Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 221856

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
256 PM EDT Sun Oct 22 2017

.SHORT TERM (Tonight - Monday)...
Isolated showers have begun to develop mainly over the interior from
Highlands county northward through Sumter county. A larger area of
rain with embedded showers is over the eastern Gulf but remaining
outside our coastal waters. The showers over the interior will
likely increase in coverage and intensity through the remainder of
the afternoon and spread westward across the Nature Coast and
possibly into the Tampa Bay area.

The ridge of high pressure responsible for our recent warm and
increasingly humid airmass will finally begin to weaken and move out
into the Atlantic tonight. A deepening upper-level trough will be
approaching the eastern states tonight and Monday, supporting our
first significant cold front of the season. The front is forecast to
reach the eastern Gulf late Monday, with a swath of showers and some
thunderstorms moving across our region ahead of it during the day.
Right now it looks like best chances for storms will be north of the
I-4 corridor during the afternoon hours. The best dynamics will be
well north of our region, so an organized severe weather threat
seems unlikely. It will be another warm and humid day, however, with
temperatures in the 80s and dew points in the lower to middle 70s.

.LONG TERM (Monday Night-Sunday)...
First shortwave trough axis will be moving away from the region
Monday night with the main trough deepening over the eastern U.S.
Tuesday into Wednesday before moving out into the Atlantic Ocean
Thursday. Meanwhile at the surface a cold front will move into the
Nature Coast during Monday night and then slowly southeastward
across the forecast area exiting the southern zones Tuesday evening.
Deep moisture will continue across the region ahead of the boundary
and with some upper level support we will see scattered to numerous
showers and a few thunderstorms Monday night into Tuesday. Behind
the front northerly flow will usher in much cooler drier air as
surface high pressure moves across the gulf and southeast states
Wednesday and Thursday. During Friday and Saturday the high will
shift out into the Atlantic Ocean with a more easterly flow setting
up bringing moderating temperatures and moisture. Global models are
still depicting different scenarios late in the week into next
weekend, but it does look like deeper moisture will return along
with the chance of a few showers as the next mid/upper level trough
moves across the central and eastern CONUS.


Mainly VFR next 24 hours. Winds will gradually shift from easterly
overnight to southeasterly toward Monday morning, then southerly by
mid-day. Some showers and perhaps even a few thunderstorms will be
possible starting mid-day Monday.


Southeast winds will increase over the waters after midnight
resulting in the need for small craft exercise caution

The first significant cold front of the year is forecast to
move into our waters Monday night and Tuesday. We will
likely see numerous showers and scattered thunderstorms
ahead of the front beginning in our northern waters on
Monday and continuing southeast through the waters Monday
night and early Tuesday. Winds will shift to the northwest
behind the front and may reach small craft advisory levels
Tuesday night and Wednesday. High pressure will build back
over the waters on Thursday then move northeast into the
Atlantic on Friday.


No fire weather concerns through Monday. We could see some near-
critical humidities behind the cold front on Wednesday and Thursday
as much drier air moves in. It currently looks like winds will
remain below 15 mph during that time.


.Preliminary Point Temps/PoPs...
TPA  76  83  73  81 /  10  60  60  30
FMY  75  86  74  83 /  10  40  60  60
GIF  74  85  72  81 /   0  60  60  50
SRQ  75  85  73  82 /  10  60  70  40
BKV  74  84  69  80 /  10  60  60  30
SPG  76  83  73  81 /  10  60  70  40


Gulf waters...None.



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