317
ACUS01 KWNS 110533
SWODY1
SPC AC 110531
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1131 PM CST WED MAR 10 2010
VALID 111200Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF FL...
...SYNOPSIS...
BROAD UPPER LOW WILL PERSIST OVER THE CNTRL U.S. THURSDAY. SEVERAL
VORTICITY MAXIMA WILL CONTINUE TO ROTATE THROUGH THIS FEATURE. THE
VORT MAX OVER ERN KS/WRN MO AS OF WEDNESDAY EVENING IS FORECAST TO
LIFT NWD INTO ERN NEB/IA...WHILE VORT MAX CURRENTLY OVER THE SWRN
U.S. WILL CONTINUE ESEWD...REACHING THE LOWER MS VALLEY BY THE END
OF THE PERIOD. INITIAL SURFACE LOW WILL OCCLUDE OVER THE UPPER MS
VALLEY WITH TRAILING FRONT EXTENDING SWD THROUGH WRN PARTS OF THE TN
AND LOWER MS VALLEY. SECONDARY LOW SHOULD DEVELOP OVER THE LOWER MS
VALLEY THURSDAY NIGHT IN ASSOCIATION WITH APPROACHING IMPULSE. A
QUASI-STATIONARY BOUNDARY WILL LIKELY PERSIST FROM SRN GA NWWD
THROUGH CNTRL AL.
...SRN PARTS OF THE GULF COASTAL STATES AND FL...
SWLY LOW-LEVEL JET LOCATED WITHIN THE DIVERGENT EXIT REGION OF A
STRONG SUBTROPICAL UPPER JET IS FORECAST TO SHIFT EWD THROUGH THE
NERN GULF AND THE FL PENINSULA THURSDAY. THIS FEATURE WILL HELP
TRANSPORT RICHER BOUNDARY LAYER MOISTURE WITH UPPER 60S DEWPOINTS
NEWD THROUGH THE PENINSULA. WEAK LAPSE RATES AND WIDESPREAD CLOUDS
WILL LIMIT MLCAPE IN MOST AREAS TO BELOW 1000 J/KG. STORMS WILL BE
ONGOING THURSDAY WITHIN THE BROAD ZONE OF ISENTROPIC LIFT AND
THETA-E ADVECTION OVER THE SRN PORTIONS OF THE GULF COASTAL STATES.
THESE STORMS WILL BE EMBEDDED WITHIN STRONG VERTICAL SHEAR WITH
LARGE LOW HODOGRAPHS SUPPORTIVE OF SUPERCELLS. HOWEVER...THE
ACTIVITY MAY BE SLIGHTLY ELEVATED...WHICH ALONG WITH A THE MARGINAL
THERMODYNAMIC ENVIRONMENT WOULD SERVE AS A LIMITING FACTOR FOR
SEVERE STORMS. A GREATER THREAT FOR SEVERE STORMS WILL MATERIALIZE
AS ACTIVITY DEVELOPS EWD THROUGH THE FL PENINSULA WHERE INFLUX OF
RICHER MOISTURE AND GRADUAL DESTABILIZATION OF THE BOUNDARY LAYER
WILL OCCUR. LARGE HODOGRAPHS AND BULK SHEAR WILL SUPPORT A THREAT
FOR EMBEDDED SUPERCELLS AND BOWING SEGMENTS WITH ISOLATED DAMAGING
WIND AND TORNADOES POSSIBLE.
SEVERE THREAT MAY UNDERGO A TEMPORARY DECREASE THURSDAY
EVENING...BUT MAY INCREASE AGAIN LATER THURSDAY NIGHT AS THE
LOW-LEVEL JET REDEVELOPS OVER THE PENINSULA DOWNSTREAM FROM
ADVANCING SRN STREAM IMPULSE.
...MID MS AND OH VALLEY AREAS...
DIABATIC WARMING WITHIN DRY SLOT AND BENEATH UPPER THERMAL TROUGH
ACCOMPANYING NWD EJECTING VORT MAX WILL CONTRIBUTE TO A ZONE OF
STEEP MID LEVEL LAPSE RATES ACROSS IL THROUGH WRN PARTS OF THE TN
VALLEY. AN AXIS OF MODEST INSTABILITY WITH MLCAPE BELOW 800 J/KG
WILL BE POSSIBLE IN THIS REGION. ADDITIONAL STORMS MAY DEVELOP ALONG
AND EAST OF OCCLUDED FRONT AS THE ATMOSPHERE DESTABILIZES DURING THE
AFTERNOON. VERTICAL SHEAR WILL REMAIN SUFFICIENT FOR UPDRAFT
ROTATION WITH ISOLATED LARGE HAIL AND PERHAPS A COUPLE OF TORNADOES.
THIS AREA WILL CONTINUE TO BE MONITORED FOR A POSSIBLE SLIGHT RISK
IN LATER UPDATES.
...LOWER MS VALLEY AND WRN TN VALLEY AREA...
TRAILING PORTIONS OF FRONT WILL LIKELY STALL OVER THE LOWER MS
VALLEY. VORT MAX NOW OVER THE SWRN STATES WILL REACH THIS REGION
THURSDAY NIGHT. ASCENT AND STEEPER LAPSE RATES ACCOMPANYING THE
IMPULSE WILL OVERTAKE THIS BOUNDARY AND CONTRIBUTE TO
DESTABILIZATION AND THUNDERSTORM INITIATION. GIVEN TIME OF DAY AND
MODEST LOW-LEVEL MOISTURE...STORMS WILL LIKELY REMAIN ELEVATED...BUT
STEEP LAPSE RATES AND A RELATIVELY DRY BOUNDARY LAYER WILL
CONTRIBUTE TO A THREAT FOR ISOLATED HAIL AND STRONG WIND GUSTS.
..DIAL/HURLBUT.. 03/11/2010
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