Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 221933

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
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.


VFR conditions prevail through this evening. Rain chances will
increase for the overnight period, with showers and MVFR or lower
cigs and vsbys possible. Sea fog will possibly move onshore tonight
and into Tuesday, mainly affecting KTPA, KPIE, and KSRQ.


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.


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


Gulf waters...None.


MID TERM/LONG TERM/DECISION SUPPORT...69/Close is the U.S. government's official web portal to all federal, state and local government web resources and services.