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| Probability of severe weather within 25 miles of a point. Hatched Area: 10% or greater probability of significant severe within 25 miles of a point. |
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SPC AC 261730 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1230 PM CDT SUN MAY 26 2013 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE PLAINS STATES... ...SYNOPSIS... SYNOPTIC UPPER TROUGH OVER THE WRN U.S. WILL GRADUALLY SHIFT EWD MONDAY. PRONOUNCED SHORTWAVE TROUGH OVER OREGON ROUNDING THE BASE OF THIS TROUGH WILL EJECT NEWD THROUGH THE NRN ROCKIES AND ERN MT DURING THE DAY. POTENTIAL WILL ALSO EXIST FOR SMALLER SCALE VORTICITY MAXIMA TO ADVANCE INTO THE CNTRL/NRN PLAINS MONDAY AFTERNOON. INCREASING WLY MID LEVEL WINDS ASSOCIATED WITH THE EWD PROGRESSION OF THE UPPER TROUGH WILL CONTRIBUTE TO THE DRYLINE MIXING A BIT FARTHER EAST ON MONDAY. BY MID AFTERNOON THIS BOUNDARY IS EXPECTED TO EXTEND FROM A SFC LOW OVER NWRN KS SSWWD THROUGH THE SRN HIGH PLAINS. A CONVECTIVELY REINFORCED FRONT WILL LIKELY EXTEND ACROSS SRN NEB INTO THE MID MS VALLEY REGION. ...CNTRL PLAINS AND MID-MS VALLEY AREA... A FEW ELEVATED STORMS SHOULD BE ONGOING FROM PORTIONS OF THE DAKOTAS SEWD INTO NEB AND INTO THE MID MS VALLEY WITHIN BROAD ZONE OF ISENTROPIC ASCENT. THIS ACTIVITY SHOULD SHIFT EWD DURING THE DAY...ALLOWING THE UPSTREAM WARM SECTOR TO DESTABILIZE. A BROAD FETCH OF SLY WINDS EAST OF THE LEE TROUGH WILL MAINTAIN INFLUX OF MID-UPPER 60S DEWPOINTS INTO THE NEB-KS WARM SECTOR AND BENEATH PLUME OF STEEP MID-LEVEL LAPSE RATES. SOME LOW CLOUDS MAY LINGER DURING THE MORNING. HOWEVER...DIABATIC WARMING IS EXPECTED IN WRN PORTIONS OF WARM SECTOR BOOSTING MLCAPE TO 2000-3000 J/KG. A CAP ASSOCIATED WITH THE EWD EXPANDING EML SHOULD INHIBIT SFC BASED DEVELOPMENT UNTIL AT LEAST MID AFTERNOON...WHEN STORMS WILL LIKELY DEVELOP. MOST PROBABLE ZONE OF INITIAL DEVELOPMENT WILL BE NEAR THE TRIPLE POINT ACROSS NWRN/NCNTRL KS INTO SCNTRL NEB WHERE CONVERGENCE SHOULD BE MAXIMIZED AS WELL AS FARTHER WEST IN THE MORE DEEPLY MIXED ENVIRONMENT. OTHER STORMS MAY DEVELOP FARTHER NORTH ACROSS CNTRL/ERN NEB DURING THE EVENING IN ASSOCIATION WITH STRENGTHENING LLJ INTERACTING WITH THE STATIONARY FRONT. EFFECTIVE SHEAR FROM 35-45 KT WILL SUPPORT SUPERCELLS WITH VERY LARGE HAIL AND POSSIBLY ISOLATED TORNADOES WITH INITIAL STORMS. ACTIVITY MAY EVENTUALLY EVOLVE INTO ONE OR MORE CLUSTERS AND SPREAD EWD INTO THE MID MS VALLEY DURING THE EVENING. ...NRN HIGH PLAINS... AN AXIS OF UPPER 50S DEWPOINTS WILL LIKELY PERSIST FROM SD INTO NERN WY AND ERN MT BENEATH STEEP LAPSE RATES SUPPORTING MODERATE INSTABILITY AS DIABATIC WARMING COMMENCES. STORMS WILL LIKELY ONCE AGAIN DEVELOP OVER THE HIGHER TERRAIN AND IN VICINITY OF THE NW-SE ORIENTED BOUNDARY AND SPREAD EWD THROUGH THE MOIST AXIS. VERTICAL SHEAR WILL SUPPORT INITIAL SUPERCELLS WITH LARGE HAIL THE INITIAL MAIN THREAT...BEFORE STORMS MAY EVENTUALLY CONGEAL INTO LINES/CLUSTERS DURING THE EVENING. ...SRN HIGH PLAINS... WIDELY SCATTERED TO ISOLATED STORMS WILL ONCE AGAIN BE POSSIBLE ALONG THE SWRN EXTENSION OF THE DRYLINE WHERE STRONG INSTABILITY WILL EXIST IN WARM SECTOR. VERTICAL SHEAR WILL RANGE FROM AROUND 30 KT IN SWRN TX TO 40+ KT OVER WRN OK SUGGESTING SUPERCELL MODES WILL BE LIKELY...ESPECIALLY FROM NWRN TX INTO WRN OK. PRIMARY THREAT WILL BE VERY LARGE HAIL...BUT ISOLATED TORNADOES WILL ALSO BE POSSIBLE ESPECIALLY ACROSS WRN OK. ..DIAL.. 05/26/2013 CLICK TO GET WUUS02 PTSDY2 PRODUCT NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z |