Jacksonville, Florida 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

509
FXUS62 KJAX 181926
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
326 PM EDT Thu Jun 18 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 to Numerous Afternoon & Early Evening Thunderstorms
  along the I-95 and U.S. Highway 17 Corridors. Strong to
  Isolated Severe T`Storms are Possible, with Wind Gusts of
  40-60 mph, Frequent Lightning Strikes, and Heavy Downpours.

- Squall Line of Strong to Isolated Severe Thunderstorms May
  Traverse Inland Portions of Southeast GA Overnight through the
  Predawn Hours on Friday. Wind Gusts of 40-60 mph, Frequent
  Lightning Strikes, and Heavy Downpours will be Possible.

- Numerous Showers and Thunderstorms Expected on Friday and
  Saturday. Strong to Isolated Severe Storms Will be Possible.

- Heat Index Values Increasing to Near Heat Advisory Levels
  Early Next Week.

- KVAX (Valdosta, GA) Radar is Out of Service. Please utilize
  other area radars for active weather this afternoon and
  tonight.


&&

.NEAR TERM /THROUGH TONIGHT/...
Main Highlights Today and Tonight:

- Scattered to Numerous Afternoon & Early Evening Thunderstorms
Along the I-95 and U.S. Highway 17 Corridors. Strong to Isolated
Severe T`Storms are Possible, with Wind Gusts of 40-60 mph, Frequent
Lightning Strikes, and Heavy Downpours.

- Squall Line of Strong to Isolated Severe Thunderstorms May
Traverse Inland Portions of Southeast GA Overnight through the
Predawn Hours on Friday. Wind Gusts of 40-60 mph, Frequent Lightning
Strikes, and Heavy Downpours will be Possible.

Afternoon surface analysis depicts remnant low pressure (1007
millibars) from former Tropical Storm Arthur traversing the
lower Mississippi Valley, with this feature beginning to
accelerate northeastward and creating an expanding region of
heavy downpours and strong to severe storms across the Deep
South. Meanwhile, a cold front extends from the eastern Great
Lakes through the Ohio Valley and the Ozarks. Aloft...troughing
that was progressing slowly across southeastern Canada and the
Great Lakes has displaced deep-layered ridging to the east of
the Bahamas, creating a deepening southwesterly flow pattern
across our area. Latest GOES-East derived Total Precipitable
Water imagery indicates that deep tropical moisture remains in
place over our area, with PWATs generally in the 1.8 - 2 inch
range, with a slightly drier air mass over the northeast Gulf,
featuring PWATs around or just below 1.75 inches poised to move
onshore along the FL Big Bend and Nature Coast later today. A
hot and unstable airmass in place across our region was aiding
in the development of widely scattered showers and
thunderstorms, with activity across southeast GA moving briskly
northeastward, while lighter steering flow was resulting in
slower moving convection over north central FL. Outside of rain
cooled locations, temperatures at 19Z were in the low to mid
90s, with dewpoints in the 70s, creating heat index values of
100-105 at most locations.

Scattered convection should continue to blossom in the warm and
unstable air mass that is in place across inland locations, with
relatively fast storm motion expected. This environment should
allow convection to pulse and become strong, with isolated
severe storms possible. Otherwise, the Atlantic sea breeze
boundary has formed at coastal locations, and this boundary will
likely serve as another focus for strong to isolated severe
thunderstorms through the late afternoon and early evening
hours. Surface based CAPE values in excess of 2,000 j/kg and
gradually strengthening southwesterly speed shear should allow
for a few storms to pulse this afternoon before moving offshore
this evening, with stronger storms capable of producing
downburst winds of 40-60 mph, along with frequent lightning
strikes and torrential downpours. Faster storm motion should
preclude flood concerns at most locations, although some threat
for training cells may develop at coastal locations based on
strengthening, mostly unidirectional flow. Activity should then
move offshore after midnight tonight.

Low pressure is expected to accelerate northeastward across AL
and GA tonight, with a trailing band of convection likely
approaching the Ocmulgee / Altamaha Rivers towards midnight.
This storm system will bring a 40-45 knot southwesterly low
level jet around 850 millibars (around 5,000 feet) across inland
portions of southeast GA tonight, which could maintain a broken
squall line containing strong to severe storms into the
overnight and predawn hours. CAMs have been wavering on whether
this activity will ultimately weaken as it moves into southeast
GA after midnight, but the Storm Prediction Center has
maintained a "Marginal" (level 1 out of 5) risk for isolated
severe storm potential, and enough low level veering may still
be in place for isolated tornado potential, mainly for locations
north and west of Waycross. A southwesterly breeze overnight
will otherwise keep lows in the 75-80 degree range across our
area.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...

- Isolated Strong to Severe T`storms Friday.

- Numerous to Widespread Showers and T`storms Saturday.

- Hot and Humid Conditions Friday into Saturday.

Pattern for daily bouts of showers and storms will continue
through  Friday and Saturday as the moist southwesterly flow
pattern persists over the forecast area between the frontal
boundary to the north and an area of high pressure rotation east
of the Florida peninsula over the Gulf. Scattered to numerous
are expected through this period with a potential for strong
storms on Friday capable of producing destructive winds,
frequent lightning, and a potential for localized flooding with
training storms as PWAT values measure upwards of 2.4 inches
over the region. High temperatures for the end of the week and
into the weekend will rise into the upper 80s and lower to mid
90s with overnight low temperatures dropping down into the lower
to mid 70s over inland areas and in the mid to upper 70s along
the coastline. Heat index values rise to values of over 100
Fahrenheit with conditions rising to be near Heat Advisory
levels over portions of southeast Georgia and northeast Florida.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Main Highlights This Period:

- Heat index values increasing to near Heat Advisory levels next
  week.

- Decreasing chances for showers Afternoon and Evening T`storms
  Sunday through next week.

Drier air will filter in over the region by end of Sunday and
into Monday as drier air associated a high pressure system
over the Gulf extends in over the forecast area resulting in
more inhibited convection for the beginning of next week, with
the prevailing flow shifting about to become more out of the
west and northwest. Temperatures will warm through the weekend
and into next week with max temps rising into the mid to upper
90s before midweek. Heat index values are expected to rise to be
100 and higher for portions of southeast Georgia and northeast
Florida, with a potential for a return to Heat Advisory level
conditions next week.

&&

.AVIATION /18Z THURSDAY THROUGH 18Z FRIDAY/...

VFR conditions will prevail through at least 20Z at the regional
terminals. Showers and thunderstorms will continue to increase
in coverage and intensity across our region later this
afternoon, with confidence remaining high enough to maintain at
TEMPO group at SGJ through 01Z for potential wind gusts up to 30
knots and IFR visibilities during heavier downpours. Confidence
has increased enough to also include TEMPO groups at CRG and
SSI during this time frame for similar conditions. PROB30 groups
were maintained at JAX and VQQ around 20Z-01Z for brief wind
gusts up to 30 knots and MVFR visibilities during heavier
downpours. We have maintained only vicinity shower coverage at
GNV for now. Scattered thunderstorms that develop along the I-95
corridor late this afternoon will move offshore before 02Z this
evening, with another round of thunderstorms expected to impact
inland portions of southeast GA towards 06Z Friday. Confidence
remains too low to include anything other than vicinity shower
coverage at SSI and the Duval County terminals overnight through
early Friday morning. Showers and thunderstorms will likely
increase in coverage towards the end of this TAF period, or
during the early afternoon hours on Friday. South-southwesterly
surface winds will remain sustained at 10-15 knots and gusty
outside of thunderstorm activity at the inland terminals through
around 00Z. The Atlantic sea breeze boundary will move slowly
inland this afternoon, shifting surface winds to southeasterly
at SGJ and southerly at SSI at 10-15 knots towards 20Z.
Southerly surface winds will remain somewhat elevated overnight,
with sustained speeds generally remaining around 10 knots.
Surface winds will then shift to southwesterly after sunrise,
with speeds increasing to around 15 knots by 16Z.

&&

.MARINE...

Low pressure moving across the southeastern states this
afternoon and tonight will result in strengthening
southwesterly winds, with Caution conditions expected throughout
our local waters tonight. Winds may briefly approach Small Craft
Advisory levels across the Georgia waters overnight through
Friday morning. Otherwise, strong to isolated severe
thunderstorms developing near coastal locations could impact
much of our local waters during the early evening hours, with
stronger storms being capable of producing strong wind gusts,
frequent lightning strikes, and torrential downpours. Activity
should move eastward over the Gulf Stream waters by midnight,
with another round of storms potentially approaching the Georgia
waters during the predawn hours on Friday from the northwest.

Low pressure will then accelerate east-northeastward across the
Carolinas on Friday, emerging off the Outer Banks towards
sunset. A frontal boundary trailing this departing low pressure
center is expected to stall just north of the Georgia waters on
Friday and Saturday. Additional rounds of strong to possibly
severe thunderstorms will potentially impact our waters from
Friday through the weekend as a prevailing west winds continue.
Coverage of showers and thunderstorms may decrease slightly
early next week ahead of another frontal boundary that will
likely stall across the southeastern states by midweek.

Rip Currents:

Breezy southerly winds developing in the wake of the inland
moving Atlantic sea breeze may create a lower end moderate
risk for the northeast FL beaches. Low surf heights should keep
the risk low at the southeast GA beaches during the next several
days. Similar conditions will prevail on Friday, with a lower
end moderate risk possibly developing during the afternoon at
the northeast FL beaches. Light offshore winds this weekend will
likely result in a low risk at all area beaches, and
strengthening offshore winds early next week should keep surf
heights low enough to maintain a low risk.

&&

.FIRE WEATHER...

- Patchy High Dispersion Values Today and Friday.

Moist and unstable airmass will continue afternoon/early evening
scattered to numerous T`storms today as west to southwest winds
allow the Gulf seabreeze to move quickly eastward to the
Atlantic coast before interacting with the pinned Atlantic
seabreeze near the Atlantic coast. T`storms will include heavy
downpours and locally heavy rainfall, frequent lightning, and
gusty winds with isolated strong to severe T`storms this
afternoon. A front will sink towards the area Friday and move
through Northeast Florida Saturday with widespread showers and
T`storms. The front will stall near north central or central
Florida Sunday with less coverage of T`storms.

Favorable transport winds and mixing heights will lead to areas
of high afternoon dispersion values today along and west of
I-95. Good level dispersions expected during each afternoon
Friday into the weekend as more clouds limit mixing heights
while transport winds decrease slightly as the front settles
south of the area by Sunday.

Temperatures will be hot today and along with elevated humidity
will create heat index values up to 102-106 near the coast and
across Northeast FL. Highs will decrease to the low 90s Friday
into the weekend, but high humidity levels will continue.

FOG POTENTIAL AND OTHER REMARKS:  Areas that receive heavier
rainfall may also experience patchy late-night and early-morning
fog.

&&

.EQUIPMENT...

The WSR-88D Radar located near the Moody AFB near Valdosta
remains offline due to technical problems. Technicians are
awaiting critical parts to restore functionality. During the
outage please utilize other area radars...KJAX, KTLH, or KJGX.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  74  85  73  88 /  80  60  40  70
SSI  78  91  77  89 /  50  70  30  70
JAX  78  92  76  90 /  30  60  50  90
SGJ  77  94  77  91 /  40  40  30  90
GNV  78  92  76  91 /  10  50  40  90
OCF  78  92  77  91 /  20  40  40  80

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory until 7 PM EDT this evening for FLZ023-024-030-
     031-038-124-125-132-136>138-140-225-232-233-236-237-240-
     325-333-340-425-433-533-633.
GA...Heat Advisory until 7 PM EDT this evening for GAZ152>154-165-
     166-264-350-364.
MARINE...None.

&&

$$