SPC 2000Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CDT WED MAY 30 2012 VALID 302000Z - 311200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS SCNTRL KS...MUCH OF OK... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM SRN NEB TO NRN TX...EWD TO NRN MS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER ERN NC... EARLIER THOUGHTS REGARDING THE EVOLUTION OF CNTRL/SRN PLAINS CONVECTION REMAIN. LATEST OA FIELDS SUGGEST AIRMASS ALONG THE I-70 CORRIDOR ACROSS KS IS DESTABILIZING SIGNIFICANTLY WITH SFC-3KM LAPSE RATES NOW APPROACHING DRY ADIABATIC. FOR THIS REASON IT APPEARS CONVECTION SHOULD DEVELOP AND INTENSIFY ALONG NRN PLUME OF MOISTURE/INSTABILITY AXIS OVER THE NEXT FEW HOURS. WITH TIME ONE OR MORE MCS-TYPE STRUCTURES SHOULD EVOLVE ACROSS NWRN KS WITH SUBSEQUENT SEWD MOVEMENT INTO OK EXPECTED AFTER DARK AS LLJ INCREASES ACROSS THIS REGION. HAVE OPTED TO LOWER THE TORNADO PROBS ACROSS SRN KS/NRN OK DUE TO THE EXPECTED MCS STORM MODE. ADDITIONALLY...LATEST VIS IMAGERY SUGGESTS THE CU FIELD IS DEEPENING ALONG THE DRYLINE JUST EAST OF THE CAPROCK OVER THE TX PANHANDLE. INDICATIONS ARE THAT A SECONDARY N-S ZONE OF TSTMS COULD EVOLVE ACROSS THIS REGION OF TX JUST WEST OF INFLUENTIAL OUTFLOW FROM EARLY MORNING CONVECTION. MODERATE-EXTREME INSTABILITY SUPPORTS VERY LARGE HAIL AND FOR THIS REASON HAVE EXTENDED THE THREAT FOR SIG HAIL TO INCLUDE DRYLINE STORMS. DOWNSTREAM...A MINOR EWD ADJUSTMENT HAS BEEN MADE TO THE SLIGHT RISK ACROSS PORTIONS OF MS TO ACCOUNT FOR ONGOING STORMS. MUCH DRIER AND MORE STABLE ENVIRONMENT DOES EXIST ACROSS NERN MS/NRN AL AND THIS ACTIVITY SHOULD WEAKEN AS IT APPROACHES THIS REGION. ..DARROW.. 05/30/2012 .PREV DISCUSSION... /ISSUED 1130 AM CDT WED MAY 30 2012/ ...SRN KS INTO WRN/CENTRAL OK... COMPLEX MESOSCALE PATTERN IS PRESENT THIS MORNING ASSOCIATED WITH THE EFFECTS OF NOCTURNAL AND MORNING CONVECTION OVER OK INTO TX...WITH MULTIPLE OUTFLOW BOUNDARIES EVIDENT IN SURFACE AND SATELLITE DATA OVER TX. NORTH OF THE BOUNDARIES...SELY SURFACE WINDS FROM NWRN TX INTO SWRN/SOUTH CENTRAL KS WILL ALLOW MOISTURE TO INCREASE NWD THIS AFTERNOON...WITH ELEVATED MOISTURE EXTENDING FARTHER NORTH INTO PARTS OF SRN NEB. A SURFACE LOW OVER THE SOUTH PLAINS OF WEST TX IS EXPECTED TO PERSIST OVER THE AREA ENHANCED BY STRONG HEATING THIS AFTERNOON. 12Z REGIONAL RAOBS INDICATE VERY STEEP MID LEVEL LAPSE RATES OVER THE HIGH PLAINS ASSOCIATED WITH THE ERN EDGE OF THE EML. AS CLOUDS DIMINISH EAST OF A N/S SURFACE TROUGH FROM EXTREME ERN CO SWD INTO WEST TX...STRONG DIABATIC HEATING AND INCREASING LOW LEVEL MOISTURE WILL CONTRIBUTE TO FURTHER DESTABILIZATION WITH MLCAPE REACHING 2500-3500 J/KG...WHILE GRADUALLY REDUCING THE CAP STRENGTH. THIS PROCESS WILL BE AIDED BY WEAK LARGE SCALE ASCENT ASSOCIATED WITH A SUBTLE SHORT WAVE TROUGH MOVING EWD FROM THE CENTRAL/SRN ROCKIES. DESPITE SOME VARIABILITY IN MODEL PREDICTIONS OF CONVECTION...GENERAL CONSENSUS INDICATES STORMS WILL DEVELOP BY MID/LATE AFTERNOON OVER PARTS OF WRN/CENTRAL KS AND WRN OK...POSSIBLY EXTENDING AS FAR SOUTH AS NWRN TX. WIND PROFILES EXHIBIT STRONG VEERING WITH HEIGHT FROM SSELY IN THE LOW LEVELS TO WESTERLY IN THE MID LEVELS...PROVIDING A FAVORABLE ENVIRONMENT FOR SUPERCELL STORMS. STRONGER CELLS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...DAMAGING WIND GUSTS...AND POSSIBLY SEVERAL TORNADOES. THE ACTIVITY MAY GROW UPSCALE INTO ONE OR MORE BOWING MCS/S BY THIS EVENING AS STORMS SPREAD EWD/SEWD...WITH AN INCREASING THREAT OF MORE WIDESPREAD DAMAGING WINDS ALONG THE LEADING EDGE OF THE MCS/S. ...SOUTH CENTRAL NEB INTO NRN KS... ELEVATED STORMS OVER SOUTH CENTRAL NEB HAVE DEVELOPED IN ASSOCIATION WITH LOW LEVEL WARM ADVECTION AND A MID LEVEL SHORT WAVE TROUGH MOVING EWD INTO THE HIGH PLAINS. HAIL WILL BE THE MOST LIKELY THREAT FROM THESE STORMS /SEE MESOSCALE DISCUSSION 977 FOR MORE DETAILS./ ...ERN AR INTO SWRN TN/WRN MS NERN LA... A BAND OF STORMS HAS BEEN PROGRESSING SLOWLY EWD INTO ERN AR AHEAD OF A WEAK SHORT WAVE TROUGH FROM SRN MO INTO WRN AR. LOW LEVEL HEATING IN THE ENVIRONMENT IMMEDIATELY DOWNSTREAM FROM THE CONVECTIVE BAND WILL RESULT IN DESTABILIZATION WITH MUCAPE OF 1500-2500 J/KG THIS AFTERNOON. THERE WILL BE POTENTIAL FOR STRONGER CELLS TO PRODUCE WET MICROBURSTS AND LARGE HAIL THIS AFTERNOON. ...ERN NC... THE WIND PROFILE FROM KMHX SHOWS STRONG LOW LEVEL SHEAR IN THE RIGHT FRONT QUADRANT OF THE REMNANTS OF BERYL...AND SEVERAL TRANSIENT ROTATIONAL COUPLETS HAVE BEEN INDICATED WHERE CG LIGHTING HAS INCREASED. POTENTIAL WILL CONTINUE FOR AN ADDITIONAL BRIEF TORNADO OR TWO ALONG COASTAL SECTIONS THIS AFTERNOON...AND A 5% TORNADO AREA /SLGT RISK/ HAS BEEN INCLUDED.
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_2000.html
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