[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 201557
SWOMCD
SPC MCD 201556 
NHZ000-MAZ000-CTZ000-VTZ000-NYZ000-NJZ000-PAZ000-201800-

MESOSCALE DISCUSSION 2056
NWS STORM PREDICTION CENTER NORMAN OK
1056 AM CDT FRI AUG 20 2004

AREAS AFFECTED...NERN PA...PORTIONS SERN NY...NWRN CT...SRN
VT/NH...WRN MA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 201556Z - 201800Z

TSTMS SHOULD DEVELOP THROUGH AT LEAST 19Z ACROSS HIGHER TERRAIN ON
EITHER SIDE OF HUDSON VALLEY IN NERN PA...NY...MA AND SRN VT. 
ACTIVITY THEN SHOULD INTENSIFY...MOVING EWD OVER SERN NY AND
PORTIONS WRN NEW ENGLAND....WITH DAMAGING WIND MAIN THREAT.  LARGE
HAIL ALSO IS POSSIBLE. OTHER ACTIVITY MAY DEVELOP SUBSEQUENTLY OVER
CENTRAL/ERN PA WHERE CAP IS WEAK BUT DESTABILIZATION WILL TAKE
LONGER.  THESE AREAS ARE BEING MONITORED FOR POSSIBLE WW.

SFC ANALYSIS SHOWS DIFFUSE FRONTAL ZONE FROM SWRN MAINE WSWWD ACROSS
SRN VT/NH TO ALB AREA...THEN ROUGHLY ORIENTED ALONG E-W PORTION OF
NY/PA BORDER.  AIR MASS IS DESTABILIZING RAPIDLY S OF
FRONT...PARTICULARLY FROM NERN PA EWD WHERE RELATIVE LACK OF CLOUDS
HAS ENABLED STRONGEST DIABATIC HEATING...AMIDST WEAK CAPPING. 
MODIFIED RAOBS AND RUC SOUNDINGS SUGGEST MLCAPE AROUND 1500
J/KG...MUCAPE NEAR 3000 J/KG...WITH SFC TEMPS LOW-MID 80S F AND DEW
POINTS UPPER 60S TO LOW 70S.  DIRECTIONAL SHEAR AND CONVERGENCE WILL
REMAIN RELATIVELY WEAK...BECAUSE OF SIGNIFICANT WLY COMPONENT TO
BOUNDARY LAYER FLOW.  HOWEVER...VWP AND RUC FCST HODOGRAPHS INDICATE
SUBSTANTIAL LOW LEVEL AND DEEP-LAYER SPEED SHEAR...RESULTING IN
HODOGRAPHS LARGE ENOUGH TO SUPPORT SUPERCELL DEVELOPMENT IN ANY
SUSTAINED/DISCRETE STORMS.  FORMATION OF SMALL BOWS IS POSSIBLE AS
WELL.  EXPECT 0-3 KM SRH 100-200 J/KG AND 40-50 KT 0-6 KM
SHEAR...LATTER BEING STRONGER WITH NWD EXTENT AND PROXIMITY TO
MID/UPPER JET.

..EDWARDS.. 08/20/2004

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

ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...BUF...CTP...

42007828 42397641 43087430 43537254 43487155 43057107
42707137 42287198 41827276 41557356 41357469 40967676
40827798 

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