ZCZC SPCSWOMCD ALL ACUS11 KWNS 281530 SPC MCD 281530 MEZ000-MAZ000-NHZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-281630- MESOSCALE DISCUSSION 0820 NWS STORM PREDICTION CENTER NORMAN OK 1030 AM CDT THU MAY 28 2015 AREAS AFFECTED...ME...NH...PORTIONS OF VT...MA...CT...SERN NY CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 281530Z - 281630Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...THUNDERSTORMS ARE EXPECTED TO DEVELOP AND INTENSIFY AHEAD OF A SURFACE TROUGH AND COLD FRONT AND MOVE NORTHEAST THROUGH THE AFTERNOON HOURS. DAMAGING WINDS WILL BE THE PRIMARY CONCERN WITH THE STRONGEST STORMS. ONE OR TWO WATCHES ARE POSSIBLE PRIOR TO 16Z. DISCUSSION...VISIBLE SATELLITE IMAGERY REVEALS SUBSTANTIAL CLEARING IN ADVANCE OF A SURFACE TROUGH/COLD FRONT THAT EXTENDS SWD THROUGH ERN PORTIONS OF NY/PA. SFC TEMPS HAVE RISEN INTO THE MID 70S/NEAR 80 AND DEW POINTS RANGED FROM THE LOWER 60S OVER ME TO THE UPPER 60S OVER SERN NY. LATEST RAP-BASED FORECAST SOUNDINGS SUGGESTS ONLY A MODEST AMOUNT OF ADDITIONAL HEATING IS REQUIRED FOR TSTM INITIATION IN THE VCTY OF THE SFC TROUGH. IN FACT...THE LATEST VIS IMAGERY DEPICTS AN INCREASING CU FIELD ACROSS WRN PORTIONS OF THE MD AREA. EXPECT TSTMS TO DEVELOP/INCREASE IN COVERAGE OVER THE NEXT FEW HOURS IN AN ENVIRONMENT CHARACTERIZED BY 40 TO 50 KTS OF SWLY EFFECTIVE BULK SHEAR AND MODERATE MLCAPE /AVERAGING 1000 TO 1500 J/KG...LOCALLY HIGHER/. AS A SHORTWAVE TROUGH APPROACHES FROM THE W PROVIDING LARGE SCALE FORCING FOR ASCENT...BOTH SUPERCELLS AND BOWING SEGMENTS WILL BE POSSIBLE WITH A RISK FOR DAMAGING WINDS AS THE PRIMARY THREAT. ISOLATED LARGE HAIL IS ALSO POSSIBLE WITH THE MOST INTENSE UPDRAFTS. CONVECTIVE TRENDS WILL BE MONITORED AND ONE OR TWO WW ISSUANCES WILL LIKELY BE NEEDED PRIOR TO 16Z. ..BUNTING/GOSS.. 05/28/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...CAR...GYX...BOX...BTV...OKX...ALY...PHI...BGM... LAT...LON 47196889 47196821 46696799 45946787 45706790 45406752 45006760 44586797 44286898 43826984 43587025 42537090 41957190 41327279 40897417 41227475 41457491 42007493 44357260 45007143 45287074 45987011 47166944 47196889 NNNN