SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1247 AM CDT SUN MAY 26 2013 VALID 261200Z - 271200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PART OF THE SRN...CNTRL AND NRN HIGH PLAINS... ...SYNOPSIS... SYNOPTIC PATTERN WILL UNDERGO LITTLE CHANGE WITH A LOW AMPLITUDE OMEGA BLOCKING REGIME FORECAST TO PERSIST THROUGH SUNDAY. SEVERAL VORTICITY MAXIMA WILL MOVE THROUGH WRN U.S. UPPER LOW CIRCULATION AND INTO THE CNTRL AND NRN HIGH PLAINS. AT THE SFC A LEE LOW WILL PERSIST OVER ERN CO WITH A DRYLINE EXTENDING SWD THROUGH THE CNTRL AND SRN HIGH PLAINS. QUASI-STATIONARY WNW-ESE ORIENTED FRONT SHOULD EXTEND FROM THE MID MS VALLEY NWWD THROUGH NEB INTO WY. ...NRN THROUGH CNTRL PLAINS... PERSISTENT BROAD FETCH OF SLY-SSELY WINDS EAST OF LEE TROUGH WILL CONTRIBUTE TO FURTHER MOISTENING OF THE BOUNDARY LAYER WITH MID TO UPPER 60S DEWPOINTS LIKELY OVER PORTIONS OF THE CNTRL PLAINS AND UPPER 50S TO NEAR 60 OVER THE NRN PLAINS. MEANWHILE...WSWLY FLOW ALOFT WILL MAINTAIN FEED OF STEEP LAPSE RATE ABOVE THE MOIST AXIS. THE ATMOSPHERE SHOULD BECOME MODERATELY UNSTABLE SUNDAY AFTERNOON WITH AN AXIS OF 2000-3000 J/KG MLCAPE FROM ERN MT AND WRN SD SWD INTO WRN/CNTRL NEB. STORMS SHOULD ONCE AGAIN DEVELOP OVER THE HIGHER TERRAIN AND INTENSIFY AS THEY MOVE ENEWD INTO THE AXIS OF STRONGER INSTABILITY. OTHER STORMS MAY INITIATE FARTHER SOUTH ALONG DRYLINE ACROSS ERN CO/WRN KS. MUCH OF THIS REGION WILL EXIST ON SERN PERIPHERY OF UPPER LOW CIRCULATION WITH 25-35 KT 500 MB FLOW ABOVE SELY NEAR SFC WINDS SUPPORTING 30-40 KT EFFECTIVE SHEAR. SUPERCELL MODES WILL BE LIKELY WITH INITIAL STORMS THAT DEVELOP WITH PRIMARY THREAT BEING VERY LARGE HAIL. ISOLATED TORNADOES MAY ALSO BE POSSIBLE. EVENTUALLY STORMS MAY EVOLVE INTO ONE OR MORE CLUSTERS...AND ADDITIONAL STORMS MAY ALSO DEVELOP DURING THE EVENING ACROSS NEB ON NOSE OF STRENGTHENING LLJ. ...SRN HIGH PLAINS... ISOLATED TO WIDELY SCATTERED STORMS MAY DEVELOP WITHIN ZONE OF DEEPER MIXING ALONG DRYLINE ACROSS THE SRN HIGH PLAINS. STORMS WILL INTENSIFY AS THEY MOVE INTO MOIST AXIS WITH 2000-3000 J/KG MLCAPE. VERTICAL SHEAR WILL BE WEAKER THAN FARTHER NORTH...BUT 25-35 KT EFFECTIVE SHEAR WILL SUPPORT MULTICELLS AND ALSO SOME SUPERCELL STRUCTURES WITH LARGE HAIL AND DAMAGING WIND GUSTS THE MAIN THREATS THROUGH MID EVENING. ..DIAL/DEAN.. 05/26/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1200.html
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