Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
330 am EDT Tuesday Aug 30 2016
what is currently tropical depression #9 was over the southeastern
Gulf of Mexico. Please refer to the latest advisories from the
National Hurricane Center for details.
Short term (today-wednesday)...
a deep and very moist easterly flow across the area will
gradually become southeasterly then southerly as dew point #9 strengthens
into a tropical storm slowly tracking north and northeast across
the Gulf...per official NHC forecast guidance. Model precipitable water values
around 2 inches increase into the 2.4 to 2.6 inch range. This will
support fairly fast moving scattered to widespread showers/rain
and isolated to scattered thunderstorms...with the highest
coverage in the afternoons during diurnal heating. Rainfall will
be very heavy at times with the potential for flooding. The
rainfall and clouds will keep highs below normal...while lows run
Middle/long term (wednesday night - monday)...
based on current model data and official NHC guidance a tropical
cyclone is forecast to over the eastern Gulf of Mexico at the start
of the period. This system is forecast to move northeast toward and
onshore the Florida Big Bend region during the day on Thursday and
then moving northeast across the Northern Peninsula Thursday night.
Copious moisture (pw's in excess of 2.5 inches) associated with this
system will support very heavy rains with flooding along with
tropical storm force winds and an increasing risk of storm surge,
rip currents, and large breaking wave action (the highest and most
significant along the nature coast) along the coast.
Increasing wind shear through the atmosphere will also bring an
increased risk for rotating storms and tornadoes as well, with the
worse of all of these conditions expected across coastal sections of
the Nature Coast from Pasco County northward to Levy County closest
to the track of the storm during Wednesday night and Thursday.
Across the remainder of the forecast area locally heavy rains and
squalls with localized flooding can be expected. Seeing that the
exact track and intensity of this system could change some during
the next day or so all residents and visitors are urged to continue
to monitor the progress of this system and make sure your hurricane
kit is up to date and know your evacuation Route. For additional
information on this system see the latest advisories being issued by
the National Hurricane Center in Miami.
During late Thursday night through Saturday the tropical cyclone
will begin to accelerate off to the northeast as it is captured by a
mid level trough moving off the southeast U.S. Coast. In its wake a
trailing trough combined with lingering deep layered moisture (pw's
2+ inches) will continue to support scattered to numerous showers
and thunderstorms across the region each day, with some additional
locally heavy rains a good bet. By Sunday and Monday drier air
filtering in from the north will bring rain chances back to more
seasonal level (pops 30-40 percent range) with scattered diurnal
showers and storms expected both days during the afternoon and early
Daytime high temperatures will run below normal through Friday due
to extensive cloud cover and rain chances with highs in the mid to
upper 80s, before returning to near normal levels during the weekend
and into early next week. Overnight lows will run above normal
through Saturday especially along the coast where lows in the upper
70s to around 80 can be expected with lows in the mid 70s over
30/08z-31/06z. Anticipate some low stratus overnight but staying
in the MVFR range. Otherwise VFR for much of the period with vicinity
shra/tsra...but with some tempo MVFR in thunderstorms and rain late afternoon. East
winds gradually become southerly with modest speeds although some
gusts near thunderstorms and rain.
east and southeast winds become southerly then southwesterly as they
increase significantly...with tropical storm conditions spreading
into the waters Wednesday or Wednesday night. Some caution or advisory
headlines will be needed tonight into early Wednesday. Marine interests
need to prepare for these conditions and remain in port.
humid and rainy conditions will preclude any low humidity concerns.
Preliminary point temps/pops...
tpa 87 77 84 77 / 70 70 70 80
fmy 83 76 85 78 / 80 60 60 70
gif 87 75 83 76 / 80 50 60 60
srq 85 78 83 79 / 60 80 70 80
bkv 87 75 84 76 / 70 60 80 70
spg 86 78 84 78 / 60 70 70 80
Synopsis/short term/aviation/marine/fire weather...09/rude
middle term/long term/decision support...57/McMichael