344
FXUS62 KJAX 231908
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
308 PM EDT Sat Aug 23 2025

...FLOOD WATCH THROUGH LATE TONIGHT FOR ALL OF SOUTHEAST GA AND
PORTIONS OF NORTHEAST FL...
...WAVES OF DOWNPOURS AND STORMS EXPECTED THROUGH SUNDAY...
...HIGH RIP CURRENT RISK CONTINUES AT THE NORTHEAST FL BEACHES...

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 309 PM EDT Sat Aug 23 2025

Afternoon surface analysis depicts a wavy stationary frontal
boundary extending west to east along the FL/GA border. Meanwhile,
high pressure (1022 millibars) was strengthening as it moves
offshore of coastal New England, with this feature wedging down
the southeastern seaboard in the wake of the aforementioned
frontal boundary. Otherwise, a strong cold front was moving
southeastward from the Great Lakes and the Plains states.
Aloft...troughing was cutting off over the southern Appalachians
and the Deep South, with a mid-level circulation developing over
inland south GA. A longwave trough was also gradually digging
southeastward from the Great Lakes region. Scattered convection
was approaching the I-95 corridor in southeast GA, with widely
scattered activity located near the Altamaha/Ocmulgee Rivers as
well as along the I-10 corridor. Following widespread morning
convection across coastal southeast GA and most of northeast and
north central FL, breaks in the multi-layered cloudiness have
allowed temperatures to climb to the mid and upper 80s as of 19Z,
with rain-cooled locations in southeast GA currently in the mid
and upper 70s. Dewpoints were in the 70s area-wide.

&&

.NEAR TERM...
(through Tonight)
Issued at 309 PM EDT Sat Aug 23 2025

The presence of stationary frontal boundary along the FL/GA
border and deep tropical moisture in place, and a cutoff, digging
trough over southeast GA should result in convection increasing
in coverage and intensity this afternoon and evening, especially
along the Interstate 10 corridor. We have maintained the Flood
Watch for southeast GA as well as Duval and Nassau Counties in
northeast FL through late tonight, as convection may linger well
into the evening hours as mesoscale boundaries and convective
outflows tend to converge along or just north of the I-10
corridor. PWATs in excess of 2 inches and lift / diffluent flow
aloft, compliments of an entrance region of a jet streak
positioned over the Delmarva area may create back-building and
potentially "training" downpours this afternoon and evening, with
widespread additional rainfall totals of 1-2 inches, with
localized amounts of 3-4 inches possible through tonight. Although
a few storms may pulse and become strong as mesoscale boundaries
and convective outflows collide across north FL and southeast GA
later today, the overall environment should keep storms sub-
severe, with heavy rainfall and flooding being the primary
threats. Stronger storms may still produce frequent cloud to
ground lightning strikes and downburst winds of 30-45 mph through
around sunset. Thickening mid and high altitude cloudiness across
north central FL may limit convective potential for those
locations, although outflow boundaries may ignite activity there
later this evening.

Mid-level low pressure will begin to migrate slowly eastward
towards coastal GA, likely pushing convection offshore from
coastal southeast GA and northeast FL towards midnight. Westerly
low level flow to the south of the stationary frontal boundary
will likely ignite nocturnal convection over Apalachee Bay and
the northeast Gulf, with activity again likely increasing in
coverage and intensity along the FL Big Bend / Nature coasts
during the predawn hours and then potentially moving into the
Suwannee Valley and towards I-75 in north central FL towards
sunrise on Sunday. Low stratus clouds will otherwise overspread at
least southeast GA and the I-10 corridor during the predawn and
early morning hours. Lows tonight will remain in the 70s area-
wide.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 309 PM EDT Sat Aug 23 2025

Numerous to widespread showers and thunderstorms persist on Sunday
as the diffuse trough/boundary does start to dissipate, though
high layer moisture sticks around as PWATs remain in the 1.9 to
2.2 inch range. Heavy rainfall and localized minor flooding will
continue to be the primary hazard potential, as the WEather
Prediction Center (WPC) continues a Marginal risk of excessive
rainfall across SE GA and NE FL on Sunday. The localized flooding
threat will be especially where storms train and in urban and low
lying areas. As of Saturday afternoon, the Flood Watch previously
in effect for southeast GA and far northeastern FL has been
cancelled given a more isolated threat expected, though will
continue to evaluate forecasts and trends through tonight for any
possible changes. Stronger downburst wind potential once again
looks to be on the lower end given the warmer temps aloft and
rather lackluster instability, though cannot rule out some
isolated gusts around 40-50 mph. Temps Sunday will be a touch
warmer than Saturday, mostly in the mid to upper 80s to near 90
furthest south.

Sunday Night and Monday, a modestly strong late summer front will
push south and eastward towards and over the area, almost clearing
the region to the south by Tuesday Morning. This will usher in
plenty of drier than normal air both aloft and near the surface
throughout Monday and Monday Night, which will start to decrease
rain chances - especially over interior GA. By Monday evening, a
fairly substantial moisture gradient is expected to setup,
ranging from about 1.7 to 1.8 inch PWATs furthest southeast to
under an inch north and west of Waycross! Accordingly, convective
chances and strong t`storm potential will be highest south of the
front where the best available moisture will be found. West to
northwest flow along and just south of the front will be strong
enough to keep the sea breeze likely pinned inside I-95, and
therefore collisions with this boundary over the northeast FL
coast will be the main focus area for the strongest storm
potential. Given that it`s still August and cloud cover will be
more scattered to even mostly clear from southeast to northwest
with the more offshore wind regime, high temperatures in the low
90s will be common. The gradient of dry air will also result in
some of the coolest temperatures in some time across interior GA
where mid to upper 60s will be common, closer to normal in the low
to mid 70s at the coasts and for most of northeast FL.

&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 309 PM EDT Sat Aug 23 2025

An early fall-like long wave upper trough with several rotating
shortwaves across the southeast US will nudge and keep the
aforementioned frontal boundary even further south of the region
for much of the long term period, with guidance suggesting the
front reaching as far south as Central to Southern FL by late
week! Drier than normal air will therefore penetrate further south
and east for much of the long term period as high pressure builds
in from the northwest, keeping rain chances well below normal on
Tuesday and Wednesday, and still trending below normal for late in
the week as well. Temps start this period above normal Tuesday,
though trend fairly quickly towards near normal for Wednesday -
Friday.

&&

.AVIATION...
(18Z TAFS)
Issued at 216 PM EDT Sat Aug 23 2025

Showers and thunderstorms are expected to increase in coverage and
intensity across our region this afternoon and evening. Activity
is expected to initially impact SSI during the 19Z-23Z time frame,
and we included a TEMPO group for IFR visibilities and briefly
gusty winds during this time frame. Although confidence is not
particularly high, it appears as if convection will likely hold
off at the northeast FL terminals until later this afternoon, with
activity possibly lingering past sunset. TEMPO groups for IFR
visibilities and briefly gusty winds were placed in the TAFs at
the Duval County terminals and SGJ, while MVFR conditions were
indicated in the TEMPO group at GNV. Convection may linger or
redevelop near the SSI terminal after sunset, but confidence was
too to indicate anything other than prevailing MVFR conditions
through around 02Z. Low stratus ceilings will then overspread our
area during the overnight and predawn hours, with IFR to MVFR
ceilings likely at the regional terminals through the morning
hours. Convection may begin to develop near the TAF sites towards
18Z Sunday as ceilings begin to gradually lift, but confidence
remains to low to include anything other than vicinity coverage at
this time.

&&

.MARINE...
Issued at 1234 PM EDT Sat Aug 23 2025

Long period swells emanating from post Tropical Cyclone Erin will
keep combined seas elevated through the weekend, especially
offshore. Small Craft should continue to Exercise Caution if
venturing into the offshore waters this weekend, where seas of
4-6 feet will prevail. Seas of 3 to 5 feet are expected to
continue near shore.

Meanwhile, a stationary frontal boundary near the FL/GA border
will remain in place through the weekend. Rounds of showers and
thunderstorms will impact our local waters through Monday evening.
The frontal boundary will then shift southward on Tuesday,
stalling across the Florida peninsula towards midweek, resulting
in a decreasing coverage of showers and thunderstorms for our area
on Tuesday. Breezy northeasterly winds will then develop by
midweek as high pressure builds over the Ohio Valley and coastal
troughing develops over the near shore waters, possibly bringing
an increasing coverage of showers and thunderstorms to the
northeast Florida waters.

Rip Currents: Long period northeasterly swells of 14-16 seconds
and breakers of 3-4 feet will keep a high rip current risk in
place at the northeast FL beaches through at least Sunday.
Breakers of 2-3 feet at the southeast GA beaches will yield a
higher end moderate risk this weekend. Swell periods will remain
in the 12-14 second range early next week, keeping a higher end
moderate risk in place at all area beaches.

&&

.FIRE WEATHER...
Issued at 309 PM EDT Sat Aug 23 2025

A weakening frontal boundary over the area through Sunday will
persist elevated chances for showers and t`storms, as well as poor
to fair dispersions, especially over southeast GA. A stronger than
normal late summer/early fall front moves into the area Monday
night into Tuesday, which will start to reduce rain chances from
northwest to southeast for the start of next week while also
returning good to borderline high dispersions in some areas as
well as a drier than normal airmass.

&&

.HYDROLOGY...
Issued at 1234 PM EDT Sat Aug 23 2025

Showers and thunderstorms increasing in coverage across southeast
GA early this afternoon will likely overspread locations along and
north of the I-10 corridor by late afternoon and early evening.
Slow moving downpours over saturated ground conditions may
result in flooding, especially at urban and low lying, normally
flood prone locations. Widespread 1-2 inch rainfall amounts
through tonight, with localized amounts of 3-4 inches, have
prompted the Weather Prediction Center to include all of southeast
GA and most of the I-10 and I-75 corridors in northeast FL and the
Suwannee Valley in a "Slight" Risk (Level 2 of 4) for Excessive
Rainfall through tonight, with a "Marginal" Risk (Level 1 of 4) in
place elsewhere. The Flood Watch remains in effect through late
tonight for all of southeast GA as well as Nassau and Duval
Counties in northeast FL. Additional rounds of heavy downpours are
possible on Sunday and Monday for locations along and south of
I-10, with some risk on Sunday afternoon for locations along the
I-95 corridor in coastal southeast GA as well.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  71  86  70  92 /  50  50  10  20
SSI  73  86  74  90 /  70  60  20  30
JAX  73  89  73  93 /  50  70  20  40
SGJ  74  89  74  90 /  60  70  30  60
GNV  73  89  73  92 /  40  70  20  60
OCF  74  88  74  90 /  40  80  30  70

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch until 2 AM EDT Sunday for FLZ024-124-125-225-325-425.

     High Rip Current Risk through late Sunday night for FLZ124-125-
     138-233-333.

GA...Flood Watch until 2 AM EDT Sunday for GAZ132>136-149-151>154-162-
     163-165-166-250-264-350-364.

AM...None.
&&

$$