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000
ACUS11 KWNS 211655
SWOMCD
SPC MCD 211654
NHZ000-MAZ000-CTZ000-VTZ000-NYZ000-211800-

MESOSCALE DISCUSSION 0751
NWS STORM PREDICTION CENTER NORMAN OK
1154 AM CDT TUE MAY 21 2013

AREAS AFFECTED...WRN/CNTRL NY...SRN NEW ENGLAND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 211654Z - 211800Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...TSTMS SHOULD CONTINUE INCREASING IN INTENSITY...PRIMARILY
FOCUSED ALONG/S OF A QUASI-STATIONARY FRONT...ACROSS PORTIONS OF
WRN/CNTRL NY AND INTO SRN NEW ENGLAND THIS AFTERNOON. THE PRIMARY
THREATS WILL BE DMGG WIND GUSTS AND LARGE HAIL. A WW MAY BE NEEDED
IF CONVECTIVE TRENDS CONTINUE TO INCREASE.

DISCUSSION...SUBJECTIVE SFC ANALYSIS FROM 16Z PLACES A
QUASI-STATIONARY FRONT FROM NEAR ROC-ALB. A FEW STORMS HAVE RECENTLY
INITIATED ALONG THIS FRONT...LIKELY IN RESPONSE TO WEAK LOW-LEVEL
CONVERGENCE...WEAKENING CONVECTIVE INHIBITION...AND MODEST MIDLEVEL
MOISTENING/ASCENT AS NOTED ON WATER VAPOR. MODIFIED 12Z SOUNDINGS
FROM BOTH BUF AND ALB SUGGEST AMPLE INSTABILITY FOR THE DEVELOPMENT
OF STRONG-SVR TSTMS...WITH MLCAPE VALUES LIKELY EXCEEDING 2000
J/KG...GIVEN THE PRESENCE OF MODERATELY STEEP MIDLEVEL LAPSE RATES
AND RICH LOW-LEVEL MOISTURE. ADDITIONALLY...BOTH SOUNDING AND RECENT
VWP DATA SHOW NEARLY 30 KTS OF MIDLEVEL FLOW AND MODESTLY VEERING
WINDS WITH HEIGHT...SUPPORTIVE FOR ORGANIZED TSTM. COVERAGE OF TSTMS
IS SOMEWHAT UNCERTAIN GIVEN RELATIVELY WEAK FORCING FOR ASCENT...BUT
WITH THE POTENTIAL FOR LARGE HAIL AND DMGG WIND GUSTS...A WW MAY BE
REQUIRED SHOULD TRENDS CONTINUE TO INCREASE.

..ROGERS/KERR.. 05/21/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BOX...ALY...BGM...BUF...

LAT...LON   41997433 42067611 42277755 42697790 43147756 43197706
            43027555 42987423 42957307 42897266 42677229 42257234
            41717280 41997433