[MCD] SWOMCD

Sun Sep 25 15:37:20 UTC 2005

ACUS11 KWNS 251438
SWOMCD
SPC MCD 251438 COR
ALZ000-TNZ000-MSZ000-KYZ000-MOZ000-ARZ000-LAZ000-251600-

MESOSCALE DISCUSSION 2277
NWS STORM PREDICTION CENTER NORMAN OK
0938 AM CDT SUN SEP 25 2005

AREAS AFFECTED...PORTIONS MS...ERN AR...WRN/MID TN...NWRN AL...MO
BOOT-HEEL

CONCERNING...TORNADO WATCH 818...

VALID 251438Z - 251600Z

CORRECTED FOR DIRECTIONAL TYPO

WW WILL BE REPLACED BEFORE SCHEDULED 18Z EXPIRATION.  BECAUSE OF
ARCHING GEOMETRY OF THREAT...TWO WWS MAY BE NEEDED -- ALIGNED NEARLY
SW-NE OVER PORTIONS SRN/CENTRAL MS AND SE-NW FARTHER N.

PRIMARY THREAT WILL SHIFT SLOWLY NEWD ACROSS NRN MS...WRN TN AND
PERHAPS ADJACENT PORTIONS NWRN AL AND MID TN THROUGH EARLY-MID
AFTERNOON.  SFC MESOANALYSIS INDICATES WEAK WARM FRONT AND
CONFLUENCE AXIS FROM NEAR MEM SEWD ACROSS NERN MS AND NWRN/CENTRAL
AL.  VERTICAL SHEAR IS FAVORABLE FOR SUPERCELLS ON BOTH SIDES OF
THIS BOUNDARY...BUT WILL REMAIN SO FOR LONGER TO ITS N WHERE
PRESSURE FALLS WILL KEEP SFC FLOW RELATIVELY BACKED.  STRONGEST
BUOYANCY WILL REMAIN S OF WARM FRONT AND AWAY FROM THICKEST CLOUD
COVER. MEANWHILE VWP AND RUC SOUNDINGS INDICATE LOW LEVEL
HODOGRAPHS REMAIN LARGE WITH 0-1 KM SRH RANGING FROM AROUND 300 J/KG
S-CENTRAL MS TO 800 J/KG WRN TN.  COLDEST IR CLOUD TOPS AND MOST
FREQUENT CG LIGHTNING REMAIN OVER SWRN/CENTRAL MS WHERE MLCAPES
500-1000 J/KG ARE INDICATED...HOWEVER AIR MASS FARTHER NE SHOULD
DESTABILIZE WITH TIME THROUGH DIABATIC HEATING AND WARM ADVECTION.

SUPERCELL/TORNADO POTENTIAL SHOULD DIMINISH WITH TIME ACROSS
PORTIONS SRN MS AS CENTRAL CORE OF RITA REMNANTS CONTINUE TO MOVE
NEWD ACROSS AR.  ASSOCIATED ISALLOBARIC FORCING -- WITH PRESSURE
FALLS RETREATING AWAY FROM AREA -- SHOULD RESULT IN PROGRESSIVELY
MORE VEERED SFC FLOW AND CORRESPONDING REDUCTION IN LOW-LEVEL AND
DEEP-LAYER SHEAR.  HOWEVER STORMS MAY ROTATE IN MEANTIME WITH
LINGERING TORNADO POTENTIAL...PRIMARILY WITHIN CONVECTIVE BAND NOW
EVIDENT FROM NEAR HEZ NEWD INTO N-CENTRAL MS.  BEHIND THAT
BAND...EVEN MORE VEERED FLOW AND WEAK SHEAR S OF CIRCULATION
CENTER...AND WEAK LOW-MIDLEVEL FLOW NEAR CENTER -- INDICATE WRN
PORTION WW MAY BE CLEARED BEHIND PRIMARY CONVECTIVE BAND.

..EDWARDS.. 09/25/2005

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

ATTN...WFO...OHX...BMX...HUN...MOB...PAH...MEG...JAN...LIX...LZK...

33238756 31988842 31378928 31219078 31389138 31649166
31979157 32399106 33329016 34389011 35219055 35899138
36219180 36419172 36569014 36438835 35988765 35248734
34418729 33468753 