[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 311954
SWOMCD
SPC MCD 311953 
ARZ000-LAZ000-TXZ000-312130-

MESOSCALE DISCUSSION 2368
NWS STORM PREDICTION CENTER NORMAN OK
0153 PM CST MON OCT 31 2005

AREAS AFFECTED...CENTRAL/EASTERN TX..SRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 838...

VALID 311953Z - 312130Z

BROKEN SQUALL LINE CONTINUES MOVING SEWD AT AROUND 30 KT ACROSS
CENTRAL TX...WITH A MORE EWD MOTION OVER NERN TX INTO FAR SWRN AR. 
WITH CONTINUED HEATING AND DESTABILIZATION...SEVERE THREAT EXPECTED
TO PERSIST WITHIN WW FOR SEVERAL MORE HOURS.  CONTINUE VALID PORTION
OF WW.

DESPITE THE MORE LIMITED INSTABILITY APPARENT INTO E-CENTRAL/NERN TX
AND SRN AR...ONGOING/VIGOROUS CONVECTION INDICATES BUOYANCY FIELDS
ARE MORE THAN ADEQUATE FOR SUSTAINED THUNDERSTORMS.  IN
ADDITION...ORIENTATION OF WLY MEAN WIND VECTORS AND MORE N-S
ORIENTED BOW ECHOES INDICATE WIND DAMAGE POTENTIAL WILL REMAIN QUITE
HIGH WITH EWD MOVING STORMS ALONG THIS PORTION OF THE LINE. 
ESPECIALLY GIVEN THE 20 DEGREE SFC T-TD SPREADS/STEEP LOW LEVEL
LAPSE RATES WHICH HAVE DEVELOPED INTO NWRN LA/SRN AR.  /REFERENCE WW
839 JUST ISSUED FOR THIS ACTIVITY./

LATEST INSTABILITY ANALYSES INDICATE AIR MASS IS NOW WEAKLY CAPPED
AND MODERATELY UNSTABLE AHEAD OF ADVANCING SQUALL LINE WITH MLCAPE
AROUND 1000 J/KG INTO MUCH OF ERN TX.  PAT PROFILER ALSO INDICATES
MODEST SHEAR WITHIN WARM SECTOR /0-3 KM SHEAR NEAR 30 KT AND 0-6 KM
SHEAR APPROACHING 40 KT/.  SEWD MOTION OF COMPOSITE OUTFLOW BOUNDARY
WILL LIKELY CONTINUE UNDERCUTTING STORMS DEVELOPING INTO CENTRAL AND
SERN TX THIS AFTERNOON...GIVEN WLY STEERING FLOW ALOFT.  THIS MAY
LIMIT SUSTAINED WIND DAMAGE THREAT ALONG SWRN PORTION OF SQUALL
LINE...THOUGH LARGE HAIL IS STILL EXPECTED WITH THE STRONGER CORES. 
IN ADDITION...BROAD REGION OF LARGE SCALE ASCENT AND WEAKENING CINH
IS SUPPORTING WIDESPREAD MOIST CONVECTION AHEAD OF THE LINE
ATTM...AND THESE STORMS MAY SUSTAIN A HAIL/WIND THREAT INTO THE
EARLY EVENING.

..EVANS.. 10/31/2005

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

ATTN...WFO...JAN...LZK...LCH...SHV...HGX...FWD...CRP...EWX...SJT...

28379885 30989876 33379406 33949391 33929174 31449211
30729423 

WWWW