Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 151750

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
150 PM EDT Sun Sep 15 2019

A complex synoptic pattern is currently in play across the region
complements of an upper-level low to the west and tropcial Storm
Humberto to the east. Sandwiched between these two features, a weak
trough axis is draped across the Florida peninsula, helping to steer
Humberto off to the northeast around the subtropical high.

Similar to Dorian a couple weeks ago, Humberto is influencing the
flow across the region at the surface. As winds rotate
counterclockwise in a cyclonic fashion, winds are out the of NNE for
northern regions, then graduatally turning to a more NNW flow across
the southern region of the state. Humberto is caught in a larger
easterly flow pattern at the surface that has been advecting a large
plume of tropical moisture from the Western Atlantic, across the
peninsula, and ultimately across most of the Gulf. Subsequently,
coastal areas are continuing to see more of a NE flow despite
Humberto`s influence as the upper level low in the Central Gulf
fights for moisture and energy from the environment.

With ample moisture and a fairly unstable environment, showers and
thunderstorms are developing this afternoon across the region, on
track with this morning`s forecast as expected. The highest rain
chances will be concentrated in and around Tampa Bay extending east
into the interior counties primarily south of I-4.

As Humberto continues to move away from the Florida coastline, the
pattern will begin to shift to a drier one. The NNE wind will
no longer be advecting tropical moisture for Humerto over the
region, but drier continental air making its way down from the
CONUS. Combined with the strong subsidence (sinking air) from
Humberto, a dry start to the work week is anticipated.


Drier conditions will continue through the rest of the work week.
By Wednesday, a "cold" front is expected to enter the scene. While
only contributing a miniscule drop in temperatures, surface
dewpoints are expected to drop significantly. Lower dewpoints will
make conditions feel much more comfortable than usual.

Unfortunately, this too shall pass. By the weekend, a more typical
late summertime pattern is expected to return as easterly flow
brings mositure back into the region and temperatures go back up.
Scattered showers and thunderstorms are expected to return by next


Mainly VFR conditions are expected through the forecast period.
Scattered showers and thunderstorms through the rest of the
afternoon could lead to brief restrictions at area terminals, then
rain will come to an end for the overnight period. Winds will remain
north to northwest.


With lighter winds throughout the remainder of the day, seas are
continuing lay down across nearshore and offshore waters. Showers
and thunderstorms cannot be ruled out in offshore waters today as
well, with the greatest chances from Tampa Bay southward as storms
that develop inland push offshore near sunset. High pressure builds
over the region for the early portion of the week with generally
light winds and seas continuing until mid-week. A front is then
expected to push through the region Wednesday night. Elevated
northeasterly winds up to 20 knots and rough seas as then expected
to persist over the eastern Gulf of Mexico for Thursday and Friday.


Scattered showers and thunderstorms are possible across the region
in the afternoon and evening hours. By tomorrow conditions begin to
dry out and will remain drier through the entire work week. Despite
the drier conditions, sufficient moisture will be present to keep
relative humidity levels above critical thresholds.


.Preliminary Point Temps/PoPs...
TPA  76  92  76  93 /  20  10   0  10
FMY  77  91  76  93 /  20  20  10  10
GIF  76  93  75  95 /  20  30   0  10
SRQ  77  90  77  92 /  20   0   0  10
BKV  74  93  73  94 /  20  10   0  10
SPG  77  91  77  93 /  20  10   0  10


Gulf waters...None.


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