SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT SAT MAY 25 2013 VALID 271200Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A PORTION OF THE NRN PLAINS...MID MO RIVER VALLEY...AND SRN HIGH PLAINS... ...SYNOPSIS... A SHORTWAVE TROUGH WILL MOVE FROM THE NRN GREAT BASIN/NRN INTERMOUNTAIN REGION THROUGH THE NRN HIGH PLAINS AND INTO S-CNTRL CANADA BY TUESDAY MORNING. AS THIS OCCURS...A LARGER-SCALE UPPER TROUGH OVER THE WRN U.S. WILL REINVIGORATE/AMPLIFY IN RESPONSE TO A POWERFUL E PACIFIC JET STREAK MOVING INTO CA LATE IN THE PERIOD. STRONGER SWLY FLOW ALOFT ON THE NOSE OF THE SRN BRANCH OF THE WLY/S IS FORECAST TO OVERSPREAD A LARGE PART OF THE PLAINS WITH A FEW LOW AMPLITUDE SPEED MAXIMA POTENTIALLY INFLUENCING STORM DEVELOPMENT OVER THE CNTRL STATES. ...MID MO RIVER VALLEY INTO THE NRN HIGH PLAINS... MOIST SLY LOW LEVEL FLOW EMANATING FROM THE CNTRL-SRN PLAINS AND EVAPOTRANSPIRATION EFFECTS WILL LEAD TO A RESERVOIR OF 60S DEWPOINTS EXTENDING FROM THE SRN PLAINS INTO THE N-CNTRL PLAINS MONDAY AFTERNOON. AN EML AND WARM H7 TEMPS WILL OVERSPREAD MUCH OF THE PLAINS ACTING TO DELAY/CONFINE STORM DEVELOPMENT THROUGH MUCH OF THE DAY WITH THE POSSIBLE EXCEPTION FOR MORNING STORMS OVER THE MID MO RIVER VALLEY EWD INTO THE MID MS RIVER VALLEY REGION. THE ECMWF DEPICTS A SHORTWAVE DISTURBANCE MOVING ACROSS THE CNTRL PLAINS DURING PEAK HEATING WITH TRAILING INFLUENCE PERHAPS AS FAR S AS THE TX PANHANDLE...IN ADDITION TO THE NRN STREAM SHORTWAVE MOVING ACROSS ERN MT/WRN DAKOTAS DURING THE DAY. THESE TWO FEATURES WILL LIKELY PROVE INSTRUMENTAL IN PROVIDING WEAK LARGE SCALE SUPPORT FOR STORMS MONDAY AFTERNOON THROUGH THE EVENING. MODELS SHOW SLIGHTLY STRONGER MID-LEVEL SWLY FLOW THAN PRIOR DAYS OVER THIS REGION /30-40 KT EFFECTIVE SHEAR/. FORECAST SOUNDINGS BY AFTERNOON BECOME QUITE UNSTABLE ACROSS THE CNTRL PLAINS FEATURING 2500-3500 J/KG MLCAPE AND 1000-2000 J/KG MLCAPE FARTHER N OVER PORTIONS OF THE NRN HIGH PLAINS/WRN DAKOTAS. DESPITE MODEST DEEP LAYER SHEAR...THE MAGNITUDE OF POTENTIAL INSTABILITY WOULD YIELD THE POSSIBILITY FOR SUPERCELLS AND ORGANIZED LINE/BOWING SEGMENTS CAPABLE OF MAINLY ISOLD LARGE HAIL/SEVERE WIND GUSTS AND PERHAPS A FEW TORNADOES. A STRENGTHENING LLJ DURING THE EVENING OVER THE CNTRL PLAINS WOULD BE SUPPORTIVE OF UPSCALE GROWTH INTO A FEW CLUSTERS OF STORMS WITH THIS ACTIVITY POSSIBLY MOVING INTO THE MID MO RIVER VALLEY LATE. ...W-CNTRL KS SWWD INTO W TX... A WEST-EAST OSCILLATING DRYLINE OVER THE CNTRL-SRN PLAINS WILL LIKELY SERVE AS A FOCUS FOR AT LEAST ISOLD DIURNALLY-DRIVEN STORMS ONCE AGAIN ON MONDAY. ISOLD STORM DEVELOPMENT WILL PREFERENTIALLY FAVOR WHERE HEATING AND WHERE LOW LEVEL CONVERGENCE ARE MAXIMIZED. ALTHOUGH STORM COVERAGE WILL LIKELY REMAIN LIMITED FROM KS SWD...THE STRONGER UPDRAFTS WOULD HAVE AN ATTENDANT LARGE HAIL/SEVERE WIND GUST THREAT BEFORE THIS ACTIVITY WEAKENS DURING THE EVENING. ..SMITH.. 05/25/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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