Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 181846
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
246 PM EDT Wed Jul 18 2018

...Some Locally Heavy Rain Possible The Next Several Days...

.SHORT TERM (Tonight - Thursday)...
Mid/upper level troughing and an attendant surface front
over the northern peninsula and northeast Gulf will
persist through the period as the subtropical ridge axis
remains suppressed across the southern Florida peninsula and
Florida Straits. With the ridge axis to the south and the
trough/front to the north a very moist (PW`s 1.8 to 2 + inch
range) deep layered southwest wind flow will persist across
the forecast area through the period. This moisture
combined with the trough and front will continue to support
scattered to numerous showers and storms (Pops in the 50 to
70 percent range) over the Gulf waters and along the coast
during the late night and early morning hours with the
convection then moving to inland locations during the
afternoon and early evening hours. The trough/front to the
north will act as a focus for some locally heavy rainfall,
especially from the Tampa Bay area north into the Nature
Coast where the highest moisture axis will reside, while
slightly lower rain chances (Pops 20 to 40 percent) can be
expected further to the south and across southwest Florida.

The onshore flow will support another warm and very muggy
night across the forecast area with above normal
temperatures expected along the coast where lows around 80
can be expected with mid to upper 70s over inland areas.
Daytime highs on Thursday will again be similar to today
with highs climbing into the upper 80s to around 90 along
the coast, and lower 90s inland with heat indices in the 100
to 105 degree range during the early afternoon.

.MID/LONG TERM (Thursday Night - Tuesday)...
Models are in good agreement showing an upper-level trough
digging southeastward through the Ohio Valley Friday and
Saturday, then less agreement in timing and placement as the
trough or weak cut-off low drifts southward toward the
northern Gulf Coast Monday and Tuesday. The surface ridge
axis will reside near the Florida Straits through the
weekend, then begin to build back over the state from the
Atlantic Monday and Tuesday.

Through Sunday...deep westerly flow will reside over the
northern half of our area with lighter winds as you head
south toward the ridge axis. A weak trough/frontal boundary
will persist near the Florida/Georgia border with deep
moisture pooling along and to the south of there. This will
favor late night and early morning showers and storms along
the coast...especially from the Tampa Bay area north through
the Nature Coast. Activity will then shift inland during
the late morning and afternoon hours each day.

Monday and Tuesday may see a pattern change as the upper-
level trough weakens and retrogrades westward allowing
stronger Atlantic ridging to build back into the region. The
GFS is faster and stronger with the ridge while the ECMWF
maintains the upper-level troughing through Tuesday. A GFS
solution would bring afternoon storms back toward the Gulf
coast while the ECMWF solution maintains a more inland
scenario. Since this is still 6 to 7 days away, will not
stray far from climatology.

Best potential for heavy rainfall is along the Nature Coast
during this period, possibly drifting south into the Tampa
Bay area for Sunday and Monday.

Rip currents are likely to increase over the weekend as a
long fetch of westerly winds develops across the northern
Gulf.

&&

.AVIATION...
Brief MVFR cig/vsbys will be possible through 00Z tonight
and again after 08Z Thursday morning as shra/tsra continue
to move onshore from the Gulf within a very moist southwest
wind flow. Outside of the convection VFR will prevail.
Southwest winds in the 7 to 10 knot range this afternoon
will diminish to around 5 knots or less after 01Z tonight,
before increasing back into the 7 to 9 knot range after 15Z
on Thursday with higher gusts near any tsra.

&&

.MARINE...
Surface high pressure will persist across the southern
peninsula and Florida Straits through the end of the week
and into the upcoming weekend with southwest winds around 10
knots with seas of 2 to 3 feet expected through the period.
Wind and seas will be higher near scattered to numerous
late night and early morning showers and storms, otherwise
no headlines are expected.


&&

.FIRE WEATHER...
Ample moisture along with daily showers and storms will keep
humidity values well above critical levels through the end
of the week and into the upcoming weekend. Some gusty winds
and frequent lightning strikes can be expected near
thunderstorms, otherwise no other fire weather hazards are
expected.

&&

.Preliminary Point Temps/PoPs...
TPA  80  88  79  88 /  30  40  30  60
FMY  78  92  78  92 /  20  20  10  10
GIF  76  91  76  90 /  10  50  10  40
SRQ  81  88  80  89 /  40  50  30  40
BKV  77  88  76  88 /  30  50  30  60
SPG  81  88  81  88 /  30  50  40  60

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Beach Hazards Statement through Thursday evening for
     Coastal Sarasota.

Gulf waters...None.
&&

$$

SHORT TERM/AVIATION/MARINE/FIRE WEATHER...57/McMichael
MID TERM/LONG TERM/DECISION SUPPORT...63/Jillson



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