SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT TUE MAY 01 2012 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE CNTRL PLAINS INTO THE UPPER MS VALLEY AND GREAT LAKES... ...SYNOPSIS... SYNOPTIC PATTERN WILL CHANGE ONLY SLIGHTLY FROM DAY 2 WITH BROAD LOW AMPLITUDE CYCLONIC FLOW LIKELY TO PERSIST OVER THE NRN THIRD OF THE COUNTRY. UPPER TROUGH IS FORECAST TO BEGIN TO AMPLIFY OVER THE PACIFIC NW RESULTING IN SLIGHT DOWNSTREAM HEIGHT RISES WITHIN THE SWLY FLOW REGIME ACROSS THE UPPER MS VALLEY AND GREAT LAKES. A QUASI-STATIONARY BAROCLINIC ZONE SHOULD STRETCH FROM KS NEWD THROUGH THE UPPER MS VALLEY INTO WRN PARTS OF THE GREAT LAKES. DRYLINE WILL PERSIST OVER THE SRN PLAINS. ...ERN PORTIONS OF CNTRL PLAINS INTO MID-UPPER MS VALLEY AND GREAT LAKES... ANOTHER IN A SERIES OF IMPULSES WILL EJECT NEWD INTO SRN CANADA EARLY IN THE PERIOD. A QUASI-STATIONARY FRONT WILL PERSIST WITHIN BROAD FETCH OF MODERATE SWLY FLOW ALOFT. THUNDERSTORMS WILL LIKELY BE ONGOING WITHIN ZONE OF ISENTROPIC ASCENT. SOME OF THIS ACTIVITY MAY PERSIST DURING THE DAY SUPPORTED BY SWLY LLJ THAT WILL SHIFT NEWD IN ASSOCIATION WITH EJECTING SHORTWAVE TROUGH. WARM SECTOR SOUTH OF THE ONGOING ACTIVITY WILL BECOME MODERATELY TO STRONGLY UNSTABLE WITH THE STRONGEST INSTABILITY EXPECTED WITH SWWD EXTEND INTO THE CNTRL PLAINS. A WEAK IMPULSE IS FORECAST TO EJECT NEWD THROUGH THE CNTRL PLAINS AND ADDITIONAL STORMS MAY DEVELOP ALONG THE BOUNDARY BY LATE AFTERNOON FROM NERN KS/SERN NEB INTO THE UPPER MS VALLEY. VERTICAL SHEAR WILL BE SUFFICIENT FOR ORGANIZED SEVERE STORMS WITH DAMAGING WIND AND LARGE HAIL THE PRIMARY THREATS. ACTIVITY MAY EVOLVE INTO ONE OR MORE MCS CLUSTERS AS THEY DEVELOP EWD DURING THE AFTERNOON AND EVENING. ...SRN PLAINS... A SRN STREAM IMPULSE IS FORECAST TO MOVE INTO THE SRN PLAINS. A FEW STORMS MAY DEVELOP ALONG THE DRYLINE DURING THE AFTERNOON WITHIN A MODESTLY SHEARED ENVIRONMENT...BUT A BELT OF STRONGER FLOW ACCOMPANYING THE IMPULSE MAY RESULT IN SUFFICIENT SHEAR FOR AT LEAST MARGINAL SUPERCELL STRUCTURES. THIS AREA WILL CONTINUE TO BE MONITORED FOR AN UPGRADE TO SLIGHT RISK IN THE NEXT DAY 2 OUTLOOK. ..DIAL.. 05/01/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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