Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 160002

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
802 PM EDT Tue Oct 15 2019

Infrared satellite imagery and radar imagery from the panhandle
show significant regions of convection over the Gulf of Mexico due
south of Apalachicola as well as significant convection across
the FL/AL and FL/GA line this evening. This convection is
associated with a frontal boundary gradually making it`s way
southward towards the Florida Peninsula. The atmosphere ahead of
this frontal system has been conducive to support convection. Most
of this has been due to diurnal heating helping to destabilize
the atmosphere. Now that the sun has set, convection will begin to
settle down with the loss of this energy source.

That being said, some convection is still anticipated overnight as
the frontal boundary provides an additional mechanism to force the
air to rise. Given the sufficient moisture and reasonably warm
temperatures, this will support some showery weather overnight
along and ahead of the front. As the front sinks southward, the
rain will gradually move southward. As such, rain chances increase
across West Central Florida overnight. The front will begin to
weaken throughout the day tomorrow as it moves farther and farther
away from the original source of cold air. Consequently, rain
chances remain low across regions south of the I-4 corridor
tomorrow. This is consistent with the forecast in place, and as
such no changes have been made.


Conditions will remain VFR overnight with calm winds. Some IFR
ceilings may be possible tomorrow morning at southern terminals,
prompting brief TEMPO groups around sunrise. As a front moves
southward into the area, northern terminals could see VCSH from
16Z onward until sunset, MVFR conditions, and some gusty winds
associated with the frontal passage. The front will loose strength
as it continues southward. As such, southern terminals are
expected to remain VFR.


Rain is currently falling in some of the northern coastal waters.
This is expected to continue through the overnight and spread
southward to the Tampa Bay area by mid-morning. As such, seas are
currently running in the 3-4ft range in northern coastal waters,
and 2ft elsewhere. This trend is expected to continue overnight
and through tomorrow. Passing showers could lead to brief higher
gusts and seas.


.Prev Discussion... /issued 312 PM EDT Tue Oct 15 2019/

DISCUSSION (Tonight-Next Tuesday)...
Mid/upper level trough will deepen and move across the eastern U.S.
tonight into Thursday with the initial stalled boundary over the
southeast states lifting north as a warm front followed by a cold
front then moving southeast into north Florida and weakening as it
moves into our area. A southwest to west flow of deeper moisture
will move into the region during this time, but the best upper level
support and lift will remain to our north and will be moving away as
the boundary moves into the area. Therefore, expect to see showers
and a few thunderstorms over the northeast gulf waters move into the
Nature Coast tonight into early Wednesday then overall coverage
should diminish as things move further south for the rest of
Wednesday and Wednesday night. The boundary will drift south into
the region during late Wednesday night and Thursday with the low
level flow veering to northerly behind it bringing some drier air
into the Nature Coast, but the really dry air will remain to our
north. Daytime heating combined with the boundary and plenty of
moisture from around the Interstate 4 corridor southward will lead
to scattered showers and a few thunderstorms, mainly over inland
areas during the afternoon.

For Friday into Saturday some shortwave energy will move across the
northern gulf coast and Florida tapping into the plume of deep
moisture over the western gulf. Models are depicting slightly
different scenarios during this time with the GFS indicating
abundant clouds and scattered to numerous PoPs while the ECMWF is
not nearly as bullish. Either way it looks like some of the
moisture will spread eastward across the Florida peninsula setting
up an overrunning pattern leading to clouds and at least a chance
of showers.

For the remainder of the weekend into early next week the next
mid/upper level trough moves across the central U.S. into the
eastern states with a weak boundary lingering over the area leading
to the chance of more showers and possibly a few thunderstorms.

VFR conditions are expected through early tonight, then some areas
of MVFR ceilings could develop toward morning and continue into mid-
morning Wednesday. Southeast winds at 5 to 8 knots will shift to
southwest at 7 to 10 knots during this afternoon at all TAF sites
except LAL, then decrease to 5 knots or less from the south after
sunset. Southwest winds will setup Wednesday morning and increase to
around 10 knots by afternoon.

A weakening cold front will approach from the north tonight and
Wednesday with winds shifting/increasing to southwest at 10 to 15
knots Wednesday with a few showers and storms possible. Flow
diminishes slightly and becomes northerly Thursday before gradually
shifting to east to southeast Friday and increasing Saturday. Seas
will generally be 3 feet or less with a light to moderate chop on
bay and inland waters.

Sufficient low level moisture will keep relative humidity values
above critical levels through the period with no Red Flag conditions
expected. No significant fog is expected.


.Preliminary Point Temps/PoPs...
TPA  76  86  75  84 /  20  40  20  20
FMY  74  89  75  87 /  10  10  20  30
GIF  72  89  72  86 /  10  30  10  20
SRQ  74  87  75  86 /  10  20  20  20
BKV  73  86  69  84 /  30  60  20  10
SPG  77  87  75  86 /  20  40  20  20


Gulf waters...None.


UPPER AIR...Fleming
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