SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1225 PM CDT WED MAY 29 2013 VALID 301200Z - 311200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE ERN PLAINS FROM THE DAKOTAS TO THE RED RIVER OF OK/TX...EWD INTO SRN WI/IL... ...SYNOPSIS... LARGE SCALE UPPER TROUGH IS EXPECTED TO SHIFT INTO THE MID SECTIONS OF THE CONUS DURING THE DAY2 PERIOD WITH CENTER OF UPPER LOW FORECAST TO SETTLE INTO THE WRN DAKOTAS. SEVERAL SPEED MAXIMA AND ASSOCIATED SHORT-WAVES WILL ROTATE AROUND THIS FEATURE ACROSS THE CNTRL ROCKIES INTO THE UPPER GREAT LAKES. EPISODIC BOUTS OF STRONG/SEVERE CONVECTION SHOULD EVOLVE WITH THESE FEATURES...MODULATED BY DIURNAL HEATING. ...SRN PLAINS INTO THE MID MS VALLEY... EARLY MORNING MID LEVEL SPEED MAX IS FORECAST TO LIFT NEWD ACROSS NRN OK INTO MO DURING THE AFTERNOON HOURS. IN RESPONSE...STRONG LLJ...IN EXCESS OF 50KT...WILL TRANSLATE INTO THE MID MS VALLEY. CONVECTION IS EXPECTED TO DEVELOP ALONG NOSE OF LLJ WHERE WARM ADVECTION SHOULD MAXIMIZE ASCENT. ONE OR MORE MCS/S MAY BE ONGOING AT THE BEGINNING OF THE PERIOD FROM ERN KS INTO IA. THIS ACTIVITY MAY PRODUCE HAIL/WIND AND COULD FORCE AN OUTFLOW ACROSS MUCH OF KS/MO. IN THE WAKE OF EARLY MORNING SPEED MAX/CONVECTION IT APPEARS STRONG HEATING WILL BE NOTED ALONG THE DRYLINE. WHILE FORCING SHOULD BE NEUTRAL/WEAK ACROSS THIS REGION CONVECTIVE TEMPERATURES SHOULD BE REACHED AS READINGS RISE INTO THE 90S. AS A RESULT...SBCAPE IN EXCESS OF 3000 J/KG IS EXPECTED ACROSS THE WARM SECTOR OF OK/KS WHERE CONVECTIVE OUTFLOW DOES NOT IMPEDE HEATING. ISOLATED THUNDERSTORMS SHOULD EVOLVE ALONG THE DRYLINE AFTER 21Z AND ENVIRONMENTAL SHEAR IS EXPECTED TO BE SEASONALLY STRONG. 50KT 500MB FLOW IS EXPECTED TO EXTEND ACROSS KS/NRN OK WHICH WILL ENHANCE THE PROSPECT FOR SEVERE SUPERCELLS. VERY LARGE HAIL AND EVEN TORNADOES MAY BE NOTED WITH THESE DISCRETE STRUCTURES...POSSIBLY ENHANCED BY OUTFLOW BOUNDARIES FROM EARLY MORNING CONVECTION. TIMING OF SHORT-WAVE MAY LIMIT AREAL COVERAGE BUT SHEAR/INSTABILITY FAVOR A FEW STRONG TORNADOES. IF IT BECOMES MORE CLEAR THAT SCT-NUMEROUS TSTMS WILL EVOLVE WITHIN THIS ENVIRONMENT THEN A CATEGORICAL UPGRADE WILL BE REQUIRED. FOR NOW WILL MAINTAIN 30 PERCENT SEVERE. ...ERN DAKOTAS INTO THE UPPER GREAT LAKES... SIGNIFICANT MID LEVEL SHORT-WAVE TROUGH IS EXPECTED TO EXTEND FROM MID LEVEL LOW...SEWD ACROSS SERN SD INTO CNTRL IA BY 31/00Z. DEEP LAYER SHEAR WILL INCREASE ACROSS THIS REGION SUCH THAT ANY STORMS THAT EVOLVE COULD ROTATE...POSSIBLY ATTAINING SUPERCELL CHARACTERISTICS. MUCH OF THE MID MS VALLEY/UPPER GREAT LAKES WILL STRUGGLE TO DESTABILIZE APPRECIABLY DUE TO EXTENSIVE CLOUD COVER. HOWEVER STRONG BOUNDARY LAYER HEATING WILL BE NOTED ACROSS NEB INTO SERN SD. STRONG/SEVERE TSTMS WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD ALONG NOSE OF LLJ AND THIS ACTIVITY SHOULD PROPAGATE/DEVELOP NEWD IN ASSOCIATION WITH THE LLJ INTO SRN WI DURING THE AFTERNOON HOURS. ..DARROW.. 05/29/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_1730.html
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