687
FXUS62 KJAX 040554
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
154 AM EDT Sat Oct 4 2025

...New AVIATION...

.KEY MESSAGES...

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

- Moderate to Minor Tidal Flooding through Weekend. Coastal Flood
  Warning: Moderate Tidal Flood impacts within the St. Johns River
  Basin, Coastal Northeast FL & Intracoastal Waterway. Coastal
  Flood Advisory: Minor Tidal Flood impacts Coastal Southeast GA &
  Nassau County

- Dangerous Beach & Marine Conditions through Early Next Week.
  High Rip Current Risk, High Surf & Small Craft Advisory.

- Locally Heavy Rain & Flood Risk through Early Next Week. Waves
  of Heavy Downpours, Isolated Coastal Thunderstorms. Localized
  Flood Risk at Coastal & Normally Flood Prone, Low-lying
  Locations

&&

.AVIATION...
(06Z TAFS)
Issued at 154 AM EDT Sat Oct 4 2025

Moderate to heavy showers will continue progressing westward from
the Atlantic waters overnight, impacting SSI and the Duval County
terminals through around 09Z. Brief periods of IFR visibilities
will be possible during heavier downpours overnight. Periods of
MVFR ceilings are expected overnight at the regional terminals,
except at GNV, where VFR conditions are expected to prevail
through at least 18Z Saturday. Shower activity will likely
increase near the SGJ terminal towards sunrise, with another wave
of showers expected to cross the terminals during the late morning
and afternoon hours. Confidence in timing and intensity was too
low for TEMPO groups, and we thus opted for PROB30 groups for IFR
conditions during heavier downpours on Saturday. Another round of
showers is likely during the overnight hours on Saturday night,
but a period of VFR conditions appears to be likely around sunset
and during the early evening hours. Breezy east-northeasterly
surface winds will remain sustained around 15 knots overnight
through the early morning hours at SGJ, followed by speeds
increasing to 15-20 knots and gusty towards 15Z. North or
northeasterly surface winds will remain sustained at 5-10 knots
elsewhere through around 14Z, followed by winds shifting to east-
northeasterly and increasing to around 15 knots and gusty by 17Z.
Speeds will diminish to around 10 knots at the inland terminals
towards 00Z Sunday.

&&

.NEAR TERM...(through Tonight)...

Local nor`easter conditions persist through tonight with enough low
level moisture and convergence on a stationary and inverted trough
hanging off the Atlantic shoreline. With the bulk of the moisture
below 700mb, drier air aloft will continue to limit thunder chances
through most of the area as the waves of quick moving showers shift
inland through the rest of the day and tonight.

Tight pressure gradients between the establish surface ridge in the
Mid Atlantic and the weak area of low pressure developing north of
Cuba will continue gusty winds along the coast which may
occasionally reach gusts near 40 mph through today.

Strong onshore winds will push ocean water into the coast and into
the St Johns River (and it`s tributaries) tonight resulting in
rising tidal levels. Coastal Flood Warnings and Advisories have been
kept as they were as confidence in Moderate tidal flood impacts are
likely tonight and through the weekend, especially as the Spring-
Perigee tides increase with the approaching Full Moon (on Monday).

Thanks to the cooling from onshore flow and cloud cover,
temperatures will stay in the low/mid 80s this afternoon. Cooling
will occur inland more so than near the coast as winds will decrease
tonight. Still, lows will only be in the mid/upper 60s whereas the
low 70s will be more common along the coast.

&&

.SHORT TERM...(Saturday through Sunday night)

Bouts of showers with embedded thunderstorms will continue through
the weekend with convection developing from east to west across
the forecast area, with conditions becoming more widespread on
Sunday along with gusty easterly winds with sustained speeds
rising to be about 15-25 mph and gusts of about 35 mph. There is a
potential this weekend for excessive rainfall capable of producing
local flooding conditions as PWAT values rise to be in excess of
2.2 inches as a moist unstable flow ahead of the boundary passes
over the region. High temperatures for the end of the week and
into the weekend will rise into the lower to mid 80s with
overnight low temperatures dropping down into the upper 60s and
lower 70s.

&&

.LONG TERM...(Monday through next Friday)

Showers with embedded storms and breezy winds will continue on
into the beginning of next week with area-wide convection becoming
less intense as the week progresses with drier extending in from
high pressure out to the northeast rotating into the region by
midweek. Winds will build on Thursday ahead of a cold front
pressing southward from out of the north. Temperatures will
experience a slight warming trend through the coming week with
daytime high temperatures rising to be near and slightly above the
seasonal average by midweek.

&&

.MARINE...
Issued at 746 PM EDT Fri Oct 3 2025

Small Craft Advisory conditions will continue for the local
Atlantic waters through midweek next week due to persistent
onshore flow and high combined seas between high pressure north of
the region and coastal troughs over the local waters. Waves of
gusty showers will continue to move onshore with a low risk of
thunderstorms.

For the evening updated...Updated the forecast with 18z WNAwave
data as the local NWPS data was running 2-4 ft above evening
observations. This did not impact Small Craft Advisory headline
criteria, but adjusted combined seas forecast into the observed
ranged this evening.

&&

.HYDROLOGY...
Issued at 746 PM EDT Fri Oct 3 2025

With persistent, strong onshore winds continuing to "trap" tides
within the St. Johns River basin combining with the approach of
Tuesday`s "Harvest" Full Moon, a more widespread moderate tidal
flooding event will continue near high tides through the weekend.

Coastal Flood Warning: This warning includes the St. Johns River
Basin, ICWW & NE FL coast from Mayport to Flagler Beach. Tidal
levels will continue to crest generally between 2 to 2.5 ft in the
St. Johns River basin and range between 2-3 feet in the ICWW and
along the coast. Moderate tidal flooding impacts include flooding
of low- lying roads and water surrounding some vulnerable
structures.

Coastal Flood Advisory: This advisory now includes the Nassau
County coast as well as coastal southeast GA. Tidal levels will
build to near 2 ft of inundation, which will mainly cause minor
tidal flooding impacts including flooding of some boat ramps,
docks, over-topping of bulkheads and some tidal-prone roads in
low- lying areas.

The tidal flooding will be an extended duration, as astronomical
tides will not peak until the mid to late part of next week. With
brisk onshore flow continuing through Monday and then potentially
re- strengthening late next week, we can expect Coastal Flood
Advisories / Watches / Warnings to continue through much of the
upcoming week, possibly longer for some locations.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  83  69  84  69 /  30  20  40  20
SSI  81  73  83  74 /  50  60  50  30
JAX  82  73  85  73 /  40  60  70  40
SGJ  82  75  84  74 /  60  60  70  50
GNV  84  72  87  72 /  40  40  60  30
OCF  84  72  85  73 /  30  30  50  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 5 AM EDT Tuesday for FLZ124.

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

     High Surf Advisory until 5 AM EDT Tuesday for FLZ124-125-138-233-
     333.

     Coastal Flood Warning until 5 AM EDT Tuesday for FLZ125-132-137-
     138-225-233-325-333-633.

GA...Coastal Flood Advisory until 5 AM EDT Tuesday for GAZ154-166.

     High Rip Current Risk through late Monday night for GAZ154-166.

AM...Small Craft Advisory until 5 AM EDT Tuesday for AMZ450-452-454-
     470-472-474.

&&

$$