Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 190823
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
323 AM EST Sun Nov 19 2017

.SHORT TERM (Today - Monday)...
The weather pattern today will revolve around a fast moving
cold front that is currently pushing southeast through the
Florida Panhandle and is on track to clear the forecast area
by this evening. Regional radar returns are showing some
narrow bands of showers focused along the frontal boundary,
and rain chances will increase over the Nature Coast this
morning as these bands move south, and then across the
Tampa Bay area and Interstate 4 corridor this afternoon.
Most high resolution models are forecasting that the
moisture will dry out as the front reaches southwest
Florida, so rain chances are more uncertain south of Tampa
Bay. Regardless, no area is expected to see a wash out, with
most of the area likely to just receive brief showers along
the frontal passage. Breezy north winds will fill in behind
the front, bringing much cooler temperatures tonight, with
lows Monday morning expected to drop into the 40s and upper
30s over the Nature Coast, and in the 50s to around 60
farther south. Increasing winds could bring an increased
risk of rip currents overnight, but the wind direction turns
to the north and offshore so quickly behind the front that
any rip current threat might be avoided.

Winds will continue veering to the northeast on Monday as
high pressure builds in north of the area, allowing temperatures
to begin to warm back up. Afternoon highs are expected to
reach into the low 70s north, and mid to upper 70s over the
southern half of the area. Conditions should also feel less
humid during the morning, although by the afternoon,
moisture will begin advecting back into the area off the
Atlantic, with increasing humidity.

.LONG TERM (Monday Night - Saturday)...
Surface high pressure along the mid Atlantic coast Monday
night will slide east into the Atlantic on Tuesday as
short wave energy slides eastward across the area during the
day. The cold front which had moved south of the region
Sunday night will lift slowly back to the north as a warm
front. Increasing lift along the warm front combined with
increasing low level moisture within the return east-
southeast wind flow around the departing surface high and
the short wave energy aloft will support scattered to
numerous showers and isolated thunderstorms (Pops 60 to 70
percent) developing across the region on Tuesday along with
moderating temperatures and increasing humidity levels.

During Tuesday night into Wednesday models show another and
more vigorous positively tilted short wave trough moving
from the southern plains across the lower Mississippi valley
and into the west central Gulf of Mexico. The GFS/ECMWF and
Canadian continue to struggle with the evolution and timing
of this system, but despite the differences the models
continue to agree that the upper level trough and or closed
low will deepen over the west central Gulf during Wednesday
night into Thursday with surface cyclogenesis likely
occurring somewhere over the eastern Gulf during Wednesday
night, with the upper trough and attendant surface low then
moving east-northeast toward and across the region during
Thursday and Friday via a blend of the model solutions.
Similar to yesterday uncertainty remains as to the exact
location of the surface low development, its intensity, and
movement, thus confidence in anyone model solution remains
rather low at this time.

Regardless of which model solution should pan out increasing
moisture within a deep layered southwest wind flow ahead of
the above mentioned features combined with increasing upper
level divergence and large scale lift ahead of the
amplifying upper level trough should support good chances
for showers and isolated storms (Pops in the 50 to 70
percent range) along with the potential for some locally
heavy rain across the forecast area Wednesday night through
Thanksgiving day and likely continuing into Friday as this
storm system lingers over the region. Pleasant dry weather
should finally return on Saturday as the storm system exits
to the east into the Atlantic and high pressure builds in
over the region.

Near to slightly above normal temperatures on Tuesday and
Wednesday will fall back to slightly below normal during
Thursday and Friday as cloud cover and rain chances increase
across the area, with near to slightly below normal
temperatures continuing into the weekend as cooler and drier
air advects into the region.

&&

.AVIATION...
Some patchy fog has already developed tonight, and will
continue to cause sporadic flight category reductions
through sunrise, mainly around KLAL and KPGD. A band of
showers associated with a passing cold front will move
southeast through the area TAF sites during the afternoon.
Winds will increase and turn to the north-northwest behind
the front, with clearing skies through the evening.

&&

.MARINE...
A cold front will quickly move southeast through the eastern
Gulf of Mexico today, with winds increasing along the front
to around 20 knots. Behind the front, winds will turn to the
north and continue to increase overnight tonight, with
periods of cautionary level winds expected. High pressure
will fill in north of the waters on Monday, with winds
turning to easterly and subsiding through Tuesday. A weak
low will develop in the Gulf on Tuesday and lift northeast
through the coastal waters, causing an increase in rain
chances, although winds are not expected to pick up
substantially.

&&

.FIRE WEATHER...
Some patchy fog will continue to be possible early this
morning, then drier air will fill in behind a front today.
No additional fire weather concerns expected through the
first half of the week.

&&

.Preliminary Point Temps/PoPs...
TPA  76  51  75  63 /  40   0  10  20
FMY  80  59  78  65 /  10  10  10  20
GIF  78  50  74  61 /  40   0  10  10
SRQ  77  54  76  64 /  40   0  10  30
BKV  76  45  74  58 /  50   0  10  20
SPG  76  53  74  64 /  40   0  10  30

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...Small Craft Advisory from 8 PM this evening to 7 AM EST
     Monday for Coastal waters from Englewood to Tarpon
     Springs FL out 20 NM-Coastal waters from Tarpon
     Springs to Suwannee River FL out 20 NM-Waters from
     Bonita Beach to Englewood FL out 20 to 60 NM-Waters
     from Englewood to Tarpon Springs FL out 20 to 60 NM-
     Waters from Tarpon Springs to Suwannee River FL out
     20 to 60 NM.

&&

$$

SHORT TERM/AVIATION/MARINE/FIRE WEATHER...18/Fleming
MID TERM/LONG TERM/DECISION SUPPORT...57/McMichael


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