SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT SAT SEP 01 2012 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NEB/SD... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE UPPER GREAT LAKES REGION... ...SYNOPSIS... QUASI-ZONAL FLOW FIELD ALOFT WILL CONTINUE THIS PERIOD...AS AN UPPER TROUGH ADVANCES SLOWLY ACROSS THE CANADIAN PRAIRIE SUPPRESSING THE CENTRAL U.S. RIDGE. AT THE SURFACE...A FAIRLY NONDESCRIPT PATTERN IS FORECAST...WITH A LOW PRESSURE TROUGH FROM THE GREAT LAKES SWWD INTO THE PLAINS FOCUSING ACTIVE CONVECTION. ...CENTRAL AND ERN NEB/S CENTRAL AND SERN SD... AS THE COLD FRONT WASHES OUT/RETURNS NWD ACROSS THE KS/NEB REGION...DIURNAL HEATING WILL AID IN MARGINAL TO MODERATE AFTERNOON DESTABILIZATION. AS A VORT MAX SHIFTS OUT OF WY INTO THIS REGION...INCREASING ASCENT SHOULD SUPPORT STORM DEVELOPMENT WITHIN THE DESTABILIZING AIRMASS. AS THE VORT MAX EJECTS...ACCOMPANYING/COMPACT 30 TO 35 KT WLY JET STREAK AT MID LEVELS WILL OVERSPREAD ENHANCED LOW-LEVEL SELYS...YIELDING SHEAR PROFILES FAVORABLE FOR SUPERCELLS. WHILE HAIL AND DAMAGING WINDS WILL BE POSSIBLE...SOME TORNADO POTENTIAL IS ALSO EVIDENT -- WARRANTING INTRODUCTION OF SLIGHT RISK ACROSS THIS REGION. DEVELOPING SLY LOW-LEVEL JET AFTER DARK MAY SUPPORT A CONTINUATION OF THE CONVECTION...WITH LINGERING SEVERE THREAT SHIFTING SLOWLY EWD THROUGH THE EVENING. ...PARTS OF UPPER MI AND ERN WI... AS THE WEAKENING COLD FRONT CROSSES UPPER MI/WI DURING THE DAY...A HEATING BOUNDARY LAYER BENEATH COOLING MID-LEVEL TEMPERATURES WILL RESULT IN A DESTABILIZING AFTERNOON AIRMASS. THIS SHOULD SUPPORT REDEVELOPMENT OF SHOWERS AND STORMS INVOF THE FRONT...MOST LIKELY ACROSS CENTRAL UPPER MI AND ERN WI. WITH 30 TO 35 KT MID-LEVEL WLYS AND GENERALLY UNIDIRECTIONAL FLOW FIELD WITH HEIGHT...POTENTIAL FOR LOCALLY DAMAGING WINDS IS EVIDENT...AND POSSIBLY MARGINAL HAIL. THREAT SHOULD LINGER INTO THE EVENING...UNTIL BOUNDARY LAYER COOLING YIELDS A DECREASE IN WIND POTENTIAL. ..GOSS.. 09/01/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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