[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 172222
SWOMCD
SPC MCD 172219 
VAZ000-NCZ000-MDZ000-DCZ000-PAZ000-WVZ000-180015-

MESOSCALE DISCUSSION 2238
NWS STORM PREDICTION CENTER NORMAN OK
0519 PM CDT FRI SEP 17 2004

AREAS AFFECTED...CNTRL MD...ERN WV PNHDL...NRN/ERN VA...DC...ERN NC

CONCERNING...TORNADO WATCH 833...834...

VALID 172219Z - 180015Z

THREATS FOR A TORNADO OR TWO WILL INCREASE FOR THE WASHINGTON D.C.
AREA THROUGH 00Z.  OTHERWISE...TORNADO WATCH 833 AND 834 WILL BE IN
EFFECT THROUGH 00Z FOR THE REMAINDER OF CNTRL MD...ERN WV
PNHDL...NRN/ERN VA AND ERN NC FOR THE THREAT FOR ISOLD TORNADOES. 
NEW TORNADO WATCHES WILL PROBABLY BE NEEDED BEFORE 00Z.

SEVERAL WELL-DEFINED SUPERCELLS HAVE BEEN MOVING NWD AT AROUND 25
KTS IN A BAND ARCING FROM THE EXTREME ERN WV PNHDL SWD INTO CNTRL
VA.  ANOTHER BAND OF TSTMS WAS BEGINNING TO APPROACH THE POTOMAC
RIVER FROM NEAR STERLING SWD TO EAST OF FREDERICKSBURG AND WILL BE
IMPACTING THE WASHINGTON D.C. AREA THROUGH 00Z.

MESOANALYSIS SHOWS THAT THE AREA ALONG THE POTOMAC RIVER EWD INTO
CNTRL MD HAD WARMED TO NEAR 80F WITH DEW POINTS IN THE MID 70S. 
THUS...IT IS REASONABLE TO EXPECT THE TSTM BAND APPROACHING THE
RIVER WILL BE MAINTAINED AND POSSIBLY INCREASE AS STRONGEST PRESSURE
FALLS TRANSLATE NWD FROM SERN VA.  USING A STORM MOTION 185/23
KTS...THE SRH VALUES ON THE STERLING VWP WERE IN EXCESS OF 180 M2/S2
IN THE LOWEST 1 KM.  THUS...POTENTIAL FOR TORNADOES WILL EXIST FOR A
FEW MORE HOURS...AND IN PARTICULAR THE WASHINGTON D.C. AREA THROUGH
00Z.

OTHERWISE...BAND OF TSTMS MOVING NEWD THROUGH CNTRL VA WILL MOVE
INTO ERN VA...CNTRL/SRN MD AND ADJACENT CHESAPEAKE BAY IN THE NEXT
FEW HOURS.  THOUGH A DECREASE IN THE DISCRETE CELLS ARE EXPECTED
AFTER SUNSET...IT IS NOT ENTIRELY CLEAR THAT THE TORNADO THREATS
WILL DECREASE. THUS...NEW TORNADO WATCH REPLACEMENTS WILL PROBABLY
BE NECESSARY BEFORE 00Z FOR PARTS OF THE REGION.

..RACY.. 09/17/2004

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

ATTN...WFO...PHI...AKQ...MHX...CTP...LWX...RAH...

34987733 39737858 39707641 34967540 

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