Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 111131
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
631 AM EST Sun Dec 11 2016

.AVIATION (12z TAFs)...
Mainly VFR conditions expected through much of the period with
light east to northeast winds. Broken VFR cigs will invade from
the east as low level moisture increases. MVFR to IFR cigs may
develop this evening and overnight as winds become more
southeasterly.

84/Austin

&&

.Prev Discussion... /issued 256 AM EST Sun Dec 11 2016/

SHORT TERM (Today - Monday)...
WV imagery and upper air plots showing fast and dry westerly
upper flow over the area this morning with all the active weather
well NW and N of the local area. Upper longwave originating from
Canadian to remain in the northern stream flow with only slight
effect on southern tier pattern through Monday. Surface high
pressure moves off the eastern seaboard today and into the Western
Atlantic sinking southward Monday while complex winter storm
system moves from the Rockies through the Great Lakes. Easterly
low level winds today veer southeasterly Monday continuing to
advect abundant Atlantic moisture into the area with increasing
temps and dew points with a few light showers over interior
sections areas while temps continue to climb to above normal
levels. Patchy fog to develop late tonight into Monday morning
with areas of dense fog possible over interior locals.

MID/LONG TERM (Monday night - Saturday)...
An upper low over northern Manitoba tracks around Hudson Bay and
into eastern Canada by late in the work week while a ridge resides
from the Greater Antilles to southern Mexico...providing nearly
zonal flow across most of the Gulf region. For the end of the
week and going into the weekend a long wave trough pushing onshore
the west coast from the Pacific will help the Greater Antilles ridge
build north from the Gulf then slide across FL. At the surface Atlantic
high pressure ridges west across Fl to the Gulf until midweek when it
slips south in response to a cold front moving into the Deep South.
This front continues moving south...crossing FL Thu then exiting Fri
as Canadian high pressure settles into the upper Mid-west/Ohio Valley
regions. The high pressure shifts across the eastern seaboard and out
over the Atlantic by Sat.

Through about midweek weak impulses moving in the zonal flow aloft
could support a few showers but moisture is limited...model PWAT runs
in the 0.9 to 1.3 inch range...so any coverage stays in the slight chance
range and mainly in the north. Low level southeast to southwest flow will
keep temperatures on the warm side of normal. As the front moves through
Thu low level flow turns to westerly then northerly...dragging in some
drier air and keeping the front rain free. As the high pressure settles
in north of the state the flow become northeasterly fairly quickly...
precluding any cool down. Temperatures do drop but remain above normal.
The main concern will be southerly flow with enough moisture and Gulf
waters cool enough to support some sea fog Mon night into Tue night.

AVIATION...
Generally VFR conditions early this morning mainly SCT 3-5k ft
cloud deck moving across the S FL Peninsula. May see occasionally
BKN cigs with this area over FMY and RSW, and possibly PGD.
Models then bring increasing likelihood of lower MVFR cigs
towards 00z areawide.

MARINE...
Will hold onto SCEC over offshore southern waters early this
morning based on latest buoy obs. High pressure moves off the
eastern seaboard today and into the Western Atlantic Monday. Ridge
axis settles over the FL Peninsula and E Gulf waters through mid
week. Gradient weakening today and winds and seas finally
subsiding to below headline criteria after 10 am. Winds veer
southerly advecting higher dewpoints airmass over cooler shelf
waters to increase the possibility of marine fog especially mid
week ahead of sagging frontal boundary. Models push cold front
over the waters Thursday with quick NE wind shift.

FIRE WEATHER...
Abundant low level more to keep humidities well above critical
levels today through mid week while patchy fog will be possible
nightly.

&&

.Preliminary Point Temps/PoPs...
TPA  78  66  79  66 /  20  10  10  10
FMY  81  66  83  67 /  20  20  20  10
GIF  77  63  83  63 /  20  20  10  10
SRQ  79  65  78  64 /  20  10  10  10
BKV  77  60  80  58 /  20  10  10  10
SPG  76  66  78  65 /  20  10  10  10

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&

$$

PRIOR AFD...
SHORT TERM/AVIATION/MARINE/FIRE WEATHER...25/Davis
MID TERM/LONG TERM/DECISION SUPPORT...09/Rude


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