Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL
FXUS62 KTBW 291558
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
1158 AM EDT MON AUG 29 2016
Updated grids and forecast with latest TD 9 information from NHC.
Radar imagery showing convection already developing and quickly
moving across the FL Peninsula in the fast easterly steering flow
as seen 12Z TBW sounding. Significant coordination continues with
all offices, regional and national centers to produce best
forecasts and graphics. Discussions regarding FL impacts from TD
9 can be viewed from NHC, WPC and SPC websites.
AVIATION... Scattered SHRA/TS to become more numerous with brief
restrictions to VSBY/cigs along with gusty winds through the
afternoon and tonight as well.
.Prev Discussion... /issued 334 AM EDT MON AUG 29 2016/
SHORT TERM (Today and Tuesday)...
A messy weather pattern continues across much of the CONUS this
morning, with weak high pressure dominating much of the southern
and eastern U.S. and Gulf of Mexico. Strong zonal flow continues
across the northern tier of the country with several small
shortwaves moving along the Canadian border. The primary weather
maker for the eastern Gulf region and Florida Peninsula will
remain the newly formed Tropical Depression Nine lingering across
the Florida Straits.
For today, expect a continuation of what our area has seen the
last few days. Spotty showers this morning will become more
numerous with scattered thunderstorms forming along the east
Florida coast and central Florida. These will spread westward
through the afternoon and evening, with greater coverage south of
I-4 nearer deeper moisture associated with the tropical
depression. Rain could certainly be heavy at times, but storms
should be fairly fast moving today. Gusty winds will likely
accompany any stronger storms.
Expect much of the storm activity to shift offshore this evening,
though showers will likely remain across south central and
southwest Florida as the weak tropical system continues to shift
into the southeastern Gulf of Mexico.
For Tuesday, the effects of the tropical depression will increase
as a plume of deep moisture overspreads the Florida peninsula
along the northern and eastern periphery of the tropical low. Even
though the center of the system is forecast to remain well
offshore through the day, bands of showers and thunderstorms look
to develop and shift west to northwest through the day. Again, the
threat of heavy rainfall will be a concern, especially in areas
that receive repetitive bands of heavy rain and thunderstorms.
Gusty thunderstorm winds will also be likely with any of the
stronger storm cells as they move quickly north and west. The
tropical depression is expected to remain over the south central
Gulf of Mexico through Tuesday evening, with some slow
strengthening into a tropical storm possible. Please continue to
follow this system carefully as it will likely have impacts across
our area beyond the first half of the week.
MID/LONG TERM (Tuesday night-Sunday)...
A low pressure center...currently TD #9...initially over the
south- central Gulf of Mexico slowly drifts north and strengths
through late WED. It turns into the northeastern gulf THU then
tracks across northern FL...exiting to the Atlantic FRI. Have
followed National Hurricane Center guidance for this period.
Residents should stay up to date with the latest forecasts from
NHC and NWS offices.
For the weekend - The low pressure system moves east or northeast
across the open Atlantic as relaxed high pressure builds into the
eastern half of the Gulf and FL.
The forecast philosophy is that deep tropical moisture will
stream across the area through the work week. Models PWAT values
run in excess of 2 inches with occasional swaths pushing 2.8
inches. Numerous to widespread rain/showers with isolated to
scattered thunderstorms will result in heavy rainfall with some
flooding issues possible. The expected track and strengthening of
the low will bring winds of tropical storm force into some of the
outer waters WED night and toward the coast during THU. These
winds will build seas that could result in a high surf and rip
current risk at the beaches. clouds and rain will keep highs below
normal. The cloud cover will hold the lows to just above normal.
For SAT and SUN slightly drier air filters in but scattered to
occasionally numerous showers/storms are still expected.
Tropical depression nine will continue to promote less than
optimal marine weather conditions over the next few days.
Cautionary to borderlined advisory level east winds will persist
this morning, especially over the offshore waters. Winds will
improve somewhat this afternoon, but increase again this evening
and overnight as another modest easterly surge develops. Winds
look to shift more to the southeast then south as we head into the
middle of the week. By this time, the tropical depression is
forecast to become a tropical storm over the central Gulf of
Mexico. This will likely lead to higher seas despite initial winds
remaining 15 knots or less through Wednesday. For the second half
of the week, the tropical storm is expected to shift northeast,
eventually reaching the west Florida coast sometime Thursday, and
bringing a rapid increase in southwest winds. Solid Advisory level
winds will overspread all the waters with tropical storm forced
winds likely over the northern waters. In addition, dangerous
waves appear probable with waves increasing from 4 to 7 feet
Wednesday, to 10 plus feet over the northern and central waters.
Scattered to numerous marine thunderstorms will occur throughout
the forecast period. All marine interests should closely monitor
this feature as the exact track and intensity remain uncertain.
Warm and moist conditions will continue over the next couple of
days with high rain chances each day as a tropical depression
shifts to the south then west of the region. This feature may
bring increased winds and heavy rainfall to the region mid to late
week. Humidities will remain well above critical levels through
the week and no fire weather concerns are expected.
.Preliminary Point Temps/PoPs...
TPA 92 76 89 77 / 60 20 70 60
FMY 90 76 87 77 / 70 40 80 60
GIF 91 75 89 76 / 50 20 70 40
SRQ 91 76 88 78 / 60 30 70 60
BKV 92 74 90 75 / 50 20 70 50
SPG 91 77 89 78 / 60 30 70 60