Severe Thunderstorm Watch Could Be Issued

Mesoscale Discussion 1218

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MESOSCALE DISCUSSION 1218 NWS STORM PREDICTION CENTER NORMAN OK 1122 AM CDT TUE JUN 25 2013 ..VT...PA...NERN OH...EXTREME NRN WV PANHANDLE. CONCERNING... AREAS AFFECTED...PORTIONS NY .SEVERE POTENTIAL...WATCH POSSIBLE VALID 251622Z - 251845Z ALLY ISOLATED/DISORGANIZED CONVECTIVE REGIME PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...INIT IACROSS THIS AREA MAY INTENSIFY AND GROW IN COVERAGE DURING NEXT FEW HOURS PECIALLY ASSOCIATED WITH ANY AGGREGATED COLD POOLS -- AND ISOLATED OF DESTABILIZATION. MAIN CONCERNS WILL BE SPORADIC DAMAGING GUSTS -- E S/MRGL HAIL. DISCUSSION...ISOLATED TO WIDELY SCATTERED CONVECTION IS DEVELOPING NERN THROUGH NWRN PA...WITH COVERAGE EXPECTED TO INCREASE AS FORE IN BROAD ARC OF WEAK TO NONEXISTENT MLCINH EVIDENT FROM CENTRAL NY SWWD ACROS SGOING AIR MASS CONTINUES TO DESTABILIZE DIABATICALLY. ONE POTENTIAL GENESIS AREA FOR ADDITIONAL CONVECTION AND SHIFT EWD ACROSS HUDSON VALLEY...CENTRAL-ERN PA AND NERN OH...PR COULD BE LAKE-BREEZE BOUNDARIES...ESPECIALLY COMING OFF LE OVER NERN OH AND PA. AS THESE TRENDS CONTINUE IMARY STORM MODE SHOULD BE MULTICELLULAR...PERHAPS EVOLVING INTO SMALL BOWS WHERE ANY PRECIP-LOADING RELATED COLD POOLS CAN DEVELOP FOR TIONS VT...CONTRIBUTING TO PATCHWORK OF MLCAPE VALUES RANGING FROM 1 FORWARD-PROPAGATIONAL PURPOSES. SFC DEW POINTS RANGE FROM MID-60S F OVER MUCH OF PA TO UPPER 60S AND LOW 70S ON OH AND ERN NY AND PO R000-2000 J/KG NEAR SFC MOIST AXES...GIVEN ANOTHER COUPLE HOURS OF INSOLATION-RELATED WARMING APPLIED TO RAOBS AND MODEL FCST SOUNDINGS. WEAK MID-UPPER PERTURBATION MOVING EWD ACROSS ERN VEL BOUNDARIES FOR FOCI...AT LEAST INITIALLY PRIOR TO ANY COLD-POOL ONT/WRN NY REGION ALSO MAY BE CONTRIBUTING DESTABILIZATION ALOFT VIA DCVA. LIMITING FACTORS FOR ORGANIZED SVR POTENTIAL INCLUDE 1. LACK OF ANY OTHER SUBSTANTIAL/SIGNIFICANT LOW-L EFORMATION... 2. WEAK SFC FLOW...LIMITING CONVERGENCE...AND 3. WEAK DEEP SHEAR ACROSS THIS ENTIRE AREA -- EFFECTIVE SHEAR MAGNITUDES ONLY 15-25 KT. ..EDWARDS/KERR.. 06/25/2013 ATTN...WFO...BTV...OKX...ALY...PHI...BGM...BUF...CTP...PBZ... 98 CLE... LAT...LON 45007198 43697257 42747326 41397471 40197642 40067830 40698095 41258229 41418187 41578145 41788093 42127989 42547906 42887870 43217759 43297656 43997618 44457580 44817531 44977472 45007 1