[MCD] SWOMCD

Sun Sep 25 18:22:57 UTC 2005

ACUS11 KWNS 251821
SWOMCD
SPC MCD 251821 
GAZ000-ALZ000-TNZ000-KYZ000-MSZ000-252015-

MESOSCALE DISCUSSION 2278
NWS STORM PREDICTION CENTER NORMAN OK
0121 PM CDT SUN SEP 25 2005

AREAS AFFECTED...PORTIONS MS...AL...MID TN

CONCERNING...TORNADO WATCH 819...820...

VALID 251821Z - 252015Z

AS OF 18Z...SUPERCELLS ARE MOVING NNEWD 35-40 KT ACROSS MS/AL BORDER
REGION BETWEEN CBM...MEI...TCL AND MSL.  ADDITIONAL DISCRETE CELLS
MAY EVOLVE FROM TOWERS/ECHOES W MGM AND SW BHM.  POTENTIALLY
TORNADIC SUPERCELLS MAY AFFECT BHM AND HSV VICINITIES WITHIN NEXT
2-3 HOURS.

PRIMARY CONFLUENCE BAND -- E OF WHICH VERTICAL SHEAR PROFILES ARE
MAXIMIZED DUE TO LACK OF VEERED/WLY FLOW -- EXTENDS SWWD ACROSS MEI
AREA TO JUST NE HBG...AND MAY SPAWN A FEW MORE SUPERCELLS BEFORE
WINDS VEER AND BOTH CONVERGENCE AND SHEAR WEAKEN.  AIR MASS WILL
CONTINUE TO DESTABILIZE ACROSS NRN AL AND SRN MID TN...AHEAD OF
MS/AL BORDER AREA SUPERCELLS AND AHEAD OF NEWER CONVECTIVE TOWERS SW
OF BHM.  STRONGEST VERTICAL SHEAR PROFILES ARE EXPECTED TO SHIFT
NEWD ACROSS NRN AL AND MID TN THIS AFTERNOON AS WELL...IN RESPONSE
TO ISALLOBARIC FORCING RELATED TO NEWD EJECTION OF LOW CENTER OVER
NERN AR.  NARROW CORRIDOR OF 800-1200 J/KG MLCAPE IS EVIDENT ACROSS
W-CENTRAL/NWRN AL JUST AHEAD OF MAIN CONVECTIVE BAND...AIDED BY
DIABATIC SFC HEATING OF INFLOW SECTOR...LOW LEVEL WAA AND SFC DEW
POINTS LOW 70S F.  AIR MASS FARTHER N INTO MID TN -- N OF DIFFUSE
SFC WARM FRONT -- IS ONLY MARGINALLY BUOYANT ATTM BUT MAY STILL
DESTABILIZE ENOUGH TO SUPPORT SEVERE.  BOTH WWS MAY BE CLEARED
BEHIND WRN EDGE OF MAIN CONVECTIVE BANDS....WHERE LOW LEVEL FLOW
VEERS...SUBSTANTIALLY REDUCING LIFT AND SHEAR.

..EDWARDS.. 09/25/2005

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

ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MOB...PAH...MEG...JAN...LIX...

31618720 31158806 31128974 31449146 32739011 33918883
35438824 36558855 36628682 36388612 34988557 33838539
33288542 32098658 

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