127
FXUS62 KJAX 200727
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
327 AM EDT Sat Jul 20 2024

...New NEAR TERM, SHORT TERM, LONG TERM, MARINE...

.NEAR TERM...
(Today and Tonight)
Issued at 322 AM EDT Sat Jul 20 2024

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

Southwest steering flow at the surface and in the mid levels
combined with atmospheric PWATs around 2 inches will continue a
near repeat of conditions from yesterday as late morning/early
afternoon convection over inland areas that will track East to
Northeast at 15-20 mph and reach the East Coast sea breeze that
should reach into the US 17 and I-95 corridors in the mid/late
afternoon hours and expect this convergence to trigger numerous to
widespread showers and storms with strong/gusty winds to 50 mph
along with heavy rainfall/localized flooding and frequent
lightning, and similar to yesterday isolated severe storms with
potential downburst winds to 60 mph are possible, mainly along the
I-95 corridor of the Atlantic Coastal counties where storm mergers
with the East Coast sea breeze are expected. This activity should
then continue at strong to isolated severe levels as it pushes
E-NE through the Atlantic Coastal Counties through the early
evening hours and into the Atlantic Coastal waters around or just
after sunset, with convection fading towards the late evening
hours and ending by midnight. Timing of the onset of convection
will determine eventual daytime Max temps, but overall expect
widespread lower to middle 90s inland and around 90F at the
Atlantic beaches and these combined with dewpoints into the middle
70s should push heat indices into the 104-108F range, likely just
below or just briefly reaching Heat Advisory levels at this time.
Overnight lows in the 70s over inland areas and near 80F at the
Atlantic beaches.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 322 AM EDT Sat Jul 20 2024

A shift in the high pressure to the north-northeast of the region
on Sunday will see the overall flow shift to be primarily from
the south. This will allow the Gulf and Atlantic sea breezes to
venture well inland. The daytime heating will see the development
of showers and storms along the breezes, with activity picking up
as the sea breezes merge during the afternoon between the I-75 and
I-95 corridors. Most activity will dwindle during the overnight
hours due to the loss of the daytime heating.

By Monday, a southeasterly flow will become established as the
high pressure shifts further north-northeast. This will setup the
Atlantic sea breeze moving further inland towards the west. Near
the I-75 corridor will be the likely area for the merger between
the Gulf and Atlantic sea breezes during the afternoon hours on
Monday, setting up the development of the stronger showers and
storms of the day.

Early afternoon showers will keep temperatures in check in the
lower to mid 90s. Heat index values currently expected to stay
just below criteria for heat advisory at this time for the
weekend, but higher values will be expected along the coast.

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 322 AM EDT Sat Jul 20 2024

The high pressure to the northeast will continue the pattern of a
far westward traveling Atlantic sea breeze. Showers and storms
will develop along the Atlantic sea breeze as it moves to the
west, but most convective activity likely to occur along the
merger of the sea breezes over the western portion of the area.
Activity will diminish each evening as the daytime heating is
loss. Temperatures will trend near to above normal with highs in
the low-mid 90s and lows in the 70s.

&&

.AVIATION...
(06Z TAFS)
Issued at 120 AM EDT Sat Jul 20 2024

Just lingering mid/high clouds at VFR levels through the
overnight hours at all TAF sites with just the usual MVFR fog
chances at VQQ towards sunrise. Southwest steering flow will
continue high rainfall chances over 60% this afternoon and
evening and will upgrade to TEMPO groups at all TAF sites with
first arrival at GNV in the 18-22Z range, at JAX/VQQ in the 19-23Z
range and SSI/SGJ/CRG in the 20-24Z range and will include at
least MVFR CIGS/VSBYS and gusty winds to 30 knots. Stronger winds
and IFR conds possible in heavier activity and will likely be
adjusted as convection kicks off Friday afternoon. Activity should
end in the 01-02Z time frame with lingering VFR convective debris
clouds through the end of the TAF period.

&&

.MARINE...
Issued at 322 AM EDT Sat Jul 20 2024

No headlines expected over the next 5 days as high pressure ridge
from the Western Atlantic will be across or just south of the
local waters through early next week. This will continue a general
south to southwest flow through the period at 10-15 knots with
seas 2-4 ft, along with daily sea breeze along the local beaches
from the Southeast. A few evening/nocturnal southerly wind surges
could briefly reach into the 15-20 knot range, but not likely to
last long enough to warrant any headlines. Main impacts will be
offshore moving storms during the afternoon and evening hours with
strong/gusty winds to 30-45 knots, heavy rainfall and dangerous
lightning.

Rip Currents: Marginal moderate risk of rip currents will
continue through the weekend as mainly south to southwest flow
becomes briefly onshore Southeasterly during the afternoon hours
at the local beaches with surf/breakers of 2-3 ft.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  91  72  92  73 /  80  40  80  40
SSI  89  76  89  77 /  90  60  60  40
JAX  94  74  93  75 /  90  70  70  30
SGJ  92  75  93  76 /  90  90  60  20
GNV  94  73  93  73 /  80  40  80  20
OCF  94  73  94  75 /  70  40  80  20

&&

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

$$