SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0220 AM CDT MON MAY 21 2012 VALID 231200Z - 241200Z ...NRN KS TO SWRN MN... MODELS CONTINUE TO SUGGEST HEIGHTS WILL FALL ACROSS THE GREAT BASIN INTO THE CNTRL ROCKIES DURING THE DAY3 PERIOD AS A BELT OF STRONGER FLOW SAGS SEWD TOWARD NRN NM. AS THE UPPER TROUGH ESTABLISHES ITSELF OVER THE WRN U.S. LEE TROUGHING ACROSS THE HIGH PLAINS WILL ENSURE SLY LOW LEVEL FLOW...AND POTENTIALLY MORE FAVORABLE TRAJECTORIES FOR MOISTURE TO RETURN ACROSS THE WRN GULF BASIN. LATEST DATA SUGGESTS THIS MORE SIGNIFICANT MOISTENING PROCESS WILL BEGIN TO OCCUR LATE IN THE PERIOD AND MOST LIKELY REACH NO FARTHER NORTH THAN TX WHERE MARITIME TROPICAL AIR SHOULD RETURN TO THE COASTAL PLAINS. ECMWF AND TO A LESSER DEGREE THE GFS SUGGEST A VERY STRONG CAP WILL OVERSPREAD THE CNTRL PLAINS WHERE 700 MB TEMPERATURES COULD APPROACH 16C. THIS PLUME OF WARM AIR ALOFT SHOULD SPREAD NEWD ACROSS KS INTO SERN NEB/SWRN IA BY EARLY EVENING. CAPPING WILL LIKELY BE AN ISSUE IN THE DEVELOPMENT OF WARM SECTOR CONVECTION. WHILE THE NAM SUGGESTS TSTMS MAY INITIATE ALONG THE COLD FRONT ACROSS WRN IA/SERN NEB AROUND 00Z IT DOES SO PARTLY BY COOLING MID LEVEL TEMPERATURES MUCH QUICKER THAN THE ECMWF/GFS. IT/S NOT CLEAR THAT THE CAP WILL ERODE AS QUICKLY AS THE NAM IMPLIES AND CONVECTION MAY BE DELAYED UNTIL AFTER SUNSET AND WITHIN A POST FRONTAL REGIME DRIVEN BY LOW LEVEL WARM ADVECTION. FOR THIS REASON HAVE INTRODUCED 5% PROBS TO ACCOUNT FOR THE UNCERTAINTY OF DAYTIME CONVECTION AND STRONG CAPPING. HAIL/WIND WILL BE THE PRIMARY SEVERE THREATS WITH NEAR-SFC BASED CONVECTION AND MOSTLY HAIL WITH ACTIVITY THAT EVOLVES NORTH OF THE WIND SHIFT. LOW LEVEL WARM ADVECTION SHOULD PROVE INSTRUMENTAL IN A CORRIDOR OF LATE NIGHT ELEVATED TSTMS THAT SHOULD SPREAD/DEVELOP NEWD ACROSS CNTRL NEB INTO MN BY SUNRISE. ..DARROW.. 05/21/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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