518
FXUS62 KJAX 191743
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
143 PM EDT Sun May 19 2024

...New AVIATION...

.UPDATE...
Issued at 955 AM EDT Sun May 19 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

Areas of low clouds over southeast GA will slowly break up in the
next couple of hours, while the westerly flow in the low levels
helps mix out patchy low clouds in northeast FL as well. High
clouds are moving out and anticipate strong heating today with
scattered to broken cumulus developing. Have tweaked high temps up
a couple of degrees for the update. The forecast overall looks
good with scattered to numerous showers and storms developing,
with greater coverage generally over southeast GA near the slow
moving cool front. Amid cool temps aloft of -10c to possibly -12c
at 500 mb, this will generate some moderately high CAPE values of
about 2500 J/kg, maybe near 3000 J/kg per modified sounding. This
along along with some shear values of about 20-30 kt will support
isolated strong to severe storm activity this afternoon and
evening. Winds aloft are generally unidirectional which is
basically keeping the shear values lower than yesterday. One of
the main threats is strong gusty winds given the high DCAPE values
of about 900-1100 J/kg anticipated. A couple of areas in the
greater strong storm threat are over southeast GA near the
Altamaha Basin down to into coastal southeast GA, and then also
isolated strong activity possible near I-75 over northeast FL.
Confidence is low to moderate at this time. Some adjustments were
made to the POPs for rest of today and into the overnight hours,
but rest of the forecast in good shape.

&&

.NEAR TERM...
Issued at 355 AM EDT Sun May 19 2024

A wave of showers and thunderstorms ahead of a slow moving, nearly
stalled cold frontal boundary from the west has brought some late
night and early morning rainfall to portions of eastern SE GA along
and south of US highway 84 to areas over NE FL from Gainesville
northeast to the Jax Beaches. These showers and storms will end
by sunrise.

Cold front will stall near NE FL today with partly cloudy skies
late this morning through afternoon and west to southwesterly
winds 8-12 mph, a bit breezier across north central FL towards the
Gulf coast 10-15 mph. Strong heating due to the high sun angle for
mid to late May (nearly one month before the upcoming summer
solstice) will raise high temperatures into the upper 80s with
isolated 90 degree readings along the St Johns river basin and
I-95 corridor over NE FL as the Atlantic seabreeze stays pinned
near the immediate coast. A positively tilted mid level trough
currently over northern GA will shift southeast into the area
through this afternoon with shortwave energy rounding the base of
the trough that will become closed with southeast extent. This
will cool mid level lapse rates over the area with thunderstorms
developing over north central Fl this afternoon with a secondary
focus over SE GA north of Waycross late this afternoon that will
move southeast into the Jacksonville area by around sunset and
then shift off the NE FL coast before midnight. Dewpoints around
70 along the coast and upper 60s inland will create strong CAPE
values over 2,000 J/KG while the closed trough will cool mid level
temperatures to -11 to -13 C which will steepen mid level lapse
rates. Strong 0-6km shear of 30-40 knots will also be present and
the Storm Prediction Center has a Marginal threat of Isolated
Severe T`storms for most of the area as the ingredients mentioned
will support large Hail and isolated strong to severe wind gusts
up to 60 mph. Not expected widespread heavy rainfall today, but
pockets of 1 inch totals will occur closer to the coast where
best focus for storms will be with a few higher isolated amounts
to 2 inches possible.

Storms should exit into the Atlantic by midnight and the cold front
will clear southeast of the area overnight with northerly to
northeasterly winds winds turning northerly 5-10 mph inland and
breezier at the coast 10-15 as high pressure builds down from the
Mid Atlantic and northeast coastline. Low stratus clouds will sink
south along the Southeast coast into SE GA with lows in the mid
60s over SE GA and the upper 60s over NE FL.

&&

.SHORT TERM...
(Monday through Tuesday night)
Issued at 355 AM EDT Sun May 19 2024

Upper trough will move over forecast area Monday, then gradually
shift just S of forecast area Monday night, continuing further S
Tuesday. Latest consensus guidance suggests continued potential
for scattered showers/ t-storms Monday with onshore flow pattern.
Guidance suggests showers mainly offshore Monday night, but
potential for coastal showers moving onshore ne FL Tuesday with
continued onshore flow.

Onshore flow pattern will result in somewhat lower high temperatures
eastern counties with upper 70s/lower 80s coast and I-95 corridor,
a little warmer further inland.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 355 AM EDT Sun May 19 2024

Upper ridge of high pressure will build over the forecast area
during this period, resulting in mainly dry and warm conditions.
An exception could be on Saturday when a weak shortwave passes
over the area, which consensus guidance suggests could lead to
scattered showers/t-storms. Near normal temperatures are expected
on Wednesday, with highs lower 80s coast, mid-upper 80s inland.
Slightly above normal temperatures are expected Thursday through
Saturday with high temperatures upper 80s coast, lower 90s inland
with low temperatures through the period in the 65-70 range.

&&

.AVIATION...
(18Z TAFS)
Issued at 140 PM EDT Sun May 19 2024

VFR clouds around at this time with scattered to broken cumulus
around 3500-4500 ft. First signs of convection so far over inland
southeast GA, but deepening cumulus field will result in chance
of showers and storms rest of the aftn with TEMPO groups in place,
with lowest confidence for SGJ and GNV at this time. Could be strong
gusty winds that accompany storms around SSI and then near JAX by
22z and 00z, respectively. Showers and storms expected to diminish
in coverage and intensity after 02z-04z time frame as frontal boundary
sags southward. Low clouds will begin to develop overnight into
Monday morning that may be close to IFR but mainly MVFR. Sfc winds
prevail from the west about 8-12 kt and will shift to northerly
and northeast by Monday morning.

&&

.MARINE...
Issued at 355 AM EDT Sun May 19 2024

A slow moving cold front will stall over the coastal waters today
with numerous showers and thunderstorms late this afternoon into
the early evening hours. Some of these storms may contain strong
gusty winds and heavy downpours. Westerly winds will turn southerly
this afternoon due to the Atlantic seabreeze and then become breezy
from the north and northeast overnight into Monday as a secondary
cold front pushes south of the waters and high pressure wedges
down from the Mid Atlantic coast against a low pressure through
early next week. High pressure builds directly over the waters
during the middle part of next week.

Rip Currents: Low risk of Rip Currents today at all area beaches.
A moderate risk of rip currents is forecast for NE FL and SE GA
beaches Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  65  84  63  86 /  20  10   0   0
SSI  69  79  69  81 /  50  20   0  10
JAX  67  82  65  83 /  60  40  10  20
SGJ  68  81  69  82 /  60  40  20  30
GNV  67  84  63  86 /  40  60   0  20
OCF  68  85  65  86 /  10  50  10  20

&&

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

$$