091
FXUS62 KJAX 220011
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
811 PM EDT Tue Jul 21 2026

.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

- Scattered Showers & Thunderstorms through Early this Evening.
Isolated Strong Thunderstorms Possible, Mainly for Locations West of
U.S.-301. Hazards: Gusty Winds 40-50 mph and Localized Flooding.
Limited Storm Coverage Wednesday to Friday

- Seasonably Hot Conditions Continue  Peak Heat Indices 102-108

- Moderate Rip Current Risk through Wednesday, lower risk Thursday

- Small Craft Advisories through Tonight Across our Local Atlantic
Waters

&&

.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
The region will be between high pressure to the east, and tropical
storm Bertha to the west Tonight. Convection will continue to
dissipate this evening, with a dry overnight. Lows Tonight in the
middle 70s will be common.

&&

.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Main Highlights This Period:

- Unseasonably Dry Weather Expected on Wednesday.

- Isolated to Widely Scattered Thunderstorms return Thursday
Afternoon and Evening at Inland Locations.

- Seasonably Hot and Humid Weather Continues, with Breezy Conditions
Persisting on Wednesday.

Stout ridging aloft centered over the Southern Plains will continue
to extend its axis east-southeastward into the southeastern states
through Thursday night. Meanwhile, a potent shortwave trough
pivoting across the eastern Great Lakes and southeastern Canada will
drive a frontal boundary southward across the Tennessee Valley and
the southern Appalachians, with this boundary then stalling to the
north of our area by Thursday evening. Ridging aloft will continue
to direct Tropical Storm Bertha westward towards coastal Louisiana,
with a drier and more subsident air mass overspreading most of our
area from east to west on Wednesday. A late day surge of slightly
deeper moisture over the FL peninsula moving northward could develop
a few thunderstorms across north central FL on Wednesday evening,
but an unseasonably dry afternoon and evening is otherwise forecast
for the rest of our area. Highs will soar to the mid and upper 90s
at inland locations and the low to mid 90s at coastal areas, with
the drier and more subsident air mass allowing dewpoints to mix down
to the upper 60s at most inland locations, keeping peak Heat Index
values just below Heat Advisory criteria. Breezy onshore winds
developing in the wake of the inland moving Atlantic sea breeze
could push Heat Index values closer to the 108 degree Heat Advisory
threshold at coastal locations as dewpoints rise to the mid and
upper 70s late on Wednesday afternoon.

Any isolated convection that develops over north central FL on
Wednesday afternoon or evening should dissipate before midnight,
with fair skies and gradually diminishing south or southwesterly
winds keeping inland lows in the mid 70s, with upper 70s to around
80 forecast at coastal locations.

Model soundings still indicate that PWATs will remain slightly below
late July climatology across most of our area on Thursday. There
should be just enough moisture for isolated to widely scattered
mainly late afternoon and evening convection to develop for
locations along and west of U.S. Highway 301 as mesoscale boundaries
moving well inland collide. The overall subsident air mass should
keep thunderstorms that manage to develop rather tame and likely
short lived, with dry conditions expected to continue at coastal
locations. Highs on Thursday will generally climb to the mid and
upper 90s inland, while an earlier developing sea breeze keeps
coastal highs mostly in the lower 90s. Dewpoints will again likely
mix down to the upper 60s and lower 70s inland, keeping heat index
values just below Heat Advisory criteria, with coastal locations
more likely to approach this criteria as dewpoints rise to the mid
and upper 70s.

Convection should again conclude before midnight on Thursday night,
with lows at inland locations mostly falling to the mid 70s, with
coastal locations again forecast to remain in the upper 70s to
around 80.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Main Highlights This Period:

- Scattered to Numerous Afternoon Thunderstorms, Especially Friday
into the Weekend.

- Increasing Chances for Afternoon and Evening Thunderstorms Late
this Weekend and Early Next Week.

- Potential Heat Advisory Conditions this Weekend and Early Next
Week.

Stout ridging aloft centered over the Southern Plains states will
retrograde to the Four Corners region of the Desert Southwest from
Friday through the weekend. This will allow troughing to dig into
the southeastern states by late in the weekend and early next week.
An extension of the ridge centered well to the west of our area will
remain in place across the Deep South on Friday and Saturday, likely
keeping a more subsident air mass in place locally, especially on
Friday. Model blends currently indicate only isolated afternoon
convective potential across inland portions of southeast GA on
Friday, with isolated to widely scattered afternoon and evening
thunderstorms returning on Saturday. Highs on Friday and Saturday
will again soar to the mid and upper 90s inland and the low to mid
90s at coastal locations. The more subsident air mass should again
allow dewpoints to mix down to the upper 60s and lower 70s at inland
locations on Friday at inland locations, keeping peak heat indices
mostly in the 100-108 degree range. Heat index values could reach
Advisory levels across portions of northeast and north central FL on
Saturday afternoon. Lows will only fall to the mid and upper 70s at
most locations.

Moisture will deepen from north to south from Sunday through the
early portion of next week as troughing digs into our area. This
should activate scattered to possibly numerous afternoon and evening
thunderstorms, mainly along mesoscale boundaries as west to
southwesterly low level flow deepens downstream of a stalled frontal
boundary. A few stronger storms will be possible on Sunday and
Monday afternoons along the I-95 corridor as convection potentially
interacts with a pinned Atlantic sea breeze boundary. Highs on
Sunday may remain in the low to mid 90s, with increasing humidity
values likely bringing heat index values close to Heat Advisory
criteria. Ridging aloft will then begin to expand into the
southeastern states early next week, potentially raising highs to
the mid to upper 90s, especially for inland locations north of the I-
10 corridor. Lows will generally remain in the mid and upper 70s
across our region this weekend and early next week.

&&

.AVIATION /00Z WEDNESDAY THROUGH 00Z THURSDAY/...
Remaining convection will dissipate early this period. Prevailing
VFR conditions forecast for the overnight, and through the day
Tuesday. While chances for convection are not zero Tuesday, the
chances are much lower than average.

&&

.MARINE...


Breezy southerly winds between the Tropical Storm Bertha and the
Bermuda high will lead a couple more days of breezy conditions.
Winds will increase to Small Craft Advisory levels this afternoon
and remain elevated through early Wednesday. Seas will rise toward 5
or possibly 6 feet today in response to the winds. Relaxing winds
are expected Wednesday night as flow generally trends offshore as a
weak cold front approaches from the northwest. The front is likely
to stalls north of the waters this weekend as waves of low pressure
track along it. Though offshore flow will be in place from Thursday
onward, afternoon winds in nearshore waters will be driven by the
coastal sea breeze development each afternoon.

Rip Currents:

Increasing southerly winds along with sea breeze development will
push elevated wind waves into the coastline this afternoon along
with strong longshore. Given a minimal onshore swell, the rip
current risk will be on the upper-end of Moderate this afternoon but
not quite High Risk. Moderate risk is likely again Wednesday before
falling Thursday.

&&

.FIRE WEATHER...
- High Daytime Dispersion Values Inland Through Wednesday

Scattered thunderstorms will be possible through early this
evening, mainly for locations west of the U.S. Highway 301 corridor
in southeast GA, the Suwannee Valley, and north central FL. Only
isolated to widely scattered afternoon and early evening
thunderstorms are forecast from Wednesday through Saturday.
Otherwise, breezy southerly transport winds will continue through
Wednesday, creating high daytime dispersion values at inland
locations. Surface winds will become southeasterly during the
afternoon hours at coastal locations, where fair to good daytime
dispersion values are forecast. Transport winds will then gradually
weaken on Thursday and Friday, with south-southwesterly winds
prevailing on Thursday and then a light westerly wind pattern
developing by Friday. Elevated mixing heights will
generally yield good daytime dispersion values inland, with fair
values forecast at coastal locations, where breezy onshore surface
winds will develop early on Thursday and Friday afternoon.

Fog Potential and Other Remarks: Significant fog development is not
expected during the next several nights.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  75  95  74  95 /  10   0   0  10
SSI  80  93  80  93 /  20   0   0   0
JAX  77  96  76  96 /  20   0  10  10
SGJ  76  95  76  93 /  20   0   0   0
GNV  74  95  74  95 /   0   0   0  20
OCF  74  95  74  95 /   0  10  10  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
MARINE...Small Craft Advisory until 5 AM EDT Wednesday for AMZ450-452-
     454-470-472-474.

&&

$$