Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 040834

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
334 AM EST Sun Dec 4 2016

.SHORT TERM (Today-Monday)...
Active pattern expected across the southern tier of the U.S. next
couple of days. A strong U/L ridge will hold over the Florida
peninsula and Caribbean today. An U/l disturbance will ride over a
strong baroclinic zone across the Lower Mississippi Valley and
southeast U.S. with numerous showers and thunderstorms developing.
The U/L ridge will prevent the shower/thunderstorm activity from
sinking south over the forecast with continued warm dry conditions
across the forecast area.

A strong U/L low currently in the vcnty of Baja California will
gradually open up and lift across the southern plains on Monday.
This will initiate an area of low pressure over the northwest Gulf
of Mexico which will enhance shower and thunderstorm activity along
the northern Gulf coast. Southerly flow will develop over the
eastern Gulf of Mexico and Florida with increasing deep layer
moisture and weak instability developing over the region. A chance
of showers and a slight chance of thunderstorms will develop across
much of west central and southwest Florida Monday afternoon.

.LONG TERM (Monday Night - Saturday)...
A upper level low over southeast Texas and an attendant developing
surface low over the western Gulf at the start of the period will
lift northeast through the lower Mississippi Valley Monday night and
through the Tennessee and Ohio valleys on Tuesday. As this storm
system lifts out to the northeast a trailing cold front will move
east across the eastern Gulf waters Monday night, and then through
the forecast area on Tuesday. Increasing moisture and weak
instability within the warm sector ahead of the cold front will
support showers and isolated thunderstorms across the forecast area
Monday night through Tuesday as the front affects the region.

A strengthening low level jet over the Gulf coast along with
increasing effective bulk shear may support a few strong to severe
storms over portions of the northern Nature Coast Monday night as a
a high shear low cape environment develops which will support the
risk of a few supercells with the main threats being damaging winds
and a tornado or two. Across the remainder of the region some
locally heavy downpours, gusty winds, and occasional lightning will
be possible with any surface based storms that develop along and
ahead of the front. At the present time the overall severe weather
threat for the northern Nature Coast is marginal and will all hinge
on how much instability can develop, which at this time looks
minimal given the expected cloud cover and rain across the region.

The front will stall out across the southern peninsula Tuesday night
through Wednesday night as it becomes parallel to the upper level
flow as weak high pressure builds in from the north. Mainly dry
weather is expected across central and northern zones during this
time frame, while a slight chance of showers (Pops 20 percent) will
continue across the far south in the vicinity of the stalled front.

During Thursday and Friday the GFS and ECMWF still differ some with
regard to the speed of the developing long wave trough and attendant
cold front forecast to affect the region, with the GFS still the
faster of the two solutions. In using a blend of the models though
it now appears that the cold front will move south through the
region Thursday night, and then south of the region early on Friday.
Sufficient moisture accompanying the front should support another
round of showers along and ahead of the front during Thursday and
Thursday night.

In the wake of the front a brisk northerly wind flow will usher in a
much cooler and drier airmass during Friday and Friday night as a
much colder air mass overspreads most of the eastern U.S. as surface
high pressure builds in from the north. Pleasant dry weather will
continue on Saturday as the high shifts east to the mid Atlantic
coast. A return easterly wind flow around the high will allow the
very cool dry airmass to slowly modify with slightly milder
temperatures expected.

Above normal temperatures at the start of the period will fall to
below normal late in the week in the wake of the second front, with
modifying temperatures again expected during the latter part of the
upcoming weekend.


VFR conditions expected at all terminals for the next 24 hours.
Mostly clear skies early this morning.  Scattered strato-cu will
develop late this morning 030-040 with areas of VFR cigs 035-040
this afternoon.


Rather tight gradient will persist over the coastal waters with
borderline SCEC conditions over the outer waters.  Gradient will
weaken a bit tonight, but will tighten again Monday and Monday night
with SCEC and borderline SCA conditions developing, especially over
the outer waters.  Winds and seas will subside late Tuesday into
Wednesday as an area of weak high pressure builds over the Gulf of
Mexico.  Increasing winds and seas Thursday as a strong cold front
approaches the waters with SCA conditions likely developing for
Thursday and Friday.


No fire weather hazards expected through Monday as
there will be sufficient low level moisture to keep minimum relative
humidity values above critical levels each day.


.Preliminary Point Temps/PoPs...
TPA  81  70  79  72 /   0  10  30  50
FMY  83  69  81  71 /  10  10  20  30
GIF  81  68  81  70 /   0  10  20  40
SRQ  81  69  78  72 /   0  10  30  40
BKV  81  67  80  71 /   0  10  30  50
SPG  80  69  78  71 /   0  10  30  50


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

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.