SPC AC 240109
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0809 PM CDT WED AUG 23 2006
VALID 240100Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPPER MS
VALLEY AND UPPER GREAT LAKES...
...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF WRN ND...
...UPPER MS VALLEY THROUGH UPPER GREAT LAKES AREA...
EARLY THIS EVENING A QUASISTATIONARY FRONT EXTENDS FROM A WEAK LOW
IN CNTRL SD ESEWD THROUGH SRN MN...SRN WI...NRN IND AND EWD THROUGH
THE OH VALLEY. THE ATMOSPHERE S OF FRONT REMAINS VERY UNSTABLE WITH
STEEP LAPSE RATES AND MLCAPE FROM 4000 J/KG ACROSS SRN MN TO AROUND
1500 J/KG ACROSS NRN IND. STORMS CONTINUE NEAR AND JUST N OF THE
BOUNDARY FROM S CNTRL WI SEWD INTO NRN IND. CURRENT THINKING IS THAT
STORMS WILL CONTINUE DEVELOPING OVER CNTRL AND S CNTRL WI NEXT FEW
HOURS AND SPREAD SEWD AS WLY LOW LEVEL JET ENHANCES ISENTROPIC LIFT
AND THETA-E ADVECTION ON COOL SIDE OF FRONT. STORMS THAT DEVELOP AND
TRACK SEWD NEAR THE FRONT WILL BE CLOSE ENOUGH TO SURFACE BASED FOR
A CONTINUING ISOLATED TORNADO THREAT NEXT FEW HOURS WITH ANY
DISCRETE SUPERCELL STRUCTURES. HOWEVER...SOME STORMS MAY ALSO EVOLVE
INTO SMALL CLUSTERS AND BOWS AS THEY SPREAD SEWD. GIVEN THE STEEP
LAPSE RATES...STRONG INSTABILITY AND FAVORABLE VERTICAL SHEAR FOR
SUPERCELLS...SOME STORMS MAY BE CAPABLE OF PRODUCING VERY LARGE
HAIL.
FARTHER W ACROSS SRN MN WHERE THE STRONGER INSTABILITY EXISTS...THE
00Z RAOB FROM MINNEAPOLIS AS WELL AS LACK OF BOUNDARY LAYER CUMULUS
CONFIRM THAT THE ATMOSPHERE IS STILL CAPPED IN THIS AREA. LIFT MAY
INCREASE ALONG MN PORTION OF THE BOUNDARY LAYER THIS EVENING AS THE
LOW LEVEL JET STRENGTHENS. HOWEVER...GIVEN THE CAP IN
PLACE...CONFIDENCE IS NOT HIGH THAT STORMS WILL BE ABLE TO DEVELOP
MUCH FARTHER W THAT CURRENT ONGOING ACTIVITY.
...ND...
ISOLATED HIGH BASED STORMS HAVE DEVELOP IN THE DEEPLY MIXED REGIME
ACROSS WRN ND. LOW LEVEL THERMODYNAMIC PROFILES WITH LARGE
TEMPERATURE/DEWPOINT SPREADS AND STEEP LAPSE RATES WILL SUPPORT A
THREAT OF ISOLATED DAMAGING WIND. SOME HAIL MAY ALSO ACCOMPANY THE
STRONGER STORMS. FORCING FOR ASCENT WILL INCREASE ACROSS WRN ND
TOWARD THE END OF THIS PERIOD AS A STRONG SHORTWAVE TROUGH
APPROACHES FROM THE W. THREAT FOR ELEVATED STORMS CAPABLE OF
PRODUCING HAIL WILL BE THE MAIN THREAT.
..DIAL.. 08/24/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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