[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 191752
SWOMCD
SPC MCD 191751 
ARZ000-LAZ000-TXZ000-OKZ000-192045-

MESOSCALE DISCUSSION 2046
NWS STORM PREDICTION CENTER NORMAN OK
1251 PM CDT THU AUG 19 2004

AREAS AFFECTED...PORTIONS E TX...WRN LA...SWRN AR

CONCERNING...HEAVY RAINFALL...SEVERE TSTM POTENTIAL 

VALID 191751Z - 192045Z

THROUGH AT LEAST 21Z...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE
AND INTENSITY ACROSS MUCH OF E TX AND ADJOINING PORTIONS
AR/LA...MAINLY WITHIN APPROXIMATELY 50 NM OF A LINE FROM
HOU...TXK...HOT.  PRIMARY HAZARD WITH THIS ACTIVITY SHOULD BE HEAVY
RAIN WITH RATES AROUND 3 INCHES/HOUR LIKELY IN SOME LOCALES AND
RATES COMMONLY 1-2 INCHES/HOUR.  LIMITED SEVERE THREAT EXISTS. A FEW
CELLS MAY ROTATE OVER PORTIONS E-CENTRAL/NE TX WITH MARGINAL/BRIEF
TORNADO POTENTIAL OR ISOLATED STRONG-SEVERE DOWNDRAFTS...BUT POOR
ORGANIZATION OF THREAT SUGGESTS WW NOT NECESSARY ATTM.

AIR MASS IS DESTABILIZING OVER MUCH OF DISCUSSION AREA...E AND SE OF
EXPANSIVE AREA OF CLOUDS/PRECIP ASSOCIATED WITH MIDLEVEL
PERTURBATION NEAR SPS. MODIFIED RAOBS AND RUC FCST SOUNDINGS SHOW
WEAKENING CAP...SUPPORTING WIDELY SCATTERED TSTMS NOW FORMING OVER
UPPER TX COASTAL PLAIN AND EXPECTED TO EXPAND NNEWD ACROSS ARKLATEX
AREA.  EXPECT MLCAPE 1500-2500 J/KG...SUPPORTED BY 70S F SFC DEW
POINTS...ALONG WITH RICH DEEP-LAYER MOISTURE...I.E. 1.75-2 INCH PW
AND RH AOA 50 PERCENT THROUGH MUCH OF LOWER-MID TROPOSPHERE.  SOME
HEAVY RAIN POTENTIAL EXISTS ACROSS ENTIRE SWATH...BUT SHOULD BE
MAXIMIZED ALONG SERN PERIPHERY OF RESIDUAL MCS FROM LFK AREA NWD
THROUGH GGG AREA TO NEAR TXK.  IN LATTER CORRIDOR EXPECT NUMEROUS
MERGING/TRAINING CELLS.  MEANWHILE...THOUGH DEEP-LAYER SHEAR WILL
REMAIN WEAK...BOUNDARY LAYER HODOGRAPHS NEAR SRN/SERN EDGE OF MCS
WILL BE FAVORABLE FOR SOME STORM ROTATION OVER E-CENTRAL TX WITH 0-1
KM SRH 100-200 J/KG...INCREASING WWD INTO PORTIONS CENTRAL/N-CENTRAL
TX.  LCLS SHOULD REMAIN BELOW 1500 M AGL INTO PEAK HEATING/MIXING. 
ANOTHER MESOSCALE DISCUSSION MAY BE NEEDED NEXT 1-2 HOURS FOR LATTER
AREA.

..EDWARDS.. 08/19/2004

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

ATTN...WFO...LZK...LCH...SHV...HGX...FWD...

30949333 30359373 29919428 29479547 29599610 30719631
31779633 32099564 32529528 33749442 34879378 34809309
33669261 31389321 

WWWW