752
FXUS62 KJAX 170655
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
255 AM EDT Sun Aug 17 2025

...New NEAR TERM, SHORT TERM, LONG TERM, MARINE, HYDROLOGY...

.NEAR TERM...
Issued at 150 AM EDT Sun Aug 17 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

Continued high rain chances today with a lingering trough axis
across the local area, which extends southward from a surface low
offshore of the mid-Atlantic coast. Early this morning, low
stratus and fog was forming near and north of the front across
southeast GA and portions of north Florida, with spotty showers
and isolated storms popping across the adjacent Atlantic waters
near convergent boundaries.

Through the day, this trough axis will shift southward across
north Florida as high pressure builds north of the region. Aloft,
a weak mid level trough will continue overhead, with the stronger
lift focused across coastal southeast GA and northeast Fl into the
afternoon. The combination of the front, upper level lift,
diurnal instability, sea breezes, high moisture (PWAT > 2.2
inches) and weak steering flow (< 10 kts) will continue to fuel
widespread to numerous showers and storms today. Convection will
expand inland from the Atlantic coast mid to late morning and
progress inland toward the I-75 corridor into the afternoon and
early evening. Slightly drier air and subsidence on the back side
of the mid level trough will bring lower rain chances today to
locations from Pearson to Jesup northward. Convection will tapper
off in coverage and intensity after sunset through midnight as
onshore flow continues and brings a chance of mainly coastal
showers overnight.

Temperatures will trend cooler compared to yesterday due to
lingering cloud cover and early onset of convection, with max
values in the lower 90s west of Highway 301 with mid to upper 80s
toward the SE GA coast and portions of northeast Florida. Peak
heat index values will near 100-105 degF, below local heat
advisory criteria. Tonight, lows will range in the 70s inland to
near 80 at the coast as onshore flow develops trailing the frontal
zone.

&&

.SHORT TERM...
(Monday through Tuesday night)
Issued at 150 AM EDT Sun Aug 17 2025

Diffuse frontal boundary will sink slightly further southward on
Monday as a weak ridge of high pressure builds down the
southeastern seaboard and into the area. Very high moisture
content will be in place across the majority of the area through
at least Monday afternoon, however guidance is in good agreement
that uptick in northeasterly flow thanks to the pressure gradient
between ridging in place and Hurricane Erin passing well to the
east will also start to advect some drier air in aloft from
northeast to southwest Monday evening and Night, settling overhead
on Tuesday. The result of this setup will be a fairly sharp
gradient in expected convection/rain chances on Monday, with the
highest POPs being mainly south of I-10 in Florida in the 50-70%
range, and the lowest being from about Waycross northward in the
10-30% range. These chances drop even further on Tuesday, mostly
in the 20-40% range for most of the area with once again the
higher end of the range being areas furthest south and east.

Temperatures will be near normal on Monday, with mostly low 90s
except upper 80s near the coast and St. Johns River. The highest
readings will likely be over interior southeast GA where lower
precip chances and cloud cover will be. After mainly low to mid
70s Monday Night, highs temps will be slightly warmer on Tuesday
with less rain/cloud cover overall as low to mid 90s will be
common area-wide. Similarly, low temps will be just a touch higher
Tuesday Night though still mainly in the low to mid 70s.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 150 AM EDT Sun Aug 17 2025

Hurricane Erin will continue to turn north and northeastward away
from the region Wednesday and Thursday, shifting the flow from
onshore/northeasterly towards the south to southwest for the end
of the week and the start of next weekend. Enough dry air looks to
remain in place Wednesday to taper rain chances once again,
however more moist south to southwest flow and an approaching
frontal boundary late in the week is expected to return higher
chances/coverage of showers and t`storms accordingly from Thursday
onward. This front is likely to stall just north of the region,
maintaining a setup featuring plentiful moisture advection south
of the boundary and numerous convection heading into next weekend.
Temperatures overall trend slightly above normal for most or all
of the long term period.

&&

.AVIATION...
(06Z TAFS)
Issued at 136 AM EDT Sun Aug 17 2025

Wavy, lingering front across the local forecast area combined
with saturated ground and light winds was brining periodic LIFR to
MVFR stratus and mist restrictions to terminals this morning.
Expect these up- and-down conditions to persist through 12-13z.
Light NNE to NE winds will develop at coastal terminals through
daybreak, speeds generally 6 kt or less. After daybreak, coastal
showers and isolated storms will approaching SSI, CRG and SGJ as
easterly winds develop. Showers and storms expand inland toward
JAX, VQQ and GNV into the afternoon and early evening with
decreasing rain chances at coastal terminals, although showers
will still be possible as onshore flow continues overnight.

&&

.MARINE...
Issued at 150 AM EDT Sun Aug 17 2025

A weak surface trough will linger across the local waters today with
rounds of showers and thunderstorms. High pressure strengthens
northeast of the region Monday as Hurricane Erin tracks northward,
east of the Bahamas. Easterly swells from Erin increase within the
local waters Monday, with Small Craft Advisory conditions expected
by Monday night. Small Craft conditions continue through Thursday as
Erin tracks well offshore of the southeast U.S. Atlantic coast,
generating hundreds of miles of large ocean waves.

Rip Currents: Moderate risk today with high risk expected for all
local beaches with waves generally 2 ft and periods increasing to
9-11 seconds. Rip current risk and surf heights increase Monday
as long period swells increase within the local waters form
distant Hurricane Erin. A high rip current risk is expected Monday
through Thursday for all local beaches. High surf conditions
(breaker heights > 7 ft) are forecast Tuesday and Wednesday for
local beaches, and potentially Thursday for northeast Florida
beaches.

&&

.HYDROLOGY...
Issued at 150 AM EDT Sun Aug 17 2025

River flooding...A river flood warning continues for minor
flooding for the Altamaha River at Baxley. A crest is expected
shortly, with a forecast fall below flood stage late today or
tonight.

Coastal flooding...Pounding surf and elevated astronomical tides
will likely create at least moderate beach erosion at the
northeast FL beaches towards midweek, especially during the late
afternoon and early evening high tide cycles Wednesday and
Thursday. At this time, latest PETSS and ETSS guidance indicate
inundation up to Minor flood stage possible around high tides at
the coast and within the St. Johns River basin with most locations
reaching Action Stage. Will continue to monitor tidal flood risk over
the coming days.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  90  72  92  71 /  60  30  20   0
SSI  87  77  88  77 /  60  20  20  10
JAX  89  76  91  75 /  80  30  50  10
SGJ  88  76  88  77 /  70  40  60  10
GNV  91  74  91  74 /  80  50  70  10
OCF  90  74  90  74 /  90  50  70  10

&&

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

$$