133
FXUS62 KJAX 171725
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
125 PM EDT Mon Aug 17 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

- Dangerously HOT Weather Continues this Week. Heat
  Advisory/Extreme Heat Warning this Afternoon & Evening and
  Tuesday. Heat Advisories & Extreme Heat Warnings Possible Wednesday
  through Friday

- Scattered Thunderstorms Today, Isolated Strong Storms Possible.
Main Impact Area: Northeast & North Central FL. Strong Storm Hazards:
Wind Gusts of 35 - 45 mph, Frequent Lightning Strikes, Heavy
Downpours

- Scattered to Numerous Afternoon & Evening TStorms Tues  Sat. Strong
to Isolated Severe Storms are Possible Each Day, Mainly Along the
I-95

&&

.NEAR TERM /THROUGH TONIGHT/...
Main Highlights through Tonight:

- Heat Advisory Area-Wide Today, Extreme Heat Warning Coastal GA

- Isolated Strong Thunderstorms this afternoon and early evening,
Mainly Across Northeast FL

Hot and humid conditions continue with high pressure ridging aloft
and a very moist airmass in the low-mid levels with the 12Z KJAX
sounding measuring a PWAT of 2.51 in. Generally westerly flow today
will keep the Atlantic sea breeze pinned to the Atlantic coast this
afternoon. Isolated showers and storms develop along the Gulf sea
breeze early this afternoon with activity increasing in coverage
across NE FL as it approaches the Atlantic sea breeze. Some mixing
out in inland SE GA will limit convection this afternoon. Best
chances for rain and stronger storms will be along the sea breeze
merger in the St Johns river basin and I-95 corridor later this
afternoon into early evening. Torrential rainfall and isolated
strong to marginally severe wind gusts will be the primary hazards
given the pulse type of showers and thunderstorms expected and
pretty warm temperatures aloft.

Extreme Heat Warnings are in effect for Glynn and Camden with Heat
Advisories in effect elsewhere across NE FL and SE GA. Peak
heat indices will be around 108 to 112 F in heat advisory areas,
and 113 F for parts of Glynn and Camden Counties. High
temperatures will be generally in the mid to upper 90s.
Overnight lows will be in the 70s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Main Highlights This Period (Tuesday and Wednesday):

- Near Record Heat and Seasonably High Humidity Will Keep
Dangerously High Heat Index Values in Place Area-Wide on Tuesday

- Strong to Isolated Severe Thunderstorms Possible on Tuesday
Afternoon & Evening, Mainly for Locations South and East of Waycross

- Drier Air Mass Filters into Southeast GA on Wednesday, with
Scattered to Numerous Afternoon and Evening Thunderstorms Possible
South of Interstate 10

West-northwesterly flow aloft will prevail across the southeastern
states on Tuesday and Wednesday as ridging retrogrades towards the
West and broad troughing digs across the Eastern US states. This
trough will continue to push a frontal boundary slowly southward
towards our area by midweek. Deeper moisture will pool downstream of
this boundary across our region on Tuesday, with PWATs well above 2
inches across coastal southeast GA and, northeast FL. A drier air
mass may begin to filter into inland southeast GA by late afternoon,
keeping widespread convective activity confined to northeast FL.
However, the presence of the approaching front should still fire off
scattered showers and thunderstorms during the early to mid
afternoon hours across southeast GA. Strong to isolated severe
thunderstorms will be possible along the I-95 corridor during the
late afternoon and early evening hours as activity along the
dominant eastward moving Gulf sea breeze boundary encounters a
pinned Atlantic sea breeze boundary, likely causing stronger storms
capable of producing downburst winds of 40-60 mph, frequent
lightning strikes, and locally heavy downpours

Breezy west-southwesterly low level flow will delay the development
of the Atlantic sea breeze at coastal locations, allowing near
record heat to extend all the way to area beaches. High temperatures
will climb to the 95-100 degree range before convection increases in
coverage and intensity, and Extreme Heat Warnings have been posted
for coastal SE GA and all of NE FL, where Heat Index Values will
peak in the 113-115 degree range. Heat indices elsewhere across
inland SE GA will peak in the Advisory range of 108-112 degrees.
Convection should shift eastward and offshore before midnight on
Tuesday night, with lows generally falling to the mid and upper 70s.

PWATs will fall below 1.5 inches throughout southeast GA late Wed
afternoon as west-northwesterly flow advects a drier air mass aloft
southward towards the I-10 corridor. However, the frontal boundary
will stall near or just north of the Altamaha River, and highs will
soar to around 100 for inland southeast GA, with mid to upper 90s
expected elsewhere. Dewpoints falling into the mid/upper 60s in the
drier air mass across inland southeast GA should keep maximum heat
index values below Heat Advisory criteria, with values elsewhere
across coastal southeast GA and northeast FL likely reaching Heat
Advisory criteria once again. Scattered to numerous afternoon and
evening thunderstorms will likely be confined to locations south of
I-10, with a few stronger storms again possible along the I-95
corridor south of Jacksonville. A few storms may linger across north
central FL on Wednesday evening, with fair skies forecast elsewhere
and lows again only falling to the mid and upper 70s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Main Highlights This Period (Thursday through Sunday):

- Near Record Heat and Dangerously High Heat Indices Continue on
Thursday and Friday.

- Scattered to Numerous Afternoon and Evening Thunderstorms Each Day
from Friday through the Upcoming Weekend

Troughing aloft will slowly dig over the eastern half of the nation
as ridging amplifies over the Western US. This weather pattern will
keep a wavy frontal boundary in place over the Deep South, with deep-
layered southwesterly flow prevailing locally. The unseasonably dry
air mass that will filter into southeast GA on Wednesday will linger
on Thursday, keeping scattered afternoon and evening thunderstorms
mostly confined to areas across NE FL. Near record heat will
continue with highs again climbing to the 95-100 degree range at
most locations. Dewpoints will again fall through the 60s across
southeast GA, keeping heat index values below Advisory levels, while
values elsewhere across coastal southeast GA, northeast and north
central FL again reach the 108-112 degree range. Convection may
linger through the mid-evening hours on Thursday along the I-95
corridor and north central FL, with fair skies after midnight again
yielding lows in the mid to upper 70s at most locations.

Friday will likely be a transition to a more typical stormier
weather pattern as deepening southwesterly flow pools tropical
moisture along and downstream of a wavy stationary frontal boundary
that will remain in place across the southeastern states. Highs may
still soar to the mid and upper 90s, with heat index values rising
to at least Heat Advisory levels for much of our area. Scattered to
numerous afternoon and evening thunderstorms should develop across
our region as PWATs likely rise above 2 inches at most locations.
Scattered to numerous afternoon and evening thunderstorms are then
expected area-wide during the upcoming weekend, with convective
initiation during the early to mid afternoon hours likely keeping
temperatures in the low to mid 90s, with heat indices staying below
Heat Advisory thresholds for most of our area. Lows in the low to
mid 70s are forecast inland, while mid to upper 70s continue at
coastal locations.

&&

.AVIATION /18Z MONDAY THROUGH 18Z TUESDAY/...
Westerly flow will generally keep the Atlantic sea breeze near the
coast, with wind shifts to southwesterly only included at SSI and
SGJ for this afternoon. Convection is expected to be found mainly
across northeast FL, and have included PROB30 groups for all sites
accordingly except SSI where chances are too low to include any TS
mention at this time. Convection will start to wane after 00Z, with
VFR returning overnight.

&&

.MARINE...


High pressure extending from the Bahamas westward across the Gulf
will gradually weaken this week as a frontal boundary sags southward
over the southeastern states. Westerly winds will prevail during the
next several days, with winds over the near shore waters shifting to
southerly and increasing during the afternoon and evening hours as
the Atlantic sea breeze shifts slowly inland. Coverage of afternoon
and evening showers and thunderstorms will increase on Tuesday ahead
of the approaching frontal boundary. Showers and thunderstorms will
shift to the northeast Florida waters on Wednesday and Thursday as
the front stalls and dissipates.

Rip Currents: Prevailing offshore winds will strengthen slightly
today, though risk will remain low to moderate that will likely
continue through the end of the work week at all area beaches.

&&

.FIRE WEATHER...
     HEAT ADVISORIES AND EXTREME HEAT WARNINGS IN EFFECT THIS
- Afternoon And Again On Tuesday

     MARGINALLY HIGH DAYTIME DISPERSIONS POSSIBLE ACROSS INLAND
- Southeast Georgia On Tuesday And Wednesday

Near record heat and seasonably high humidity values will result in
dangerously high heat index values nearly area-wide this week.
Otherwise, scattered afternoon and evening thunderstorms are
expected this afternoon and evening, mainly across Northeast
Florida. Elevated mixing heights will yield good daytime dispersion
values at inland locations this afternoon, with fair values forecast
at coastal locations.

A similar weather pattern will prevail on Tuesday, with scattered
to numerous afternoon and evening thunderstorms possible. Elevated
mixing heights and slightly stronger westerly transport winds may
create marginally high daytime dispersion values across portions of
inland southeast Georgia on Tuesday and Wednesday afternoons.  A
drier air mass will filter into southeast Georgia on Wednesday and
Thursday, limiting chances for afternoon and evening showers and
thunderstorms. Scattered to numerous afternoon and evening
thunderstorm coverage will shift southward to northeast Florida by
Wednesday and Thursday.

Fog Potential: Significant fog formation is not expected. Gusty and
erratic winds are possible within stronger thunderstorms.

&&

.CLIMATE...
Near record high temperatures are possible at some of our designated
climate sites during the next several days:

Monday, August 17:
KJAX: 99/1954
KGNV: 97/1954
KAMG: 104/1995
KCRG: 97/2005

Tuesday, August 18:
KJAX: 98/1954
KGNV: 98/1954
KAMG: 105/1995
KCRG: 96/2023

Wednesday, August 19th:
KJAX: 99/1900
KGNV: 100/1954
KAMG: 103/1995
KCRG: 97/2010

Thursday, August 20th:
KJAX: 101/1900
KGNV: 99/1900
KAMG: 104/1995
KCRG: 98/2016

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  97  77  98  76 /  20   0  20   0
SSI  96  80  95  79 /  20   0  40  20
JAX  97  78  97  78 /  30  10  60  30
SGJ  95  78  95  78 /  40  20  50  20
GNV  96  77  94  78 /  30  20  60  20
OCF  95  77  94  78 /  30  20  50  30

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory until 8 PM EDT this evening for FLZ021-023-024-
     030-031-035-038-120-124-125-132-136>138-140-220-225-232-
     233-236-237-240-322-325-333-340-422-425-433-522-533-633.
     Extreme Heat Warning from 11 AM to 8 PM EDT Tuesday for FLZ021-
     023-024-030-031-035-038-120-124-125-132-136>138-140-220-
     225-232-233-236-237-240-322-325-333-340-422-425-433-522-
     533-633.
GA...Heat Advisory until 8 PM EDT this evening for GAZ132>136-149-
     151-152-162-163-250-264-350-364.
     Extreme Heat Warning from 11 AM to 8 PM EDT Tuesday for GAZ153-
     154-162-165-166.
     Heat Advisory from 11 AM to 8 PM EDT Tuesday for GAZ132>136-
     149-151-152-163-250-264-350-364.
     Extreme Heat Warning until 8 PM EDT this evening for GAZ153-
     154-165-166.
MARINE...None.

&&

$$