Southwest Florida Weather Forecast Discussion - Tampa Bay National Weather Service

000
FXUS62 KTBW 231349
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
950 AM EDT THU MAY 23 2013

.UPDATE (REST OF TODAY AND TONIGHT)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER CHAOTIC UPPER 
LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS DOMINATED BY 
THREE LONGWAVE FEATURES. LOOKING FAR UPSTREAM WE FIND A LARGE AND 
VIGOROUS UPPER LEVEL LOW SPINNING OVER THE PACIFIC NORTHWEST. MAIN 
FLOW AROUND THE SOUTHERN PERIPHERY OF THIS CIRCULATION EMERGES 
THROUGH THE FOUR-CORNERS REGION AND THEN RIDGES UP OVER THE CENTRAL 
PLAINS. THIS FLOW THEN QUICKLY DIVES BACK TO THE SOUTHEAST AND 
MERGES WITH AN IMPRESSIVE LONGWAVE TROUGH PIVOTING THROUGH MUCH OF 
EASTERN CANADA AND THE EASTERN CONUS. OUR FORECAST AREA RESIDES NEAR 
THE SOUTHERN PERIPHERY/BASE OF THIS EASTERN TROUGH. WV IMAGERY 
CLEARLY DEFINES A WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WITHIN THE 
BASE OF THE LONGWAVE TROUGH WHICH WILL PIVOT THROUGH THE REGION THIS 
MORNING AND EARLY AFTERNOON. 

BEHIND THIS SHORTWAVE FOR THE SECOND HALF OF THE DAY/EVENING THE 
DEPTH OF DRY AIR WITHIN THE COLUMN WILL INCREASE (ESPECIALLY OVER 
THE NORTHERN HALF OF THE AREA AS WEAK NVA AND DEEP LAYER SUBSIDENCE 
ARRIVES FROM THE WEST AND NORTHWEST.  

THE PASSAGE OF THIS SHORTWAVE TO OUR EAST BEFORE THE TIME OF PEAK 
DIURNAL HEATING WILL WORK IN THE FAVOR FOR THOSE LOOKING FOR LESS 
CONVECTIVE ACTIVITY THAN HAS BEEN SEEN THE PAST COUPLE OF DAYS. 

STILL UNLIKELY THAT THIS SETUP WILL BE ENOUGH TO COMPLETELY SUPPRESS 
THE THUNDERSTORM THREAT FOR ALL AREAS. SEEING A FEW FAVORABLE 
ASPECTS IN THE SHORT TERM FOR UPDRAFT INITIATION AND SUPPORT. WILL 
BE WATCHING A WEAK LOW LEVEL TROUGH DROP SOUTH TOWARD THE I-10 
CORRIDOR EARLY THIS AFTERNOON. LOW LEVEL FOCUS ALONG AND JUST SOUTH 
OF THIS BOUNDARY MAY BE ENOUGH TO SUPPORT A FEW SHOWERS/STORMS UP 
TOWARD LEVY COUNTY BY MID AFTERNOON BEFORE THE MORE SIGNIFICANTLY 
HOSTILE AIR ALOFT TOWARD CONVECTION ARRIVES. LOCAL HIGH-RES WRFARW 
SIMULATIONS ARE IN FAVOR OF THIS CONVECTIVE DEVELOPMENT...BUT ALSO 
KEEP THE CONVECTION FAIRLY SHALLOW WITH UPDRAFT RATES THAT ARE 
GENERALLY UNSUPPORTIVE OF SIGNIFICANT WEATHER. BY THIS 
EVENING...THETA-E VALUES AROUND 700MB ARE WELL BELOW 320K UP TOWARD 
CHIEFLAND WHICH WILL MAKE IT VERY DIFFICULT FOR ANY CUMULUS TOWERS 
ATTEMPTING TO GROW.

THE OTHER AREA WE AREA LOOKING FOR WIDELY SCATTERED CONVECTIVE 
ACTIVITY IS ACROSS OUR INTERIOR SOUTHERN ZONES...MAINLY WELL INLAND 
FROM I-75. MORE FAVORABLE MOISTURE PROFILES WILL HOLD ON A LITTLE 
LONGER DOWN TOWARD THESE AREA...AND A RAPID INLAND PROPAGATION OF 
THE SEA-BREEZE WILL ADD SOME LOWER LEVEL FOCUS. 

LESS CONVECTIVE ACTIVITY AND 850MB TEMPS OF 16-17C GIVE THE 
BOUNDARY LAYER A WARM POTENTIAL TODAY. THOSE AREAS NOT SEEING ANY 
QUICK SHOWER AND AWAY FROM THE BEACHES SHOULD EASILY MIX OUT INTO  
THE LOWER 90S...WITH WARMER SPOTS PEAKING IN THE MID 90S. ONSHORE 
FLOW DEVELOPING QUICKLY TODAY WILL HOLD THE BEACHES IN THE 80S.   

PATTERN SUGGESTS ANY LINGERING STORMS BY MID-EVENING WILL BE OVER 
TOWARD THE I-95 CORRIDOR WHICH SHOULD SET UP A MAINLY DRY...QUIET 
AND SEASONABLE OVERNIGHT PERIOD. ENJOY!

&&

.AVIATION...
PREVAILING VFR WITH FEW-SCT CLOUDS. LIGHT AND VARIABLE WINDS BECOME 
WESTERLY LATE MORNING AND AFTERNOON...KEEPING LIMITED TSRA EAST OF 
THE TERMINALS.

&&

.MARINE...
WINDS AND SEAS WILL REMAIN RATHER LIGHT THROUGH TODAY AND
TONIGHT. A WEAKENING COLD FRONT WILL SLIDE SOUTHWARD THROUGH THE
WATERS FRIDAY AND FRIDAY NIGHT...WITH STRONG HIGH PRESSURE THEN
BUILDING NORTH OF THE STATE OVER THE WEEKEND INTO EARLY NEXT WEEK.
ELEVATED EASTERLY FLOW WILL LIKELY RESULT IN A NEED FOR EXERCISE
CAUTION OR ADVISORY HEADLINES FOR MUCH OF THE MARINE AREA DURING THE 
EVENING AND OVERNIGHT HOURS EACH DAY THROUGH THE PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  90  73  91  71 /   0   0   0   0 
FMY  91  72  91  72 /  10  10  10  10 
GIF  92  71  93  68 /  20  10  10   0 
SRQ  86  71  89  71 /   0   0   0   0 
BKV  90  65  91  63 /  10   0  10   0 
SPG  90  75  89  74 /   0   0   0   0 

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

$$

UPDATE...MROCZKA
AVIATION...RUDE

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