000
FXUS62 KTBW 160653
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
253 AM EDT WED SEP 16 2009
.SYNOPSIS...AN UPPER LOW IS SPINNING ALONG THE WESTERN AR/LA LINE
WHILE RIDGING EXTENDS FROM THE YUCATAN EAST OVER CUBA TO THE
BAHAMAS. AT THE SURFACE...A LOW ALONG THE LA/MS BORDER TRAILS A
COLD
FRONT SOUTH OVER THE GULF AND HAS A WARM
FRONT REACHING
EASTWARD ALONG THE GULF COAST. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS WEAKLY RIDGING TOWARD FL. A LOW PRESSURE
TROUGH IS OVER
AND NE OF THE BAHAMAS.
&&
.SHORT TERM (TODAY - FRIDAY)...THE UPPER LOW WILL WANDER OVER THE
LOWER MISSISSIPPI RIVER VALLEY...MAINTAINING WEST AND SW
FLOW ALOFT
THE AREA...AND THEN BEGIN TO WEAKEN FRI. THE SURFACE LOW AND
ASSOCIATED FRONTS REMAIN NEARLY IN PLACE OVER THE CENTRAL GULF
COAST. THE HIGH OFF THE MID-ATLANTIC COAST WILL BEGIN TO
RIDGE IN
ACROSS THE STATE THU...AS THE BAHAMA
TROUGH EXITS NE...AND CONTINUE
FRI.
THE
ATMOSPHERE WILL BEGIN TO DRY SOME AS THE UPPER LOW WEAKENS AND
THE SURFACE
RIDGE BUILDS IN. HOWEVER THIS WILL BE SLIGHT AS
PWAT
VALUES OF 2.0-2.5 TODAY GO TO 1.8-2.1 BY FRI. LIGHT SOUTHERLY LOW
LEVEL
FLOW WILL BACK TO SOUTHEASTERLY THU AND FRI AS THE AREA
COMES UNDER THE INFLUENCE OF THE SURFACE
RIDGE WITH A TIGHTENING
GRADIENT. WIND SPEEDS PICK UP SOME BUT WILL STAY LIGHT ENOUGH FOR
AFTERNOON SEA BREEZES. THE
MOISTURE AND SEA BREEZES BOUNDARIES
WILL RESULT IN
SCATTERED SHOWERS AND THUNDERSTORMS THAT BEGIN IN
THE AFTERNOONS AND LINGER INTO THE EARLY EVENINGS. TEMPERATURES
WILL RUN NEAR OR A COUPLE OF DEGREES ABOVE
NORMAL.
.LONG TERM (FRIDAY NIGHT-TUESDAY)...OVERALL FORECAST FOR THE LONG
TERM PERIOD REMAINS UNCHANGED. MID/
UPPER LEVEL CUTOFF LOW OVER THE
LOWER MISSISSIPPI VALLEY WILL GRADUALLY WEAKEN AND LIFT NORTHWARD
BECOMING ABSORBED INTO A DEVELOPING
TROUGH OVER THE CENTRAL U.S
EARLY NEXT WEEK. THIS WILL ALLOW RIDGING TO BUILD IN FROM THE EAST
ACROSS FLORIDA DURING THE PERIOD WHILE A SURFACE HIGH PRESSURE
BUILDS DOWN THE U.S. EAST COAST HELPING TO SETUP A GENERAL EAST TO
SOUTHEAST
FLOW ACROSS THE REGION. PLENTY OF
MOISTURE WILL REMAIN AND
THIS WILL COMBINE WITH THE SEA BREEZES AND DAYTIME HEATING TO CAUSE
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
EACH DAY. TEMPERATURES WILL REMAIN NEAR
NORMAL WITH DAYTIME HIGHS IN
THE UPPER 80S TO AROUND 90 AND OVERNIGHT LOWS MAINLY IN THE LOWER TO
MID 70S.
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS WILL CAUSE SOME
MVFR/LOCAL
IFR CONDITIONS TODAY...OTHERWISE
VFR CONDITIONS WILL
PREVAIL.
&&
.MARINE...LIGHT SOUTHERLY WINDS PICK UP SOME AND BECOME SOUTHEASTERLY
THROUGH THE END OF THE WEEK...AND THEN SE TO EAST FOR THE WEEKEND.
SPEEDS WILL BE 10
KT OR LESS WITH
SEAS FOR THE MOST PART BELOW 3
FT. THE MAIN MARINE CONCERN WILL BE PERIODS OF
SCATTERED
THUNDERSTORMS.
&&
.FIRE WEATHER...HIGH
RH ALONG WITH LOW
D.I. VALUES...DUE TO LIGHT
WINDS...WILL CONTINUE FOR THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/
POPS...
TPA 90 76 90 76 / 50 30 40 30
FMY 91 75 91 76 / 50 30 40 30
GIF 91 75 91 75 / 50 20 40 30
SRQ 88 74 90 75 / 50 30 40 30
BKV 90 71 90 72 / 50 30 40 30
SPG 89 79 90 79 / 50 30 40 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...09/RUDE
LONG TERM/AVIATION...69/CLOSE