[MCD] SWOMCD

Fri Oct 27 02:03:10 UTC 2006

ACUS11 KWNS 270206
SWOMCD
SPC MCD 270205 
ARZ000-LAZ000-TXZ000-OKZ000-270400-

MESOSCALE DISCUSSION 2160
NWS STORM PREDICTION CENTER NORMAN OK
0905 PM CDT THU OCT 26 2006

AREAS AFFECTED...ERN TX...EXTREME SERN OK...SWRN AR AND NWRN LA

CONCERNING...SEVERE THUNDERSTORM WATCH 840...

VALID 270205Z - 270400Z

BULK OF THE LARGE SCALE ASCENT ASSOCD WITH THE UPSTREAM TROUGH HAS
YET TO SPREAD ACROSS THE ARKLATEX REGION THIS EVE.  TSTMS ARE
BEGINNING TO FORM ALONG A PRE-DRYLINE CONFLUENCE FROM THE RED RVR
VLY OF NERN TX/SERN OK SWD TO JUST EAST OF THE DALLAS METRO AREA AT
MID-EVENING.  PRIND THAT TSTMS SHOULD EXPAND NEWD INTO SWRN/CNTRL AR
THROUGH THE NEXT SEVERAL HOURS AS THE TROUGH SPREADS EWD.  RUC
SOUNDINGS SUGGEST THAT STORMS WILL LIKELY BE ELEVATED JUST ABOVE THE
SURFACE WHERE THE BOUNDARY LAYER REMAINED COOL/CLOUDY MOST OF THE
DAY ACROSS AR. THUS...WHILE THE DEEP VERTICAL SHEAR WILL BE
CONDUCIVE FOR SUPERCELLS...DAMAGING WIND THREAT APPEARS MINIMAL. 
MOREOVER...MID-TROPOSPHERIC LAPSE RATES ARE RATHER POOR BASED ON
EVENING SOUNDINGS AND ONLY THE STRONGEST STORMS WILL PRODUCE HAIL.

FARTHER S...TSTMS THAT FORMED FROM MID-LEVEL CONVECTION EARLIER HAVE
EVOLVED INTO SHORT-LINE SEGMENTS.  THERE CONTINUES TO BE THE
OCCASIONAL BRIEF SUPERCELL STRUCTURE...BOTH EMBEDDED WITHIN THE
LINES AND WITH NEWER STORMS NW-W OF KLFK.  WHILE LAPSE RATES DO NOT
SUPPORT LARGE HAIL...DAMAGING WINDS WILL REMAIN A THREAT WITH THE
STRONGER STORMS.  THE ACTIVITY ACROSS ERN TX HAS BEEN THRIVING ALONG
NRN EDGE OF WHERE THE BOUNDARY LAYER HEATED THE MOST TODAY. 
MODIFYING THE 00Z KSHV SOUNDING SUGGESTS THAT AS THE STORMS MOVE
TOWARD THE ERN EDGE OF THE WW...THEY WILL BECOME SLIGHTLY ELEVATED. 
WHILE THE ATTENDANT SEVERE THREATS WILL LIKELY DIMINISH...THE HEAVY
RAINFALL PROSPECTS WILL INCREASE AS TSTMS TRAIN IN A SW-NE FASHION
ACROSS NRN LA AND SERN TX.

..RACY.. 10/27/2006

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

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

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