SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT WED MAY 23 2012 VALID 231200Z - 241200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL PLAINS/UPPER MIDWEST... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CAROLINAS... ...SYNOPSIS... HEIGHT FALLS WILL OCCUR ACROSS THE SOUTHERN ROCKIES/CENTRAL PLAINS AS AN AMPLIFYING LONGWAVE TROUGH BECOMES INCREASINGLY PREVALENT OVER THE WESTERN HALF OF THE CONUS DURING THE PERIOD. SPLIT UPPER FLOW/WEAKER WESTERLIES WILL EXIST OVER THE EASTERN CONUS AS A RELATIVELY WEAK/SLOW-MOVING UPPER LOW CONTINUES A NORTHEASTWARD PROGRESSION OVER THE SOUTHEAST COAST. ...CENTRAL PLAINS/UPPER MIDWEST... GIVEN THE LARGE SCALE SCENARIO AS PREVIOUSLY DESCRIBED...CENTRAL HIGH PLAINS SURFACE CYCLOGENESIS IS EXPECTED TODAY AS A COLD FRONT MAKES A SLOW BUT STEADY SOUTHEASTWARD PROGRESSION FROM THE EASTERN DAKOTAS TO MN/EASTERN NEB/WESTERN IA AND WESTERN/NORTHERN KS BY EARLY THIS EVENING. BENEATH A RELATIVELY STOUT EAST-NORTHEASTWARD ADVECTING ELEVATED MIXED LAYER...STEADY SOUTH-SOUTHWESTERLY MOISTURE TRANSPORT WILL CONTINUE TO OCCUR ALONG/AHEAD OF THE FRONT...BUT AMPLE MIXING/LIMITED SOURCE REGION MOISTURE WILL LIKELY LIMIT WARM SECTOR SURFACE DEWPOINTS TO THE 50S/LOWER 60S F. GIVEN THE EXPECTED STRENGTH/EXTENT OF THE ELEVATED MIXED LAYER/MARGINAL MOISTURE...SURFACE BASED DEEP CONVECTIVE DEVELOPMENT WILL GENERALLY BE RELEGATED TO THE IMMEDIATE SOUTHWEST-NORTHEAST ORIENTED FRONTAL ZONE. THIS SEEMS LIKELY TO INITIALLY OCCUR BY AROUND MID-AFTERNOON ACROSS PORTIONS OF CENTRAL/SOUTHERN MN INTO FAR SOUTHEAST SD/NORTHEAST NEB/NORTHWEST IA. OTHER/SEPARATE DEVELOPMENT SEEMS LIKELY TO OCCUR THIS AFTERNOON ACROSS NORTHEAST CO AMID DEVELOPING LOW-LEVEL UPSLOPE TRAJECTORIES. WITH STRONG VERTICAL SHEAR MAXIMIZED NEAR/BEHIND THE FRONT...VERY STEEP LAPSE RATES AND MODERATE BUOYANCY...1000-2500 J/KG MLCAPE /STRONGEST ACROSS SOUTHEAST NEB AND NORTHERN KS/...WILL SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL. A TORNADO OR TWO WILL BE POSSIBLE AS WELL...ALTHOUGH MARGINAL MOISTURE CONTENT AND EVENTUAL FRONTAL UNDERCUTTING/STORM MERGERS SHOULD LIMIT THE OVERALL TORNADO THREAT. ...SOUTHEAST STATES/CAROLINAS... A COOL MID-LEVEL POCKET /-14C TO -16C/ WILL OVERSPREAD THE CAROLINAS TODAY IN ASSOCIATED WITH A PERSISTENT/SLOW-MOVING UPPER LOW. COUPLED WITH LOCALLY STRONGER INSOLATION/HEATING...A VERY STEEP LAPSE RATE/MODEST SHEAR ENVIRONMENT BE WILL BE FAVORABLE FOR THE DEVELOPMENT AND SUSTENANCE OF MULTICELLS CAPABLE OF SEVERE HAIL AND LOCALLY DAMAGING WINDS...ESPECIALLY THIS AFTERNOON/EARLY EVENING. GIVEN THE POTENTIAL FOR STRONGER DESTABILIZATION...THIS ESPECIALLY APPEARS TO BE THE CASE ACROSS THE PIEDMONT/COASTAL AREAS OF THE CAROLINAS AND PERHAPS SOUTHEAST VA. ..GUYER/ROGERS.. 05/23/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1200.html
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