Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 191945
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
245 PM EST Sun Nov 19 2017

.SHORT TERM (Rest of today - Monday)...
Aloft - A massive ridge was over the western states...from west of
Baja California to the western Canadian prairies. A low above the
Manitoba, Canada coast had a trough that arced down across the
lower Great Lakes to the northern Gulf of Mexico. Surface - High
pressure centered in TX sprawled to the Mid-Mississippi Valley while
a cold front stretched from northern ME...across Atlantic coastal
waters...to north-central FL.

The initial upper low slides to James Bay, Canada with the northern
potion of the trough lifting into the Canadian Maritimes. However a
second upper low drops from the Yukon Territory, Canada to the ND/MN
border and helps maintain troughing over the Gulf of Mexico. The TX
high pressure tracks east-northeast...reaching the Mid-Atlantic
coast late Mon afternoon. The cold front settles through south FL
tonight and Mon...stalling south of the Florida Keys late in the
day.

A compact band of showers southwest to northeast across Tampa Bay
with cloudiness trailing back to the front back across the Nature
Coast early this afternoon will proceed southeastward through the
afternoon...losing some stream as it does...and exit the far south
around sunset. A few of the showers have been heavy but brief...
overall rainfall is expected to be on the lighter side.

Northwesterly 1000-700MB flow this afternoon becomes northerly over
night then northeast to east Mon. This will bring in some drier
air...with PWAT values of less than 1 inch spreading down to south
of Lee County by sunrise Mon...but values just over 1 inch creep
back to near Charlotte Harbor in the Afternoon. This drier air will
keep skies clear to mostly from later tonight through Mon and along
with modest overnight wind speeds preclude any fog. Temperatures
will drop below normal for the lows in the north and central
locations...the south will be a bit warmer and just around normal.
the high temperatures Mon run near normal for the south and
central while the north stays just below.

The threat of a high rip current risk is still under consideration
but winds...while robust to strong...turn fairly quickly to the
north then northeast...reducing the threat. Beach conditions will
continue to be monitored but no beach hazard statement will issued.

.MID TERM/LONG TERM (Monday Night-Sunday)...
The next mid/upper level trough will be developing Monday night and
Tuesday over the eastern half of the CONUS and deepen southward into
the Gulf of Mexico Wednesday into Thursday. This trough will then
lift out to the northeast late in the week quickly followed by yet
another one developing over the eastern U.S. during the second half
of the weekend. At the surface, high pressure along the Carolina
coast Monday evening will move well out into the Atlantic Ocean
Tuesday with the front that moved south of the region tonight
lifting back north as a warm front. This will lead to increasing
clouds and a chance of showers and possibly a few thunderstorms late
Monday night with better chances during Tuesday. During midweek the
global models continue to develop an area of low pressure in the
central gulf as the trough deepens which then drifts east northeast
across the southeast states/Florida peninsula late in the week. The
exact timing and location of this system varies in the models, but
it does look like clouds and a chance of showers and possibly a few
thunderstorms will continue for Wednesday into Thanksgiving Day, and
possibly Friday if the ECMWF is correct. High pressure will return
by Saturday bringing a return to fair dry weather, but the next cool
front is expected to be moving south into the region Sunday.

&&

.AVIATION...
19/18Z. Band of SHRA with lower CIGs and gusty winds is at TPA/PIE
and will continue southeastward through the afternoon but losing
some steam as it does. What ever is left of the band will clear the
southern sites around 23Z with VFR taking over for all terminals.
Gusty NW-N winds through the afternoon become N over night then
NE to ENE Mon.

&&

.MARINE...
Winds continue to crank up as the front moves southeastward...
caution headlines are in place this afternoon with a small craft
advisory starting tonight. This now includes all the waters except
Charlotte Harbor. Tampa Bay is a bit problematic as only the mouth
and lower bay will reach 20 knots. High pressure builds in then
tracks to the eastern seaboard with winds diminishing Mon night and
Tue. The front which had stalled south of the Florida Keys lifts
back across the state during midweek with a possible low forming
on the Gulf portion. While this is not expected to result in
significantly increased winds rain chances do go up.

&&

.FIRE WEATHER...
Drier air behind the front fills in tonight and Mon but then begins
to moisten Mon night as the front lifts back north over the
state...with a possible low forming the Gulf portion of the front.
However no low RH concerns are anticipated.

&&

.Preliminary Point Temps/PoPs...
TPA  53  76  64  75 /   0   0  20  70
FMY  61  79  65  80 /   0  10  20  50
GIF  52  76  61  76 /   0   0  20  70
SRQ  55  78  63  76 /   0   0  30  60
BKV  45  75  58  75 /   0   0  20  70
SPG  57  74  63  75 /   0   0  30  70

&&

.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 Bonita Beach to
     Englewood FL out 20 NM-Coastal waters from Englewood
     to Tarpon Springs FL out 20 NM-Coastal waters from
     Tarpon Springs to Suwannee River FL out 20 NM-Tampa
     Bay waters-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...09/Rude
MID TERM/LONG TERM/DECISION SUPPORT...69/Close


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