706
FXUS62 KJAX 301212
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
812 AM EDT Sat Aug 30 2025

...New UPDATE...

.UPDATE...
Issued at 806 AM EDT Sat Aug 30 2025

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

Not much change in the ongoing forecast as plenty of deep moisture
available for shower activity with embedded storms with heavy
rainfall, although most of the strongest activity lies closer to
the old frontal boundary across SE GA and the Atlantic Coastal
waters. Main trigger for more heavy storm activity today will be
the amount of insolation that happens and for now it appears as
though cloud cover will remain intact across most of SE GA with
highs only reaching the lower 80s, while some breaks and also
thinning in the clouds are expected across NE FL with highs
reaching into the middle to upper 80s and a few strong storms with
gusty winds and heavy rainfall possible, with greater chances near
any sea breeze or outflow boundaries if enough heating occurs.

&&

.SYNOPSIS...
Issued at 500 AM EDT Sat Aug 30 2025

Early morning surface analysis depicts a wavy stationary frontal
boundary stalled along the Interstate 10 corridor. Meanwhile, a
strong cold front was pushing into the southeastern states, with
high pressure (1022 millibars) building over the Great Lakes
states. Aloft...deep troughing prevails across the eastern third
of the nation, with northwesterly flow prevailing above 750
millibars (around 8,500 feet) per last evening`s sounding at
Jacksonville. Shortwave energy embedded within this northwesterly
flow is currently moving offshore of coastal southeast GA, with
another shortwave located upstream of our region across central
portions of MS and AL. Latest GOES-East derived Total Precipitable
Water imagery indicates that deep tropical moisture prevails
across our area, with PWAT values around or above 2 inches.
Convection associated with the passing shortwave trough pushed
offshore during the predawn hours, with lingering showers located
across southeast GA. Multi-layered cloudiness otherwise prevails
across our region, with temperatures at 09Z in the 70s area-wide.
Dewpoints were in the low to mid 70s for locations in northeast
and north central FL, with upper 60s prevailing for locations to
the north of the stalled frontal boundary across inland portions
of southeast GA.

&&

.NEAR TERM...
(Today and Tonight)
Issued at 500 AM EDT Sat Aug 30 2025

Troughing will continue to dig over the eastern third of the
nation today, with northwesterly flow aloft sending another
shortwave trough currently traversing central portions of AL and
MS southeastward across our region this afternoon and evening. Our
region will be positioned between these two shortwaves this
morning, but abundant moisture and the presence of the stationary
boundary will likely only allow for a few breaks in the multi-
layered cloud cover to develop as the morning progresses. This
cloud cover could limit instability somewhat as the upstream
shortwave trough arrives later today. This feature will generate
isentropic lift (overrunning) for locations north of the stalled
frontal boundary, which should develop scattered to numerous
showers and a few embedded thunderstorms during the early to mid
afternoon hours across inland portions of southeast GA and
western portions of the Suwannee Valley. Activity will progress
east- southeastward, with a warmer and humid air mass south of the
I-10 corridor likely helping to enhance convective coverage later
this afternoon through early this evening. Depending on the amount
of instability that develops, west-northwesterly bulk shear values
of 20-30 knots and mesoscale boundary collisions could promote a
few storms pulsing to strong levels later this afternoon and early
this evening, with locations south of the the I-10 corridor and
along the I-95 corridor being favored for both stronger storms and
potentially back-building or "training" downpours. Stronger storms
later this afternoon will be capable of producing briefly strong
wind gusts of 35-45 mph, frequent lightning strikes, and
localized flooding due to slow moving, torrential downpours.

Plenty of cloud cover should keep highs in the lower 80s for most
of southeast GA, with mid to upper 80s forecast for northeast and
north central FL. A few locations in north central FL may once
again touch 90 degrees.

Convection pushing east-southeastward across coastal southeast GA
and northeast FL late this afternoon should move across north
central FL this evening, departing our region by midnight. A drier
air mass will begin to filter into southeast GA after midnight,
with breaks in the multi-layered cloud cover during the predawn
hours likely allowing lows to fall to the upper 60s across all of
inland southeast GA and northern portions of the Suwannee Valley.
Meanwhile, shortwave troughing will move offshore later this
evening, with strengthening surface high pressure currently over
the Great Lakes states expected to wedge down the southeastern
seaboard after midnight. A surge of northeasterly winds may arrive
for coastal southeast GA during the predawn hours, with
strengthening low level convergence possibly developing bands of
heavy downpours that could move onshore towards sunrise. Cloudy
skies will keep lows elsewhere in the lower 70s inland and the mid
70s at coastal locations.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 500 AM EDT Sat Aug 30 2025

Sunday, a strong shortwave will dive southeastward behind an exiting
trough near Nova Scotia. The movement of the former feature will
create northwesterly flow aloft over our area and serve to push
the stationary cold front from NE FL into north central FL. Chances
for showers and T`storms will be highest along the front where
higher PWAT (Precipitable Water) values 1.8-2.2 inches will support
numerous to widespread showers and T`storms. Slightly drier air
will sink southward behind the front to 1.5-1.8 inches between
Waycross and Gainesville with scattered to numerous showers and a
few T`storms with scattered showers north and west of Waycross as
PWATs fall below 1.5 inches. Some isolated stronger T`storms may
develop over north central FL near the front where higher moisture,
greater lift along the front and seabreezes moving inland, higher
instability under cooler mid level temperatures near -8 Celsius
combine to support more robust updrafts. The presence of shear
around 25-30 knots may also support a few more briefly potent
T`storms which may produce wind gusts of 40-55 mph and small hail.

As the front sinks southward, northeasterly winds will increase to
10-15 mph along the coast with gusts to 25 mph and around 10 mph
inland as a weak low developing along the southward moving front
moves out into the Atlantic early in the day. Atlantic stratocumulus
clouds will press in from the waters under increasing high level
clouds as a jet streak moves in from the TN valley and deep south
states creating partly to mostly cloudy skies. The cloud cover will
keep high temperatures below average with low 80s over SE GA, mid 80s
over NE FL and upper 80s over north central FL for the final day of
August.

Sunday night, the onshore northeasterly flow between high pressure
wedging down the east coast from the northeast will create weak
inverted troughing that will produce coastal convergent showers and
a few embedded T`storms occasionally moving onto the coast. Winds
on the coast will remain around 10-15 mph due to the pinched local
gradient and provide warmer overnight lows in the mid 70s at the
coast while cooling with north and west extend to the around 70 for
inland NE FL and the upper 60s for inland SE GA.

Monday, a closed shortwave trough will form over the Mid Atlantic
states with subsident sinking air over the lee side of appalachians
wedging southward into the region. This will press the surface cold
front south into central FL, but weak coastal troughing will push
onshore during the day bringing scattered to numerous showers and
a few embedded T`storms onto coastal NE FL and the St Johns river
basin/north central FL due to moist low levels/coastal convergence
with decreasing chances north and west due to drier air. Northeast
winds will be breezy at the coast 15-20 mph with gusts to 30 mph
and 10-15 mph inland between the high to the north and inverted
troughing moving onshore. Low level stratocumulus clouds will
undercut high level clouds supported by high level jet stream winds
over the Gulf coast into northern FL. Highs will be below average
again due to mostly cloudy skies and strong onshore flow in the
low to mid 80s.

Monday night, coastal showers will persist and move onshore at times
overnight, but diminish with inland extent. Lows will range from
mid 70s at the coast to the upper 60s over inland SE GA and the
Suwannee river Valley.

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 500 AM EDT Sat Aug 30 2025

Tuesday, the closed mid level shortwave will open and lift into New
England as an upstream shortwave dives from the central plains into
the southern MS valley. As flow aloft in the mid levels becoming zonal
between these features, a coastal front will develop in the onshore
flow as high pressure stays wedged over the Mid Atlantic. Moisture
will slowly increase as low level flow becomes more easterly and
scattered to numerous showers and embedded T`storms expected along
the coast into NE FL and north central FL with less coverage over
northwest zones.

Wednesday, potent shortwave trough over Manitoba will descend into
the northern plains as weaker shortwave trough swings across the
deep south downstream of this feature. Mid level flow aloft will
become southwesterly as a wave of low pressure develops along the
front lifting northward from the NE Gulf into the FL panhandle.
Numerous showers and T`storms are expected as the low lifts quickly
ENE across the area with less coverage over NW portions of SE GA.

Thursday, the wave of low pressure will exit to the NE with a
frontal passage bringing westerly flow and drier air into the area
as deep troughing extends from the Great Lakes into the Gulf
coast. This will bring partly cloudy skies and only isolated to
scattered showers and afternoon T`storms. Friday, as deep
troughing carves into the eastern third of the nation, another
dry cold front will pass through the area with west to northwest
flow, limiting isolated to scattered shower and T`storm coverage
to NE FL with dry conditions over inland SE GA.

Temperatures will begin the period below normal with highs in the
mid 80s and then trend to near normal as high rebound to the low
90s on Friday with decreased cloud cover and shower coverage.

&&

.AVIATION...
(12Z TAFS)
Issued at 717 AM EDT Sat Aug 30 2025

Lingering frontal boundary in the region will continue high
rainfall chances and an abundance of at least lower MVFR CIGS at
times through the period. LIFR CIGS will impact GNV at times
through 13-14Z this morning before lifting, otherwise mostly VFR
CIGS with tempo MVFR CIGS in potential SHRA and/or TSRA activity
through the afternoon and evening hours before light low level
north to northeast flow and boundary cooling will help to lower
CIGS late in the TAF period with IFR CIGS development at most
locations in the 06-12Z time frame, with LIFR CIGS possible again
at GNV towards sunrise Sunday morning.

&&

.MARINE...
Issued at 500 AM EDT Sat Aug 30 2025

A stationary front will linger across the northeast FL waters
this weekend as strong high pressure over the Great Lakes begins
to wedge down the southeastern seaboard, sending a surge of
northeasterly winds and building seas across our local waters from
north to south on Sunday. Seas of 2 to 4 feet both near shore and
offshore through tonight will build to 3-5 feet on Sunday and then
to Caution levels of 4-6 feet from Sunday night through Tuesday.
Waves of showers and embedded thunderstorms will impact our
local waters this weekend, with stronger storms capable of
producing excessive lightning, strong winds, and waterspouts.
Northeasterly winds will increase to Caution levels of 15-20 knots
by Sunday afternoon both near shore and offshore, with onshore
winds likely peaking near Small Craft Advisory levels on Monday
before gradually weakening by midweek. Widespread showers and
embedded thunderstorms will continue through midweek, with less
coverage expected ahead of an approaching cold front later in the
week. Prevailing winds will shift to offshore ahead of this
approaching cold front, allowing seas to gradually subside.

Rip Currents: Onshore winds this morning will combine with a east
northeasterly ocean swell to bring a lower end moderate rip
current risk to area beaches today. Strengthening northeasterly
winds and building surf heights on Sunday afternoon will create a
high risk at all area beaches, with these conditions likely
prevailing through midweek.

&&

.HYDROLOGY...
Issued at 500 AM EDT Sat Aug 30 2025

Locally heavy downpours will be possible this afternoon and
evening, with flooding possible at urban and low-lying areas where
downpours move slowly and persist, mainly across coastal southeast
GA, north central and coastal northeast FL. The Weather Prediction
Center has outlooked our entire area within a "Marginal" Risk
(Level 1 of 4) for Excessive Rainfall through this evening.
Downpours will likely shift to coastal southeast GA, northeast and
north central FL on Sunday, where Marginal Risks for Excessive
Rainfall will continue, with the threat for localized flooding
then shifting to the I-95 corridor and north central FL during the
early to middle portions of next week. As ground conditions
continue to become more saturated, Flood Watches could be issued
later this weekend and early during the upcoming week, especially
along the I-95 corridor, where additional rainfall amounts of 2-4
inches are expected, with locally higher amounts possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  80  67  83  66 /  90  30  40  10
SSI  82  74  83  73 /  80  50  70  40
JAX  85  72  85  71 /  90  50  80  40
SGJ  86  73  86  74 /  80  60  80  50
GNV  88  71  88  70 /  70  50  70  20
OCF  88  71  87  72 /  70  40  80  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

$$