724
FXUS62 KJAX 230731
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
331 AM EDT Mon Sep 23 2024

...MINOR TIDAL FLOODING CONTINUES WITH ST JOHNS RIVER...
...PLEASE READ THE *MESSAGE OF THE DAY* IN THE NEAR TERM
DISCUSSION...

.NEAR TERM...(through Tonight)...

Outside of cloud cover along a surface trough in far northern SE
GA, clear skies and calm conditions will favor the formation of
patchy fog in inland areas through the rest of the morning.
Locally dense fog has potential (30-60%) to develop along the I-75
& Highway-301 corridors in NE FL around dawn. Fog should lift to
a low stratus deck and break up between 9/10 AM.

A stagnant pressure pattern remains in place, keeping conditions
mostly dry again amid anomalously warm (stable) air aloft. The
aforementioned weak surface trough in SE GA is providing enough
convergence along it to sprout isolated showers near the Altamaha
River early this morning. That trough will move very little as it
dissipates today but, with diurnal heating, there`s a slight
chance (~20%) that a few spotty afternoon showers develop along
once again this afternoon. Given the warm air aloft, probability
of thunderstorm development is near nil.

Otherwise, temperatures will warm a degree or two over
yesterday`s highs with inland areas reaching the low 90s. Temp
differential will generate an Atlantic sea breeze this afternoon
which will keep the coast cooler, generally in the mid/upper 80s.
Little change in the pattern through tonight with lows in the
upper 60s to low 70s and potential for patchy inland fog.


~~ MESSAGE OF THE DAY ~~


While there is still uncertainty regarding the disturbed area of
weather in the northwestern Caribbean, please take advantage of
this tranquil period of weather over the next couple of days to
review plans and ensure necessary supplies are assembled in the
event of tropical storm or hurricane impacts later on this week.
Please pay close attention to the forecast information locally as
well as from the National Hurricane Center to stay abreast of the
latest forecast information.

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

&&

.SHORT TERM...(Tuesday through Wednesday night)

High pressure over the region will gradually begin to shift east
towards the western Atlantic as an upper level trough over the
central CONUS begins to digs south towards the Gulf coast states
by the end of this forecast period. Early morning fog on Tuesday
will dissipate by the early daylight hours, with another day of
mainly dry conditions on Tuesday as high pressure will begin to
shift towards the east. Come Wednesday, the weather pattern will
be heavily influenced by the evolution of the broad area of low
pressure currently located over the northwestern Caribbean Sea and
the aforementioned upper level trough. The NHC currently
anticipates the broad area of low pressure to develop into a
tropical depression or storm with a high chance (70%) of formation
during the short term. Some moisture is expected to advect over
north central FL counties from Wednesday afternoon and through the
overnight hours into Thursday.

Temperature highs for in the mid to upper 80s along the coast,
with highs in the lower 90s for inland locations on Tuesday.
Cooler max temperatures on Wednesday as cloud cover will increase
as moisture moves into the area. Overnight lows expected to be in
the 70s across SE GA and NE FL.

&&

.LONG TERM...(Thursday through Sunday)

The forecast period is still uncertain as we continue to
monitor the evolution of the broad area of low pressure over the
northwestern Caribbean Sea. Guidance continues trending towards
the development into a tropical system, NHC now gives chance of
formations over the next 7 days as high (90%). As stated in the
short term discussion, the exact path of any system that may
development will be contingent on the upper trough that is
expected over to influence whether the system takes a more
northward or northeastern path. This of course will leave the
extent of any local impacts from this system still uncertain. But
an abundant amount of rainfall from the system will be possible
during the end of the week, with chances of precipitation
beginning to dwindle over the weekend.

Be sure to restock supply kits and review family evacuation plans.
Monitor official tropical forecasts from the National Hurricane
Center at hurricanes.gov and local emergency management officials.

&&

.AVIATION...(06Z TAFS)

Patchy fog may lead to intermittent impacts at all sites, ranging
from MVFR to LIFR visibility. Per usual, fog and visibility will
become degraded most between 10-12z this morning. Fog will lift to
low stratus and scatter out quickly by 15z or earlier, followed
by VFR conditions and light winds. A light sea breeze will push
inland this afternoon around 6-9 knots; winds will taper off and
trend calm under nearly clear skies after sunset.

&&

.MARINE...

A generally weak pressure pattern and light onshore flow
continues through Tuesday. Southeasterly winds strengthen through
Wednesday in response to a tropical system that is expected to
develop quickly from an area of disturbed weather in the
northwestern Caribbean Sea and then move northward into the
eastern Gulf of Mexico. There is still uncertainty in the scale,
intensity and track of the tropical system as it develops. All of
those factors will influence the local coastal water conditions.
At the moment, Small Craft Advisory conditions are expected to
develop by Wednesday night with gales possible Thursday.
Conditions are expected to improve quickly Friday and through the
weekend as the tropical system rapidly tracks northward.

RIP CURRENTS...Moderate risk of rip currents continues, mainly
during the afternoon as the sea breeze develops, today and again
Tuesday. Building breakers (3-5 feet) and increasing southeasterly
flow on Wednesday enhances risk to *High* levels for at least NE
FL beaches. Dangerous surf conditions are likely Thursday as
influences from tropical system are most likely to begin.

&&

.HYDROLOGY...

Minor tidal flooding continues within the St Johns River basin
through mid week before influences from a tropical system tracking
northward across the eastern Gulf of Mexico begin. Current
probabilistic forecast guidance, understandably, has considerable
spread in potential forecasts given the forecast uncertainty in
the possible evolution/track of the tropical system. Strong
southeasterly flow in response to the tropical system may bring
tidal levels back into Minor or low-end Moderate flood at times of
high tide along the Atlantic coast by Thursday evening. Given the
current elevated tides already ongoing in the St Johns River, the
potential for Moderate Flooding and impacts are possible during
at least Thursday and Friday high tides.

Preparations should be considered for low-lying areas along the
St Johns River, especially in the Downtown Jacksonville, San
Marco, & Riverside areas along with other flood prone locations in
the upper St Johns in Clay, St Johns, and Putnam counties.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  92  70  91  70 /  10  10   0   0
SSI  87  75  86  76 /   0   0   0   0
JAX  91  71  89  74 /   0   0   0   0
SGJ  88  75  88  76 /   0   0   0   0
GNV  91  69  91  72 /   0   0   0   0
OCF  93  70  93  74 /   0   0  10   0

&&

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

GA...None.
AM...None.
&&

$$