Monday, September 5, 2011

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 051258
SWODY1
SPC AC 051257

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0757 AM CDT MON SEP 05 2011

VALID 051300Z - 061200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF AL AND GA...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
AREA...FROM ERN MS ENE INTO THE CAROLINAS...

...SYNOPSIS...
SHORTWAVE TROUGH NOW DROPPING SE ACROSS THE LWR MS VLY WILL CONTINUE
TO INTERACT WITH REMNANTS OF T.S. LEE TODAY/TNGT...WITH THE COMBINED
CIRCULATION CENTER LIKELY EVOLVING INTO AN ELONGATED CLOSED LOW OVER
THE MS/AL BORDER BY 12Z TUE. AT THE SAME TIME...SEPARATE...MORE
STRONGLY AMPLIFIED SHORTWAVE IMPULSE NOW OVER THE CNTRL GRT LKS
SHOULD CONTINUE E TO THE LWR LKS/NRN NEW ENGLAND BY EARLY TUE AS
BROAD RIDGE PERSISTS OVER THE RCKYS.

AT LWR LVLS...REMNANT SFC CIRCULATION CENTER OF LEE...NOW OVER FAR
SRN MS...IS EXPECTED TO TRACK SLOWLY NEWD...REACHING CNTRL AL THIS
EVE AND NRN GA BY 12Z TUE.

...SERN STATES TODAY/TNGT...
SHOWERS/TSTMS SHOULD INCREASE IN COVERAGE AND STRENGTH OVER PARTS OF
AL AND GA LATER TODAY AS MODEST SFC HEATING BOOSTS SBCAPE TO BETWEEN
1000 AND 2000 J/KG IN WARM SECTOR OF REMNANT T.D. LEE. CONTINUED
EXTRATROPICAL TRANSITION OF THE SYSTEM THAT ALREADY WAS OF HYBRID
ORIGIN WILL STRENGTHEN AND POSSIBLY BROADEN ASSOCIATED SSWLY
LLJ...WITH SPEEDS INCREASING TO AOA 50 KTS. AT THE SAME
TIME...700-500 MB FLOW WILL INCREASE TO 50-60 KTS AS UPR CIRCULATION
BEGINS TO ELONGATE.

LOW LVL CONVERGENCE MAY FOCUS IN SEVERAL AREAS INCLUDING /1/ ALONG
NWD-MOVING CSTL BOUNDARY NOW OVER SRN AL AND THE FL PANHANDLE.../2/
ALONG DEVELOPING N/S CONFLUENCE ZONE NOW ALONG THE MS-AL
BORDER...AND /3/ ALONG AXIS OF LOW LVL FRONTOGENESIS EXTENDING
WSW-ENE ACROSS NRN PARTS OF AL AND GA. EACH OF THESE AXES MAY SERVE
TO CONCENTRATE STORM/SHOWER DEVELOPMENT...WITH MOIST LOW LVL
ENVIRONMENT AND MODERATE TO LOCALLY STRONG LOW LVL DIRECTIONAL SHEAR
FOSTERING SPORADIC EPISODES OF MESOCYCLONES AND POSSIBLE TORNADOES.
THE GREATEST TORNADO THREAT MAY DEVELOP ALONG AND N OF THE CSTL
BOUNDARY LATER THIS MORNING THROUGH LATE THIS AFTN...WHERE THE
LARGEST LOW LVL HODOGRAPHS WILL COINCIDE WITH AXIS OF GREATEST
BOUNDARY LAYER MOISTURE. SCTD SMALL BOWS WITH LOCALLY DMGG WIND
ALSO MAY OCCUR.

LATER TODAY...AND CONTINUING TNGT THROUGH EARLY TUE...EMBEDDED
ROTATING STRUCTURES/LEWPS MAY POSE A THREAT FOR MORE ISOLD TORNADOES
AND LOCALLY DMGG WIND GUSTS ALONG THE AFOREMENTIONED FRONTOGENETIC
ZONE AS THAT FEATURE DEVELOPS ENEWD FROM NRN GA INTO WRN AND CNTRL
PARTS OF THE CAROLINAS.

...MID-ATLANTIC TO SRN NEW ENGLAND THIS AFTN...
THE STRONGEST LARGE SCALE FORCING FOR ASCENT AND SHEAR WITH GRT LKS
TROUGH WILL LAG ASSOCIATED COLD FRONT SETTLING SE ACROSS THE MID
ATLANTIC AND NEW ENGLAND STATES TODAY...RESULTING IN AN ANA-TYPE
FRONTAL SETUP. COUPLED WITH WIDESPREAD EXISTING CONVECTION/CLOUD
COVER AND DIMINISHED SFC HEATING...PROSPECTS FOR
APPRECIABLE SVR ACTIVITY APPEAR LOW. NEVERTHELESS...POTENTIAL WILL
EXIST FOR A FEW POCKETS OF SUFFICIENT DESTABILIZATION TO SUPPORT
ISOLD STRONG TO LOCALLY SVR WIND GUSTS...ESPECIALLY ALONG THE
IMMEDIATE CST FROM NJ TO ME.

..CORFIDI/GARNER.. 09/05/2011

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