964
FXUS62 KJAX 180528
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
128 AM EDT Wed Sep 18 2024

...New AVIATION...

.NEAR TERM...
(This afternoon and Tonight)
Issued at 204 PM EDT Tue Sep 17 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

This afternoon...Drier airmass aloft will keep most of SE GA
rain-free, while diurnal heating into the mid/upper 80s and inland
moving sea breeze fronts across NE FL will be enough to trigger
scattered showers and isolated storms, mainly south of the I-10
corridor, with best chances of any isolated storm activity across
Marion/Putnam/Flagler counties. A few storms could have some gusty
winds up to 40 mph/brief heavy downpours, but not expecting any
significant issues.

Tonight...Overall steering flow becomes Southwesterly and this
will begin to lift the old frontal boundary currently across
Central Florida northward into the NE FL/SE GA area during the
overnight hours. A few isolated showers/storms will be possible
across inland NE FL early this evening, otherwise expect a few
isolated showers possible over land areas as this feature lifts
northward through the night, although rainfall chances will remain
less than 20%, while scattered showers and isolated storms will
develop over the Atlantic Coastal waters as this feature lifts
northward. Patchy fog is expected again over inland areas as winds
become near calm, with locally dense fog possible. Low temps just
slightly warmer than last night with lows in the upper 60s over
inland areas and lower/middle 70s along Atlantic Coastal Counties.

&&

.SHORT TERM...
(Wednesday through Thursday night)
Issued at 204 PM EDT Tue Sep 17 2024

Remnant stacked low pressure over far northern GA will lift north
and eastward further away from the area throughout Wednesday,
which in response will help pull the nearly stationary weak front
south of the area into northeast FL/southeast GA. As a result,
higher chances for afternoon/evening convection will return to the
area on Wednesday, and especially for northeast FL. There may be
some pockets of lingering drier aloft which could limit coverage
to being more than of the scattered variety. However, on the flip
side of this point, some drier air intrusion could help to produce
some stronger downbursts up to 40-55mph in some isolated storms,
especially with cell mergers/boundary collision situations. The
front lifting northward will also help high temps bump up a little
bit compared to today, with generally mid to upper 80s to some
low 90s south.

Some convection could linger into the first part of Wednesday
Night with the boundary in the area, and also should keep some
clouds around for most of the night as lows fall closer to normal
in the upper 60s to low 70s. Thursday, the frontal boundary
becomes more diffuse over the area as the upper trough overhead on
WEdnesday starts to lift northeastward. This will keep most of the
area under the influence of the more subsident upstream side of
the same trough, and also rotate in some drier air as a more
northwesterly flow develops both near the surface and aloft.
Diurnal convection will therefore will revert back towards a more
limited/isolated capacity on Thursday, with the best chances for
isolated to widely scattered coverage being south of I-10 in
northeast FL as well as near the pinned sea breeze. The lower
convective coverage and drier northwesterly flow combo generally
offset to result in similar temperatures Thursday as compared to
Wednesday.

&&

.LONG TERM...
(Friday through next Tuesday)
Issued at 204 PM EDT Tue Sep 17 2024

An overall drier than normal pattern looks to be in store for most
of the long term, as guidance is coming into better agreement with
the upper level pattern. The upper low/trough south of New England
that lifts away from the area on Wednesday/Thursday looks persist
a generally broad/weak trough overhead for Friday before the low
dives southward this weekend, north and east of the region into
the western Atlantic. This will result in an increasingly
subsident flow aloft on the west side of the same low, as well as
a coinciding surface ridge building southward along the eastern
seaboard, dropping the above mentioned frontal boundary well south
of the region. The extent of how far south the upper level energy
digs will certainly play a big role in how far south the frontal
boundary drops, and therefore the precip/temperature outlook.
However, confidence is increasing with respect to below normal
layer moisture, below normal chances for convection, and
temperatures trending towards below normal for the weekend and
possibly into the start of next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 128 AM EDT Wed Sep 18 2024

A lone storm over KJAX moves away within the next hour. Potential
for early morning fog developments by around 08-12z for inland
sites, reducing visibility to MVFR and IFR levels and then lifting
by around sunrise. West-southwesterly winds around 5 kts develop
today. The Atlantic sea breeze shifts inland to the I-95 corridor
shifting winds to southeasterly. Scattered showers and storms will
be possible in the afternoon across the TAF sites. A couple of
storms may be strong at the KJAX, KCRG and KSGJ when the sea
breezes collide.

&&

.MARINE...
Issued at 204 PM EDT Tue Sep 17 2024

Weak flow pattern will remain in place through Wednesday with
daily sea breeze for the near-shore waters and expect to remain
headline free through the short term period. Frontal passage on
Thursday will be followed by high pressure building to the north
of the local waters Friday through the upcoming weekend.
Northeast/Onshore flow will set in on Friday and increase through
the weekend, with at least Small Craft Exercise Caution headlines
expected and possible Small Craft Advisories by the Sunday time
frame as winds/seas continue to build.

Rip Currents: High risk of rip currents and rough surf/breakers of
3-5 ft today will become Moderate on Wednesday in the light wind
flow pattern as surf/breakers subside to 2-3 ft.

&&

.HYDROLOGY...
Issued at 204 PM EDT Tue Sep 17 2024

No changes planned to current headlines as Coastal Flood Warning
will remain in place for most of this week and into the upcoming
weekend for the St. Johns River Basin as Moderate flooding is
expected to continue due to the freshwater inflow along with high
tides due to the full moon with peak water levels of 2 to 2.5 feet
above MHHW. Will continue Coastal Flood Advisory for Minor
Flooding along the NE FL beachfront locations, mainly due to the
higher tides due to the full moon phase with peak water levels of
1.5 to 2 feet above MHHW.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  86  68  87  68 /  40  10  10   0
SSI  85  72  85  72 /  40  20  10   0
JAX  89  71  88  71 /  50  30  20  10
SGJ  90  73  88  73 /  50  40  20  10
GNV  90  70  89  70 /  50  10  30   0
OCF  91  72  90  71 /  40  10  30   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Warning until 5 AM EDT Thursday for FLZ033-038-125-
     132-137-225-325.

     Coastal Flood Advisory until 5 AM EDT Thursday for FLZ124-133-
     138.

     High Rip Current Risk until 5 AM EDT early this morning for
     FLZ124-125-133-138.

GA...High Rip Current Risk until 5 AM EDT early this morning for
     GAZ154-166.

AM...None.
&&

$$