SPC 1630Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1130 AM CDT FRI OCT 12 2012 VALID 121630Z - 131200Z ...THERE IS A SLGT RISK OF SVR TSTMS THROUGH EARLY AFTERNOON ACROSS THE FOUR CORNERS... ...THERE IS A SLGT RISK OF SVR TSTMS THROUGH TONIGHT FOR THE SRN HIGH PLAINS... ...SRN HIGH PLAINS THROUGH TONIGHT... THE CLOSED LOW OVER THE LOWER CO RIVER VALLEY WILL EVOLVE INTO MORE OF AN OPEN WAVE AND PROGRESS ENEWD TO THE FOUR CORNERS THIS EVENING AND ERN CO/NM BY SATURDAY MORNING. A SURFACE FRONT IS NOW STALLING ACROSS NE NM...THE TX SOUTH PLAINS...AND NW OK. THE EJECTING MIDLEVEL TROUGH APPROACHING CO/NM WILL CONTRIBUTE TO CYCLOGENESIS IN THE LEE OF THE CENTRAL ROCKIES...THOUGH RAINFALL REINFORCING THE FRONT ACROSS NM/TX/OK WILL LIMIT EROSION OF THE COOL/STABLE AIR AND NWD PROGRESS OF THE SURFACE FRONT. S OF THE FRONT...RICH BOUNDARY LAYER MOISTURE IS PRESENT /DEWPOINTS IN THE MID-UPPER 60S/...AND REGIONAL 12Z SOUNDINGS SUPPORT MLCAPE VALUES OF 1500-2500 J/KG WITH AFTERNOON TEMPERATURES IN THE 70S NEAR THE FRONT. OTHER THAN THE POSITION OF THE SURFACE FRONT...THE PRIMARY UNCERTAINTY THIS AFTERNOON THROUGH TONIGHT CONCERNS THE IMPACTS OF ONGOING CONVECTION. RELATIVELY WIDESPREAD CLOUDS AND CONVECTIVE OUTFLOW WILL INHIBIT DAYTIME HEATING NEAR THE FRONT...WITH THE POSSIBLE EXCEPTION OF A SMALL AREA OF E CENTRAL NM. THUS...THE MOST PROBABLE SCENARIO WILL BE FOR ADDITIONAL STORM DEVELOPMENT LATER THIS AFTERNOON/EVENING NEAR THE ERN NM/TX BORDER...POSSIBLY AS FAR S AS SE NM/W CENTRAL TX. STRENGTHENING MID-UPPER SWLY FLOW AND MAINTENANCE OF THE LOW-LEVEL WAA REGIME WILL RESULT IN HODOGRAPHS FAVORABLE FOR SUPERCELLS. POTENTIALLY MODERATE INSTABILITY IN THE MOIST ENVIRONMENT...IN COMBINATION WITH EFFECTIVE BULK SHEAR OF 40-50 KT AND EFFECTIVE SRH NEAR 250 M2/S2...WILL SUPPORT THE RISK FOR A FEW TORNADOES AND LARGE HAIL/DAMAGING WINDS. ...FOUR CORNERS THROUGH MID AFTERNOON... AN EMBEDDED SPEED MAX IS ROTATING NEWD OVER AZ THIS MORNING...WITH THE DOWNSTREAM ZONE OF ASCENT EXPECTED TO SPREAD NEWD OVER THE FOUR CORNERS THROUGH EARLY-MID AFTERNOON. SOME SURFACE HEATING IN CLOUD BREAKS...AND SURFACE DEWPOINTS IN THE MID 40S AT A RELATIVELY HIGH ELEVATION...WILL SUPPORT SBCAPE VALUES OF 500-1000 J/KG. VERTICAL SHEAR WILL BE FAVORABLE FOR ORGANIZED SEVERE STORMS...WHERE COOL MIDLEVEL TEMPERATURES AND STEEP LOW-MIDLEVEL LAPSE RATES WILL SUPPORT A RISK FOR ISOLATED SEVERE GUSTS AND LARGE HAIL. ...KS/NE/MO/IA AREA THROUGH TONIGHT... THE RESIDUAL COOL/STABLE AIR MASS WILL BE SLOW TO ERODE TODAY GIVEN WIDESPREAD CLOUDS AND PRECIPITATION FARTHER TO THE S IN TX/OK. THOUGH THE COOL AIR SHOULD RETREAT SOME OVERNIGHT IN RESPONSE TO HIGH PLAINS CYCLOGENESIS...THE SHORT-TERM MODEL FORECASTS APPEAR A LITTLE TOO AGGRESSIVE IN WARMING/MOISTENING THE LOW LEVELS. THUS...THE RISK FOR SEVERE STORMS OVERNIGHT IS IN QUESTION...WITH LARGELY SUB-SEVERE/ELEVATED CONVECTION EXPECTED. ..THOMPSON/GARNER.. 10/12/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1630.html
Be First to Comment