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000
FXUS62 KTBW 200712
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
312 AM EDT THU JUN 20 2013

.SHORT TERM (THURSDAY-SATURDAY)...
STAGNANT PATTERN WILL PERSIST WITH A WEAK U/L TROUGH OVER THE
SOUTHEAST U.S. AND AN U/L RIDGE OVER THE SOUTHERN PLAINS.  THE
TROUGH WILL REMAIN OVER THE SOUTHEAST U.S. THROUGH THE PERIOD AND
GRADUALLY WEAKEN...WHILE THE U/L RIDGE BRIDGES OVER THE TROUGH
ACROSS THE OHIO RIVER VALLEY AND MID ATLANTIC COAST.  THIS WILL LIFT
THE MAIN U/L WESTERLY FLOW WELL NORTH OF THE AREA ACROSS THE GREAT
LAKES AND NORTHEAST.  AT THE SURFACE...INVERTED TROUGH WILL BE FROM
NORTH FLORIDA TO OFF THE CAROLINA COAST TODAY AND GRADUALLY WEAKEN
THROUGH SATURDAY.  SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC
WILL GRADUALLY BUILD WEST TO EXTEND OVER THE FLORIDA PENINSULA WITH
INCREASING EAST TO SOUTHEAST FLOW.  ONSHORE FLOW TODAY OVER THE
NATURE COAST ASSOCIATED WITH THE WEAK TROUGH WILL ALLOW AFTERNOON
CONVECTION TO PUSH INLAND WITH LOWER POPS NEAR THE COAST.  WEAK
SOUTHEAST FLOW OVER THE SOUTHERN HALF OF THE FORECAST AREA WILL
FOCUS LOW LEVEL CONVERGENCE FROM THE INTERIOR AND SOUTH ACROSS
SOUTHWEST FLORIDA...WHERE NUMEROUS SHOWERS AND THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON AND SCATTERED THUNDERSTORMS ELSEWHERE.  WITH
BROADER SOUTHEAST FLOW ON FRIDAY...MAIN FOCUS OF CONVECTION WILL BE
OVER WEST CENTRAL FLORIDA OVER THE INTERIOR PORTION OF THE COASTAL
COUNTIES...ESPECIALLY AROUND TAMPA BAY.  SLIGHTLY STRONGER EASTERLY
FLOW ON SATURDAY WILL HOLD THE WEST COAST SEA BREEZE NEAR THE COAST
WHICH WILL BE THE FOCUS OF AFTERNOON THUNDERSTORMS...WITH BEST
CHANCE OF THUNDERSTORMS NEAR THE COAST FROM THE TAMPA BAY AREA SOUTH
TO FORT MYERS.

.LONG TERM (SATURDAY NIGHT - WEDNESDAY)...
MID AND UPPER LEVEL RIDGING OVER THE WESTERN ATLANTIC WILL BUILD
WEST ACROSS THE NORTH CENTRAL PENINSULA AND SOUTHEASTERN U.S DURING
THE LONG TERM PERIOD...WHILE THE ATTENDANT SURFACE HIGH REMAINS IN
PLACE ALONG 30N RIDGING WEST ACROSS THE NORTHERN PENINSULA AND
NORTHERN GULF REGION. AMPLE MOISTURE (PW`S IN THE 1.7 TO 2 INCH
RANGE) WITHIN THE DEEP LAYERED EAST TO SOUTHEAST WIND FLOW AROUND
THE HIGH TO THE NORTH WILL SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS
ALONG THE SEA BREEZE CIRCULATIONS...WITH AN EAST-SOUTHEAST STEERING
FLOW FAVORING HIGHEST RAIN CHANCES (50 PERCENT) ALONG COASTAL
LOCATIONS EACH DAY DURING THE AFTERNOON AND EARLY EVENING HOURS AS
THE EAST COAST SEA BREEZE BOUNDARY INTERACTS WITH THE WEST COAST
BOUNDARY WHICH WILL STAY CLOSE TO THE WEST COAST DUE TO THE EAST
SOUTHEAST WIND FLOW.

TEMPERATURES WILL RUN A FEW DEGREES ABOVE NORMAL THROUGH THE PERIOD
WITH OVERNIGHT LOWS IN THE LOWER 70S INLAND AREAS...AND MID TO
UPPER 70S ALONG THE COAST...WITH DAYTIME HIGHS IN THE LOWER TO MID
90S...EXCEPT SLIGHTLY COOLER READINGS ALONG THE IMMEDIATE COAST DUE
TO THE SEA BREEZE.

&&

.AVIATION...
A MOIST AND UNSTABLE AIR MASS WILL SUPPORT SOME MVFR CEILINGS AT THE
TERMINAL SITES AFTER 08Z THIS MORNING AND HAVE INCLUDED SHORT TEMPO
GROUPS TO COVER THIS. DEVELOPING SHOWERS AND STORMS WILL BE IN THE
VICINITY OF TERMINALS AFTER 14Z AND HAVE INCLUDED VCTS AT ALL SITES
FOR NOW...WITH POSSIBLE INCLUSION OF TEMPO MVFR/IFR CIGS AND VSBYS
IN LATER FORECAST ISSUANCE OR AMENDMENTS ONCE TIMING AND OVERALL
AREAL COVERAGE OF STORMS BECOMES MORE CERTAIN. LIGHT AND VARIABLE
WINDS THIS MORNING WILL BECOME SOUTHWEST TO WEST IN THE 7 TO 10 KNOT
RANGE AFTER 15Z...WITH GUSTS UP TO 30 KNOTS POSSIBLE IN THE VICINITY
OF THUNDERSTORMS.

&&

.MARINE...
BENIGN CONDITIONS THROUGH THE PERIOD WITH WINDS LESS THAN 15 KNOTS
AND SEAS 3 FEET OR LESS THROUGH THE PERIOD.  MAIN HAZARD WILL BE
ISOLATED TO SCATTERED THUNDERSTORMS EACH DAY...WITH THE BEST CHANCE
DURING THE EVENING OR OVERNIGHT HOURS...WHICH MAY CAUSE GUSTY WINDS
AND LOCALLY ROUGH SEAS.

&&

.FIRE WEATHER...
NO FIRE WEATHER HAZARDS THROUGH THE PERIOD AS ABUNDANT LOW LEVEL
MOISTURE WILL KEEP AFTERNOON RELATIVE HUMIDITY VALUES ABOVE CRITICAL
VALUES EACH DAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  91  76  91  76 /  40  20  50  30
FMY  92  75  92  74 /  60  20  50  30
GIF  93  75  92  74 /  50  20  50  20
SRQ  90  75  91  75 /  30  20  40  30
BKV  92  71  91  71 /  40  20  60  30
SPG  90  79  89  78 /  40  20  50  30

&&

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

$$

SHORT TERM/MARINE/FIRE WEATHER...13/OGLESBY
LONG TERM/AVIATION...57/MCMICHAEL