423
FXUS62 KJAX 211832
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
232 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 through Saturday

- Seasonably Hot Conditions Continue, with Peak Heat Indices
  102-108 through Saturday.

- Moderate Rip Current Risk through Wednesday, lower risk on
  Thursday.

- Small Craft Advisories through Tonight Across our Local
  Atlantic Waters.

&&

.NEAR TERM /THROUGH TONIGHT/...

- Seasonably Hot Summer Conditions.

- Isolated strong storms capable of strong outflow wind gusts
  this afternoon.

GOES derived total precipitable water shows a range of PWATs
across the area, our western counties (closer to TS Bertha in
the Gulf) have PWATs near 2.0" whereas closer to the Atlantic
coast, PWATs are below average near 1.5". Higher storm coverage
through the early afternoon is expected closer to the Suwannee
Valley area and interior southeast GA, with potential for a
secondary location closer to I-95 where sea breezes merge.
However, with the drier air in place, confidence is low in
having more than widely scattered storms later this afternoon
into the evening near the east coast. If any strong
thunderstorms are able to develop, the main concern will be
gusty winds as DCAPE values are currently around 800-1,000 J/kg,
and expected to further increase this afternoon. May see some
lingering showers and isolated storms past sunset, however
convection will begin decreasing overall after the sun goes
down. Southerly winds and mostly clear skies expected overnight,
with mild lows in the mid to upper 70s.

&&

.SHORT TERM /WEDNESDAY 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 /18Z TUESDAY THROUGH 18Z WEDNESDAY/...

PROB30s are in place for most of the TAF sites this late
afternoon into the evening, as thunder chances are a little
lower than normal, GNV has the best chance for storms over the
next few hours. Gusty winds will continue through around sunset,
and convection will begin to simmer down after sunset as well.
VFR conditions are then expected overnight after the potential
storm impacts.

&&

.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.

&&

$$