Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 222352
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
652 PM EST Mon Jan 22 2018

.AVIATION...
VFR this evening will deteriorate into the MVFR range with
brief IFR between 02-06Z as showers and embedded tsra along
with lowering cigs/vsbys develop over the region ahead of a
cold front, with prevailing MVFR cigs/vsbys and isolated
IFR conditions continuing through the remainder of the Taf
forecast period. Southeast to south winds in the 5 to 7 knot
range this evening will become south to southwest at 8 to
10 knots after 15Z, then becoming west-northwest at 8 to 10
knots after 21Z with the frontal passage. Higher winds gusts
will be possible in the vicinity of tsra.


&&

.Prev Discussion... /issued 233 PM EST Mon Jan 22 2018/

SHORT TERM (Tonight-Tuesday)...
A highly amplified pattern is in place aloft, with a strong
closed low moving through the central part of the country.
At the surface, Florida remains in a low-level southeast to
south flow between high pressure over the western Atlantic
and low pressure over the Plains, with a trailing cold front
making its way into the southeast. The sea fog that
impacted the area this morning is now limited to just
offshore the Nature Coast region.

A rather subtle shortwave is forecast to move across the
Gulf and over the region later this evening, with a round
of showers and a few thunderstorms likely, especially for
the Nature Coast area but even extending south into the
Tampa Bay region. This rainfall will be well ahead of the
approaching cold front and will likely end prior to the
frontal passage. Much of the upper-level support for this
boundary will remain north of the area, so we are still
really only looking for a broken line of showers with it
tonight into Tuesday. Look for rain to end from north to
south starting around midday, but a few showers could still
be around over our southern zones for the end of the day.

The biggest forecast challenge continues to be the
possibility of additional sea fog development. A mentioned
above, a large area remains over the Gulf adjacent to the
Nature Coast, but other areas have cleared out. However, as
the sun sets and mixing ends, additional development is
likely as a southeast or south moist flow moves over the
still-cool waters. The forecast shows some of this fog
moving over coastal areas and this is probably the trickiest
part of this forecast, but there is enough of a possibility
to include it for tonight. The sea fog threat ends from
north to south through the day as the front moves through.

LONG TERM (Tuesday Night-Monday)...
Mid/upper level troughing will be over the eastern U.S.
through midweek then some weak ridging will build over the
Gulf of Mexico and Florida late in the week before the next
trough develops over the eastern states early next week.
Cooler drier air will be moving into the area Tuesday night
and Wednesday with temperatures returning to a few degrees
below normal for midweek. Breezy northerly winds Wednesday
will shift to northeast Thursday and then east on Friday as
surface high pressure moves across the southern U.S. and
eventually out into the western Atlantic during Friday.
Mainly dry weather with seasonable temperatures are expected
during this timeframe under partly to mostly cloudy skies.
Over the weekend and into early next week the next storm
system will take shape over the Deep South and Gulf of
Mexico and move east bringing more clouds and increasing
rain chances for late Saturday into Monday. Temperatures
will remain seasonable with no big extremes either cold or
warm expected.

MARINE...
Southeast low-level flow will shift southward tonight ahead
of an approaching cold front. Expect areas of showers and
isolated thunderstorms tonight into early Tuesday ahead of
this boundary, with the greatest coverage expected from
Tampa Bay northward. Winds will become north to northeast
late Tuesday into Wednesday behind the front, with speeds
increasing to cautionary levels at times.

An area of sea fog is lingering offshore the Nature Coast
region this afternoon and additional development is likely
tonight and into Tuesday morning, extending southward
across the rest of the waters. The sea fog potential will
end from north to south Tuesday evening with the passage of
the cold front.

FIRE WEATHER...
Relative humidity values will remain above critical levels
with no fire weather concerns. There is a good potential
for a wetting rain for most locations tonight into Tuesday
ahead of a cold front, then drier and cooler air arrives for
Wednesday. There is the potential for some sea fog to move
onshore from the Gulf tonight into Tuesday morning, with the
greatest potential from Sarasota northward.

&&

.Preliminary Point Temps/PoPs...
TPA  64  72  51  66 /  60  50   0  10
FMY  65  77  59  73 /  30  50  10  10
GIF  64  76  52  69 /  60  50   0  10
SRQ  63  71  54  68 /  60  50  10  10
BKV  63  73  46  66 /  70  60   0   0
SPG  63  71  52  65 /  60  50  10  10

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&

$$

AVIATION...McMichael
SHORT TERM/MARINE/FIRE WEATHER...05/Carlisle
LONG TERM...69/Close



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