[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 282245
SWOMCD
SPC MCD 282245 
ARZ000-TXZ000-OKZ000-290045-

MESOSCALE DISCUSSION 2291
NWS STORM PREDICTION CENTER NORMAN OK
0545 PM CDT WED SEP 28 2005

AREAS AFFECTED...N-CENTRAL/NERN TX...FAR SERN OK...AND FAR SWRN AR

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 282245Z - 290045Z

AN ISOLATED SEVERE THUNDERSTORM THREAT IS EXPECTED ACROSS N-CENTRAL
TX DURING THE NEXT FEW HOURS WITH LOCALIZED DAMAGING WINDS THE MAIN
THREAT. ADDITIONAL TSTM DEVELOPMENT ANTICIPATED ACROSS NERN TX INTO
SWRN AR/SERN OK MAY RESULT IN MARGINALLY SEVERE STORMS LATE THIS
EVENING. ORGANIZATION OF ACTIVITY IS EXPECTED TO BE LIMITED...LIKELY
PRECLUDING WW. HOWEVER...TRENDS WILL BE MONITORED.

AT 2230Z...SEVERAL SURFACE BOUNDARIES EXIST ACROSS THE SRN PLAINS. A
STRONG COLD FRONT WAS MOVING GENERALLY SWD...AND EXTENDED FROM 10S
LBB TO SPS TO 25W MLC BEFORE ARCING NEWD INTO FAR NWRN AR. A WIND
SHIFT PRECEDES THE COLD FRONT BY ROUGHLY 70NM IN N-CENTRAL TX AND
ROUGHLY 30NM IN SERN OK. AN ADDITIONAL BOUNDARY EXTENDS N-S THROUGH
THE DFW METRO AREA TO 10W ACT. INTERSECTION OF THIS DRYLINE-LIKE
FEATURE WITH PREFRONTAL TROUGH HAS BEEN SUFFICIENT FOR ISOLATED
STRONG TO SEVERE CELLS ACROSS N-CENTRAL TX.

BOUNDARY LAYER IS EXTREMELY HOT ACROSS N-CENTRAL TX...WITH SURFACE
TEMPERATURES IN THE LOW 100S IN THE DALLAS METRO AREA.
ADDITIONALLY...VERTICAL MIXING HAS RESULTED IN SURFACE DEWPOINT
DEPRESSIONS OF 50-60F WEST OF MOIST AXIS/N-S BOUNDARY. LOW SUB-CLOUD
RH SHOULD BE SUFFICIENT FOR STRONG EVAPORATIVELY ENHANCED DOWNDRAFTS
AND MAY PRODUCED LOCALIZED AREAS OF SEVERE WIND GUSTS. LOW-MID LEVEL
WIND FIELDS ARE WEAK IN THE REGION...WHICH SHOULD LIMIT STORM
ORGANIZATION AND LONGEVITY OF INDIVIDUAL CELLS. OUTFLOW DOMINANT
CHARACTER OF THUNDERSTORMS IS EVIDENT IN 0.5DEG REFLECTIVITY DATA
FROM FWS...AND THIS TREND SHOULD PERSIST THROUGH THE REMAINDER OF
THE EVENING. AFTER SUNSET...BOUNDARY LAYER STABILIZATION SHOULD
REDUCE SEVERE WEATHER THREAT AND INTENSITY OF THIS CONVECTION.

AS COLD FRONT PUSHES SSEWD THROUGH FAR SERN OK AND INTO SWRN AR
LATER THIS EVENING...ADDITIONAL TSTM DEVELOPMENT IS POSSIBLE. AIR
MASS IS MODERATELY UNSTABLE IN THIS REGION...AND SHOULD SUPPORT AT
LEAST AN ISOLATED THREAT OF DAMAGING WINDS OR LARGE HAIL ACROSS FAR
NERN TX/FAR SERN OK/SWRN AR LATER THIS EVENING AS LOW-LEVEL
CONVERGENCE INCREASES WITH APPROACH OF COLD FRONT.

..BANACOS.. 09/28/2005

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

ATTN...WFO...SHV...TSA...FWD...OUN...

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