SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1253 AM CDT WED MAY 30 2012 VALID 301200Z - 311200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS WRN AND CENTRAL OK/N TX AND A SMALL PORTION OF SRN KS... ...THERE IS A SLGT RISK OF SVR TSTMS EXTENDING FROM PARTS OF WRN NEB SWD INTO N TX/SWRN MO/WRN AR... ...SYNOPSIS... BROAD/WEAK TROUGHING OVER THE ERN U.S. IS FORECAST TO BECOME REINFORCED ON ITS WRN FRINGE AS SHORT-WAVE TROUGHING MOVES OUT OF THE ROCKIES AND INTO THE CENTRAL U.S. THROUGH THE PERIOD. AT THE SURFACE...DEPARTING T.D. BERYL IS PROGGED TO BE SHIFTING OFF THE SERN U.S. COAST EARLY...LEAVING A WEAK WIND SHIFT/CONVERGENCE AXIS IN ITS WAKE -- EXTENDING WWD ALONG THE GULF COAST REGION. MEANWHILE...LOW PRESSURE IS FORECAST TO REMAIN INVOF NWRN TX DURING THE DAY...WITH A COMBINATION FRONT/OUTFLOW EXTENDING EWD ACROSS THE OK VICINITY AND A DRYLINE EXTENDING SWD. THESE TWO BOUNDARIES IN THE OK/TX VICINITY AND THE WIND SHIFT ACROSS THE GULF COAST REGION SHOULD SERVE AS THE PRIMARY CONVECTIVE FOCI THIS PERIOD. ...PARTS OF THE CENTRAL AND SRN PLAINS REGION... ANOTHER DAY OF SUBSTANTIAL SEVERE WEATHER POTENTIAL IS EXPECTED ACROSS THE OK/TX VICINITY...WITH SOME THREAT EXTENDING NWWD INTO THE CENTRAL HIGH PLAINS REGION. ACROSS THE SRN PLAINS...HEATING/DESTABILIZATION IS FORECAST IN THE WAKE OF OVERNIGHT CONVECTION -- AND AN ASSOCIATED OUTFLOW BOUNDARY WHICH SHOULD BE RETREATING NWD ACROSS THE RED RIVER VALLEY/SRN OK DURING THE DAY. BY MID TO LATE AFTERNOON...THIS BOUNDARY -- EXPECTED TO RESIDE ACROSS CENTRAL OR NRN OK...AND A DRYLINE MIXING EWD ACROSS THE TX PANHANDLE/NWRN TX TOWARD WRN OK...WILL LIKELY FOCUS UPDRAFT INITIATION -- AIDED BY THE A SUBTLE FEATURE ALOFT WHICH SHOULD BE SHIFTING INTO THE SRN HIGH PLAINS. WITH VERY STEEP MID-LEVEL LAPSE RATES BEING CONTINUALLY SUPPLIED BY WLY FLOW ALOFT -- SPREADING ATOP A MOIST/HEATING BOUNDARY LAYER...STRONG DESTABILIZATION WILL OCCUR...WITH AFTERNOON CAPE VALUES OVER WRN OK AND VICINITY FORECAST TO EXCEED 4000 J/KG MIXED-LAYER CAPE. THIS THERMODYNAMIC ENVIRONMENT WILL ALLOW EXPLOSIVE CONVECTIVE GROWTH ONCE STORMS INITIATE...FURTHER AIDED BY DEEP-LAYER SHEAR SUPPORTIVE OF UPDRAFT ROTATION. ISOLATED STORMS DEVELOPING ACROSS WRN OK AND VICINITY WILL LIKELY PRODUCE VERY LARGE/DAMAGING HAIL...AND WILL ALSO BE CAPABLE OF PRODUCING DAMAGING WINDS. WHILE SOMEWHAT WEAK LOW-LEVEL FLOW MAY LIMIT TORNADO POTENTIAL IN MOST AREAS...ENHANCED SHEAR NEAR/N OF THE SURFACE FRONT/REMNANT OUTFLOW MAY SUPPORT A ZONE OF SLIGHTLY HIGHER TORNADO PROBABILITY. MORE ISOLATED STORMS MAY ALSO DEVELOP NWWD ACROSS THE CENTRAL HIGH PLAINS REGION...WHERE LESSER -- BUT SUFFICIENT -- INSTABILITY WILL SUPPORT SOME HAIL/WIND POTENTIAL. AS STORMS INCREASE IN COVERAGE ACROSS OK AND VICINITY...COLLIDING STORM OUTFLOWS COMBINED WITH THE DEGREE OF INSTABILITY SUGGEST THAT STORM CLUSTERING/UPSCALE GROWTH IS LIKELY INTO THE EVENING. ALONG WITH VERY LARGE HAIL AND ISOLATED TORNADO POTENTIAL WITH ROTATING CELLS...WIND POTENTIAL SHOULD INCREASE -- WITH STORMS EVENTUALLY FORECAST TO SHIFT EWD ACROSS OK/N TX LIKELY IN THE FORM OF ONE OR MORE MCS/S. ...THE GULF COAST REGION FROM LA EWD TO SRN GA/FL... AFTERNOON DESTABILIZATION INVOF THE WEAK W-E SURFACE BOUNDARY/WIND SHIFT IN THE WAKE OF BERYL SHOULD FOCUS ISOLATED TO SCATTERED AFTERNOON CONVECTIVE DEVELOPMENT. GENERALLY WEAK SHEAR SUGGESTS DISORGANIZED/PULSE STORMS...BUT DEGREE OF INSTABILITY IN SOME AREAS COULD SUPPORT BRIEF GUSTY WINDS AND MARGINAL HAIL. ..GOSS/MOSIER.. 05/30/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1200.html
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