Friday, April 25, 2008

SPC

Sorry but again I don;t have much time this morning, but here is the SPC disscusion for today's severe weather. Does look like a semi decent outbreak if storms can break the cap this afternoon from what I have looked at this morning.
SPC AC 250553 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1253 AM CDT FRI APR 25 2008 VALID 251200Z - 261200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPR MIDWEST/CNTRL GRTLKS SWWD INTO E/SCNTRL TX... ...CNTRL GRTLKS TO E/SC TX... A MID-LVL TROUGH EMERGING ONTO THE PLAINS WILL SLOW AND TAKE ON A NEGATIVE TILT OVER THE UPR MS VLY REGION TONIGHT AS A SECONDARY IMPULSE DIGS SEWD ACROSS THE NRN ROCKIES. THE ASSOCD SFC LOW WILL DEVELOP NEWD FROM NEB AT 12Z TO N WI BY THIS EVE WITH AN INTENSIFYING COLD FRONT SWEEPING SEWD INTO THE MS VLY...OZARKS AND CNTRL TX BY TONIGHT. THE FRONT WILL BE A FOCUS FOR PSBL SVR TSTMS TODAY AND TONIGHT. EARLY THIS MORNING...AN INTENSIFYING MCV WAS NOTED OVER CNTRL NEB. THIS FEATURE SHOULD PROGRESS ENEWD TODAY ALONG THE FOOTPRINT OF THURSDAY EVENING TSTM CLUSTERS OVER WI...CNTRL/NRN IA AND ERN NEB. COMBINATION OF ENHANCED LOW-LVL FLOW ALONG ERN PERIPHERY OF THE MCV AND ADDED LARGE SCALE RESPONSE TO THE APCHG TROUGH SHOULD SUPPORT A WIDESPREAD REGION OF TSTMS FROM THE MID-MO VLY NEWD INTO WI DURING THE MORNING AND PSBLY INTO THE EARLY AFTN. AS A RESULT...THE EFFECTIVE BAROCLINIC ZONE MAY REMAIN IN ITS CURRENT AFOREMENTIONED ORIENTATION THROUGH MOST OF THE DAY...LIMITING DESTABILIZATION NWD INTO THE UPR MS VLY/CNTRL GRTLKS REGION. THIS OTLK WILL MAINTAIN CONDITIONAL SVR PROBABILITIES OVER MOST OF WI EWD INTO PARTS OF MI. LATER SHIFTS CAN BETTER ASCERTAIN HOW MORNING CONVECTION MODULATES INSTABILITY FIELDS. WHATEVER THE CASE...THE MORNING ACTIVITY WILL PROBABLY OFFER AT LEAST ISOLD HAIL/DMGG WIND GUSTS. FARTHER SW...LARGER SCALE HEIGHT FALLS ASSOCD WITH THE PRIMARY TROUGH WILL BEGIN TO OVERSPREAD THE WARM SECTOR CHARACTERIZED BY 60-65F SFC DEW POINTS FROM ERN IA SWWD INTO WRN MO AND ERN OK DURING THE EARLY AFTN. LOW-LVL HEATING JUST AHEAD OF THE FRONT AND MODEST COOLING ALOFT WILL WEAKEN INHIBITION AND RESULT IN DEVELOPMENT AND/OR STRENGTHENING OF TSTMS. A MIXED-MODE OF LINEAR AND PSEUDO-DISCRETE CELLS IS LIKELY TO EVOLVE WITH LARGE HAIL AND DMGG WIND GUSTS THE PRIMARY THREATS. A SLIGHTLY MORE CONCENTRATED AREA OF SVR POTENTIAL MAY EVOLVE SOMEWHERE OVER NERN MO/WRN IL NWD TO THE SRN PERIPHERY OF MORNING ACTIVITY WHERE STRONGER LARGE SCALE ASCENT TRANSLATES ACROSS THE REGION. ALL STORMS WILL PROBABLY PEAK BY MID-EVE OVER THE MIDWEST AND MID-MS VLY REGIONS BEFORE THEY MOVE AWAY FROM THE NARROW MOIST/INSTABILITY AXES AND AS THE LLJ TRANSLATES NWD INTO THE GRTLKS REGION. FINALLY...STRONG HEATING WILL EXIST ACROSS CNTRL/E TX DURING THE DAY WITH CURRENT MID-60S SFC DEW POINTS BEING MAINTAINED. VERY STEEP MID-TROP LAPSE RATES ATOP THIS MOISTURE WILL CAP OFF SFC BASED PARCELS UNTIL LATE IN THE AFTN/EARLY EVE. AT THAT POINT...SRN PERIPHERY OF THE PLAINS TROUGH WILL GLANCE THE REGION AND LIKELY SUPPORT TSTM INITIATION ACROSS NERN/NCNTRL TX. THIS ACTIVITY WILL THEN BACKBUILD SWWD INTO PARTS OF SC TX DURING THE EVE HOURS. STRONGER DEEP LAYER SHEAR WILL EXIST ACROSS NE TX...BUT GIVEN THE STRONG INSTABILITY EXPECTED AND SUSTAINED FRONTAL CONVERGENCE...STG-SVR TSTMS WILL BE POSSIBLE...INCLUDING BRIEF SUPERCELL STRUCTURES WITH LARGE HAIL. SOME OF THIS ACTIVITY MAY PERSIST OVERNIGHT AS IT MOVES INTO THE SABINE RVR VLY/UPR TX COAST WITH SW SIDES OF ANY GROWING TSTM CLUSTERS REMAINING STG TO PERHAPS SVR WITH DMGG WIND GUSTS/HAIL.

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