030 ACUS3 KMKC 281010 SWOMCD MKC MCD 281009 OHZ000-PAZ000-NYZ000-281200- SPC MESOSCALE DISCUSSION 1898 FOR NERN OH...NWRN PA AND WRN NY CONCERNING...SEVERE THUNDERSTORM POTENTIAL... STORMS HAVE BECOME BETTER ORGANIZED AS LINES OVER PORTIONS OF LAKE ERIE THROUGH SRN ONTARIO. THOUGH SOME THREAT FOR STRONG WIND GUSTS MAY EXIST AS THIS ACTIVITY MOVES ONSHORE NEXT FEW HOURS...CURRENT THINKING IS THAT OVERALL THREAT APPEARS TO MARGINAL FOR A WW. AREA WILL CONTINUE TO BE MONITORED. SCATTERED STORMS HAVE DEVELOPED AHEAD OF COLD FRONT WITHIN A REGION OF FAVORABLE UPPER DIVERGENCE AND LARGE SCALE ASCENT DOWNSTREAM FROM SHORTWAVE TROUGH MOVING EWD THROUGH GREAT LAKES. MOIST AXIS EXTENDS FROM THE OH VALLEY NEWD THROUGH SRN ONTARIO AND SRN QUEBEC WITH DEWPOINTS GENERALLY IN THE 60S SUPPORTING MUCAPES LESS THAN 1500 J/KG. INSTABILITY IS MORE MARGINAL FARTHER EAST ACROSS NERN OH...NWRN PA AND WRN NY WHERE DEWPOINTS ARE ONLY IN THE UPPER 50S. ATMOSPHERE MAY UNDERGO SOME DESTABILIZATION EWD WITH TIME PROMOTED BY MOIST ADVECTION ALONG SWLY LOW LEVEL JET. HOWEVER...MARGINAL LAPSE RATES WILL LIMIT OVERALL DEGREE OF DESTABILIZATION DOWNSTREAM OF DEVELOPING STORMS. INCREASING UNIDIRECTIONAL LOW-MID LEVEL FLOW ASSOCIATED WITH APPROACHING SHORTWAVE TROUGH MAY ENHANCE POTENTIAL FOR STRONG WIND GUSTS AS LINE MOVES EWD. HOWEVER...LESS THAN FAVORABLE THERMODYNAMIC PROFILES INCLUDING MARGINAL LAPSE RATES/ INSTABILITY AND PRESENCE OF A STABLE BOUNDARY LAYER SHOULD LIMIT AN ORGANIZED WIND THREAT. ..DIAL.. 08/28/01 ...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
767 ACUS3 KMKC 281541 SWOMCD MKC MCD 281540 OHZ000-PAZ000-NYZ000-281800- SPC MESOSCALE DISCUSSION 1900 FOR ERN OH / PA / SRN NY... CONCERNING...SEVERE THUNDERSTORM POTENTIAL... SHOWERS AND THUNDERSTORMS ARE FORECAST TO CONTINUE ALONG AND AHEAD OF APPROACHING COLD FRONT ACROSS THIS REGION. A MARGINAL SEVERE WEATHER THREAT WILL EXIST...ALTHOUGH EXPECTED MARGINAL / ISOLATED NATURE OF THREAT WILL LIKELY PRECLUDE WW ISSUANCE OVER THE NEXT COUPLE OF HOURS. LATEST SURFACE ANALYSIS SHOWS COLD FRONT MOVING SEWD ACROSS WRN NY / NWRN PA / NRN OH ATTM...WITH SHOWERS AND DEVELOPING THUNDERSTORMS ALONG AND JUST AHEAD OF BOUNDARY. SURFACE AND MORNING UPPER AIR ANALYSES SHOW MORE SIGNIFICANT LOWER TROPOSPHERIC MOISTURE REMAINS ACROSS WRN PA / ERN OH...WITH DRIER CONDITIONS ACROSS CENTRAL PA / CENTRAL AND ERN NY / NEW ENGLAND. AS A RESULT...GREATEST INSTABILITY REMAINS GENERALLY WEST OF THE APPALACHIANS...WHERE 1000 TO 2000 J/KG SURFACE-BASED CAPE EXISTS. AS SHORT WAVE TROUGH EVIDENT ON WV IMAGERY OVER SRN ONTARIO AND ASSOCIATED 40 TO 50 KT SPEED MAX MOVES EWD ACROSS NY THIS AFTERNOON...DEEP-LAYER WIND FIELD WILL LIKELY BE STRONG ENOUGH TO SUPPORT SOME STORM ORGANIZATION. ISOLATED MARGINALLY SEVERE HAIL / WIND EVENTS WITH A FEW OF THE STRONGER STORMS WILL BE THE MAIN SEVERE THREATS. ALTHOUGH DEEP-LAYER WLY / WSWLY FLOW IS UNIDIRECTIONAL AND RELATIVELY STRONG...ORIENTATION OF THE BOUNDARY AND ASSOCIATED THUNDERSTORM DEVELOPMENT IS ALSO WSW-ENE... WHICH ALONG WITH THE LIMITED INSTABILITY SUGGESTS THE THREAT FOR A MORE ORGANIZED CLUSTER OF STORMS CAPABLE OF MORE SIGNIFICANT WIND DAMAGE APPEARS TO BE LOW. ..GOSS.. 08/28/01 ...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
199 ACUS3 KMKC 281951 SWOMCD MKC MCD 281950 PAZ000-NYZ000-NJZ000-CTZ000-282200- SPC MESOSCALE DISCUSSION 1905 FOR ERN PA / SRN NY / NRN NJ / CT.. CONCERNING...SEVERE THUNDERSTORM POTENTIAL... BROKEN LINE OF STRONG / ISOLATED SEVERE THUNDERSTORMS EXTENDING FROM NERN PA WSWWD INTO CENTRAL PA WILL CONTINUE MOVING EWD ACROSS THE LOWER HUDSON VALLEY / CATSKILLS REGION OF NY ALONG WITH PARTS OF ERN PA AND NRN NJ OVER THE NEXT FEW HOURS. ALTHOUGH ISOLATED MARGINALLY-SEVERE HAIL / WIND EVENTS REMAIN POSSIBLE WITH STRONGER STORMS IN THIS LINE POSSIBLE...WW NOT ANTICIPATED ATTM. MAIN COLD FRONT REMAINS ACROSS WRN PA / WRN NY...WHILE SEVERAL PRE- FRONTAL MESOSCALE CONVERGENCE AXES ARE ANALYZED OVER THIS REGION. ALTHOUGH INSTABILITY REMAINS LIMITED /1000 TO 1500 J/KG SURFACE- BASED CAPE / ACROSS ERN PA / SRN NY...HIGHER DEWPOINTS /MID 60S TO NEAR 70/ CLOSER TO THE ATLANTIC ACROSS ERN NJ / SRN NY / CT ARE RESULTING A MORE UNSTABLE AIRMASS WITH SURFACE-BASED CAPE 1500 TO 2500 J/KG. AREA VWPS SHOW WEAK TO MODERATE DEEP-LAYER WINDS WHICH VEER SLIGHTLY WITH HEIGHT ACROSS THE REGION...HOWEVER MID-LEVEL FLOW IS FORECAST TO CONTINUE INCREASING INTO THE 30 TO 40 KT RANGE FROM W-E AS UPPER VORT MAX / SPEED MAX CONTINUES EWD FROM SRN ONTARIO TOWARD NRN NY. THIS WILL RESULT IN INCREASING DEEP-LAYER SHEAR...AND THUS A CONTINUED THREAT FOR ISOLATED DAMAGING WIND / HAIL WITH THE STRONGER STORMS. ..GOSS.. 08/28/01 ...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
