721
FXUS62 KJAX 211128
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
728 AM EDT Thu Aug 21 2025

...New AVIATION...

.NEAR TERM...
Issued at 204 AM EDT Thu Aug 21 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

Warmer with higher rain chances today as a wake low level trough
trailing Hurricane Erin shifts southward across the local area and
deep layer moisture increases from the Gulf as WSW steering flow
develops. As surface winds back more westerly this morning,
convection across the Gulf will begin to edge inland across the
Suwannee River Valley of north FL through early afternoon.
Additional showers and storms will break out across inland areas
into the afternoon and evening as diurnal instability increases
under added mid/upper level lift with the approach of a mid level
trough from the NNW. The main convective hazards today will be
locally heavy rainfall due to relatively slow storm motion of < 10
kts and localized wet downbursts due to heavy precip loading and
cell mergers. Rainfall will tapper off across northeast FL early
this evening, while passing short wave trough energy keeps
southeast GA storms going a little longer after sunset.
Precipitation will tapper off in coverage and intensity through
midnight, with another resurrection of Gulf Coast convection
toward daybreak Friday under moist WSW steering flow.

Temperatures will continue to warm with above average highs today
in the low to mid 90s, even toward the Atlantic coast under
westerly winds before the east coast sea breeze develops. Peak
heat index values will increase into the the 100 to 105 degF given
high dew pts. Tonight, lows will range near average in the 70s.

&&

.SHORT TERM...
(Friday through Saturday night)
Issued at 204 AM EDT Thu Aug 21 2025

Cold front over central GA Friday morning gradually shifts
southward into NE FL by Saturday night bringing a return to a wet
and unsettled pattern. Southwest steering flow and deep tropical
airmass (PWATs 2-2.3 in) situated over the region will support
waves of numerous to widespread showers and storms capable of
producing heavy downpours. WPC has a Marginal risk of excessive
rainfall Friday and Saturday for locally heavy rainfall potential
that could produce localized minor flooding in urban and low lying
areas. Stronger storms will be mainly focused along the frontal
boundary, as well as the sea breeze and outflow interactions.
Highs will be in the low 90s area-wide on Friday and then range
from the upper 80s to around 90 on Saturday. Overnight lows will
be in the 70s.

&&

.LONG TERM...
(Sunday through Wednesday)
Issued at 204 AM EDT Thu Aug 21 2025

Frontal boundary over NE FL on Sunday weakens as it continues its
slow trek southward before dissipating over north-central FL on
Monday. Above normal moisture, lift from the front and the
Gulf/Atlantic sea breeze interactions will keep numerous to
widespread showers and storms on Sunday. Localized flooding
potential continues into Sunday. On Monday, a mid-upper trough
over the Great Lakes amplifies and digs southward pushing a dry
cold front into SE GA. Drier air begins to filter in from the
northwest Monday afternoon in the wake of front limiting the best
chances for showers and storms to NE FL. The cold front passes
through the area and into central FL on Tuesday. Isolated to
widely scattered showers and storms prevail through Wednesday with
the lingering drier air. Highs will generally be in the upper 80s
to low 90s. Drier airmass next week will keep heat indices around
or less than 100.

&&

.AVIATION...
(12Z TAFS)
Issued at 720 AM EDT Thu Aug 21 2025

No significant changes to the forecast at this morning`s update,
as higher chances for afternoon convection expected today as
compared to Wednesday. Confident enough to include TEMPO groups at
all airfields, which will likely be tweaked later this morning and
for the afternoon update accordingly for timing/impacts. Generally
expecting inland terminals to be affected earlier in the day,
migrating towards coastal airfields this afternoon. Lighter flow
from the west to southwest with Hurricane Erin pulling away from
the eastern seaboard will also allow a sea breeze influence
today, which will both shift wind direction for coastal terminals
late this morning and into the afternoon while also helping to
enhance convection as breezes collide. VFR expected to return
after 00Z as convection wanes.

&&

.MARINE & SURF ZONE...
Issued at 204 AM EDT Thu Aug 21 2025

Adjusted forecast wave heights down significantly by 4-6 ft when
compared with observations over the local waters early this
morning and used the WNAwave10 model guidance verse the NWPS run
which was still much too high compared to observations. This
adjustment supported dropping the Small Craft Advisory for the GA
near shore waters and supported us dropping the Small Craft for
the FL nearshore by 18z today. Based on trends, later shifts may
be able to end the Small Craft for the outer waters late tonight
or Friday verses Friday night. Prevailing westerly flow is
expected into the weekend as a surface trough approaches from the
north late tonight. The front lingers across the local waters
through the weekend bringing an increase in shower and
thunderstorm activity.

Rip Currents: High rip current risk for all local beaches through
Friday due to long period swells from Erin. High risk may need to
extended into Saturday for northeast Florida beaches.

Surf: High surf advisory remains in effect today for northeast FL
breaches due to breakers of 5-8 ft, potentially up near 9 ft
early this morning. Baselined the wave heights toward
observations early this morning lowered our breaker height
forecast for southeast GA beaches today into the 3-5 ft range,
below High Surf Advisory criterion. Dropped the High Surf Advisory for
GA beaches this morning. Even though the breaker height forecast
has been adjusted downward, rough, hazardous surf conditions will
continue at all local beaches today with frequent, life-
threatening rip currents. Breaker heights will continue to subside
tonight into Friday with breakers of 4-6 ft impacting the
northeast Florida beaches to 2 to 4 feet for southeast Georgia
beaches.

Coastal/Tidal Flooding: Action stage tidal flooding impacted the
St. Johns River basin overnight with high tide and expected only
Action stage for the coast this evening with the higher diurnal
tide, thus a coastal flood advisory is not expected.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  94  72  90  72 /  50  50  80  60
SSI  93  76  88  75 /  30  40  70  80
JAX  96  74  92  74 /  50  40  80  60
SGJ  94  75  91  75 /  60  50  80  60
GNV  94  74  92  74 /  60  40  80  50
OCF  93  75  91  74 /  70  20  80  50

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Friday evening for FLZ124-125-138-
     233-333.

     High Surf Advisory until 8 PM EDT this evening for FLZ124-125-
     138-233-333.

GA...High Rip Current Risk through Friday evening for GAZ154-166.

AM...Small Craft Advisory until 2 PM EDT this afternoon for AMZ452-
     454.

     Small Craft Advisory until 8 AM EDT Saturday for AMZ470-472-474.

&&

$$