Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 171840

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
240 PM EDT Sat Mar 17 2018

.SHORT TERM (Today-Sunday)...
Quiet weather expect for our weekend thanks in part to zonal
flow and a weak high pressure over the area. Temperatures
will be on a warming trend with highs back in the low 80`s
for the weekend and lows around 60 degrees Sunday morning.
The warmer morning will mean a more muggy start to Sunday.
That coupled with light winds will bring some fog in
overnight. The typically low laying areas in the inland part
of the state could see that visibility drop below one mile
right before sunrise on Sunday.

.LONG TERM (Sunday Night - Saturday)...
Models for the most part are in decent agreement with synoptic scale
features during the long term period so a blend will be used. At the
start of the period weak upper level ridging will be shifting east
into the Atlantic as a short wave trough advances east into the
southern and central plains. At the surface, a deepening surface low
associated with the short wave trough will move slowly east into the
lower and mid Mississippi Valley through Monday, and then toward the
mid Atlantic coast Monday night. An increasing southwesterly wind
flow ahead of this storm system will advect increasing moisture
across the northern Florida peninsula, which will support increasing
chances for scattered showers and a few thunderstorms across the
Nature Coast during Sunday night, and along and north of the I-4
corridor into the Nature Coast during Monday and Monday night.

During Tuesday a stronger shortwave trough will move east across the
northern Gulf coast. As this feature moves eastward deepening
surface low pressure will move east across Georgia during the day
with this low then moving offshore the southeast coast Tuesday
night. As the low moves eastward a trailing cold front will move
southeast through the eastern Gulf waters and Florida. Ample
moisture and instability will support increasing chances (Pops 70 to
80 percent range) for showers and storms along and ahead of the
front area-wide on Tuesday. With forecast sounding data showing
increasing wind fields (50 knots at 850mb), increasing wind shear,
steep mid level lapse rates in excess of 7 C/KM, MUCAPE values
exceeding 2000 J/kg, and 500MB temperatures in the -12 to -13C range
some severe storms will be possible along and ahead of the front
on Tuesday with damaging winds and large hail the primary hazards.

The severe threat along with rain chances will end from
north to south Tuesday night as the short wave trough exits
to the east into the Atlantic and the cold front moves to
the south of the forecast area. An increasing northwest to
northerly wind flow in the wake of the front will usher in
cooler and drier air Wednesday through Friday as surface
high pressure builds in from the west. The increasing winds
in the wake of the front will help to quickly builds seas
over the adjacent Gulf waters with a period of very
hazardous marine conditions developing Tuesday night through
early Thursday.

Temperatures will run above normal through Tuesday with lows in the
50s and 60s, with daytime highs in the mid to upper 70s along the
coast, and lower to mid 80s inland. Temperatures will fall back to
below normal Wednesday through Friday in the wake of the front with
lows falling back into the 40s, with daytime highs in the upper 60s
to lower 70s. Temperatures will moderate again on Saturday as winds
veer into the east as the surface high moves offshore the mid
Atlantic coast.


VRF conditions expect throughout the day and into our
overnight hours. Fog is expected to form in the early
morning hours tomorrow. Most sites will see a brief period
of MVFR conditions right around sunrise while LAL and PGD
will see a brief period of IFR conditions at the same time.


Weak high pressure over the area this weekend will help to
keeps winds light and out of the W to SW. A strong cold
front will be heading our way on Monday and Tuesday which
will cause our winds and seas to slowly increase out of the
SW. Strong high pressure will build in behind the front
causing hazardous boating conditions for Wednesday as winds
start to shift to the NW. Winds and waves will slowly be
coming down on Thursday and Friday.


Today will be the last day of low humidity and high ERCs
with a Red Flag warning continuing for Polk County. As
moisture starts to increase Sunday and into our next work
week fire weather should not be an issue.


.Preliminary Point Temps/PoPs...
TPA  62  78  64  80 /   0   0  10  20
FMY  61  81  64  83 /   0   0  10  10
GIF  57  83  61  85 /   0   0  10  20
SRQ  61  75  64  78 /   0   0  10  10
BKV  55  79  61  81 /   0   0  10  30
SPG  62  78  65  78 /   0   0  10  20


FL...Red Flag Warning until 8 PM EDT this evening for Polk.

Gulf waters...None.


MID TERM/LONG TERM/DECISION SUPPORT...57/McMichael is the U.S. government's official web portal to all federal, state and local government web resources and services.