tim66214's blog: "Tim's Blog"

SPC AC 280725 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0225 AM CDT WED MAR 28 2007 VALID 301200Z - 311200Z ...THERE IS A SLGT RISK OF SVR TSTMS SERN NEB/SWRN IA TO S-CENTRAL/SW TX... ...SYNOPSIS... LARGE MID/UPPER LEVEL CYCLONE -- NOW DEVELOPING ACROSS GREAT BASIN -- IS FCST TO MOVE VERY SLOWLY EWD ACROSS INTERMOUNTAIN W AND ROCKIES THROUGH EARLY DAY-3 PERIOD. MEANWHILE...SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER ERN GULF OF AK -- IS EXPECTED TO PIVOT SEWD/EWD AROUND BASE OF UPPER LOW JUST W OF AK PANHANDLE...PERHAPS PHASING WITH ANOTHER TROUGH PRESENTLY OVER N-CENTRAL PACIFIC. AS HEIGHTS FALL OVER PACIFIC NW AND SWRN CANADA AHEAD OF THIS PERTURBATION...AND STRONG SHORTWAVE TROUGH PIVOTS THROUGH SRN ROCKIES/SRN HIGH PLAINS...BROADER SCALE TROUGH OVER ROCKIES FINALLY SHOULD BEGIN TO EJECT NEWD. CONSIDERABLE DIFFERENCES ARE EVIDENT AMONG VARIOUS OPERATIONAL PROGS AND SREF MEMBERS ON RELATIVE STRENGTH DURING DAY-3 OF OCCLUDING NRN PLAINS LOW AND SRN/CENTRAL PLAINS LOW THAT SHOULD DEVELOP DAY-2. ...CENTRAL/SRN PLAINS... ANOTHER ELONGATED/MERIDIONALLY ALIGNED SWATH OF SVR TSTM POTENTIAL EXISTS DAY-3. STRONGEST DEEP-LAYER BULK SHEAR SHOULD BE OVER CENTRAL PLAINS AND PERHAPS OK...IN ADVANCE OF EJECTING MID/UPPER LEVEL WAVE. HOWEVER...DIRECTIONAL SHEAR AND LOW LEVEL HODOGRAPHS STILL MAY SUPPORT SUPERCELLS EVEN AS FAR S AS S TX. LARGEST MID/UPPER LEVEL LAPSE RATES -- DOWNSTREAM FROM MEXICAN ELEVATED MIXED-LAYER -- AS WELL AS HIGHEST BOUNDARY LAYER THETAE...SHOULD BE ACROSS PORTIONS CENTRAL/SRN TX...BUT POCKETS OF FAVORABLE HEATING MAY DEVELOP ACROSS CENTRAL PLAINS ALONG/AHEAD OF FRONT/DRYLINE. AS WITH DAY-2...SPECIFIC/ENHANCED THREAT AREAS WOULD BE STRONGLY CONDITIONAL ON CONVECTIVE MODE...MAGNITUDE/EXTENT OF DESTABILIZATION BEHIND EARLY TSTM COMPLEXES...AND PERHAPS BOUNDARIES LEFT BY EARLIER ACTIVITY. BECAUSE OF THIS STRONG DEPENDENCE ON MESOSCALE FOCI...OUTLOOK IS INITIATED AS BROAD AREA OF PROBABILITIES MRGLLY SUPPORTING CATEGORICAL SLGT RISK...WITH POTENTIAL FOR MORE CONCENTRATED AREA OF GREATER PROBABILITIES WITH TIME. ..EDWARDS.. 03/28/2007