[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 211728
SWOMCD
SPC MCD 211728 
TXZ000-211900-

MESOSCALE DISCUSSION 2555
NWS STORM PREDICTION CENTER NORMAN OK
1128 AM CST TUE DEC 21 2004

AREAS AFFECTED...UPPER TX COAST AND ADJACENT COASTAL WATERS

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 211728Z - 211900Z

TSTMS HAVE BEEN INCREASING ALONG THE UPPER TX COAST FROM NEAR KIAH
TO KGLS AND FROM 60-90 NM OFFSHORE KGLS THIS MORNING.  THE STORMS
ARE PROBABLY BEING AIDED BY WEAK LARGE SCALE ASCENT ASSOCIATED WITH
A SHORTWAVE TROUGH MIGRATING ACROSS SERN TX.  MESOANALYSIS PLACES A
1012 MB LOW JUST SOUTH OF GALVESTON ISLAND WITH THE COASTAL TROUGH
EXTENDING FROM THE UPPER TX COAST SWD ACROSS THE WRN GULF BASIN. 
TONGUE OF LOW-MID 60S DEW POINTS HAS ADVECTED NWD ALONG THIS TROUGH
BENEATH STEEP LAPSE RATES IN THE H7-H5 LAYER.  THOUGH STRONGER
INSTABILITY WILL LIKELY REMAIN OFFSHORE SUPPORTING THE STRONGER
TSTMS/SUPERCELLS...INSOLATION ALONG THE COAST...RELATIVELY COOL
TROPOSPHERE AND 30 KTS OF 0-6KM SHEAR MAY CONTRIBUTE TO SOME STORM
ORGANIZATION INLAND THIS AFTERNOON.  SEVERE HAIL WILL BE THE PRIMARY
THREAT...BUT AN ISOLD TORNADO IS POSSIBLE.  FUNNEL CLOUDS WERE
OBSERVED EARLIER THIS MORNING OFFSHORE OF GALVESTON ISLAND.

FARTHER S WHERE GREATER INSTABILITY IS BEING OBSERVED...THE THREATS
FOR SUPERCELLS WITH LARGE HAIL AND WATERSPOUTS WILL CONTINUE.  THESE
STORMS SHOULD STAY OFFSHORE...BUT LEFT SPLITS COULD MOVE ONSHORE
WITH HAIL POSSIBLE.

..RACY.. 12/21/2004

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

ATTN...WFO...LCH...HGX...

29019527 30049529 30189410 29139384 28599410 28439493 

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