Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 050813

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
313 AM EST Mon Dec 5 2016

...A Few Strong To Severe Storms Possible Tonight Into Tuesday...
...Turning Much Cooler Late In The Week...

.SHORT TERM (Today - Tuesday)...
A upper level low over northern Mexico early this morning will
open up and lift out to the northeast as a negatively tilted
upper level trough across Texas later today then through the lower
Mississippi valley tonight, and though the Tennessee and Ohio
valleys on Tuesday. As this upper trough lifts out a developing
surface low over the western Gulf will lift out in tandem with the
upper trough. A trailing cold front from this storm system will
move east across the Gulf waters tonight, and then through the
forecast area on Tuesday. Increasing moisture (Pw`s increasing to
2+ inches by afternoon) along with weak instability and increasing
lift within the warm sector ahead of the approaching cold front
will support increasing chances for showers and isolated
thunderstorms across the forecast area during the afternoon and
continuing through Tuesday as the front affects the region. In
addition to the rain chances the increasing moisture will also
favor some fog, some of which could become locally dense
especially across the fog prone areas of the Nature Coast and
southward into interior portions of the West Central and Southwest
Florida early this morning and again late tonight with some areas
of sea fog also possible over the adjacent Gulf waters as the warm
moist air overrides the cooler Gulf waters.

A strengthening low level jet over the Gulf coast later today
along with increasing effective bulk shear may support a few
strong to severe storms over portions of the Nature Coast tonight
and then into portions of West Central Florida toward sunrise on
Tuesday and continuing through mid day as a high shear low cape
environment develops. This type of environment will increase the
risk of a few supercells with the main threats being damaging
winds and a tornado or two.

In addition to the severe weather threat some locally heavy rain,
gusty winds, and occasional lightning strikes will be possible.
Similar to yesterday the extent and overall strength of the severe
weather threat will hinge on how much instability can develop,
which at this time still looks to be marginal given the expected
cloud cover and ongoing rain expected across the region.

Temperatures today and Tuesday will remain well above normal with
highs reaching around 80 to the lower 80s, with lows tonight in
the lower 70s.

.LONG TERM (Tuesday Night - Sunday)...
Tuesday night, a massive mid-level trough will be centered over
Ontario, while the remnants of a shortwave trough lift out of the
Mid-Atlantic Coast, dragging a surface cold front through southern
Florida. This front will linger across southern Florida, with a
few showers still possible over Southwest Florida Tuesday night
and Wednesday, even as much drier air works into the northern half
of the forecast area. Temperatures will begin to cool off behind
the front, but the cool down will be modest at first. However,
continued cold air advection Wednesday and Thursday will keep
temperatures trending downward through the middle of the week.

By Thursday morning, the upper level trough axis will be swinging
east through the Great Lakes, bringing a secondary cold front
sweeping through the southeastern states. Low level moisture will
build up in the warm sector ahead of this front, with rain chances
increasing for Thursday and Thursday night across the Florida
Peninsula. This front will move through the forecast area late
Thursday or early Friday and will bring a much stronger push of
cold air than the one earlier in the week. Highs on Friday are
forecast to only range from the low 50s to mid 60s. Lows Saturday
morning will be around freezing in parts of the Nature Coast, and
generally in the upper 30s and 40s across most of the rest of the
area. Winds will quickly turn around to the east on Saturday as
strong surface high pressure builds into the eastern US, allowing
gradually increasing temperatures through the weekend.


Some IFR cigs and vsbys will be possible at all of the terminal
sites after 08Z this morning as some low stratus and fog develops
over the region, otherwise VFR is expected. Additional MVFR/IFR
cigs and vsby can be expected after 20Z this afternoon as cloud
heights lower and rain chances increase across the region with
prevailing MVFR cigs/vsby likely after 00Z tonight through the end
of the Taf forecast period. Southeast winds at 5 to 7 knots this
morning will become south and increase to 10 to 12 knots after 18Z
with higher gusts in the vicinity of TSRA.


A storm system over the western Gulf early this morning will lift
northeast through the Mississippi valley later today and tonight
and into the Tennessee and Ohio valley on Tuesday. This storm
system combined with high pressure over the Atlantic will support
a southeast to southerly wind flow over the adjacent Gulf waters
today and tonight with some exercise caution conditions likely
developing over the offshore waters by tonight, with winds in the
10 to 15 knot range near shore. An increasingly moist air mass
(dew points in the lower 70s) overriding the cooler Gulf shelf
waters will also favor some sea fog development later today
through early Tuesday.

On Tuesday a cold front will move south through the waters during
the day with south winds shifting to the southwest and west late
in the day, then becoming northwest to north Tuesday night into
Wednesday as the front moves to the south and stalls out across
the southern peninsula. During late Thursday into early Friday a
stronger cold front will sweep south through the waters with a
tightening pressure gradient supporting northerly winds increasing
into the 20 to 25 knot range with higher gusts along with
building seas with solid small craft and hazardous boating
conditions likely.


Increasing moisture and rain chances will keep humidity values
well above critical levels through mid week with no fire weather
issues expected. Some patchy fog...some locally dense will be
possible this morning and again late tonight and early Tuesday
morning. Much drier and cooler air is expected to overspread the
region late in the week and long durations of low humidity values
below 35 percent will be possible on Friday.


.Preliminary Point Temps/PoPs...
TPA  80  71  78  66 /  50  60  70  10
FMY  84  72  80  69 /  20  40  60  20
GIF  83  71  81  63 /  40  50  70  10
SRQ  79  71  78  66 /  40  50  70  10
BKV  81  72  78  58 /  50  60  70  10
SPG  79  70  77  66 /  40  60  70  10


FL...Beach Hazards Statement through this evening for Coastal

Gulf waters...None.


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