRN KY/TN. FORECAST SOUNDINGS INDICATE MODERATE INSTABILITY DEVELOPING DESPITE WHAT WOULD BE AN OTHERWISE MARGINAL LOW LEVEL MOISTURE PROFILE FOR THIS TIME OF YEAR. BUT GIVEN 500 MB TEMPERATURES OF -20 C OR COLDER OVERSPREADING THE WARM SECTOR...AND STRONG DEEP LAYER SHEAR PROFILES IN PLACE...POTENTIALLY WIDESPREAD SEVERE WEATHER WILL BE POSSIBLE. OVERALL STRONG BUT UNIDIRECTIONAL WIND PROFILES...IN COMBINATION WITH VERY COOL PROFILES ALOFT...SUGGEST SUPERCELLS WILL BE LIKELY...SOME SPLITTING...CAPABLE OF PARTICULARLY LARGE HAIL. SOME OF THESE STORMS MAY BE PARTICULARLY DAMAGING WITH LARGE AMOUNTS OF HAIL. FAST STORM MOTIONS AND COLD DOWNDRAFT POTENTIAL WILL ALSO FAVOR DAMAGING WINDS. THE TORNADO THREAT SHOULD REMAIN LIMITED DUE TO WEAK LOW LEVEL SHEAR...ALTHOUGH A FEW MAY OCCUR WITH ANY STRONGLY ROTATING STORMS AND LARGE LOW LEVEL CAPE. THE SEVERE THREAT WILL DECREASE IN MAGNITUDE WITH THE LOSS OF HEATING BUT MAY EXTEND EWD ACROSS THE APPALACHIANS INTO THE DELMARVA WITH ELEVATED HAIL POSSIBLE. ..JEWELL/STOPPKOTTE.. 03/23/2011 |
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