[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 220425
SWOMCD
SPC MCD 220425 
ARZ000-OKZ000-220630-

MESOSCALE DISCUSSION 1999
NWS STORM PREDICTION CENTER NORMAN OK
1125 PM CDT THU SEP 21 2006

AREAS AFFECTED...SERN OK AND CNTRL AR

CONCERNING...TORNADO WATCH 784...

VALID 220425Z - 220630Z

AIR MASS WAS DESTABILIZING ACROSS CNTRL/SRN AR LATE THIS EVENING AS
MID-UPPER 60S SFC DEW POINTS ADVECT NWD FROM LA.  LONG-LIVED CYCLIC
SUPERCELL THAT HAD ITS ROOTS IN SOUTHERN OK...CONTINUES TO THRIVE
WITHIN THE ERN-MOST GRADIENT OF INSTABILITY.  OTHERWISE... LINE
SEGMENTS TO THE WEST OF KRUE HAVE RECENTLY BECOME MORE DISCRETE WITH
THE SRN-MOST CELL TAKING ON SUPERCELL CHARACTERISTICS...PROBABLY
TAKING ADVANTAGE OF ELY FLOW WITHIN THE RVR VLY.

GIVEN THE NWD TRANSPORT OF MORE QUALITY MOISTURE OVERNIGHT INTO MOST
OF AR...CURRENT STORMS MAY VERY WELL REMAIN WITHIN THE ERN-MOST
GRADIENT OF INSTABILITY FOR SEVERAL MORE HOURS.  THIS WOULD SHIFT
THE SUPERCELL THREAT INTO CNTRL AR BY 06Z.  

USING A STORM MOTION OF 260/40...0-1KM SRH DERIVED FROM THE DE QUEEN
PROFILER WAS 550+ M2/S2.  THIS SUGGESTS THAT IF THE STORMS CAN
REMAIN ROOTED CLOSE TO THE SFC...THE TORNADO THREAT WILL CONTINUE
INTO CNTRL AR THROUGH 06Z.  ANOTHER TORNADO WATCH MAY BE NEEDED
FARTHER EAST.

..RACY.. 09/22/2006

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

ATTN...WFO...LZK...SHV...TSA...

34029545 36049488 35899241 34019273 

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