MESO: Mesoscale Discussion 0902

ACUS11 KWNS 271712
SWOMCD
SPC MCD 271712
NYZ000-PAZ000-271845-

MESOSCALE DISCUSSION 0902
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT SUN MAY 27 2007

AREAS AFFECTED...NY...PA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 271712Z - 271845Z

ISOLATED TSTM INITIATION HAS COMMENCED ACROSS PARTS OF CNTRL NY AND
A GENERAL INCREASE IN SEVERE TSTM POTENTIAL IS EXPECTED OVER THE
NEXT HOUR OR TWO. A WATCH APPEARS POSSIBLE FOR PARTS OF THE REGION
THIS AFTERNOON.

A FEW CELLS HAVE RECENTLY ERUPTED NEAR/ALONG MESOSCALE WARM FRONT
AND WEAK WIND SHIFTS SITUATED ACROSS SRN/CNTRL NY ATTM. DOUBLE WARM
FRONTAL STRUCTURE APPEARS IN RECENT MESOANALYSIS TO THE SE OF
LO...AND A WIND SHIFT/CONFLUENCE AXIS EXTENDS SOUTH OF A WEAK
SURFACE WAVE NEAR THE SRN SHORE OF LO. WIND SHIFT HAS BEEN SPREADING
EAST ACROSS THE SRN TIER AND EXTENDS SWD INTO PA. WITH AREAS OF
STRONGER SURFACE HEATING ELIMINATING REMAINING INHIBITION ACROSS THE
AREA...THESE WEAK MESOSCALE FEATURES WILL LIKELY AID ADDITIONAL TSTM
DEVELOPMENT OVER THE NEXT FEW HOURS. OBSERVED AND MODEL SOUNDINGS
ACROSS THE REGION SHOW SOMEWHAT MARGINAL MID LEVEL LAPSE RATES THAT
ARE LIMITING GREATER CONVECTIVE INSTABILITY. HOWEVER...LOW LEVEL
MOIST ADVECTION AND STEEPENING LOW LEVEL LAPSE RATES SHOULD BOOST
INSTABILITY ENOUGH FOR AT LEAST A FEW ROBUST UPDRAFTS. CURRENT AND
FORECAST SHEAR ACROSS NY AND NRN PA WILL SUPPORT UPDRAFT
ORGANIZATION/PERSISTENCE WITH PRIMARY THREAT LIKELY COMING FROM
BOWING LINE SEGMENTS PRODUCING STRONG TO DAMAGING WINDS.

LARGER SCALE FORCING ASSOCIATED WITH THE UPPER TROUGH AND FRONT OVER
MI WILL ARRIVE ACROSS THE REGION MUCH LATER TODAY. BUT...WEAK MID
LEVEL HEIGHT FALLS AHEAD OF THIS SYSTEM WILL CONTRIBUTE TO
STEEPENING MID LEVEL LAPSE RATES...AND RESULT IN A SUBSEQUENT
INCREASE IN INSTABILITY THROUGH LATE TODAY. THE REGION MAY
EXPERIENCE A COUPLE OF ROUNDS OF STRONG TO SEVERE STORMS AS INITIAL
ACTIVITY NEAR THE WARM FRONT AND WIND SHIFTS SPREADS EWD TOWARD THE
HUDSON VALLEY/NERN PA...AND PRE-FRONTAL ACTIVITY NOW DEVELOPING OVER
OH /REF. MCD 901/ MOVES EWD INTO PARTS OF NWRN PA AND WRN NY...WITH
ACCOMPANYING WIND DAMAGE THREAT...LATER THIS AFTERNOON.

.CARBIN.. 05/27/2007

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

ATTN...WFO...ALY...BGM...BUF...CTP...PBZ...

41787483 40497798 41097932 41987919 42347851 43327692
43397532 43327481 42547468

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