115
FXUS62 KJAX 251734
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
134 PM EDT Sat May 25 2024

...New AVIATION...

.UPDATE...
Issued at 1008 AM EDT Sat May 25 2024

No significant updates to the forecast this morning. Two main
concerns today: 1) HOT temps and 2) risk of isolated strong to
severe storms, mainly late this afternoon across southeast GA.

Southwesterly flow and mostly sunny skies through the afternoon will
promote decent mixing, which will send temperatures well into the
low and mid 90s this afternoon with peak heat index values pushing
to near triple-digits, particularly right at the coast. Given the
holiday weekend and outdoor festivities, heat-related impacts and
illness will be more of risk - stay cool and hydrated!

Secondly, in addition to the heat, there will be increasing rain and
storm chances this afternoon. PWAT on the morning RAOB was fairly
minimal (~1.3"), however, an uptick in moisture will accompany a
shortwave that will drop southeastward into SE GA this afternoon and
continue across NE FL this evening. As it does so, an associated MCS
to the northwest will push out sufficient outflow and should
initiate new convection to the west which will drift southwestward
into inland SE GA around 2-4 pm. Meanwhile, the southwest flow
will pin the Atlantic sea breeze and gradually push the Gulf sea
breeze across NE FL. Showers and isolated storms are possible once
these sea breezes interact, generally along the I-95 corridor
late this afternoon. A few storms, particularly across SE GA,
could become strong or marginally severe. The primary threat with
any robust storms will be strong, localized outflow wind gusts
around 40-60 MPH. Anticipate storms to generally track
southeastward around 15-20 mph and eventually fade or shift off
over the waters around midnight.

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

&&

.NEAR TERM...
(Today through Tonight)
Issued at 310 AM EDT Sat May 25 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

A weak surface high pressure ridge is over central and south FL
and is expected to persist into tonight, but strengthen slightly
by late tonight. Aloft, a shortwave trough is passing over the
area this morning but the airmass has stabilized from the daytime
heating with just scattered cirrus debris and a few mid clouds per
IR imagery at this time.

Today, winds will be westerly at about 5-10 mph and will be light
enough for the Atlantic sea breeze to move past I-95 to produce
fairly strong convergence for at least isolated shower and thunderstorms
to develop later in the afternoon. In addition, another shortwave
disturbance looks to push in from the northwest this afternoon
and evening, and will help kick off some isolated to scattered
showers and storms mainly north portions. The forecast POPs
leaned toward HRRR and HREF, and to some extent the FV3. Some of
the models suggest a small MCS is possible coming out of the
northwest in the late afternoon or early evening through southeast
GA and into northeast FL late evening. Uncertain on this scenario
at this time. In any event, isolated storms may be strong to
severe with gusty winds and marginal severe hail given higher CAPE
airmass over southeast GA and fairly strong DCAPE values. SPC has
highlighted north half of the forecast area in a marginal risk (1
out of 5). Highs today will be in the upper 80s to near the mid
90s, which supports heat indices reaching to about 100.

Tonight, isolated to scattered convection is expected, likely confined
over the eastern parts of the forecast area. The convection will
be moving southeastward, and will move into the coastal waters.
Lingering isolated convection will persist offshore after midnight
but move out before sunrise. Light patchy fog possible inland
near I-75 given the light to calm winds, clearing skies, and
sufficiently high dewpoints. Lows in the upper 60s to lower 70s
anticipated.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 310 AM EDT Sat May 25 2024

Ridging extending across the GOMEX begins to shift southward as
troughing swings through the Great Lakes pushing a surface cold
front into the Deep South. Southwesterly flow develops ahead of
the front keeping the Atlantic sea breeze pinned to the coast.
This will allow for hot temperatures to extend all the way to the
beaches. Highs will be in the low to mid 90s with heat indices
around 100 degrees with the highest daytime temperatures focused
along the I-95 corridor each afternoon. Prevailing subsidence and
mid-level dry air will help limit convection Sunday and Monday.
Pre-frontal showers and storms move into SE GA late Monday
afternoon into night.

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 310 AM EDT Sat May 25 2024

One last day of area-wide 90s and heat indices in the upper 90s to
100 on Tuesday. A cold front enters SE GA Tuesday morning
spreading scattered showers and storms across the area from the
northwest. A few stronger storms may be possible Tuesday afternoon
with decent instability and potential additional lift from passing
upper shortwaves. The front then shifts into central FL on
Wednesday and stalls Thursday into Friday focusing convection to
areas south of I-10. Drier and `cooler` air filters into SE GA in
the wake of the front as a surface ridge builds WNW of the region.
The drier air mass will bring a return of cool morning lows in the
60s for the latter half of next week. Highs will then range from
the upper 80s in SE GA to the mid 90s in north-central FL.

&&

.AVIATION...(18Z TAFS)
Issued at 134 PM EDT Sat May 25 2024

Diurnal cumulus has develop ahead of a disturbance that will drop
southeastward into the region this afternoon and evening.
Thunderstorm impacts are possible at most airfields, however
confidence is highest for sites along the I-95 corridor north of
KSGJ. Outside of convection, VFR conditions will persist with
increasing cirrus being pushed out from upwind storms. West winds
will be dominant at inland airfields through the afternoon while
coastal sites shift ESE to SE with the slow-moving Atlantic sea
breeze that should stall near the I-95. By midnight, convection will
fizzle and clouds will scatter out allowing patchy fog to develop
inland. Any fog that develops will quickly erode after sunrise with
VFR conditions and light winds thereafter.

&&

.MARINE...
Issued at 310 AM EDT Sat May 25 2024

No significant winds or seas expected through the Memorial Day
Holiday. Winds will be southwest to west near 10 kt today before
a sea breeze develops in the aftn. Main hazard looks to be
offshore moving thunderstorms, mainly today, but less so Sunday
and Monday. Chance of storms ramps up again Monday night through
Tuesday.

Rip Currents: Looks to be a low-end moderate risk both today and
Sunday with surf near 2 ft or less. Surf is composed of small wind
wave of about 2 ft from the south-southeast and half a foot swell
from the east about 9-10 seconds.

&&

.HYDROLOGY...
Issued at 200 AM EDT Sat May 25 2024

Moderate river flooding is forecast next due to `backwater` is
forecast to begin next week from Thursday to Friday for the Santa
Fe at Three Rivers Estates (lower Santa Fe basin). The Satilla
River basin remains in Minor Flood stage and portions of the
Suwannee are expected to rise into Minor Flood stage by early next
week.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  93  70  93  71 /  40  30  10   0
SSI  91  73  90  73 /  20  30  10   0
JAX  95  71  95  71 /  30  30  10   0
SGJ  94  72  93  72 /  30  20   0   0
GNV  94  68  93  68 /  30  10  10   0
OCF  94  69  95  69 /  20  10  10   0

&&

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

$$