The SPC is forecasting ...severe thunderstorms expected over parts of the upper ohio valley...mid atlantic states...and new england this afternoon and evening.... Please read the latest public statement about this event.
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SPC AC 161243 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0743 AM CDT MON JUN 16 2008 VALID 161300Z - 171200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM THE UPR OH VLY INTO THE MID ATLANTIC STATES AND SOUTHWEST NEW ENGLAND... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA FROM THE LWR OH VLY INTO MUCH OF NEW ENGLAND... ...THERE IS A SLGT RISK OF SVR TSTMS FROM OK/NRN TX AND THE ARKLATEX N/W INTO THE CNTRL/NRN HI PLNS... ...SYNOPSIS... CLOSED LOW NOW N OF LK SUPERIOR SHOULD CONTINUE SLOWLY E TO NEAR GEORGIAN BAY EARLY MONDAY AS BAND OF FAST WLY FLOW ON ITS SRN FLANK SPREADS FROM THE MID MS/OH VLYS TO THE MID ATLANTIC CST. AT THE SAME TIME...SWRN STATES RIDGE EXPECTED TO AMPLIFY SLIGHTLY N ACROSS THE RCKYS AND NRN HI PLNS. COLD FRONT ASSOCIATED WITH ERN TROUGH SHOULD REACH A NERN NY-CNTRL PA-ERN KY LINE BY EVENING. BOUNDARY LIKELY WILL REMAIN DIFFUSE...WITH LEE TROUGH BECOMING BETTER DEFINED BY AFTN FROM CNTRL VA TO SERN NY. WRN PART OF THE FRONT WILL CONTINUE SETTLING S ACROSS THE LWR MS VLY AND SRN PLNS. ...OH VLY INTO MID ATLANTIC STATES/NEW ENGLAND... 60+ KT MID LVL SPEED MAX AND ASSOCIATED LOBE OF ASCENT NOW OVER THE MID/UPR MS VLY SHOULD REACH IND/OH THIS AFTN...BEFORE CONTINUING E/SE TO THE DELMARVA REGION TONIGHT. MODERATE LOW LVL MOISTURE WILL CONTINUE TO SPREAD NEWD AHEAD OF AFOREMENTIONED COLD FRONT TODAY...WHILE CLOSER TO THE CST... SOMEWHAT GREATER MOISTURE EXPECTED TO CONTINUE SPREADING N AHEAD OF LEE TROUGH. AT THE SAME TIME...UNSEASONABLY COOL TEMPS WILL PREVAIL AT MID LVLS...WITH 500 MB READINGS AOB MINUS 12C AS FAR S AS THE VA/NC BORDER. WITH THIS SETUP...SFC HEATING SHOULD YIELD MODERATE INSTABILITY FROM SRN OH/KY/WV E/NE INTO SRN NEW ENGLAND...WITH SBCAPE AOA 1500 J/KG. COMBINATION OF INCREASING INSTABILITY WITH DEEP...LARGELY UNIDIRECTIONAL CYCLONIC FLOW...AND INCREASING UVV WITH APPROACHING JET STREAK WILL CREATE ENVIRONMENT FAVORABLE FOR NUMEROUS STRONG TO SVR STORMS BY EARLY AFTN. THESE LIKELY WILL ORGANIZE INTO SEVERAL CLUSTERS AND BANDS ALONG AND AHEAD OF COLD FRONT AND LEE TROUGH. EMBEDDED SUPERCELLS AND ASSOCIATED BOWING SEGMENTS LIKELY WILL PRODUCE FAIRLY LONG SWATHS OF DMGG WIND GIVEN SIZABLE BOUNDARY LYR TEMP-DEWPOINT SPREADS/STEEP LOW LVL LAPSE RATES...AND STRENGTH OF MEAN FLOW. THE STRONGEST STORMS LIKELY WILL HAVE MOVED OFFSHORE AND/OR WEAKENED BY MID TO LATE EVENING. ...OK/TX/ARKLATEX NW INTO CNTRL/NRN HI PLNS... UVV/WAA IN ENTRANCE REGION OF MS VLY JET STREAK APPEAR LARGELY RESPONSIBLE FOR ONGOING STORM CLUSTERS IN THE CNTRL PLNS. FARTHER SE...ASCENT WITH MCV AND WAA ON ERN FRINGE OF SWRN U.S. RIDGE ARE MAINTAINING STORMS FROM ERN OK INTO THE OZARKS. SFC HEATING AND ASSOCIATED REORIENTATION OF LOW LVL FLOW LIKELY WILL SUPPORT ADDITIONAL STORM DEVELOPMENT INVOF /1/ MCV.../2/ WEAKENING COLD FRONT...AND /3/ OUTFLOW BOUNDARIES OVER PARTS OF OK...WRN AR...AND NRN/WRN TX LATER TODAY. THE GREATEST DESTABILIZATION SHOULD OCCUR ALONG FRONT/LOW LVL MOISTURE AXIS OVER SRN KS/NRN OK INTO THE OK/NRN TX PANHANDLES. CONVERGENCE ALONG THE FRONT...AND LEE TROUGH EXTENDING S INTO NW AND W CNTRL TX...SHOULD INITIATE STORMS BY MID TO LATE AFTN. THIS REGION WILL BE ALONG SRN EDGE OF MODERATE WNW UPR FLOW TOPPING THE RIDGE. WHILE NOT EXCESSIVE...DIRECTIONAL SHEAR SHOULD SUPPORT A FEW SUPERCELLULAR STRUCTURES LATE THIS AFTN/EARLY THIS EVENING THAT WILL BE CAPABLE OF LARGE HAIL/DMGG WINDS AND POSSIBLY A TORNADO. FARTHER NW...OTHER TSTMS EXPECTED IN LOW LVL UPSLOPE FLOW FROM NE NM/ERN CO THROUGH ERN WY INTO ERN MT. DEEP SHEAR WILL GENERALLY INCREASE WITH NWD EXTENT WHILE MOISTURE DECREASES. ACROSS THE HI PLNS...COMBINATION OF VEERING WIND PROFILES AND UPPER 40S TO MIDDLE 50S F SFC DEWPOINTS SHOULD YIELD SCTD SUPERCELLS WITH HAIL...DMGG WINDS AND PERHAPS A TORNADO. ..CORFIDI/JEWELL.. 06/16/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z