878
FXUS62 KJAX 040607
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
207 AM EDT Thu Jul 4 2024

...New AVIATION...

.NEAR TERM...
Issued at 128 PM EDT Wed Jul 3 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

Squeeze play between a trough just to our north, the Atlantic sea
breeze and Gulf Sea Breeze front this afternoon and evening will
lead to scattered to widespread convection over the spine of the
FL peninsula and extreme SE GA. Convection is already popping and
will be most significant in the Ocala-Gainesville to Lake City
areas. Convection should die off between 10 p.m. and midnight.

&&

.SHORT TERM...(Independence Day through Friday night)

Broad surface high stretching across the western Atlantic,
Florida and into the Gulf of Mexico will stay in place while
ridging aloft centered over the Gulf, builds eastward and overhead
through Friday. The overall diurnal convective regime will not
change considerably between Thursday and Friday amid the stagnant
flow pattern. Storm motion will be slow (<5mph) and driven almost
entirely by the sea breeze and subsequent outflow interactions
through the afternoon. The Atlantic sea breeze will "win out"
each day, focusing the corridor of numerous showers and t`storms
inland during the late afternoon and early evening hours.
Convective coverage will be reduced along the coast by Friday as
dry air aloft noses in from the Atlantic, but scattered to
numerous showers storm are still expected inland, favoring the
I-75 corridor.

With deep moisture entrenched across the area, concerns with
developing storms will be localized flooding due to hefty rainfall
rates (3-5" per hour) and slow movement. The secondary hazard of
concern will be strong outflow winds, around 30-50 mph, with a few
storms.

Though temperatures will be on par with climo for early July, the
risk of heat-related illness will be higher given the holiday and
potential for prolonged heat exposure. A "situational" heat advisory
may be needed to highlight the risk and amplify messaging for the
Independence Day holiday. Heat index values on the Fourth will range
from 100-108 and increase toward Advisory levels Friday.

&&

.LONG TERM...(Saturday through next Wednesday)

Lingering subsidence beneath stout ridging aloft and a "drier"
airmass hanging along the coast will reduce storm coverage a bit
Saturday before another slug of deep moisture pooling ahead of a
slowing front seeps in from the north. This moisture uptick will
reinvigorate convection and numerous afternoon showers are expected
beginning Sunday with PoPs of 50-70% each day through the middle of
the week.  Hot and humid conditions will remain above climo temps
and heat index (average heat index is around 101F for JAX) through
the period with heat headlines possible each day.

&&

.AVIATION...
(06Z TAFS)
Issued at 149 AM EDT Thu Jul 4 2024

Showers and storms have dissipated for the night with VFR
conditions in place for most sites through the morning with a
potential for early morning mist/fog obscurations for VQQ and GNV
occurring between about 08-12z. Convection will build in this
afternoon by around 17-18z with storms forming nearer to the
Atlantic coast and then developing towards inland sites as the
afternoon and evening progresses. Winds will build from out of the
east this afternoon and become more mild and variable in the
evening and overnight hours.

&&

.MARINE...

Prevailing winds have shifted to easterly as high pressure
building over the Mid-Atlantic states wedges down the southeastern
seaboard. Showers and thunderstorms will increase in coverage
across our local waters along and south of a stalled frontal
boundary through today. The frontal boundary will gradually slide
southward dissipate over the local waters by Thursday, with
prevailing onshore winds continuing as high pressure weakens off
the eastern seaboard. Storm coverage will decrease Friday through
Saturday, with prevailing winds then shifting to southwesterly
during the weekend ahead of the next slowing frontal boundary
approaching from the north.

Rip Currents: Surf around 2-3 feet and onset of the Atlantic sea
breeze will bring a Moderate risk of rip currents through
Independence day.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  94  74  95  75 /  30  10  40  10
SSI  90  79  91  79 /  20   0  20  10
JAX  93  75  95  76 /  50  10  40  10
SGJ  91  77  92  76 /  50  10  40  10
GNV  92  74  93  74 /  70  10  60  10
OCF  93  75  94  75 /  70  10  70  10

&&

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

$$