541
FXUS62 KJAX 010806
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
406 AM EDT Mon Sep 1 2025

...WINDY WITH OCCASIONAL SHOWERS FOR COASTAL NORTHEAST FL TODAY...
...HIGH RIP CURRENT RISK AT AREA BEACHES THROUGH TUESDAY...
...HOT WEATHER RETURNS LATE THIS WEEK AND THE UPCOMING WEEKEND...

For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

.SYNOPSIS...
Issued at 407 AM EDT Mon Sep 1 2025

Overnight surface analysis depicts weak low pressure (1011
millibars) situated near Cape Canaveral, with coastal troughing
extending north of this feature over the near shore Atlantic
waters adjacent to northeast FL. Meanwhile, the stationary frontal
boundary that has persisted over our area during the past several
days has been pushed southward to the Interstate 4 corridor in
central FL by strong high pressure (1026 millibars) positioned
across the eastern Great Lakes and New England that was wedging
down the southeastern seaboard. Aloft...troughing over the eastern
third of the nation has become cutoff over the Mid-Atlantic states
as ridging building over the Upper Midwest and the western Great
Lakes develops a blocking pattern. Latest GOES-East derived Total
Precipitable Water imagery indicates that a drier air mass
continues to advect across inland locations, where PWATs range
from around 1.2 inches for locations along the Altamaha / Ocmulgee
/ Alapaha Rivers in southeast GA to around 1.75 inches across
north central FL. PWATs near early September climatology persist
along the northeast FL coastal counties, where values were in the
1.8 - 2 inch range.

A tight local pressure gradient persists locally in between the
low pressure center near Cape Canaveral and surface ridging that
was wedging down the southeastern seaboard, with strong low level
northeasterly flow organizing bands of mostly low topped showers
that extend from the offshore waters adjacent to southeast GA
southwestward across the northeast FL waters, with these rain
bands continuing to occasionally move onshore from the
Jacksonville Beaches and points southward, with this activity
extending inland to southern portions of the St. Johns River
basin. Fair skies and lighter northeast winds across inland
southeast GA have allowed temperatures and dewpoints to fall to
the mid and upper 60s as of 08Z, while temperatures remain in the
70s elsewhere, except around 80 along the northeast FL coast.
Dewpoints have fallen to the upper 60s all along the Interstate 10
corridor, while lower 70s prevail for north central and coastal
northeast FL.

&&

.NEAR TERM...
(Today and Tonight)
Issued at 407 AM EDT Mon Sep 1 2025

Strong high pressure over New England and the Mid-Atlantic states
will continue to wedge down the southeastern seaboard today.
This surface ridge will push weak low pressure currently centered
near Cape Canaveral slowly southward, in tandem with a persistent
frontal boundary. This weather pattern will maintain a coastal
trough over the near shore waters adjacent to northeast FL, with
a tight local pressure gradient keeping windy conditions going
across coastal northeast FL through late this afternoon, where
frequent gusts of 35-40 mph are expected. Breezy conditions will
also continue across coastal southeast GA and will expand inland
during the mid to late morning hours. Persistent northwesterly
flow aloft will advect an unseasonably dry air mass across
southeast GA and the Suwannee Valley, where dewpoints will fall
into the 50s this afternoon. Plenty of sunshine will boost highs
into the mid to upper 80s at most locations, which is still a few
degrees below early September climatology.

Bands of moderate to occasionally heavy showers and possibly a few
embedded thunderstorms will continue to pivot onshore along the
northeast FL coast today, mainly for locations south of Mayport,
where moisture levels will remain closer to climatology. Rain
bands through this evening will be more frequent for locations
from St. Augustine southward, with these bands continuing to
occasionally move inland across southern portions of the St.
Johns River basin through tonight. Locally heavy rainfall amounts
of 1-2 inches, with locally higher totals, will remain possible
across Flagler and southern portions of St. Johns Counties today
and tonight, which could cause localized flooding, particularly at
urban and normally flood prone, low lying coastal locations.
Strong onshore winds and plenty of cloud cover will keep highs
in the 80-85 degree range along the I-95 corridor, which is 4-8
degrees below early September climatology.

High pressure wedging down the southeastern seaboard will begin to
gradually weaken tonight as low pressure and the long-lived
frontal boundary shift southward across south FL. Our local
pressure gradient will begin to loosen, but breezy onshore winds
will continue at coastal locations, with persistent coastal
troughing continuing to generate occasional bands of low topped
showers over the northeast FL waters that will occasionally move
onshore across coastal locations in northeast FL, with showers
also continuing to impact southern portions of the St. Johns River
basin. Lows tonight will fall to the low and mid 60s for inland
southeast GA, with mid and upper 60s for the Suwannee Valley.
Breezy onshore winds will keep lows in the mid 70s for coastal
locations and lower 70s for inland portions of north central FL.

&&

.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 407 AM EDT Mon Sep 1 2025

High pressure will stretch south along the eastern coast of the
CONUS, pushing the lingering frontal boundary toward southern FL.
With high pressure building towards the area, relatively drier
conditions will continue for much of the local area, limiting the
amount of showers and storms across inland locations of SE GA and
NE FL heading into midweek. Isolated to scattered afternoon
showers and storms will still be possible over north-central and
coastal FL, where PWATs will remain slightly higher thanks to
northeasterly onshore flow bringing in moist marine air. As
showers and storms move onshore, periods of heavy rainfall along
coastal NE FL could bring isolated Flash Flood risk for low-lying
areas and urban areas, particularly along the I-95 corridor.

Tuesday, high temperatures are forecast to be in the 80s
across the area, cooler temperatures along the coast as
onshore flow brings in cooler marine air. Wednesday, slightly
warmer temperatures with inland locations in upper 80s to lower
90s, coastal locations in the mid 80s.

Overnight lows will be in the mid to upper 60s for inland
SE GA and NE FL. Coastal locations and north-central FL will
see slightly warmer lows, generally in the lower 70s.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 407 AM EDT Mon Sep 1 2025

By the back half of the upcoming week, the high pressure will
shift off toward the north-northeast ahead of a dry cold front
from the northwest, bringing about drier air to the local area.
This will see precipitation chances trend downward relative to
earlier half of the week.

The weekend cold front is not expected to bring much in the
way of a cool down, rather temperatures are expected to trend
near to a bit above seasonal averages. Highs will be in the lower
90s by the end of the upcoming week and into the weekend.

&&

.AVIATION...
(06Z TAFS)
Issued at 215 AM EDT Mon Sep 1 2025

MVFR ceilings will prevail at SGJ through the period, with
occasional moderate to heavy showers potentially resulting in
brief periods of MVFR to IFR visibilities. A TEMPO group for MVFR
visibilities was used overnight through the predawn hours on
Monday at SGJ, with a PROB30 group for IFR visibilities during the
morning and early afternoon hours. Confidence was too low for
anything other than vicinity shower coverage at the Duval County
terminals, while dry conditions will likely continue at GNV and
SSI. Occasional MVFR ceilings of 2,000 - 3,000 feet will continue
at the northeast FL terminals, while VFR ceilings above 3,000 feet
prevail at SSI until around 00Z Tuesday, when ceilings may then
lower to around 3,000 feet. Strong northeasterly surface winds
will continue at SGJ, with sustained speeds around 20 knots with
frequent gusts around 30 knots through 00Z Tuesday. Sustained
surface speeds of 10-15 knots at CRG and SSI and around 10 knots
at the inland terminals overnight will increase to around 15 knots
and gusty towards 14Z. Surface speeds will then diminish to 5-10
knots at the inland terminals and 10-15 knots at the coastal
terminals after 02Z Tuesday.

&&

.MARINE...
Issued at 407 AM EDT Mon Sep 1 2025

Low pressure centered along the east central Florida coast will
shift slowly southward in tandem with a frontal boundary today as
strong high pressure over New England continues to wedge down the
southeastern seaboard. Gusty northeasterly winds and elevated seas
will continue through early Tuesday, with Small Craft Advisories in
place throughout our local waters today and tonight. Seas will
peak in the 6-9 foot range for the near shore and offshore waters
north of St. Augustine today, with 5-8 foot seas south of St.
Augustine. Speeds will diminish slightly to Caution levels of
15-20 knots tonight and Tuesday, with seas expected to fall to
Caution levels of 4-6 feet by early Tuesday. Winds and seas will
then fall below Caution levels by Tuesday night. Bands of showers
and embedded thunderstorms will continue to impact our local
waters through midweek, as coastal troughing remains situated over
our near shore waters. Coverage of showers and thunderstorms will
then decrease later this week ahead of a series of approaching
cold fronts.

Rip Currents: Breaker heights today will peak just below High Surf
criteria at the northeast FL beaches, where 5-6 foot values are
expected, while breakers of 4-5 feet prevail at the southeast GA
beaches. Rough surf conditions will continue to promote a high
rip current risk at all area beaches through Tuesday evening, with
breakers falling slowly to the 4-5 foot range at the northeast FL
beaches on Tuesday and 3-4 feet at the southeast GA beaches.
Slowly subsiding surf may allow for the risk to be moderate by
Wednesday.

&&

.HYDROLOGY / COASTAL FLOODING...
Issued at 407 AM EDT Mon Sep 1 2025

Heavy rainfall potential will continue for coastal northeast FL
and the St. Johns River basin today, with additional rainfall
amounts of 1-2 inches with locally higher amounts remaining
possible through Tuesday. Localized flooding will be possible
wherever these heavier rain persist or "train" over the same
locations, and the Weather Prediction Center has maintained a
"Marginal" Risk (level 1 of 4) for flooding for these locations.

Middle St. Johns River Basin south of JAX to Palatka vicinity will
continue to run at elevated/Action stage water levels as the
Northeast flow pattern traps some of the higher water levels in
the basin. Minor flooding will be possible in the Putnam county
areas around times of high tide on Tuesday and Wednesday, with
water levels potentially peaking around 1.5 ft above Mean Higher
High Water (MHHW). We will continue to monitor forecasts today for
a possible Coastal Flood Advisory issuance for Tuesday and
Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  84  62  86  65 /   0   0  10   0
SSI  82  72  83  73 /  20  10  30  10
JAX  84  72  86  72 /  30  10  50  20
SGJ  84  75  85  74 /  60  30  60  30
GNV  86  69  88  70 /  40  10  40  20
OCF  86  72  88  72 /  50  10  50  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Wednesday morning for FLZ124-125-
     138-233-333.

     Wind Advisory until 5 PM EDT this afternoon for FLZ125-138-233-
     333.

GA...High Rip Current Risk through Wednesday morning for GAZ154-166.

AM...Small Craft Advisory until 11 PM EDT this evening for AMZ450-452-
     454-470-472-474.

&&

$$