Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS62 KTBW 261811

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
211 PM EDT Wed Jul 26 2017

.SHORT TERM (Tonight - Thursday)...
In the mid/upper levels, ridging extends across central and
southwest Florida while troughing extends over Georgia into the
Florida panhandle. This pattern will hold in place through early
Thursday as the ridge sinks slightly farther south over southern
Florida. On the surface, the main feature is high pressure located
in the Gulf of Mexico. This feature should keep a general onshore
flow later today, which would allow for the highest rain chances
over the inland counties later this afternoon, but still only in the
30-40 POPs range. The main weather concern today has been hot
temperatures. Most places saw heat indices near 100 degrees with
some inland areas reaching 108 degrees. Things will cool down this
evening, but will still be warm and muggy overnight with low temps
in the mid to upper 70`s with humidity values near 100 percent in
some places.

On Thursday, conditions will only be slightly different than what we
saw today. The surface ridge slips slightly southward which will
produce a more southwest onshore flow, which in turn will bring an
increase in moisture, with expected PWAT values to increase to 1.8 -
2.0 inches across the region. Chances of rain will be slightly
higher (30-50 POPs) over the inland counties. Temperatures will be
slightly cooler, but still above average with the heat indices. Heat
indices will approach 100 in some locations by late morning with
most of the region seeing 100-103 degree heat indices through the
afternoon on Thursday.


.Long Term (Thursday Night-Wednesday)...
Initially a weak stationary upper trough extending across north
Florida to the eastern gulf will remain in place but weaken through
Friday with very weak surface ridging across north central Florida.
On Saturday a north wave moving southeast across the
eastern U.S. will overtake the weak upper trough while
pushing a weak front with moisture and convection toward the
Florida panhandle which will push the surface ridge south
of Florida. On Monday the frontal trough moves over central
Florida and becomes stationary. During this period the
forecast area will be under westerly flow and will have deep
layer moisture leading to a rainy period that will last
into Wednesday.


VFR conditions are expected to prevail through the period.
TPA/PIE/SRQ should remain rain free today, but will hold VCTS for
LAL/PGD/FMY/RSW between 18Z to 00Z. Winds are expected to turn on
shore with a west-southwest component remaining less than 10 knots
through the evening, then becoming light and variable overnight. No
other aviation impacts expected.


High pressure in the Gulf of Mexico will keep mostly rain free
conditions, light winds below 10 knots and minimal seas less than 2
feet through the remainder of the week and into the beginning of the
weekend. A frontal boundary approaches the area early Sunday and
will bring increasing rain and storm chances over the coastal
waters. The tighter pressure gradient between this front and high
pressure to the south will also increase the southwest winds to 10-
15 knots, which will also build the seas to 3-4 feet in some areas.
Wind and seas will be higher in the vicinity of thunderstorms,
otherwise no marine headlines are anticipated through the period.


No fire weather concerns are expected for the remainder of the week
and into the weekend as humidity levels remain above critical
levels and ERC values remain low.


.Preliminary Point Temps/PoPs...
TPA  79  91  79  90 /  10  20  20  20
FMY  78  92  77  92 /  20  20  20  30
GIF  77  94  76  94 /  30  40  20  30
SRQ  78  90  79  90 /  10  20  20  30
BKV  74  92  74  91 /  10  20  30  40
SPG  80  91  80  90 /   0  10  20  20


Gulf waters...None.


MID TERM/LONG TERM/DECISION SUPPORT...03/Paxton is the U.S. government's official web portal to all federal, state and local government web resources and services.