SPC MESOSCALE DISCUSSION 2067 FOR SRN MO...NWRN AR
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

VALID 231741Z - 232030Z

TSTMS ARE EXPECTED TO DEVELOP AND INCREASE IN COVERAGE OVER OZARKS
NEXT FEW HOURS...WITH DAMAGING WIND POSSIBLE.  WW MAY BE REQUIRED.

COLD FRONT -- ANALYZED AT 17Z NEAR A STL-TBN-SGF-TUL LINE -- IS
ALSO DENOTED BY LOW CLOUD BAND ON VIS IMAGERY.  FLOW IN WARM SECTOR
SHOULD REMAIN LIGHT AND VARIABLE WITH STRONGEST ISALLOBARIC FORCING
WELL TO THE NE OVER NRN INDIANA/MI.  HOWEVER...CAP APPEARS TO BE
WEAKENING OVER FRONT ENOUGH TO ALLOW CONVECTIVE DEVELOPMENT AMIDST
WEAK-MODERATE CONVERGENCE ALONG WIND SHIFT.  SEVERAL TCU AND SMALL
CB HAVE FORMED ALONG A FRONTAL WAVE JUST S SGF...AND OTHER
DEVELOPMENT IS POSSIBLE WITHIN NEXT 2-3 HOURS EWD ACROSS PORTIONS
OZARKS AS FRONT CONTINUES SEWD 20-25 KT MOTION.  AREA IS ON SRN
PERIPHERY OF STRONGEST MID LEVEL FLOW AND OF LOW-MID LEVEL SHEAR
FAVORABLE FOR SEVERE...WITH 30-35 KT IN 3-6 KM AGL LAYER AT SGF BUT
50 KT REMAINING AROUND STL.  SGF RAOB MODIFIED AND MIXED FOR NEXT
2-3 HOURS YIELDS 1500-2000 J/KG MLCAPE...WITH NO CINH...AND AN
INVERTED-V PROFILE IN BOUNDARY LAYER SUPPORTING MAINTENANCE OF
INTENSE DOWNDRAFT CURRENTS FROM CLOUD BASE TO SURFACE.

..EDWARDS.. 09/23/01

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