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ACUS02 KWNS 110701
SWODY2
SPC AC 110700

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CST THU MAR 11 2010

VALID 121200Z - 131200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTHERN HALF OF THE
FL PENINSULA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF AL/GA AND
SOUTHERN APPALACHIANS...

...SYNOPSIS...
CENTROID OF CLOSED/EXTENSIVE LONGWAVE TROUGH WILL SLOWLY PIVOT
EAST-SOUTHEASTWARD OVER THE LOWER MO/MIDDLE MS RIVER VALLEYS ON
FRIDAY...WITH A SOUTHERN PERIPHERY/BASAL SHORTWAVE TROUGH
PROGRESSING EAST-NORTHEASTWARD OVER THE GULF COAST STATES/TN VALLEY
IN CONJUNCTION WITH PHASING POLAR/SUBTROPICAL JETS OVER THE GULF OF
MEXICO/SOUTHEAST STATES/FL PENINSULA. IN THE WEST...THE INLAND
ADVANCEMENT OF A CONSIDERABLE UPPER TROUGH AND STEEPENING LAPSE
RATES IN THE WAKE OF ASSOCIATED COLD FRONT MAY YIELD ISOLATED TSTMS
FOR COASTAL PORTIONS OF THE PACIFIC NORTHWEST/NORTHERN CA AND
OFFSHORE PACIFIC WATERS.

...FL PENINSULA/FL KEYS...
FULL-PERIOD SEVERE RISK IS PROBABLE ACROSS THE SOUTHERN THIRD TO
HALF OF THE FL PENINSULA/PERHAPS FL KEYS ON FRIDAY. CURRENT THINKING
IS THAT PLENTIFUL EARLY DAY SHOWERS/TSTMS...WITH AT LEAST SOME
ISOLATED SEVERE THREAT...SHOULD SERVE TO ESTABLISH/REINFORCE A
RAIN-COOLED EFFECTIVE WARM FRONT...MOST LIKELY ACROSS THE CENTRAL FL
PENINSULA VICINITY. WHILE DETAILS OF SUCH ONGOING SHOWERS/TSTMS ARE
DIFFICULT TO PORTEND IN ADVANCE...IT DOES SEEM PROBABLE THAT A
GRADUALLY MOISTENING BOUNDARY LAYER /UPPER 60S TO LOWER 70S F
SURFACE DEWPOINTS/ AND POCKETS OF STRONGER HEATING SOUTH OF THE
AFOREMENTIONED WARM FRONT SHOULD SUPPORT A DAYTIME UPSWING IN DEEP
CONVECTIVE VIGOR COINCIDENT WITH GRADUAL HEIGHT FALLS AND THE
APPROACH OF A MID LEVEL IMPULSE. WHILE LOW LEVEL FLOW MAY TEND TO
VEER /BUT STRENGTHEN/ DURING THE DAY...VERY STRONG DEEP TROPOSPHERIC
WIND FIELDS WILL SUPPORT A MIXED MODE OF SEMI-DISCRETE HIGH
PRECIPITATION SUPERCELLS AND/OR LINEAR EMBEDDED BOWS...WITH THE
POSSIBILITY OF TORNADOES/DAMAGING WINDS AS THE PRIMARY CONCERNS
ASIDE FROM HEAVY RAINFALL.

...AL/GA TO SOUTHERN APPALACHIANS...
SHOWERS/TSTMS WILL LIKELY BE ONGOING EARLY FRIDAY ACROSS PORTIONS OF
THE TN VALLEY/CENTRAL GULF COAST STATES TO FL. AN EARLY DAY SEVERE
THREAT IS POSSIBLE MAINLY ACROSS PORTIONS OF AL...BUT THE SEVERE
POTENTIAL MAY CONTINUE/INCREASE AND DEVELOP EASTWARD DURING THE DAY
AS A MID LEVEL SHORTWAVE TROUGH/SPEED MAX APPROACHES WITHIN A
BROADER DIFFLUENT REGIME/EXIT REGION OF POLAR JET. WHILE THE TRUE
MARITIME WARM/MOIST SECTOR WILL BE CONFINED TO FL/ADJACENT GULF
COAST...AND EXTENSIVE CLOUD COVER/PRECIPITATION MAY EXIST EARLY IN
THE DAY...50S F SURFACE DEWPOINTS AHEAD OF A POSSIBLE WEAK SURFACE
LOW AND NORTH-SOUTH COLD FRONT/DEVELOPING OCCLUSION COULD LEAD TO AN
UPSWING IN DEEP CONVECTIVE COVERAGE/VIGOR DURING THE DAY. EVEN WITH
MARGINAL BOUNDARY LAYER MOISTURE AND RELATIVELY MODEST BUOYANCY
/PERHAPS ONLY 500-1000 J PER KG MLCAPE/...STEEPENING MID LEVEL LAPSE
RATES VIA MID/UPPER DRY SLOT AND VERY STRONG LOW TO MID TROPOSPHERIC
FLOW WILL SUPPORT A RISK FOR SEVERE HAIL/DAMAGING WINDS.

...OH/TN RIVER VALLEYS...
AS THE COLD/CLOSED UPPER LOW SLOWLY SHIFTS TOWARD THE MIDDLE MS
RIVER VALLEY...IT APPEARS THAT MULTIPLE LOW AMPLITUDE/MID LEVEL
DISTURBANCES WILL PIVOT NORTH-NORTHEASTWARD OVER THE OH/TN VALLEYS
ON FRIDAY. GIVEN COOL THERMAL PROFILES ALOFT /-20 TO -22C AT 500 MB/
IN PROXIMITY TO THE COLD/CLOSED UPPER LOW...EVEN MODEST DAYTIME
HEATING AND UPPER 40S/LOWER 50S F SURFACE DEWPOINTS COULD YIELD
STRONG/SEVERE LOW-TOPPED TSTMS...ESPECIALLY FRIDAY AFTERNOON IN
VICINITY OF THE SURFACE LOW AND ASSOCIATED ROUGHLY NNW-SSE ORIENTED
COLD/OCCLUDED FRONT. MARGINALLY SEVERE HAIL WILL LIKELY BE THE
PRIMARY HAZARD...WITH ANY SUCH RISK TENDING TO WANE BY AROUND
SUNSET.

..GUYER.. 03/11/2010