SPC 0100Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0759 PM CDT FRI MAY 04 2012 VALID 050100Z - 051200Z ...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE NRN/CNTRL PLAINS AND UPPER MS VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS FOR N-CNTRL TX/FAR S-CNTRL OK... ...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE LOWER OH/MID-MO VALLEY... ...NRN/CNTRL PLAINS TO THE UPPER MS VALLEY... MAINTAINING SLIGHT RISK FOR THREE AREAS OF FOCUSED SEVERE POTENTIAL THROUGH TONIGHT. QLCS PROGRESSING INTO NERN IA/FAR SERN MN IS EXPECTED TO LARGELY WEAKEN AS IT SHIFTS NEWD OF THE QUASI-STATIONARY FRONT EXTENDING FROM NERN INTO E-CNTRL IA. TRAILING CONVECTION ALONG THE COMPOSITE FRONT/CONVECTIVE OUTFLOW SHOULD PERSIST FOR SEVERAL HOURS IN ERN NEB. MODIFIED 00Z OAX RAOB SAMPLED A STRONGLY UNSTABLE AIR MASS WITH MLCAPE AROUND 3000 J/KG AMIDST EFFECTIVE SHEAR AROUND 30 KT. MID-LEVEL WLYS AND DEEP-LAYER SHEAR ARE WEAKER INTO KS /PER 00Z TOP RAOB/...AND SHOULD DECREASE FURTHER TONIGHT AS THE OZARK PLATEAU IMPULSE MEANDERS EWD WHILE LARGE-SCALE RIDGING BUILDS DOWNSTREAM OF THE AMPLIFIED UPPER-LEVEL TROUGH OVER THE WEST. CONSOLIDATING COLD POOLS WITH ONGOING STORMS ALONG THE FRONT MAY BE SUFFICIENT FOR DEVELOPING A SEWD MOVING MCS ACROSS THE MID-MO VALLEY. BUT THE LACK OF STRONGER SHEAR SUGGESTS SEVERE POTENTIAL MAY BE ONLY MARGINAL OVERNIGHT. FARTHER NW TOWARDS THE BLACK HILLS/NRN HIGH PLAINS...LOW-LEVEL ELYS WILL STRENGTHEN TONIGHT WITH APPROACH OF THE WRN CONUS UPPER-LEVEL TROUGH. THIS WILL ADVECT WWD A RESERVOIR OF 50S TO LOWER 60S SURFACE DEW POINTS FROM THE CNTRL DAKOTAS/NEB. OPERATIONAL GUIDANCE AND RECENT HRRR RUNS SUGGEST CONVECTION SHOULD INCREASE OVERNIGHT WITHIN A VERY STRONGLY SHEARED ENVIRONMENT /EFFECTIVE SHEAR OF 50-60 KT/ SUPPORTIVE OF SUPERCELLS. ...N-CNTRL TX/FAR S-CNTRL OK... SEE MCD 702 FOR SHORT-TERM FORECAST DISCUSSION. GIVEN THE PRESENCE OF VERY STEEP MID-LEVEL LAPSE RATES OF 9 C/KM IN THE 00Z FWD/DRT RAOBS...ONGOING TSTM CLUSTERS SHOULD PERSIST FOR THE NEXT FEW HOURS ACROSS MAINLY N-CNTRL TX. AN IMPULSE OVER THE OZARK PLATEAU WILL SHIFT AWAY FROM THE REGION RESULTING IN DECREASING MID-LEVEL WLYS. THIS COMBINED WITH THE ONSET OF NOCTURNAL COOLING STRENGTHENING MLCIN...SHOULD YIELD GRADUALLY WEAKENING STORM INTENSITY. ...LOWER OH/MID-MO VALLEY... SEE MCD 703 FOR SHORT-TERM FORECAST DISCUSSION. A REMNANT OUTFLOW BOUNDARY EXTENDS FROM ROUGHLY STL TO SDF AS OF 01Z. AIR MASS S OF THIS BOUNDARY IS MODERATE TO STRONGLY UNSTABLE AND A FEED OF 25-30 KT LOW-LEVEL W/SWLYS IS EXPECTED TO IMPINGE ACROSS THE BOUNDARY THROUGH TONIGHT. THIS SHOULD ALLOW CONVECTION TO BE SUSTAINED /PERHAPS INCREASE/ DURING THE NEXT SEVERAL HOURS.WITHIN A BELT OF CONFLUENT/ENHANCED MID-LEVEL NWLYS...ORGANIZED UPDRAFTS WILL BE CAPABLE OF SEVERE HAIL AND SOME WIND SHOULD A CLUSTER EVENTUALLY FORM. ..GRAMS.. 05/05/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_0100.html
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