676
FXUS62 KJAX 201250
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
850 AM EDT Fri Sep 20 2024

...New UPDATE...

.UPDATE...
Issued at 842 AM EDT Fri Sep 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

Forecast on track as Northerly steering flow becomes more
Northeast this afternoon as weak surge of onshore/NE flow develops
today and pushes the East Coast sea breeze inland this afternoon.
Limited moisture aloft with PWATs around 1.5 inches might be
enough to squeeze out a few afternoon/early evening showers across
inland NE FL but instability appears limited so any thunderstorm
chances remain less than 10% at this time. Max temps will top out
in the middle 80s along the Atlantic Coast prior to the sea breeze
pushing onshore and into the upper 80s over inland areas, with a
few near 90 degree readings possible over inland NE FL/I-75
corridor. Light onshore flow conditions continue tonight with a
few coastal showers possible towards morning along the NE FL
coastal areas, otherwise mostly clear inland with patchy/areas of
fog towards morning. Lows in the upper 60s inland and lower to
middle 70s closer to the Atlantic Coast.

&&

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

Light fog has started to develop across portions of southeast GA
near the Altamaha river. Amid clear skies and calm conditions,
it`s possible for locally dense fog to develop toward sunrise
across inland areas of SE GA north of Waycross.

A weak boundary stalled across north central FL will become more
diffuse through the day while a surface ridge builds to the north.
Though forecast soundings are offering generous diurnal instability
(SBCAPE ~1500 j/kg) this afternoon, the dry air aloft will keep PoPs
isolated at best and focused across north-central FL. Any lingering
showers this evening will fade quickly and be followed by mostly
clear skies which may allow patchy fog development inland early
Saturday. The onshore flow will keep the beaches cooler today with
temps peaking around the low/mid 80s while inland areas push into
the upper 80s.

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...(Saturday through Sunday night)

Breezy northeasterly flow through the weekend as high pressure
continues to build over the region. Drier air (PWATs <=1.5") over
the area will limit precipitation chances through the weekend for
most locations. Northeasterly flow may bring some showers and
storms onshore along coastal locations south of the JAX metro
during the afternoon both Saturday and Sunday, with PoPs currently
around the 20% to 35% range. The coastal flood advisory will
remain in place through Saturday evening as the combination of
northeasterly flow and high tide will bring about some minor
flooding along the coast. Temperature highs for this weekend will
be in the mid to upper 80s, with Sunday expected to be slightly
warmer as the northeasterly flow begins to weaken a bit. Overnight
lows again expected to be in the upper 60s for locations across
SE GA and in the lower 70s across NE FL.

&&

.LONG TERM...(Monday through Thursday night)

The dry weather will continue during the early half of the
upcoming week as the dry airmass and high pressure is expected to
remain over the region into Tuesday. Uncertainty in the
development of a tropical cyclone over the northwestern Caribbean
Sea during the upcoming week leaves the back half of the forecast
period still in question. With the models differing in the
evolution of the eastward moving trough from the High Plains has
led to run-to-run shiftiness and a wide envelope of possible
tracks among the ensemble models. At this time, NHC still has
chance of development at 40% for the area in the northwestern
Caribbean Sea.

&&

.AVIATION...
(12Z TAFS)
Issued at 725 AM EDT Fri Sep 20 2024

A few patches of LIFR conds in fog/low clouds at SSI early this
morning while some brief MVFR fog at VQQ should all fade in the
13-14Z time frame, as conds become VFR for all locations with NE
winds developing today in the 8-12 knot range along with fair
weather SCT cumulus cloud deck in the 2500-4000 ft range. Rain
chances remain around 20 percent or less, so have left out of the
TAF forecast for now. VFR conds continue this evening with
decreasing NE winds after sunset. The near calm winds over inland
TAF sites will support MVFR fog at VQQ/GNV in the 06-12Z time
frame while the light onshore flow along the Atlantic Coast will
support some isolated showers over the waters, but likely only
some SCT strato-cu clouds in the 1500-2500 ft range for the
Coastal TAF sites at this time.

&&

.MARINE...

Northeast winds will increase today as an area of high pressure
builds from the north. As winds and seas build, small craft will
need to exercise caution on the local waters through Saturday. By
Sunday, flow turns onshore through as the high weakens and settles
to the northeast. A weak pressure pattern will set up through the
first half of next week before a cold front approaches from the
northwest during the latter part of next week.

RIP CURRENTS...There will be a moderate risk of rip currents today
with risk increasing to High by Saturday as surf heights rise amid
the breezy onshore flow.

&&

.HYDROLOGY...

Due to the compounding effects of lingering runoff from recent
heavy rains, onshore flow, and high astronomical "spring" tides,
minor coastal flooding is anticipated this morning and likely
through the weekend. The flooding potential will be greatest
around times of high tide. A Coastal Flood Advisory continues for
the St Johns River basin (including the Intracoastal Waterway) and
Atlantic coast of NE FL. This morning the Advisory has been
expanded northward to cover the stretch of the SE GA
beaches/sounds Tidal flooding should lower through Sunday and into
Monday as astronomical departures decrease and onshore flow eases
up.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  88  67  87  67 /  10   0   0   0
SSI  83  73  82  73 /  10  10   0   0
JAX  86  70  85  72 /  20  10  10   0
SGJ  85  73  85  74 /  10  10  30  10
GNV  89  69  88  70 /  20  10  10   0
OCF  90  69  90  72 /  30  10  20   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 5 AM EDT Sunday for FLZ033-038-124-
     125-132-133-137-138-225-325.

GA...Coastal Flood Advisory until 5 AM EDT Sunday for GAZ154-166.

AM...None.
&&

$$