247
FXUS62 KJAX 151527
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
1127 AM EDT Sun Jun 15 2025

...STRONG STORMS POSSIBLE ALONG THE I-95 CORRIDOR LATER TODAY...
...AFTERNOON AND EVENING STORM COVERAGE WANES ON TUES & WED...
...DAILY HEAT INDEX VALUES AROUND 105 DEGREES THIS WEEK...

For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

.UPDATE...
Issued at 1128 AM EDT Sun Jun 15 2025

Late morning surface analysis depicts Atlantic high pressure (1027
millibars) centered to the southeast of Bermuda, with this feature
extending its axis westward across central FL. Meanwhile, a wavy
frontal boundary extends from the Southern Plains eastward across
the Ozarks, the Ohio Valley, and the Delmarva region.
Aloft...deep-layered ridging extends from the southwestern
Atlantic waters across the FL peninsula and into the southeast
Gulf, while a de-amplifying trough was progressing eastward across
the southern Appalachians, with the base of this decaying trough
positioned over the Deep South and the lower Mississippi Valley.
Latest GOES-East derived Total Precipitable Water imagery
indicates that deep tropical moisture blankets our region, with
PWAT values generally in the 1.8 - 2 inch range. Scattered showers
and thunderstorms are developing along the Gulf coast sea breeze
along the FL Big Bend and Nature Coasts late this morning, with
low level south-southwesterly flow steering flow pushing activity
towards the Suwannee River in Gilchrist County. Some high altitude
debris clouds emanating from convection over the eastern Gulf are
traversing our region, while a healthy cumulus field was otherwise
developing across portions of our area. Temperatures were soaring
through the mid and upper 80s at most locations as of 15Z, with
dewpoints generally in the mid 70s.

Southwesterly flow will prevail this afternoon and evening as
deep-layered Atlantic ridging extends its axis across central FL.
With plenty of tropical moisture in place and convective
initiation temperatures around 90 per the morning sounding at
Jacksonville, we expect numerous showers and thunderstorms to
develop along the I-95 corridor late this afternoon as the Gulf
and Atlantic sea breezes collide. Convective coverage will
gradually increase earlier in the afternoon across the Suwannee
Valley along the inland moving Gulf coast sea breeze, with
convective outflows pushing into southeast GA as well this
afternoon, serving as the trigger for scattered showers and
thunderstorms. ML CAPE values along the I-95 corridor will rise to
around 2,500 j/kg as temperatures soar to the low and mid 90s,
creating an environment that will favor a few pulsing storms that
may contain wet microbursts this afternoon, particularly where
mesoscale boundaries collide. Heavier downpours will likely
coincide with low tide later this afternoon at coastal locations,
but torrential downpours at urban areas along the I-95 corridor
may create a threat for localized flooding that may extend into
the evening hours, particularly for coastal southeast GA. Heat
index values this afternoon should peak in the 100-105 range at
most locations before cloud cover and rainfall chances increase
later this afternoon.

A later developing Atlantic sea breeze boundary over east central
FL towards sunset may keep some convective coverage going into the
evening hours for north central FL, with activity also potentially
continuing across southeast GA due to mesoscale boundary
collisions. Most of the convection will shift offshore of the
northeast FL coast shortly after sunset. Lingering convection this
evening should dissipate by midnight across southeast GA and north
central FL, with debris cloudiness thinning out during the
overnight and predawn hours. A light southerly breeze should will
keep coastal lows in the mid to upper 70s, while lower 70s are
forecast for most inland locations.

&&

.SHORT TERM...
(Monday through Tuesday night)
Issued at 245 AM EDT Sun Jun 15 2025

Low to mid level ridge will slowly work northward into the area on
Monday and mean deep layer flow will remain south to southwest at
about 10 kt. PWATs remain healthy around 1.75 to 2 inches. NBM
guidance shows numerous to widespread showers and storms. Given
the influence of the mid level ridge and some drying noted in the
mid levels, will lean toward scattered to numerous showers and
storms, mainly during the afternoon hours. Initial activity will
likely form along the I-75 corridor. Peak heating and progression
of the west coast sea breeze, and the later forming east coast sea
breeze should be helpful for additional convective development. A
few stronger storms are possible with heavy rainfall and gusty
winds. Some of the stronger storms will be in the late afternoon
over the eastern zones where the airmass will already be primed
with instability. Mon night, isolated to scattered convection
should dissipate gradually through the evening hours.

Tuesday, mid level ridge will be across north central FL and
guidance has been fairly consistent showing mid level drying
working in and some subsidence aloft. This should lead to lower
rain chances so will have POPs capped at 30-50 percent. It is
possible this may even be a little generous. With sfc ridge closer
to the area and weaker southwest flow, the area of best
convergence will shift a little further inland toward Highway 301
as the east sea breeze inland progression will be improved.
Tuesday night, mainly isolated convection in the evening before
dissipating overnight.

Highs will be trending a little higher Monday to Tuesday with
lower to mid 90s anticipated by Tuesday. Max heat indices likely
up to near 100-105. Lows in the lower to mid 70s.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 245 AM EDT Sun Jun 15 2025

High pressure ridge at the sfc and aloft will be located across
northern and central FL Wed and Thu with flow from the south and
southwest. PWATs remain near or below average and temps at 500 mb
will be above average. The subsidence from the ridge and lower
moisture in the mid levels will result in near or below average
rain chances both days.

A mid level trough will drop into the region by Thursday night
into Friday with an associated cool front moving into central GA.
A pre-frontal trough will pivot southward into the forecast area.
A slight cooling of temps aloft and an increase in deep moisture
will help boost rain chances Friday and Saturday, with the weak
trough likely laying over or near the forecast area on Saturday.
For now, will cap POPs at about 50-60 percent given the
uncertainty at this time range on moisture availability and
mesoscale features.

Max temps expected in the lower to mid 90s, with lows in the
lower to mid 70s or slightly above average this period. Heat index
values may rise a bit further after Wed, with values of up to
around 107 on Thursday and Friday.

&&

.AVIATION...
(12Z TAFS)
Issued at 754 AM EDT Sun Jun 15 2025

VFR conditions will prevail at the regional terminals through at
least 16Z. Showers and thunderstorms will begin developing after
16Z along sea breeze boundaries that will progress inland during
the afternoon hours, with the Gulf coast sea breeze being dominant
and faster moving, possibly bringing impacts to the GNV terminal
as early as 18Z. Thunderstorms should then impact the Duval County
terminals and SGJ late this afternoon, with activity likely not
arriving at SSI until after 21Z. Colliding mesoscale boundaries
along the I-95 corridor late this afternoon may allow convection
to continue through around 02Z, especially at SSI. TEMPO groups
were used at each terminal this afternoon through early this
evening, with brief wind gusts up to 30 knots and IFR conditions
possible within heavier storms. We will attempt to narrow the
focus of thunderstorm activity at the regional terminals for the
18Z TAF package. VFR conditions should then prevail after 03Z,
with periods of IFR visibilities likely during the predawn hours
at VQQ. Southerly surface winds will increase to 5-10 knots
towards 14Z, followed by shifting surface winds as sea breezes
progress inland and thunderstorms develop this afternoon.
Southeasterly surface winds should increase to 10-15 knots at the
SSI and SGJ coastal terminals after 16Z.

&&

.MARINE...
Issued at 1128 AM EDT Sun Jun 15 2025

Atlantic high pressure centered to the southeast of Bermuda will
continue to extend its axis westward across the Florida peninsula
through Monday, keeping a prevailing southerly wind flow across
our area. Afternoon sea breezes will increase wind speeds to near
Caution levels over the near shore waters late in the afternoon.
Showers and thunderstorms will impact our local waters during the
late afternoon and evening hours, with a few strong storms
possible, bringing briefly gusty winds, frequent lightning
strikes, and torrential downpours. Atlantic high pressure will
then lift its axis northward towards our local waters on Tuesday
and Wednesday, likely resulting in less afternoon and evening
thunderstorm coverage as southeasterly winds prevail. Atlantic
high pressure will then shift its axis southward across the
Florida peninsula late this week as a cold front enters the
southeastern states, resulting in prevailing southwesterly winds
and increasing chances for late afternoon and evening
thunderstorms by Friday. Seas of 2 to 4 feet will prevail both
near shore and offshore during the next several days.

Rip Currents: Strengthening onshore winds this afternoon following
the passage of the sea breeze will combine with a persistent
easterly ocean swell to create a lower end moderate rip current
risk at all area beaches. Similar conditions will prevail on
Monday, followed by a low risk forecast at the southeast GA
beaches beginning on Tuesday due to low surf heights, with the
afternoon sea breeze keeping a lower end moderate risk in place at
the northeast FL beaches.

&&

.FIRE WEATHER...
Issued at 1128 AM EDT Sun Jun 15 2025

Southwesterly transport winds will prevail this afternoon through
Monday, creating fair to good daytime dispersion values at most
inland locations. Breezy onshore surface winds following the
passage of the afternoon sea breeze at coastal locations will
yield poor to fair daytime dispersion values through Monday.
Elevated mixing heights will combine with breezy southwesterly
transport winds on Tuesday to create high daytime dispersion
values across inland portions of southeast GA, with good values
generally forecast for inland northeast and north central FL, with
fair values at coastal locations due to prevailing onshore surface
winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  90  72  92  73 /  60  30  50  20
SSI  91  76  91  76 /  70  80  40  30
JAX  93  72  93  73 /  90  60  70  30
SGJ  91  75  91  75 /  70  50  60  20
GNV  92  72  92  72 /  70  20  70  20
OCF  91  73  91  72 /  70  20  70  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

$$