Area Forecast Discussion
Issued by NWS Jacksonville, FL

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863
FXUS62 KJAX 210716
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
316 AM EDT Thu Sep 21 2017

.NEAR TERM /Today-Tonight/...

Early this morning...Much of the convective debris clouds aloft
has dissipated and some patchy fog is developing over inland SE
GA. Otherwise fair skies and temps falling into the upper 60s/near
70 inland and lower/middle 70s coast. Not expecting dense fog but
some vsbys across inland SE GA could fall to around 1 mile towards
sunrise.

Today...Mid level trof extending down the SE US Coast into SE GA
will remain in place today and small area of deeper level moisture
in place across SE GA/NE FL with PWATS into the 1.7-1.9" range
will be enough to trigger scattered showers and storms by the
afternoon hours over inland areas as the Atlc Coast Sea Breeze
pushes inland in developing E/NE surface flow. Enough insolation
is expected to push Max Temps to around 90 degrees over inland and
mid/upper 80s at the coast as E/NE flow develops this afternoon.
A few storms may become strong again this afternoon with gusty
winds and frequent lightning. Storm motion will be slow at 10 mph
or less with a slow drift towards the NE.

Tonight...A few evening showers/storms inland that should end
shortly after sunset otherwise expect mostly clear/partly cloudy
skies overnight with lows in the upper 60s/near 70 inland and
middle 70s along the coast as E/NE surface winds keep temps
elevated overnight. The E/NE convergent flow over the Atlc Coastal
Waters may start to kick off some showers over the NE FL waters
overnight, some of these may start to drift towards the coast and
some widely scattered showers are possible south of St Augustine
through Flagler county.

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...

High pressure both surface and aloft will be positioned over the
Great Lakes with an upper level low over the upper Gulf coast.
Tropical Storm Jose located southeast of Cape Cod will continue to
provide a weakness in the ridge for Maria to move well east of
the region over the weekend and early next week. With the primary
astronomical tide each day peaking near Mean Higher High Water
(MHHW) along the oceanfront and a long period easterly swell will
see a risk of rip currents along our beaches and ocean swells/wave
run up may reach to the dune line. Additionally, the ridge will
be nosing south into the region will see a mild northeaster along
the beach to chop up the surf especially on Sunday. The subsidence
around Maria should keep the coastal showers to a minimum.
Temperatures will be slightly above climatology on Friday and over
the weekend with decreasing rain chances on Sunday.

.LONG TERM /MONDAY THROUGH THURSDAY/...

On Monday Maria begins to pull north of the area with the swell
becoming more northeasterly. Still enough subsidence around from
both the ridge and Maria to limit showers to a few coastal
showers. An upper level trough digs southward into the Mississippi
River Valley by mid week pushing a dry frontal system into the
region on Friday. Temperatures will continue to be slightly above
normal with precipitation chances in the 20 percent range.

&&

.AVIATION...
Some inland Fog expected to remain generally west of TAF sites so
VFR conds expected through much of the day as rainfall chances
still too low to include in TAF sets yet.

&&

.MARINE...
Light/Variable winds become E/NE today and tonight at 10-15 knots
with seas still in the 3-5 ft range. E/NE flow increases Friday
into the weekend with sustained winds at 15-20 knots but the
bigger increase will be in the seas from Maria that increase to
5-8 ft on Friday, then 7-11 feet over the weekend and SCA due to
seas will need to be posted in upcoming packages.

Rip Currents: Moderate risk continues in lingering long period
swells at the coast with surf in the 2-4 ft range with a few
breakers to 5 feet at times.

&&

.HYDROLOGY...
Santa Fe and St. Marys river flooding slowly improving to
moderate levels while minor flooding continues on the Satilla
River basin in SE GA.

Coastal Flood Advisory remains in effect for the St. Johns River
basin as minor flooding continues during each high tide cycle from
Jacksonville southward into Putnam County.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  90  68  87  69 /  30  10  20  20
SSI  85  74  83  74 /  10   0  20  20
JAX  89  71  86  72 /  20   0  20  20
SGJ  87  74  85  74 /  10  10  30  30
GNV  91  69  88  70 /  30   0  30  20
OCF  91  69  88  71 /  20   0  40  10

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 8 PM EDT this evening for Clay-
     Coastal Duval-Flagler-Inland Duval-Putnam-St. Johns.

GA...None.
AM...None.
&&

$$

Hess/Sandrik



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