SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT FRI MAY 25 2012 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE CNTRL PLAINS AND MID-MO VALLEY THROUGH EARLY SAT... ...THERE IS A SLGT RISK OF SVR TSTMS FOR NRN/WRN NY INTO NRN PA THIS AFTERNOON/EVENING... ...SYNOPSIS... A SHORT WAVE TROUGH CENTERED OVER THE UPPER GREAT LAKES WILL RAPIDLY PROGRESS EWD ACROSS ONTARIO/QUEBEC...WHILE AN AMPLIFIED LARGE-SCALE TROUGH PERSISTS IN THE WEST. THIS WILL RESULT IN RISING MID-LEVEL HEIGHTS ACROSS MUCH OF THE CNTRL/ERN CONUS. AT THE SURFACE...COLD FRONT WILL SHIFT EWD ACROSS THE LOWER GREAT LAKES...WITH TRAILING PORTION BECOMING QUASI-STATIONARY IN THE MIDWEST AND ADVANCING NWD AS A WARM FRONT IN THE CNTRL PLAINS/MID-MO VALLEY. DRYLINE SHOULD MIX INTO SWRN KS S/SWWD TOWARDS THE PECOS VALLEY OF WRN TX. ...CNTRL CONUS... COMPLEX FORECAST TODAY WITH MID-LEVEL HEIGHT RISES OCCURRING THROUGH MOST OF THE PERIOD...RESULTING IN STRENGTHENING OF AN EML ATOP A STRONGLY UNSTABLE WARM/MOIST SECTOR. THE LACK OF APPARENT UPSTREAM UPPER-LEVEL IMPULSES SUGGEST CONVECTIVE DEVELOPMENT WILL BE LARGELY DRIVEN BY LOW-LEVEL WARM THETA-E ADVECTION N OF A GRADUALLY ADVANCING WARM FRONT IN THE CNTRL PLAINS/MID-MO VALLEY...AND ALONG THE DRYLINE AND UPSLOPE NEAR HIGHER TERRAIN. AREAS OF ELEVATED TSTMS WILL BE MOST LIKELY THIS MORNING IN THE CNTRL PLAINS TO WRN MO...REDEVELOPING/EXPANDING IN COVERAGE THIS EVENING THROUGH TONIGHT AS A S/SWLY LLJ NOCTURNALLY STRENGTHENS IN THE CNTRL/SRN PLAINS. PRESENCE OF 65-70 F SURFACE DEW POINTS IN THE WARM/MOIST SECTOR AND STEEP MID-LEVEL LAPSE RATES SHOULD RESULT IN ROBUST ELEVATED INSTABILITY...N OF THE EXPANDING EML. COMBINED WITH STRONG MID-LEVEL SWLYS...RISK FOR LARGE HAIL SHOULD BE PRESENT WHILE A CLUSTER-TYPE CONVECTIVE MODE MAY LIMIT SIGNIFICANT HAIL PRODUCTION. POTENTIAL FOR SURFACE-BASED CONVECTION SHOULD BE TIED TO THE DRYLINE IN WRN OK TO THE RIO GRANDE VALLEY IN WRN TX. WITH MORE MERIDIONAL/SLIGHTLY WEAKER DEEP-LAYER FLOW RELATIVE TO AREAS FARTHER N...AND WITH COVERAGE PROGGED TO REMAIN ISOLATED...WILL ONLY ADD MARGINAL SEVERE PROBABILITIES ATTM. ...LOWER GREAT LAKES... UPPER 50S TO LOWER 60S SURFACE DEW POINTS SHOULD REMAIN PREVALENT AHEAD OF THE COLD FRONT APPROACHING LK ONTARIO/ERIE. WITH STRONG HEATING...MLCAPE WILL LIKELY REACH 1000-2000 J/KG. GIVEN VEERING LOW-LEVEL WINDS WITH HEIGHT...ON THE SRN FRINGE OF AN INTENSE MID-LEVEL JET ACROSS NRN LOWER MI INTO SRN QUEBEC...SUPERCELL WIND PROFILES ARE EXPECTED TO DEVELOP. THIS WILL FAVOR A RISK FOR LARGE HAIL AND DAMAGING WINDS WITH ISOLATED TO SCATTERED TSTMS DURING THE LATE AFTERNOON/EARLY EVENING. ..GRAMS/MOSIER.. 05/25/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1200.html
Be First to Comment