Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 100052
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
752 PM EST Fri Dec 9 2016

.UPDATE...
01Z water vapor and H4 RAP analysis continue to show an
unamplified upper level pattern over the CONUS this evening.
Northern stream flow runs in a mostly zonal configuration across
the mid-section of the country...while the subtropical jet cuts
across the Gulf of Mexico and over the southeastern States/FL
peninsula before exiting into the Atlantic. High level clouds
over our heads this evening are being forced by RRQ dynamics/lift
within the exit region of the the subtropical jet core. As this
core/jetstreak moves away later tonight/Saturday morning...so
should the upper level moisture/lift for the clouds. Other than
perhaps are far southern zones down toward Fort Myers...this
should allow for quite a bit of sunshine to develop Saturday
morning. This will be nice...since it will be rather chilly to
start the day. Later in the day...winds shift more to the east in
the lower levels will begin to deliver some added moisture below
850mb...and this will lead to a sct-bkn fair weather cumulus/stratocu
fields in the afternoon. Most fair weather cu will be south of the
I-4 corridor where the influx of Atlantic moisture will be
greatest.

Otherwise...the forecast is dry for the remainder of tonight and
Saturday for all zones. Low temperatures by dawn range from the
lower 30s over inland Levy county to the middle 40s along the I-4
corridor...and then lower 50s down toward Fort Myers. While a few
locations in Levy county may approach freezing for an hour or
2...it is unlikely any spots will fall below 32. Also...a steady
4-6mph wind from the north should generally prevent the formation
of frost for all but the most sheltered locations. Anywhere from
Crystal River south should have no frost/freeze concerns tonight.

After the cool start to the morning...temperatures should rebound
nicely by the afternoon Saturday. Will see temps into the
lower/mid 60s over Levy County...to the upper 60s/lower 70s along
I-4...and lower to middle 70s headed southward to Fort Myers.

A steady warming trend continues in both overnight lows and
daytime highs during the second half of the weekend and early
portion of next week.

Have a great Friday night and a safe/fun weekend everyone! Stay
warm tonight!

&&

.AVIATION (10/00Z through 11/00Z)...
VFR conditions will prevail at all terminals through the TAF
period. High level clouds will be thinning out and retreating
later tonight into Saturday morning...followed by a sct-bkn
cumulus field developing during Saturday afternoon. Moderate winds
from the northeast through the period.

&&

.MARINE...
Elevated winds and seas over the eastern Gulf waters have led to a
small craft advisory into Saturday morning. Winds and seas will
subside below advisory levels during Saturday and through the
remainder of the weekend as high pressure shifts east of the
region into the Atlantic. However...periods of near cautionary
level easterly winds will remain in the forecast through much of
the weekend.

&&

.Prev Discussion... /issued 228 PM EST Fri Dec 9 2016/

SHORT TERM (Tonight through Saturday)...
High pressure to continue to build into area with overnight lows
near normal in Fort Myers and 5 to 10 degrees colder than normal
elsewhere. Temperatures around Williston in Levy County could
reach 32 degrees by morning but it is not expected to be
widespread. Wind chills in this area could reach 29 degrees but
this is still above the wind chill criteria of 25 degrees.

The moisture returns quickly this weekend with dew point
temperatures warming into the 50s Saturday and 58 to 65 Sunday.
High temperatures Saturday to be only 1 to 2 degrees below normal.

LONG TERM (Saturday Night through Friday)...
Fast zonal flow will over spread the CONUS to kick off the medium
range period, setting up a highly progressive weather pattern for
several days into next week. Surface high pressure will reside over
the eastern half of the CONUS with strong surface cyclogenesis over
the Central and Southern Plains regions. This will favor moist
southeasterly flow across the Gulf Coast for the first half of the
period.

From Saturday Night through early next week, we will experience a
rather fast warmup as moisture-rich southerly flow persists across
the region. Highs will reach the mid to upper 70s and 80s each day
with lows only falling into the lower 60s most areas. A weak front
will approach the region Monday, but looks to stall to the north as
much of the upper level energy driving it southward departs to the
north. These scenarios often favor fog and low clouds, and
especially marine fog, assuming the shelf waters have cooled
substantially. Thus, have opted to add a mention of patchy marine
fog beginning Monday night and continuing through at least Tuesday
night.

Much uncertainty exists as we head into the middle of next
week. Several shortwave impulses look to move through the fast zonal
flow pattern, producing a highly unpredictable setup. At this time,
it does appear a stronger front will near the Florida peninsula
during the latter half of next week, but longer range solutions
differ wildly on the strength of the front, any associated rainfall,
and the depth and intensity of trailing cold air. For now, will lean
toward a slow frontal progression late Wednesday into Thursday with
only slightly cooler air moving in. However, the ultimate result
will likely be vastly different from the existing forecast.

FIRE WEATHER...
No fire weather and no fog concerns in the forecast through the
weekend.

&&

.Preliminary Point Temps/PoPs...
TPA  48  71  58  78 /   0   0   0  10
FMY  54  74  61  81 /  10   0  10  20
GIF  48  70  56  78 /   0   0   0  10
SRQ  51  72  59  80 /   0   0   0  10
BKV  42  69  52  78 /   0   0   0  10
SPG  51  70  60  76 /   0   0   0  10

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...Small Craft Advisory until 7 AM EST Saturday
     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-Waters from Tarpon
     Springs to Suwannee River FL out 20 to 60 NM.

     Small Craft Advisory until 1 PM EST Saturday for Waters
     from Bonita Beach to Englewood FL out 20 to 60 NM-
     Waters from Englewood to Tarpon Springs FL out 20 to
     60 NM.

&&

$$

UPDATE/AVIATION/MROCZKA
Previous Discussion...Noah/Austin



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