May 1, 2006 0600 UTC Day 1 Convective Outlook Updated: Mon May 1 06:06:14 UTC 2006 Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
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SPC AC 010603 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0103 AM CDT MON MAY 01 2006 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH VALLEY TO NCNTRL TX... ...MID MS/OH VALLEY... BROAD TROUGHING WILL REMAIN OVER THE CNTRL U.S. MONDAY AS UPPER RIDGE HOLDS ALONG THE MIDDLE ATLANTIC COAST...AND ACROSS THE SWRN U.S. TWO DISTINCT SHORTWAVE TROUGHS WILL PLAY IMPORTANT ROLES IN CONVECTIVE EVOLUTION DURING THE PERIOD...INITIALLY OVER THE OH VALLEY...THEN LATER ACROSS THE MID MS VALLEY. EARLY EVENING WATER VAPOR IMAGERY CLEARLY DEPICTS A SIGNIFICANT UPPER VORT ALONG THE MO/AR BORDER WHICH WILL LIFT/SHEAR ENEWD ALONG THE OH RIVER VALLEY BY LATE MORNING. THIS FEATURE WILL GRADUALLY WEAKEN AS UPSTREAM HEIGHTS FALL IN RESPONSE TO SECONDARY SHORTWAVE TROUGH ADVANCING INTO THE CNTRL PLAINS STATES. EVEN SO THIS LEAD FEATURE WILL LIKELY AID RENEWED CONVECTIVE DEVELOPMENT EARLY IN THE PERIOD OVER ERN MO/IL WHICH SHOULD INTENSIFY DURING THE AFTERNOON HOURS AS BOUNDARY LAYER WARMS WITHIN VEERED SWLY FLOW REGIME. JUST DOWNSTREAM...IT APPEARS PSEUDO WARM FRONT-TYPE BOUNDARY WILL RETREAT NEWD IN RESPONSE TO EJECTING SHORTWAVE MAINTAINING SOMEWHAT OF AN ELY COMPONENT AND FOCUSED CONVERGENCE FOR ASCENT FROM CNTRL IL INTO SERN IN. MUCH WEAKER INSTABILITY WILL BE NOTED TO THE NORTH-EAST OF THIS ZONE THROUGH THE PERIOD. ALTHOUGH BOUNDARY LAYER MOISTURE WILL BE SOMEWHAT LIMITED...MOSTLY IN THE LOW-MID 50S...COLD UPPER TROUGH WILL RESULT IN MUCAPE VALUES ON THE ORDER OF 1000-1500J/KG. VERTICAL SHEAR PROFILES WILL BE STRONGER ACROSS THIS REGION MONDAY THAN ON SUNDAY AND SUPERCELL STRUCTURES SEEM POSSIBLE...ESPECIALLY THROUGH MID AFTERNOON HOURS BEFORE MORE SIGNIFICANT CLUSTERS COULD EVOLVE FORCING STORM MODE TO TRANSITION INTO POSSIBLE LEWP-TYPE ECHOES. A COMPLICATING FACTOR IN STORM EVOLUTION ACROSS THIS REGION IS THE WEAK SHORTWAVE RIDGING AROUND MID DAY AND THE POSSIBILITY OF WEAK SUBSIDENCE BEFORE THE INFLUENCE OF UPSTREAM SHORTWAVE APPROACHES LATE AFTERNOON. REGARDLESS...ANY LULL IN THUNDERSTORM ACTIVITY SHOULD INCREASE AGAIN AS LARGE SCALE ASCENT BECOMES FOCUSED AS MID LEVEL JET INCREASES OVER SRN MO. SEVERAL THUNDERSTORM CLUSTERS SHOULD EVOLVE AND SPREAD EWD ACROSS THE LOWER OH VALLEY DURING THE EVENING HOURS...FINALLY SPREADING INTO SWRN OH/CNTRL KY LATE IN THE PERIOD. LARGE HAIL AND DAMAGING WINDS ARE THE PRIMARY SEVERE THREATS WITH THIS ACTIVITY. ...SRN PLAINS... SFC WIND SHIFT WILL EASE SWD ACROSS OK INTO NWRN TX LATER MONDAY. THIS BOUNDARY WILL LIKELY FOCUS CONVECTIVE DEVELOPMENT SHORTLY AFTER PEAK HEATING INTO THE EARLY EVENING WHEN SFC PARCELS APPROACH THEIR CONVECTIVE TEMPERATURES. WEAK CAP WILL LIKELY HOLD WARM SECTOR FROM FREELY CONVECTING THUS CONVERGENCE/WARM ADVECTION WILL LIKELY BE NECESSARY FOR SCATTERED THUNDERSTORM DEVELOPMENT ACROSS NCNTRL TX INTO ERN OK NEAR SUNSET. INCREASING LLJ ALONG THIS BOUNDARY AFTER DARK MAY ALLOW THUNDERSTORMS TO SPREAD NEWD INTO AR DURING THE OVERNIGHT HOURS. LARGE HAIL IS THE MOST LIKELY SEVERE THREAT WITH THIS ACTIVITY. ..DARROW.. 05/01/2006 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z |