015
FXUS62 KJAX 190200
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
1000 PM EDT Sat May 18 2024

...STRONG TO ISOLATED SEVERE STORMS POSSIBLE ON SUNDAY
AFTERNOON AND EVENING...
...NORTHEASTERLY WIND SURGE ARRIVES EARLY ON MONDAY, BRINGING
BREEZY AND COOLER CONDITIONS THROUGH TUESDAY...
...TEMPERATURES REBOUND TO SEASONABLY HOT LEVELS LATE IN THE
UPCOMING WEEK...

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

.UPDATE...
Issued at 1000 PM EDT Sat May 18 2024

Late evening surface analysis depicts a wavy frontal boundary
extending across the southeastern states. Aloft...a potent
shortwave trough was digging southeastward from the Tennessee
Valley towards the Deep South, creating deep west-southwesterly
flow across our region. Flow aloft over the northeast Gulf of
Mexico is highly diffluent to the south of this potent shortwave
trough, with weaker shortwave energy embedded within the flow
pattern triggering a large area of convection over the loop
current waters of the eastern Gulf of Mexico, with debris
cloudiness and lighter shower activity extending northeastward
across the FL Panhandle and Big Bend region, with a few showers
beginning to develop near the Alapaha River in south Georgia
recently. Cirrostratus blowing off from the convection over the
Gulf of Mexico was blanketing southeast GA and the Suwannee
Valley, with fair skies in place along the I-95 corridor in
northeast FL. A warm and humid air mass otherwise prevails across
our region late this evening, with temperatures at 02Z generally
in the 70-75 degree range, wile dewpoints were in the upper 60s to
lower 70s.

The aforementioned shortwave trough will continue to dig
southeastward towards our area by Sunday evening. This feature
will propel weaker shortwave energy currently traversing the
northeast Gulf of Mexico across our area overnight, resulting in
an increasing area of showers and possibly some low-topped
thunderstorms, mainly after midnight. This activity should remain
below severe limits, with an uptick in coverage expected for
locations along and north of the Interstate 10 corridor during the
midnight through 3 AM time frame, with activity then shifting
southeastward while gradually weakening as it moves into north
central FL during the predawn hours on Monday. Isolated
thunderstorms within this activity will be capable of producing
heavy downpours and lightning strikes, but a lack of CAPE
overnight should keep storms from producing any strong downburst
winds. Lows tonight will remain seasonably warm, as values only
fall to the upper 60s inland and the lower 70s at coastal
locations.

A break in convective activity is expected on Sunday morning, with
showers and thunderstorms then increasing in coverage and
intensity during the afternoon hours, especially along the I-10
and I-95 corridors. The approach of the potent shortwave trough
should steepen lapse rates, with morning sunshine boosting highs
to the 85-90 degree range for locations from Waycross south and
eastward, adding fuel to the atmosphere for strong to potentially
isolated severe thunderstorms. Stronger storms late on Sunday
afternoon will be capable of producing damaging wind gusts of
40-60 mph, small hail, frequent lightning strikes, and heavy
downpours. Activity should push south-southeastward ahead of the
approaching frontal boundary towards coastal locations during the
late afternoon and early evening hours.

&&

.AVIATION...
(00Z TAFS)
Issued at 816 PM EDT Sat May 18 2024

VFR conditions will prevail at the regional terminals through at
least 03Z. The next round of showers and embedded thunderstorms is
expected to push across our region during the overnight hours,
mainly from around 04Z through 09Z. Confidence was high enough to
include vicinity thunderstorms and an MVFR TEMPO group for heavier
showers at SSI from 05Z through 08Z. Confidence was only high
enough to include vicinity showers elsewhere overnight. VFR
conditions should then prevail by 10Z area-wide. Showers and
thunderstorms will redevelop over our region late on Sunday
afternoon, mainly for locations along and east of U.S. Highway
301, with activity generally progressing south-southeastward into
the early evening hours. A few stronger storms will be possible
after 21Z along the I-95 corridor. We included PROB30 groups for
gusty winds and MVFR conditions during heavier downpours at all
terminals except GNV from 19Z-00Z. Confidence was only high enough
for vicinity thunderstorm coverage at GNV. Southerly surface winds
sustained at 5-10 knots this evening will shift to southwesterly
overnight, with speeds diminishing to around 5 knots by 06Z.
Surface winds will continue to veer to westerly after sunrise,
with speeds increasing to around 10 knots by 14Z. A pinned
Atlantic sea breeze boundary east of I-95 may shift surface winds
to southerly at the SSI and SGJ coastal terminals towards 20Z
before thunderstorm activity increases on Sunday afternoon and
evening.

&&

.MARINE...
Issued at 1000 PM EDT Sat May 18 2024

A frontal boundary will remain stalled over our local waters
through Sunday night. The next wave of showers and possibly a few
embedded thunderstorms will occur after midnight through the
predawn hours on Sunday. A break in activity is expected on Sunday
morning, followed by the next round of showers and thunderstorms
during the afternoon and evening hours on Sunday. Strong to
isolated severe thunderstorms will be possible with this activity,
with stronger storms being capable of producing damaging wind
gusts, frequent lightning strikes, and heavy downpours. Seas of
2-4 feet will prevail both near shore and offshore through Sunday
night.

High pressure building over New England on Sunday will then wedge
down the southeastern seaboard during the predawn and early
morning hours on Monday, pushing the frontal boundary south of our
local waters. North-northeasterly winds will surge to Caution
levels of 15-20 knots throughout our local waters on Monday, with
speeds gradually decreasing on Tuesday and Tuesday evening as
high pressure begins to settle directly over our waters. Chances
for showers and a few embedded thunderstorms will persist on
Monday and Monday night. Seas will build to the 3-5 foot range
both near shore and offshore from Monday through Tuesday night.
High pressure will then shift offshore towards midweek,
resulting in prevailing southerly winds across our local waters,
with seas diminishing back to the 2-4 foot range throughout our
local waters.

Rip Currents: Prevailing offshore winds and low wave heights will
keep the rip current risk low at all area beaches on Sunday.
Strengthening north-northeasterly winds early on Monday will
result in a higher end moderate risk at all area beaches that will
persist through at least Tuesday, due to building and increasingly
choppy surf conditions.

&&

.FIRE WEATHER...
Issued at 1000 PM EDT Sat May 18 2024

Westerly transport winds will become breezy after sunrise on
Sunday for locations south of Waycross. West southwesterly surface
winds will also become breezy for locations along and south of the
Interstate 10 corridor by the mid to late morning hours on Sunday.
These breezy winds will combine with elevated mixing heights to
create good daytime dispersion values for locations south of
Waycross, with pockets of high daytime dispersion values possible
for locations along and east of U.S. Highway 301 on Sunday
afternoon. Strong to isolated severe thunderstorms will be
possible for locations along and east of U.S.-301 during the late
afternoon and early evening hours, with damaging wind gusts,
frequent lightning strikes, and heavy downpours possible within
stronger storms. Surface and transport winds will then shift to
northeasterly early on Monday morning, with breezy surface winds
developing along the I-95 corridor shortly after sunrise, with
breezy transport speeds expanding inland during the late morning
and early afternoon hours. These breezy conditions will create
good daytime dispersion values area-wide on Monday. These breezy
northeasterly winds will persist into Tuesday, keeping good
daytime dispersion values in the forecast.

&&

.HYDROLOGY...
Issued at 1000 PM EDT Sat May 18 2024

Water levels along lower portions of the Santa Fe River near the
Three Rivers Estates gauge will rise above flood stage on Sunday
morning, with minor flooding expected to then continue during the
next several days. Otherwise, minor flooding along upper portions
of the Satilla River and also along the Little Satilla River may
result in water levels rising above flood stage along lower
portions of the Satilla River near the gauge at Atkinson by late
in the upcoming week.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  67  83  66  81 /  20  70  30  10
SSI  73  87  70  78 /  40  60  70  20
JAX  71  89  69  81 /  50  60  70  30
SGJ  73  89  71  80 /  30  50  60  40
GNV  71  88  68  86 /  40  20  30  50
OCF  72  88  69  89 /  60  20  20  50

&&

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

$$