SPC 2000Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0255 PM CDT SAT JUL 27 2013 VALID 272000Z - 281200Z ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON THROUGH EARLY TONIGHT FOR PARTS OF ERN CO AND SW KS... ONLY MINOR EWD ADJUSTMENT TO THE 10 PERCENT THUNDER PROBABILITY LINE OVER THE SRN GREAT LAKES AND LOW HAIL/WIND PROBABILITIES. NO OTHER CHANGES FROM THE PREVIOUS FORECAST. ...SERN LOWER MI AND N-CNTRL OH... REFERENCE MESOSCALE DISCUSSION 1539 FOR A NEAR-TERM FORECAST. ...CO FRONT RANGE AND ADJACENT HIGH PLAINS / ERN WY... REFERENCE MESOSCALE DISCUSSION 1540 REGARDING SHORT-TERM FORECAST DETAILS FOR THIS CORRIDOR. ..SMITH/GUYER.. 07/27/2013 .PREV DISCUSSION... /ISSUED 1130 AM CDT SAT JUL 27 2013/ ...ERN CO/SW KS THROUGH EARLY TONIGHT... A LEE CYCLONE WILL PERSIST ACROSS SE CO...ON THE SW FRINGE OF THE MAIN BELT OF NWLY FLOW ALOFT. STRONG SURFACE HEATING NEAR THE LEE CYCLONE WILL ERODE CONVECTIVE INHIBITION AND SUPPORT SCATTERED THUNDERSTORM DEVELOPMENT BY MID AFTERNOON BOTH ALONG THE E SLOPES OF THE HIGHER TERRAIN...AND ALONG THE BAROCLINIC ZONE FROM SW KS INTO ERN CO. WEAK-MODERATE INSTABILITY AND DEEP-LAYER NWLY SHEAR WILL BE SUFFICIENT FOR ORGANIZED CLUSTERS AND PERHAPS A COUPLE OF SUPERCELLS...WITH AN ATTENDANT RISK FOR AT LEAST ISOLATED LARGE HAIL AND DAMAGING GUSTS. A STORM CLUSTER OR TWO MAY PERSIST AFTER DARK INTO SW KS AS LOW-LEVEL WAA STRENGTHENS IN CONJUNCTION WITH THE DEVELOPMENT OF A 30-35 KT LLJ. ...SE LOWER MI THIS AFTERNOON... VISIBLE SATELLITE IMAGERY SHOWS SOME CLOUD BREAKS OVER SE LOWER MI...IN ADVANCE OF THE SURFACE COLD FRONT AND THE ASSOCIATED MIDLEVEL LOW OVER THE UPPER GREAT LAKES. THOUGH LAPSE RATES WILL NOT BE PARTICULARLY STEEP...RELATIVELY COOL MIDLEVEL TEMPERATURES WILL SUPPORT MLCAPE OF 500-750 J/KG...WHILE A FEW ORGANIZED STORMS WILL BE POSSIBLE IN THE ENVIRONMENT WITH DEEP-LAYER SSWLY SPEED SHEAR. MARGINALLY SEVERE HAIL AND ISOLATED STRONG OUTFLOW GUSTS WILL BE THE MAIN THREATS. ...APPALACHIANS AREA TODAY... WIDESPREAD CLOUDS/RAIN AND POOR LAPSE RATES ALOFT WILL LIMIT BUOYANCY ACROSS MUCH OF THE APPALACHIANS. HOWEVER...SMALLER POCKETS OF STRONGER SURFACE HEATING WITHIN /AS WELL AS E OF/ THE PRIMARY CLOUD BAND COULD SUPPORT A FEW STORMS WITH STRONG GUSTS...GIVEN THE BELT OF 30+ KT MIDLEVEL FLOW. ...N CENTRAL/NW GULF COAST... THE REMNANT MIDLEVEL TROUGH/MCV CONTINUES TO MOVE SEWD OVER THE LOWER MS VALLEY. STRONGER SURFACE HEATING FROM SE TX INTO SW LA WILL RESULT IN MODERATE INSTABILITY THIS AFTERNOON...COINCIDENT WITH THE BELT OF ENHANCED MIDLEVEL FLOW S-W OF THE MIDLEVEL TROUGH. A FEW ORGANIZED STORM CLUSTERS COULD PRODUCE ISOLATED STRONG GUSTS THIS AFTERNOON.
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_2000.html
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