Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 251929

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
229 PM EST Mon Jan 25 2021

Some amplification of the upper-level pattern is beginning to
take shape as the ridge that has been helping to reinforce
surface high pressure continues to slide to the east. Now that the
surface axis is situated off the eastern coast of Florida, winds
have shifted southerly and will continue to veer to the southwest
by later today and tonight. This south to southwesterly flow is
helping to advect additional warm and moist air across the area,
making for a highly favorable setup for fog.

This evening, skies should clear of cumuliform clouds. Coupled
with light winds, this allows the ground efficiently radiate the
heat away, cooling the surface. With the added moisture from the
southerly flow, conditions look pretty favorable for land fog
and/or low clouds to develop once again tonight, and will likely
be more area-wide and dense in spots. Diurnal effects from daytime
heating and increasing wind speeds should help destabilize the
boundary layer and mix this out after the sun rises.

The impacts from fog are not expected to stop with the land
though. Sea fog is also likely to form. This occurs because
warmer air moves over the relatively cooler Gulf Waters. Along the
shelf, where the waters are typically the coolest, we are most
likely to see fog form. However, water temperatures are cool
enough everywhere to see at least patchy dense fog. The
dissipation of sea fog is much more tricky. Some spots will clear
mid-to-late morning, but patchy sea fog will likely stick around
until the next front arrives on Wednesday.

A trough axis will propagate eastward out of the Rockies on Tuesday,
dragging an attendant cold front with it across the SE. This front
should arrive in our area on Wednesday. Enough instability should
exist along and ahead of the front to have some showers and possibly
even a few thunderstorms across our area. However, much of the
energy will not make it this far south, and ultimately will only get
further away from the front as it makes the southward push. This
means that whatever showers and thunderstorms we do have will likely
fall apart the farther south it goes. Southwest Florida has a meager
10-20% chance of seeing any precip with this front because of this

However, the front will bring a change to our weather that will
last into the weekend. The unseasonably warm and more humid
weather will go away at least for a few days. In its place,
cooler, drier, and breezier conditions will return. High
temperatures are only expected to climb into the upper 60s to
around 70 on Thursday, and only into the mid 70s for Friday. The
gradual warmup will begin on Saturday as the northerly component
of the wind begins to fade and is replaced by easterly, then
southeasterly flow this weekend. Overall, though, conditions look
pretty nice for the weekend. Whether our current weather is nice
or awful, change is once again on the way later this week.


VFR conditions prevail through the rest of the day with southerly
winds becoming more southwesterly this evening. Conditions are
highly favorable for fog/low cloud formation overnight, thanks to
ample moisture and efficient cooling at the surface. This should
begin to dissipate by late morning, but sea fog may remain an issue
for northern coastal TAF sites during the day. There is uncertainty
at this time as to how much these elements could effect airports..


Southerly winds veer to more southwesterly this evening, helping to
bring additional warm, moist air over the cooler Gulf Waters. This
is highly favorable for the formation of sea fog overnight. Once it
forms, we`ll likely have at least some patches sticking around
until the next front arrives on Wednesday. This front will bring a
chance for showers and some thunderstorms over coastal waters,
and should finally clear out any fog that develops. Winds then
take on a northerly component and increase, bringing seas up to
cautionary/advisory criteria Thursday. Conditions for boating
begin to improve this weekend as high pressure regains control
with lighter winds shifting E then SE by Sunday.


Decent dispersions this afternoon begin to fade overnight with
conditions becoming very stable. Fog is likely to develop across the
interior and may be dense in some spots. By mid-morning, fog should
begin to dissipate as daytime heating promotes additional
instability. Another front arrives on Wednesday, bringing showers
and some thunderstorms back into the forecast. Behind the front,
winds increase and RH values drop, but are not expected to meet
critical thresholds at this time. As winds begin to shift out of
the east with high pressure regaining control, moisture will begin
to return and winds will settle once more.


.Preliminary Point Temps/PoPs...
TPA  79  65  78  65 /   0   0   0   0
FMY  81  64  82  65 /   0   0   0   0
GIF  81  63  82  64 /   0   0   0   0
SRQ  79  65  78  64 /   0   0   0   0
BKV  81  60  80  61 /   0   0   0   0
SPG  75  65  75  65 /   0   0   0   0


Gulf waters...None.


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