Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 280144
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
944 PM EDT TUE SEP 27 2016

.UPDATE...
CONVECTION HAS SETTLED DOWN SIGNIFICANTLY THIS EVENING...WITH JUST
A FEW ISOLATED CELLS STILL AROUND THE LAKELAND AREA AS OF 930 PM.
CONTINUE TO WATCH A DEFINED CONVECTIVE OUTFLOW BOUNDARY PUSH BACK
TO THE WEST THROUGH THAT MAY STILL HAVE POTENTIAL TO POP AN
ISOLATED SHOWER OR STORMS DURING THE NEXT 1-2 HOURS ACROSS
HILLSBOROUGH/PINELLAS/PASCO COUNTY. THIS BOUNDARY HAS EXITED THE
COAST DOWN TOWARD MANATEE AND SARASOTA COUNTIES...SO ANY ISOLATED
CONVECTION THAT FAR SOUTH SHOULD NOW OCCUR OVER THE MARINE ZONES.
THIS BOUNDARY SHOULD RUN OUT OF GAS BY MIDNIGHT...AND ALLOW A THE
LIGHT SYNOPTIC SOUTHWESTERLY FLOW TO RETURN TO ALL AREAS.

A WEAK UPPER SHORTWAVE APPROACHING FROM THE WEST LATER TONIGHT IS
EXPECTED TO INCREASE THE POTENTIAL FOR SCT SHOWERS AND STORMS OVER
THE COASTAL WATERS...MAINLY TO THE NORTH OF TARPON SPRINGS...AND A
FEW OF THESE SHOWERS MAY REACH THE NATURE COAST BY DAWN.
OTHERWISE...MOSTLY DRY OVERNIGHT WITH TEMPS MAINLY IN THE 70S.

Just realized everything above I typed in ALL CAPS. Old habits
really do die hard. Have a great evening everyone and enjoy your
Wednesday.

&&

.Prev Discussion... /issued 231 PM EDT TUE SEP 27 2016/

SYNOPSIS...
Ridge axis of weak high pressure extended across the Florida Straits
with westerly low level flow across forecast area. Visible satellite
and surface observations showed sea breeze front from Inverness to
Sarasota then down to Naples. Isolated showers were found along the
front. Water vapor loop showed weak upper level low in east central
Florida with drier air wrapping into the forecast area. Best chance
of afternoon storms to be in Highlands County as it is closer to
the deep layer moisture across south Florida.

SHORT TERM (Tonight and Wednesday)...
Will keep a small chance of thunderstorms in forecast 00-03Z east of
Highway 27 in Polk and Highlands counties and in Punta Gorda and
Fort Myers as HRRR model has gust front from Highlands County
convection heading back to the coast.

Large and stacked upper level low centered near eastern Lake
Superior is forecast to drift south into Indiana Wednesday. Our
forecast area will be on the southern end of the cyclonic flow
aloft. Weak impulses in this flow combined with a stalled front in
the Florida Pan Handle will bring scattered showers and storms to
the Nature Coast late tonight and will continue through the
afternoon. Expected cloud cover and sea breeze will keep highs in
the mid 80s rather than the upper 80s in this area. Elsewhere,
westerly low level flow will be a bit stronger Wednesday with the
sea breeze front moving well inland. Best chance of storms will be
east of Interstate 75 from 18-21Z.

MID TERM/LONG TERM (Wednesday Night-Tuesday)...
A mid/upper level low meanders between the Great Lakes and the
Tennessee Valley through most of the weekend. The low nudges a
weakening frontal boundary out of the Deep South...through northern
FL on THU...then into central FL where it dissipates during FRI. A
ridge of high pressure from the Atlantic initially across south FL
slides off to the east. The front settles in with drier and more
stable air behind it...with limited to nil rain chances from around
the I-4 corridor northward. South of there scattered showers and
storms will continue. Some deeper moisture will begin to creep back
north SAT. Temperatures will run around normal for the highs.
However lows for the nature coast will be just below normal while
lows south of I-4 stay on the warm side.

On SUN the upper low tracks across the lower Great Lakes to NY or
southwest Quebec by MON. For TUE the low remains near NY (GFS) or
pushes east to the Canadian Maritimes (ECMWF). At the surface...
Atlantic high pressure builds back in across and north of the state
as a low approaches... near the Bahamas (GFS) or central Cuba
(ECMWF)...at the very end of the period. Moisture will significantly
increase and spread northward as low level flow takes on an easterly
component. Showers will be scatted to numerous with isolated to
scattered thunderstorms. High temperatures will be near to a bit
above normal. The lows will be a degree or two above normal.
The last day or so of this forecast could change depending upon the
exact track of the low...in the Bahamas or near Cuba?

AVIATION...
VFR conditions for most of the next 24 hours. Best chance for
afternoon storms this afternoon and Wednesday afternoon will be east
of the terminals as a westerly low level flow pushes the Gulf Coast
sea breeze inland.

MARINE...
A cold front will move into the coastal waters Thursday and will
wash out. This will bring scattered showers and thunderstorms to the
central and northern coastal waters through Thursday. Easterly flow
develops for the weekend with late afternoon and overnight showers
and storms.

FIRE WEATHER...
Relative humidity is forecast to remain above critical thresholds
through the week, with no fire weather concerns expected.

&&

.Preliminary Point Temps/PoPs...
TPA  76  88  75  87 /  20  30  40  40
FMY  74  89  75  88 /  20  30  30  40
GIF  73  89  73  87 /  20  50  20  50
SRQ  76  87  76  87 /  20  30  40  50
BKV  72  87  72  86 /  20  50  40  50
SPG  78  87  77  86 /  20  30  40  50

&&

.TBW Watches/Warnings/Advisories...
FL...Beach Hazards Statement through Thursday evening for
     Coastal Manatee-Coastal Sarasota.

Gulf waters...None.

&&

$$

UPDATE...Mroczka
PREVIOUS DISCUSSION...NOAH/RUDE


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