SWODY1
SPC AC 051953
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0253 PM CDT FRI OCT 05 2007
VALID 052000Z - 061200Z
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
PARTS OF THE UPPER MS VALLEY...
..UPPER MS VALLEY...
EARLY AFTERNOON MESOANALYSIS INDICATED SURFACE LOW OVER S-CNTRL SD
WITH ATTENDANT WARM FRONT EXTENDING EWD THROUGH SRN MN INTO NRN WI.
CONSIDERABLE CLOUDINESS HAS LIMITED HEATING AND RESULTANT AIR MASS
DESTABILIZATION SO FAR TODAY OVER ERN SD INTO NWRN IA AND SWRN MN.
HOWEVER...BREAKS IN THE CLOUDS OVER SERN MN INTO WRN WI HAVE ALLOWED
TEMPERATURES TO WARM INTO THE LOWER 80S AS OF 19Z WITH A WEAKENING
CAP. ALOFT...WATER VAPOR IMAGERY SHOWS A LEAD SHORT WAVE TROUGH
LIFTING NEWD THROUGH ERN MN INTO WI. AN ASSOCIATED ZONE OF FORCING
FOR ASCENT ACTING ON MODEST ELEVATED INSTABILITY APPEARS TO BE
SUPPORTING ONGOING STORMS OVER PARTS OF ERN WI WHERE
ISOLATED...SEVERE HAIL WILL BE POSSIBLE NEWD INTO THE UP OF MI. OF
POTENTIALLY MORE INTEREST IS UPSTREAM SHORT WAVE TROUGH OVER WRN NEB
INTO S-CNTRL SD WHICH WILL TRANSLATE NEWD ACROSS REGION TONIGHT.
CONSIDERABLE UNCERTAINTY STILL EXISTS AS TO WHETHER SURFACE-BASED
STORM DEVELOPMENT WILL OCCUR THIS AFTERNOON AND EVENING INVOF WARM
FRONT. SHOULD THIS OCCUR...CURRENT PROFILERS/VWPS AND MODEL
FORECAST SOUNDINGS INDICATE A FAVORABLE KINEMATIC ENVIRONMENT FOR
SUPERCELLS CAPABLE OF TORNADOES...DAMAGING WINDS AND HAIL. A MORE
LIKELY SCENARIO WHICH IS SUPPORTED BY LATEST SHORT TERM MODEL
GUIDANCE IS THE DEVELOPMENT OF ELEVATED TSTMS JUST N OF WARM FRONT
THIS EVENING /I.E. 06/00-03Z/ PERHAPS IN ASSOCIATION WITH
ABOVEMENTIONED NEB/SD SHORT WAVE TROUGH. FORECAST SOUNDINGS
INDICATE SUFFICIENT VERTICAL SHEAR THROUGH THE CLOUD BEARING LAYER
TO SUPPORT ORGANIZED/ROTATING UPDRAFTS WITH LARGE HAIL BEING THE
PRIMARY SEVERE WEATHER THREAT.
..UT/CO NEWD INTO ERN MT...
SCATTERED TSTM DEVELOPMENT IS OCCURRING EARLY THIS AFTERNOON OVER
PORTIONS OF UT...WRN CO AND WRN WY IN ADVANCE OF INTENSIFYING UPPER
TROUGH OVER THE GREAT BASIN. BREAKS IN THE CLOUDS HAVE ALLOWED FOR
RATHER STRONG DIABATIC HEATING TO OCCUR...LEADING TO THE DEVELOPMENT
OF STEEP LOW-LEVEL LAPSE RATES AND RESULTANT SBCAPES OF 250-500
J/KG. FURTHER HEATING/DESTABILIZATION SHOULD SUPPORT ADDITIONAL
STORM DEVELOPMENT THIS AFTERNOON AND EVENING ACROSS SAME GENERAL
AREAS...AND EVENTUALLY NEWD INTO PORTIONS OF ERN MT. A CONCURRENT
STRENGTHENING OF MID-LEVEL WIND FIELDS DOWNSTREAM FROM TROUGH AXIS
IS RESULTING QUITE STRONG VERTICAL SHEAR ACROSS THE REGION. ANY
UPDRAFTS THAT CAN BECOME SUSTAINED IN THIS ENVIRONMENT WILL BE
CAPABLE OF LOCALLY DAMAGING WINDS AND PERHAPS SOME HAIL.
.MEAD.. 10/05/2007
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