SPC 1300Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0725 AM CDT MON APR 30 2012 VALID 301300Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL AND SOUTHERN PLAINS... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE MID MS AND OH VALLEYS... MORNING WATER VAPOR IMAGERY SHOWS BROAD CYCLONIC FLOW OVER MOST OF THE WESTERN...PLAINS...AND MIDWEST STATES. A SERIES OF SHORTWAVE TROUGHS EMBEDDED IN THIS FLOW REGIME WILL TRACK ACROSS THE CENTRAL PLAINS INTO THE OH VALLEY...PROVIDING A AXIS OF SHOWERS AND THUNDERSTORMS FROM WEST TX INTO WV/PA. ...CENTRAL/SOUTHERN PLAINS... WIDESPREAD THUNDERSTORMS HAVE BEEN ONGOING OVERNIGHT ACROSS PARTS OF KS/OK/MO. THESE STORMS HAVE RESULTED IN A WELL-DEFINED OUTFLOW BOUNDARY THAT EXTENDS ROUGHLY FROM AMA-SPS-ADM-FSM. EASTERLY LOW LEVEL WINDS ON THE NORTH SIDE OF THE BOUNDARY WILL HELP TO TRANSPORT AMPLE MOISTURE WESTWARD INTO THE TX PANHANDLE. MOST MODEL SOLUTIONS AGREE ON STORMS FORMING ALONG THE DRYLINE/REMNANT OUTFLOW BOUNDARY BETWEEN 19-22Z...AS A WEAK SHORTWAVE TROUGH NOW NEAR THE 4-CORNERS AREA APPROACHES THE REGION. THE 12Z AMA RAOB ALSO SUPPORTS RATHER EARLY INITIATION WITH STEEP LAPSE RATES AND ONLY A MINIMAL CAP. STRONG DEEP LAYER EFFECTIVE SHEAR AND MEAN FLOW ORTHOGONAL TO DRYLINE WILL PROMOTE DISCRETE SUPERCELL DEVELOPMENT WITH VERY LARGE HAIL POSSIBLE. THE TORNADO POTENTIAL WILL BE DEPENDENT ON THE EVOLUTION OF THE REMNANT OUTFLOW BOUNDARY...BUT THERE DOES APPEAR TO BE SOME RISK OF A FEW TORNADOES DURING THE EVENING FROM SOUTHWEST KS INTO THE TX PANHANDLE AND SOUTHWEST OK. DURING THE EVENING...STORMS MAY GROW UPSCALE AND SPREAD EASTWARD ACROSS PORTIONS OF WESTERN/CENTRAL OK WITH AN CONTINUED RISK OF HAIL AND DAMAGING WINDS. ...MID MS AND OH VALLEYS... WEAKENING SHOWERS AND THUNDERSTORMS ARE ONGOING THIS MORNING ALONG AN AXIS FROM SOUTHWEST MO/NORTHWEST AR INTO CENTRAL IL. THIS ACTIVITY IS AHEAD OF A SHORTWAVE TROUGH OVER NORTHERN OK...WHICH IS FORECAST TO TRACK EASTWARD INTO IL/IND BY LATE AFTERNOON. THE OUTFLOW BOUNDARY/FRONT ASSOCIATED WITH THESE STORMS WILL BE POSITIONED ROUGHLY ALONG/NORTH OF THE OH RIVER LATER TODAY AND SHOULD BE THE FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT. EARLY VISIBLE SATELLITE IMAGES SUGGEST THAT RATHER STRONG HEATING WILL OCCUR ACROSS THIS REGION...LEADING TO MLCAPE VALUES OF 1500-2000 J/KG. MODERATELY STRONG WESTERLY FLOW ALOFT WILL RESULT IN ORGANIZED MULTICELL AND OCCASIONAL SUPERCELL STORMS CAPABLE OF LARGE HAIL AND DAMAGING WINDS. ACTIVITY MAY PERSIST WELL INTO THE EVENING AS A LOW LEVEL JET STRENGTHENS ACROSS KY. ..SMITH/HART.. 04/30/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1300.html
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