[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 211626
SWOMCD
SPC MCD 211626 
MEZ000-MAZ000-NHZ000-RIZ000-VTZ000-CTZ000-NYZ000-211830-

MESOSCALE DISCUSSION 2048
NWS STORM PREDICTION CENTER NORMAN OK
1126 AM CDT SUN AUG 21 2005

AREAS AFFECTED...PORTIONS VT...NH...MA...CT...RI...SERN AND EXTREME
E-CENTRAL NY...SWRN MAINE

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 211626Z - 211830Z

THREAT WILL INCREASE FOR SEVERE TSTMS THROUGH 19Z AS BOUNDARY LAYER
CONTINUES TO HEAT/DESTABILIZE...IN ENVIRONMENT OF AT LEAST MARGINAL
VERTICAL SHEAR.  MAIN THREAT IS DAMAGING GUSTS...ISOLATED HAIL
POSSIBLE.  AREA IS BEING UPGRADED TO CATEGORICAL SLGT RISK IN 1630Z
OUTLOOK AND WILL BE MONITORED FOR POSSIBLE WW.

SFC MESOANALYSIS SHOWS DIFFUSE COLD FRONT -- BETTER DEFINED IN
ISODROSOTHERMAL THAN ISOTHERMAL FIELDS GIVEN DIABATIC HEATING --
FROM NERN NY SWWD ACROSS CENTRAL/WRN PA...PRECEDED BY SFC TROUGH AND
WEAK WIND SHIFT LINE FROM WRN LONG ISLAND NEWD ROUGHLY UP CT RIVER
VALLEY.  WARM FRONT IS ANALYZED FROM NRN VT SEWD ACROSS EXTREME SWRN
MAINE OFFSHORE MA.  FRONTS AND TROUGH EACH SHOULD MOVE EWD ACROSS
REGION.  THERMAL AXIS IS ANALYZED FROM DE VALLEY NEWD TOWARD CT
VALLEY OF VT/NH BORDER...MEETING A MOIST AXIS THAT EXTENDS FROM LONG
ISLAND NWD UP CT VALLEY NEAR TROUGH/WIND SHIFT LINE.  BOUNDARY LAYER
OVER THIS AREA WILL CONTINUE TO HEAT AND DESTABILIZE...WITH EARLY
AFTERNOON INSOLATION AND DEW POINTS 70S F YIELDING MLCAPES THAT
RANGE FROM ABOUT 500 J/KG NEAR CANADIAN BORDER TO 1500 J/KG AROUND
SRN CT.  MOISTURE CHANNEL IMAGERY AND RAOB ANALYSES INDICATE SERN
EDGE OF BOTH COOLING AND DRYING ALOFT SHIFTING INTO REGION...AIDING
POTENTIAL INSTABILITY. NEGATIVE FACTOR IS VEERING SFC FLOW AND
RESULTING LIMITATIONS ON CONVERGENCE.  HOWEVER...CINH SHOULD BE
REMOVED THROUGH DIABATIC HEATING ALONE...SO WEAKER CONVERGENCE MAY
SERVE TO KEEP ANY ACTIVITY THAT DEVELOPS MORE DISCRETE.

VERTICAL WIND PROFILES ARE LARGELY UNIDIRECTIONAL WITH STRONG WLY
COMPONENT.  SPEED SHEAR STRENGTHENS WITH NWD EXTENT...NEARLY INVERSE
TO TREND OF BUOYANCY.  40-45 KT EFFECTIVE SHEAR IS EXPECTED IN
PREFRONTAL AIR MASS OVER SRN NEW ENGLAND...STRENGTHENING TO AROUND
55 KT OVER NRN PORTIONS NH/VT.

..EDWARDS.. 08/21/2005

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

ATTN...WFO...GYX...BOX...BTV...OKX...ALY...

44667315 44947266 44967212 44757144 44377101 44067071
43747065 43287073 42957087 42367103 41867093 41497140
40977223 40757262 40657332 40757364 41197383 41917424
42647386 43907312 

WWWW