436
FXUS62 KJAX 290821
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
421 AM EDT Fri Aug 29 2025

...STRONG TO ISOLATED SEVERE STORMS POSSIBLE SOUTH OF I-10 LATE
THIS AFTERNOON AND EVENING...
...WAVES OF HEAVY DOWNPOURS AND EMBEDDED STORMS THIS WEEKEND AND
EARLY NEXT WEEK...
...BECOMING BREEZY AT COASTAL LOCATIONS ON SUNDAY AND LABOR DAY
WITH A HIGH RISK OF RIP CURRENTS AT AREA 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 421 AM EDT Fri Aug 29 2025

Overnight surface analysis depicts a wavy stationary frontal
boundary draped from west to east along the Interstate 10
corridor. Meanwhile, a stronger cold front was diving south-
southeastward across the eastern Great Lakes and the Ohio Valley,
with high pressure (1025 millibars) building over Lake Superior in
the wake of this frontal passage. Aloft...deep troughing continues
to dig over the eastern third of the nation, while ridging
prevails over west Texas and New Mexico. Latest GOES-East derived
Total Precipitable Water imagery indicates that deep moisture,
with PWATs around 2 inches, prevails for locations along and north
of I-10, while a slightly drier air mass was located across north
central FL, where PWATs were around 1.75 inches. Shortwave energy
at the base of the eastern U.S. trough continues to migrate across
the Deep South, with a few light showers or sprinkles falling
beneath thick mid and high altitude cloud cover for locations
north of I-10. A few locations in St. Johns and Flagler Counties,
located along the stalled frontal boundary, received heavy
downpours overnight, with this activity since weakening as it
pushed offshore into the adjacent Atlantic waters. Fair skies
otherwise prevail for locations south of the I-10 corridor.
Temperatures at 08Z were mostly in the low to mid 70s inland and
around 80 at coastal locations. Dewpoints remain in the 60s for
locations north of the stalled front across southeast GA, while
values elsewhere were mostly in the low to mid 70s.

&&

.NEAR TERM...
(Today and Tonight)
Issued at 421 AM EDT Fri Aug 29 2025

Shortwave energy at the base of a longwave trough over the eastern
third of the nation will migrate across the Deep South today and
tonight. This troughing will spin up a mid-level vorticity center
across central Alabama this afternoon, with this feature likely
buckling the stationary frontal boundary currently in place along
I-10 slightly northward tonight and Saturday. Thick mid and high
altitude cloudiness will tend to overspread locations along and
north of I-10 this morning, and this will set up an instability
gradient this afternoon along the stalled frontal boundary over
northeast FL, with warmer temperatures and higher dewpoints
continuing across north central FL, where highs will climb to the
upper 80s to around 90. Cloud cover and increasing chances for
afternoon and evening thunderstorms elsewhere will keep highs in
the mid to upper 80s, which is slightly below late August
climatology.

Troughing digging into our area will provide gradually cooling
temperatures aloft, and the development of a mid-level vorticity
center will increase bulk westerly shear to the 25-35 knot range
this afternoon, which could result in a few strong or even
isolated severe thunderstorms for locations along and south of
I-10. Brisk and increasingly diffluent northwesterly flow aloft
should promote pulsing storm clusters this afternoon and evening
across northeast and north central FL, with storm intensity likely
muted for southeast GA, which will mostly remain north of the
instability gradient and wavy stationary boundary today. Scattered
showers will occasionally move across southeast GA through this
evening, with likely POPs used for northeast and north central FL
this afternoon. Pulsing storms will be capable of producing
downburst winds of 40-60 mph, along with frequent lightning
strikes and possibly some small hail. Slower moving downpours for
locations south of the I-10 corridor later this afternoon and
evening may create localized flooding (see "Hydrology" section
below for details).

Convection and shower activity may linger across our region
through around midnight, with multi-layered cloud cover lingering
overnight through the early morning hours on Saturday as the wavy
frontal boundary remains stuck along the I-10 corridor. Lows will
likely fall to the upper 60s to around 70 for inland southeast GA,
ranging to the low and mid 70s elsewhere.

&&

.SHORT TERM...
(Saturday through Sunday night)
Issued at 421 AM EDT Fri Aug 29 2025

Numerous to widespread showers and storms, with a potential for
heavy rainfall capable of producing localized flooding, will build
across the forecast area on Saturday as an upper level short wave
crosses through the region ahead of the receding frontal boundary.
Drier air will be drawn in over southeast Georgia on Sunday as low
pressure to the south of the Florida peninsula treks westward,
making for less widespread convection over Georgia for the latter
part of the weekend with more widespread convection with a
potential for locally heavy rainfall is still expected for
northeast Florida. High temperatures for the weekend will range
within the 80s with overnight low temperatures dropping into the
upper 60s over inland southeast Georgia and in the lower 70s over
northeast Florida and in the mid 70s along the coastline.

&&

.LONG TERM...
(Monday through Wednesday)
Issued at 421 AM EDT Fri Aug 29 2025

Predominantly wet pattern is expected through the long term period
with daily bouts of showers and storms building across the
forecast area. The placement and intensity of convection during
this period will depend on the position of the stalled frontal
boundary and the timing of of any upper level instability passing
over the southeastern US, ahead of the front. Daily max
temperatures will be slightly below the seasonal average for the
beginning of next week and then rise to be near seasonal by
midweek.

&&

.AVIATION...
(06Z TAFS)
Issued at 222 AM EDT Fri Aug 29 2025

Periods of IFR conditions and brief wind gusts up to 25 knots are
expected at SGJ through around 07Z as heavy showers pass over the
terminal. This shower activity may attempt to develop northward
towards CRG during the predawn hours, but confidence was too low
to indicate anything other than vicinity coverage at this time.
Otherwise, periods of MVFR ceilings of 2,500 - 3,000 feet will be
possible through the morning hours at the northeast FL terminals.
Showers and thunderstorms will redevelop after 15Z near the
northeast FL terminals. Activity should increase in coverage and
intensity for locations along and south of the Interstate 10
corridor after 18Z, and confidence was high enough to include a
TEMPO group for brief wind gusts around 30 knots and IFR
conditions during heavier downpours at GNV after 21Z through the
early evening hours. PROB30 groups for these conditions were used
at the Duval County terminals and SGJ during the late afternoon
and early evening hours on Friday. VFR conditions are otherwise
expected to prevail at SSI, with confidence only high enough to
indicate vicinity showers after 09Z. MVFR ceilings and vicinity
showers will likely persist at the northeast FL terminals after
Friday evening`s thunderstorm activity dissipates.

&&

.MARINE...
Issued at 421 AM EDT Fri Aug 29 2025

A nearly stationary frontal boundary will remain situated over the
northeast Florida waters through the weekend as high pressure builds
southeastward from the Great Lakes towards the Mid-Atlantic states
and New England. Showers and a few embedded thunderstorms may
increase in coverage overnight through the early morning hours on
Friday from south to north across our local waters. Another round
of potentially strong thunderstorms may impact the northeast
Florida waters on Friday afternoon and evening, with stronger
storms capable of producing strong wind gusts, waterspouts, and
frequent lightning strikes. Seas of 2 to 4 feet will prevail both
near shore and offshore through Saturday night.

Waves of showers and thunderstorms will likely impact our local
waters this weekend through the middle portion of next week as the
frontal boundary remains stuck over our area. Outside of
thunderstorm activity, breezy onshore winds are expected to
develop from Sunday afternoon through at least Tuesday as high
pressure wedges down the southeastern seaboard. Speeds will reach
Caution levels of 15-20 knots offshore on Sunday, with Caution
conditions then expanding into the near shore waters by Sunday
evening. Seas of 3-5 feet both near shore and offshore on Sunday
will build to 4-6 feet offshore early next week.

Rip Currents: Onshore winds will become breezy at area beaches
this afternoon, with choppy surf conditions promoting a moderate
rip current risk that will continue into Saturday. A surge of
northeasterly winds and building surf on Sunday will raise the
threat to high at all area beaches, with this high risk expected
to continue through at least Tuesday as onshore winds and rough
surf conditions persist.

&&

.HYDROLOGY...
Issued at 421 AM EDT Fri Aug 29 2025

Locally heavy downpours will be possible this afternoon and
evening, especially for locations along and south of the
Interstate 10 corridor. The Weather Prediction Center has
outlooked most of our area within a "Marginal" Risk (Level 1 of 4)
for Excessive Rainfall later today. Downpours will likely become
more widespread on Saturday afternoon and evening, with waves of
downpours likely continuing through Sunday area-wide. Marginal
Risks for Excessive Rainfall continue this weekend, with the
threat for localized flooding then shifting to northeast 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 during the weekend and early next week, especially
for northeast and north central FL, where total rainfall amounts
of 2-5 inches are expected, with locally higher amounts possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  86  69  81  67 /  40  40  70  30
SSI  85  75  82  74 /  40  40  70  50
JAX  86  73  84  71 /  60  40  80  50
SGJ  85  75  85  74 /  70  50  90  50
GNV  87  72  87  72 /  70  40  80  30
OCF  89  72  87  72 /  60  20  80  30

&&

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

$$