Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL
FXUS62 KTBW 090748
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
248 AM EST Fri Dec 9 2016
.SHORT TERM (Today - Saturday)...
The surface cold front has completely passed through the forecast
area and into southern Florida, as evidenced by the lower dew
points and northerly surface winds. Despite the drier airmass in
the low levels, ample moisture is continuing to overrun the front,
allowing for abundant upper level cloudiness and widespread light
rain on radar. A look at regional surface obs shows that not much
of the rain is actually reaching the surface, although a few sites
have reported light rain at times. This light rain/virga will
continually moisten the drier low levels through the morning,
allowing for occasional periods of perhaps moderate rain. As the
front continues to sag south and surface ridging north of the
state strengthens, the upper level moisture will gradually shift
south, allowing rain chances to subside this afternoon. The
cloudiness will gradually start to clear out from north to south
this afternoon through Saturday, although the southern half of the
forecast area will not be able to fully clear out as well as the
Nature Coast will.
Perhaps the more notable change will be the significantly cooler
air, with highs this afternoon only ranging from the upper 50s to
mid 60s, thanks to the cold air advection behind the front and the
cloudy skies. Saturday morning lows will dip into the mid 30s over
the northern part of the Nature Coast, and a few spots could
possibly hit freezing. Farther south, lows will bottom out in the
40s and low to mid 50s. Breezy winds will also make conditions feel
even colder, with wind chills Saturday morning generally about 5
degrees cooler than the low temperatures. As winds turn to
northeasterly on Saturday and a bit more sunshine reaches the
surface, temperatures will rebound, with afternoon highs ranging
from the mid 50s to mid 60s.
.MID/LONG TERM (Saturday Night-Thursday)...
Models continue in good agreement with fast zonal upper flow setting
up over the region with several small impulses quickly moving
through the progressive pattern next week.
At the surface, high pressure along the eastern seaboard Sunday
moves into the Western Atlantic Monday with axis settling over the
FL Peninsula Tuesday then sinking even further south mid week as
frontal boundary sags into the Gulf Coast region by Thursday.
Surface features to produce easterly low level flow Sunday rapidly
moderating temps and dew points with veering SE-S flow early next
week then S-SW flow mid week to keep warm, above normal temps and
humid conditions in place. Also expect some rain shower chances late
Sunday and through the week, but only fluctuating in the 10-30% range
with generally light QPF amounts as well.
Overcast upper level clouds are producing some light rain and
virga across the area, but drier air near the surface is
preventing ceiling and visibility restrictions at this time. Any
area terminal could see some showers or possibly brief MVFR
ceilings at times through morning, but VFR conditions will
dominate. Conditions aloft will slowly dry out from north to
south beginning late this morning and continuing through Saturday.
Otherwise, breezy north-northeast winds will continue into the
Strong surface high pressure is gradually building in north of the
coastal waters in the wake of the cold front, with breezy north to
northeast winds gradually turning to easterly by Saturday night.
Winds over the Gulf waters will run around 20-25 knots today into
Saturday afternoon with seas of up to 8 feet. Winds and seas will be
slightly more favorable over the Tampa Bay and Charlotte Harbor,
although Small Craft Exercise Caution conditions are expected there.
Winds and seas will gradually subside Saturday afternoon into the
early next week, although periods of continued cautionary or
advisory level conditions will be possible through at least Sunday
Drier air is filling in behind the latest cold front, with relative
humidity percentages forecast to drop into the 30s over parts of the
Nature Coast this afternoon. Up to 4 hours of critical humidity is
expected in Levy and Citrus counties today, and while wind speeds
will be on the breezy side, they are expected to be just shy of
triggering red flag warnings. Farther south, critical relative
humidity is not expected. Moisture will gradually increase during
the weekend, with no further fire weather concerns expected during
the next several days.
.Preliminary Point Temps/PoPs...
TPA 61 49 72 59 / 20 0 0 0
FMY 64 56 75 62 / 30 10 10 10
GIF 61 49 70 56 / 20 0 10 0
SRQ 63 51 72 59 / 40 0 0 0
BKV 59 43 69 52 / 20 0 0 0
SPG 62 51 70 60 / 20 0 0 0
Gulf waters...Small Craft Advisory until 1 PM 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 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...25/Davis