SPC 0100Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0801 PM CDT SAT APR 28 2012 VALID 290100Z - 291200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS ERN MO TO OH VALLEY AND ERN KY... ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS SRN PLAINS... ...SYNOPSIS... IN MID-UPPER LEVELS...SPLIT-FLOW PATTERN PREVAILS ACROSS WRN NORTH AMERICA...DOMINATED BY 500-MB CYCLONE NOW CENTERED OVER MT/SD BORDER AREA. THIS FEATURE SHOULD DRIFT ERRATICALLY THROUGH REMAINDER PERIOD...WITH SLIGHT NET NWD MOTION MOST PROBABLE. SATELLITE IMAGERY INDICATES WEAK PERTURBATION HAS EJECTED FROM SUBTROPICAL STREAM OVER MEX...AND IS MOVING NEWD ACROSS PORTIONS W-CENTRAL TX AND EDWARDS PLATEAU REGION. THIS FEATURE SHOULD PROCEED NEWD ACROSS ARKLATEX REGION OVERNIGHT...AND IS POORLY RESOLVED BY MOST MODELS. 23Z SFC ANALYSIS SHOWED WAVY/QUASISTATIONARY FRONTAL ZONE FROM NERN GA NNEWD ACROSS NC/TN BORDER REGION TO EXTREME WRN VA AND NERN KY...THEN WWD THROUGH SMALL MESOLOW CORRESPONDING TO SVR TSTM THAT MOVED THROUGH SDF AREA DURING PAST HOUR. FRONT EXTENDS WWD FROM THERE TO SRN IL TO ANOTHER WEAK LOW OVER S-CENTRAL/SERN MO...THEN SWWD OVER NERN AND CENTRAL OK. SRN IL/SRN INDIANA/NRN KY PORTION OF FRONTAL ZONE IS EFFECTIVELY SHUNTED SWD BY AGGREGATED CONVECTIVE OUTFLOWS. FARTHER SW...FRONT IS RETREATING WWD ACROSS SWRN OK AND NW TX...BUT STILL QUASISTATIONARY AND LOCALLY MOVING SWWD OVER SOUTH-PLAINS REGION. MESONET ANALYSES AND REFLECTIVITY ANIMATIONS REVEAL INFLECTION POINT ALONG BOUNDARY...BACKING WSWWD THROUGH FDR AREA ATTM. DRYLINE INTERSECTS FRONT NEAR SNK...WHERE ANOTHER SVR TSTM HAS DEVELOPED. DRYLINE EXTENDS SWWD ACROSS PERMIAN BASIN REGION AND SHOULD CONTINUE BACKING NWWD. ...ERN MO TO OH VALLEY AND ERN KY... CONVECTION THAT PASSED THROUGH SDF AREA IS LIKELY TO CONTINUE ESEWD ACROSS ERN KY. HOWEVER...THETAE WILL BE DECREASING WITH TIME AND EWD EXTENT INTO FRONTAL ZONE NEAR VA BORDER. OUTLOOK HAS BEEN EXTENDED EWD ACROSS THAT REGION. SCATTERED-NUMEROUS TSTMS COMPRISE LOOSELY ORGANIZED MCS OVER ERN MO AND SRN IL...WHICH MAY PERSIST FOR A FEW MORE HOURS ESEWD OVER SRN IL...SRN INDIANA AND NWRN KY. PRIND LOW-LEVEL THETAE ADVECTION FROM SW WILL OFFSET SFC DIABATIC COOLING SOME IN HELPING TO MAINTAIN FAVORABLE THERMODYNAMIC ENVIRONMENT...AMIDST 45-50 KT EFFECTIVE SHEAR MAGNITUDES. DAMAGING GUSTS/HAIL REMAIN POSSIBLE...HOWEVER...MLCINH WILL CONTINUE TO INCREASE WITH SEWD EXTENT. REF WWS 198-199 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST NEAR-TERN GUIDANCE ON SVR THREAT OVER THIS CORRIDOR. ...SRN PLAINS... ISOLATED TO WIDELY SCATTERED TSTMS ARE DEVELOPING IN CORRIDOR FROM W-CENTRAL TX NEAR SNK NEWD TO NEAR OKC. REF WWS 200 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST NEAR-TERN GUIDANCE ON SVR THREAT OVER THIS CORRIDOR. CONVECTIVE COVERAGE IS FCST TO INCREASE THROUGH EVENING OVER THIS REGION INVOF SFC FRONT...AMIDST FAVORABLE BUOYANCY AND SHEAR FOR SUPERCELLS WITH DAMAGING HAIL LIKELY FROM MOST ROBUST STORMS. WINDOW OF POTENTIAL FOR A TORNADO OR TWO EXISTS ESPECIALLY NEAR AND NE OF INFLECTION POINT....WHERE SFC WINDS REMAIN RELATIVELY BACKED BOTH ALONG AND JUST E OF FRONT. SEPARATE AREA OF TSTM DEVELOPMENT REMAINS POSSIBLE OVERNIGHT FROM PANHANDLE EWD/ENEWD OVER NWRN OK AND PERHAPS SRN KS...IN ZONE OF STG LOW-LEVEL WAA AND ISENTROPIC ASCENT TO LFC. FCST ELEVATED MUCAPE 1500-2500 J/KG AND ROUGHLY 50-60 KT EFFECTIVE SHEAR SUPPORTS POTENTIAL FOR AT LEAST ISOLATED LARGE HAIL...THOUGH LOCAL CONCENTRATIONS WITHIN THIS CORRIDOR MAY BE WIDELY SCATTERED TO SCATTERED. ..EDWARDS.. 04/29/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_0100.html
Be First to Comment