718
FXUS62 KJAX 161118
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
718 AM EDT Sun Aug 16 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 Area-
Wide from 11 AM  8 PM on Sunday. Heat Advisories & Extreme Heat
Warnings Possible Monday through Thursday

- A Few Strong Thunderstorms Possible Late this Afternoon & Evening.
Main Impact Area: Inland Southeast GA and the Interstate 10 Corridor.
Strong Storm Hazards: Wind Gusts of 35 - 45 mph, Frequent Lightning
Strikes,

- Scattered to Numerous Afternoon & Evening TStorms from Mon  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 Conditions Continue Area-Wide Today.

- Scattered to Numerous Thunderstorms late this Afternoon and
Evening, Mainly Across Southeast GA and the Interstate 10 Corridor.

Overnight surface analysis depicts weakening high pressure (1021
millibars) extending from the FL peninsula northwestward along the
northern Gulf coast. Meanwhile, a wavy frontal boundary extends from
the Carolinas northwestward across the southern Appalachians, the
Ohio Valley and the Missouri Valley. Aloft..."Heat Wave" ridging
remains centered over the lower Mississippi Valley and eastern
Texas, with this ridge extending its axis eastward across the
southeastern states. Latest GOES-East derived Total Precipitable
Water imagery indicates that seasonably moist conditions prevail
across our area, with PWATs generally in the 1.8 - 2.1 inch range.
Cirrus cloud cover leftover from evening convection across central
and southern GA was drifting across southeast GA, while fair skies
prevail elsewhere. Less rainfall coverage across our area on
Saturday afternoon and evening has allowed temperatures to run
warmer overnight, with values at 07Z still in the upper 70s and
lower 80s, with dewpoints generally in the mid to upper 70s.

"Heat Wave" ridging positioned over the lower Mississippi Valley and
eastern Texas will begin to slowly retrograde westward later today,
allowing for a subtle low level trough to push southeastward across
southeast GA late this afternoon and evening. Deep-layered moisture
will pool along this trough axis, with PWATs climbing up to near
2.25 inches across southeast GA late this afternoon. Meanwhile,
surface ridging will continue to slowly weaken over the FL peninsula
and the central / eastern Gulf, with low level westerly flow this
morning veering to northwesterly by this afternoon and evening.
Strong subsidence this morning should weaken by late this afternoon
and early this evening as ridging aloft begins to retrograde further
away from our area, and convection should develop along the low
level trough axis across mainly inland portions of southeast GA by
late this afternoon. There should be enough moisture in place for at
least isolated thunderstorms to develop along the Atlantic and Gulf
sea breezes by late afternoon, and convective outflows should allow
at least scattered convection to drift southward towards the I-10
corridor early this evening. Storms may pulse and become strong as
mesoscale boundaries collide, mainly for locations along and north
of I-10 through the mid-evening hours before activity dissipates.
Stronger storms late this afternoon and evening may produce
downburst winds of 35-45 mph, frequent lightning strikes, and
locally heavy downpours.

Strong subsidence this morning beneath filtered sunshine due to thin
cirrus cloud cover will again allow highs to soar to the mid and
upper 90s by the mid to late afternoon hours. Dewpoints may again
mix down to the low and mid 70s, yielding peak heat index values in
the 108-112 degree range nearly area-wide, which means another day
of Heat Advisory conditions, with the onset of advisory criteria
beginning as soon as 11 AM this morning and continuing until 8 PM
this evening, especially at locations that remain rain-free later
today. Convection over southeast GA and northeast FL will dissipate
before midnight tonight, with debris cloud cover then gradually
thinning overnight through the predawn hours on Monday. Lows will
again only fall to the 75-80 degree range by early Monday morning.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Main Highlights This Period:

- Isolated Strong to Severe Storms Monday & Tuesday
Afternoon/Evening, Especially for Northeast FL

- Heat Index Values Near or Above Heat Advisory Each Day

Surface frontal boundary will drop southward throughout the day on
Monday, though lose forward progress rather quickly as it runs
into persistent high pressure ridging in the upper levels.
Between the overall timing and drier air that tries to fill in
behind the boundary, overall best chances for showers and
thunderstorms Monday, and likely Tuesday as well, will be across
NE FL as well as near the Atlantic sea breeze up the I-95
corridor and coast. Given the presence of some drier air aloft
and high late summer instability with above normal temps (more
on that below), some isolated strong to severe updrafts will
certainly be possible, with downburst winds being the primary
threat in addition to torrential rainfall/minor flooding
potential.

Though guidance has backed off a bit for the start of the work week,
still expecting temps to climb into the mid to upper 90s both
Tuesday and Wednesday. Combined with August humidity, Heat
Advisories will be likely for at least a portion of the region both
days, with Extreme Heat products not our of the realm of
possibility.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Main Highlights This Period:

- Hazardous Heat Continues Mid Week

- Isolated to scattered thunderstorms each afternoon and evening,
some which could become strong

Prevailing flow continue from out of the west and northwest through
the end of the week as the above mentioned frontal boundary settles
just north of the region for mid to late week. Available moisture
overall increases later this week with several waves passing along
the boundary, and therefore chances for showers and t`storms will
overall be on a upward trend for all during the long term period as
ridging aloft weakens. This will also slowly drop temperatures
closer to normal, though Wednesday and possibly Thursday could still
see the hotter temperatures and heat headlines hanging on before
this occurs.

&&

.AVIATION /12Z SUNDAY THROUGH 12Z MONDAY/...
VFR conditions will prevail at the regional terminals through at
least 19Z. Showers and thunderstorms developing over interior
southeast GA during the early to mid afternoon hours will expand
southeastward towards the terminals during the mid to late afternoon
hours. However, confidence in coverage and timing remains too low to
indicate anything other than vicinity thunderstorm coverage after
19Z, with activity possibly not progressing as far south as north
central FL, where we only indicated vicinity showers at GNV after
21Z. Convection should diminish by 03Z Monday, with VFR conditions
then expected to prevail at the regional terminals. The Atlantic sea
breeze boundary will develop towards noon at coastal locations and
will progress inland during the afternoon hours, resulting in
surface winds shifting to east-southeasterly around 10 knots at SGJ
and southeasterly around 10 knots at SSI before 18Z. Light
southwesterly surface winds will diminish to around or less than 5
knots after 02Z. Fog chances still remain too low to include for the
overnight hours late Sunday night.

&&

.MARINE...


Atlantic high pressure will continue to extend its axis westward
across the Florida peninsula today, creating a prevailing westerly
wind pattern across our local waters. Winds will become onshore
across the near shore waters early this afternoon as the sea breeze
progresses slowly inland. Southerly winds will then surge this
evening, but speeds should remain below Caution levels. Isolated to
widely scattered late afternoon and evening thunderstorms will be
possible today, mainly for the waters north of St. Augustine. A
frontal boundary will then push into the southeastern states by
Monday afternoon, with this feature stalling just north of the
Georgia waters by midweek. Chances for mainly afternoon and evening
showers and thunderstorms will increase across our local waters
during the work week. Southwest to westerly winds will continue to
prevail, with a westerly evening wind surge forecast on Monday that
may bring speeds briefly up to Caution levels.

Rip Currents: A lower end moderate risk is expected today at area
beaches as the afternoon sea breeze creates an onshore breeze that
will combine with the outgoing tide and a persistent long period
east-southeasterly ocean swell. Prevailing offshore winds will
strengthen on Monday and Tuesday, creating a low risk that will
likely continue through the end of the work week at all area
beaches.

&&

.FIRE WEATHER...
- Heat Advisory In Effect Today
- Patchy High Dispersions Inland Southeast Ga Monday And Tuesday

Hot conditions are expected to persist through the rest of the
weekend and into at least the start of next week, with Heat
Advisories likely and possibly even Extreme Heat Warnings possible
each day for most or all of the region. This will come with a flow
direction generally out of the southwest to west through the next
several days except for a wind shift with the sea breeze generally
east of the I-95 corridor. A frontal boundary dropping southward
tonight and Monday will return more "usual" chances for showers and
storms for all today, then mainly over northeast Florida for early
to mid week as some drier air moves into southeast GA behind the
front. Better mixing and transport winds will result in good to
patchy high dispersions over inland GA, with fair to good
dispersions elsewhere. The front will linger just north of the
region by late week, with shower and storm chances generally
increasing as well.

Fog Potential: Significant fog developments are not expected,
however late-night or early-morning fog developments are expected to
be shallow and patchy, mainly occurring over areas that have
received locally heavy rainfall. Gusty and erratic winds are often
possible within and nearby any stronger showers or storms.

&&

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

Sunday, August 16:
KJAX: 97/1957
KGNV: 97/1918
KAMG: 100/1995
KCRG: 95/2022

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

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  96  76  99  78 /  40  30  20  10
SSI  93  79  95  79 /  60  40  30  10
JAX  96  77  97  77 /  50  40  40  10
SGJ  96  77  96  78 /  30  30  50  10
GNV  96  76  95  77 /  30  20  60  20
OCF  96  75  95  77 /  20  10  50  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 11 AM this morning to 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.
GA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for GAZ132>136-149-151>154-162-163-165-166-250-264-350-
     364.
MARINE...None.

&&

$$