Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 221333
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
833 AM EST Fri Jan 22 2021

.UPDATE...
Showers in the vicinity of the nearly stationary boundary across
the Deep South and north Florida could move south into Levy
county this afternoon and possibly down to around the Interstate 4
corridor later tonight and Saturday. For now have bumped PoPs up
slightly for Levy county this afternoon, but will wait to see
what 12z model guidance indicates for tonight and Saturday before
changing. Remainder of forecast looks ok at this time with no
changes planned.

&&

.AVIATION...
Mainly VFR conditions are expected into early tonight, then some
areas of MVFR/local IFR conditions could develop. South to
southwest winds at 6 to 11 knots are expected today diminishing
and becoming light tonight.

&&

.Prev Discussion... /issued 247 AM EST Fri Jan 22 2021/

DISCUSSION...
Models are pretty consistent since yesterday. A trough over the
Southwestern states will kick out and fill as it moves east. In
its place a deeper trough will build over the southwest building a
deep layer ridge over Florida. This ridge will translate into some
unseasonably warm temperatures next week with areas over the
southern interior seeing widespread mid 80s and maybe even a few
upper 80s. 80 degree temperatures are possible as far north as
inland Levy County by mid next week. Water temperatures are still
in the lower and mid 60s so do not expect 80s in you live
anywhere near the coast.

There is a boundary of sorts (although I really cannot find any
discernible difference in the air mass on either side of it,
Valdosta is 60 degrees with a 59 TD and Tampa is 60 degrees with a
56 TD) across North Florida that the models are insisting will
bring a shower or two to Levy County. The bigger impact is that
the col associated with the boundary will bring light onshore
winds Saturday morning blowing mid and upper 60s dew point air
over low and mid 60s water temperatures. I will introduce some sea
fog to the forecast for Saturday. Sunday the surface ridge builds
to the north and the winds turn offshore so sea fog should not be
an issue again until Tuesday when the wind switches to onshore
ahead of an approaching front.

That front which will impact us late in the forecast period is the
result of the longwave trough over the southwest kicking out to
the east through the Ohio Valley. That in turn will lower surface
pressures over South Georgia and then eastward into the Atlantic.
The surface low will tap Gulf Stream energy and deepen pulling
cold air southward in its wake. Yesterday it looked like the axis
of the maximum of cold advection would be a couple hundred miles
east of the state. Today it is starting to look like a cold air
damming/backdoor cold front event setting up for a week from
today. For those of us that do not like cold wx it does not look
like it will last too long as the system is very progressive. I
have also learned to take models seven days out with a grain of
salt, but it is something to watch.

MARINE...
Very light winds and warm weather will make for great boating all
week. There may be some sea fog issues Saturday morning and again
starting Tuesday morning.

FIRE WEATHER...
Humidities will be increasing and dispersion decreasing the next
few days. The next shot of dry air should be in about a week.

&&

.Preliminary Point Temps/PoPs...
TPA  73  62  73  60 /   0  10  10   0
FMY  75  60  77  61 /   0   0   0   0
GIF  76  61  72  60 /   0  10  10   0
SRQ  73  62  74  60 /   0   0   0   0
BKV  74  58  71  55 /   0  10  10   0
SPG  71  62  71  61 /   0  10   0   0

&&

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

$$

UPDATE/AVIATION...Close
PREV DISCUSSION...Sobien
UPPER AIR/DECISION SUPPORT...Carlisle


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