540
FXUS62 KJAX 271746
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
146 PM EDT Mon May 27 2024

...New AVIATION...

.UPDATE...
Issued at 1109 AM EDT Mon May 27 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

Not many substantial changes to the forecast this morning with
timing of potentially strong storms and hot afternoon temps
tracking well against the inherited forecast.

Stagnant pattern over the last few day has started to break down
with the mean low layer high shifting off to the southeast this
morning while the upper ridge flattens and an upstream trough
carves its way into the Deep South. Strengthening southwesterly
(offshore) flow will stifle the Atlantic sea breeze and confine
it the immediate coast today. Breezy winds will enhance mixing
and promote hotter conditions this afternoon as temps soar to the
mid 90s, with heat index into the upper 90s to near 100 once
again. Temperatures are already running 2-4 degrees warmer than
this time yesterday.

Significant subsidence capping in the low levels will inhibit
storm chances through most of the day until a prefrontal trough
enters SE GA early this evening from the northwest. While the
latest RAOB verifies the strong low-level cap, there is also very
steep lapse rates aloft which will foster a surplus (2,500+ j/kg)
of elevated instability through tonight. These competing factors
have kept confidence in the low side. That said, isolated strong
to marginally severe storms cannot be ruled out, with primary
threats being hail and downburst/outflow winds. The threat appears
to be more likely this evening across SE GA rather than NE FL as
dry air and surface inhibition remain prominent into the late
evening there.

&&

.NEAR TERM...
(Today through Tonight)
Issued at 335 AM EDT Mon May 27 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 transition day begins as the sfc ridge axis will be south of the
area today while a cool front moves in from the northwest later
tonight. Some low stratus will be possible over the western zones
as well as patchy fog which will dissipate by 8-9 AM. Deep layer
flow is southwest averaging about 15-20 kt but increasing to near
25 kt as shortwave troughing moves into AL and parts of GA by
late aftn and early evening. Anticipate scattered to numerous
showers and storms convection to move into our northwest zones by
the 22z-03z time frame, as suggested by CAM model solutions. The
environment is conducive to a few strong to possibly severe
storms with marginal shear values of 30 kt, DCAPE of about 1000
J/kg, MLCAPE of around 1500 to near 2500 J/kg. Strong to damaging
wind gusts and marginally severe hail are possible. SPC has placed
the far northwest part of the forecast area in a slight risk of
severe storms, with marginal risk down to FL/GA state line. Otherwise,
it will be a hot and breezy day with southwest to west winds of
about 10-15 mph, with Atlantic sea breeze having a tougher time
pushing inland compared to yesterday. Max temps in the lower to
mid 90s, but fortunately dewpoints will mix lower in the aftn and
keep heat indices in check to below 102. Should see increased
mid/high clouds coming in from the northwest and west late today.

Tonight, as mentioned, scattered to numerous showers and storms
should be ongoing over southeast GA this evening. As the shortwave
trough transverses the area, the semi-organized convection, possibly
in short segments occasionally generated by outflow boundaries,
will shift east to southeast. The airmass will remain unstable as
dewpoints will be around 70 or lower 70s. This should further
support convection persisting into the overnight hours and pushing
into northeast FL near and after midnight. Isolated strong to
severe storms may persist through around midnight mainly over
southeast GA, but a couple of strong storms possible around the
Suwannee Valley area overnight. Lows will be muggy in the lower to
mid 70s with light westerly or southwest winds continuing
overnight.

&&

.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 335 AM EDT Mon May 27 2024

A cold front over northeast FL will gradually shift and stall over
north-central FL on Wednesday as high pressure ridging builds
south across the MS River Valley. Showers and storms will be
ongoing along the frontal boundary Tuesday morning. Dry, "cool"
air filtering in from the northwest in the wake of the front will
mostly suppress convection over SE GA on Tuesday. Best moisture
and lift will remain along the frontal boundary focusing
convection mainly south of the I-10 corridor. A few showers and
storms may form along the pinned Atlantic sea breeze in the
afternoon with better chances along the NE FL coast due to the
front interacting with the sea breeze. Rain wanes Tuesday night
with the loss of daytime heating and the front weakening. Dry
airmass builds across the area with PWATs < 1 inch. Mostly dry
conditions prevail on Wednesday with a few showers possible in
north-central FL along the lingering frontal boundary. Hot days
continue with highs in the low to mid 90s each day. Heat indices
will be around 100 degrees in NE FL on Tuesday. The drier air will
help keep heat indices below 100 on Wednesday.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 335 AM EDT Mon May 27 2024

Moisture gradually returns with developing southwesterly flow on
Thursday. A frontal boundary stalled over NE FL on Thursday will
shift southward Friday into the weekend as high pressure builds to
the north and into the mid-Atlantic states this weekend. Rain will
primarily be in NE FL on Thursday where the best moisture is and
lingering lift from the frontal boundary. Passing upper shortwaves
and an increase in moisture will lead to isolated to scattered
showers and storms area-wide on Friday. Pattern returns to sea-
breeze driven convection for the weekend with high pressure
ridging over the SE US. Onshore flow develops over the weekend
with highest rain chances focused along the I-75 corridor where
the sea breezes will likely collide. Highs will then range from
the upper 80s in SE GA to the low 90s in north-central FL.
Overnight lows will be "cool" in the 60s

&&

.AVIATION...(18Z TAFS)
Issued at 143 PM EDT Mon May 27 2024

VFR cumulus and a west to southwesterly wind prevails at all sites
with a wind shift to an ESE to SE direction at KSSI, KSGJ, and
KCRG over the next couple of hours as the pinned sea breeze
attempts to push inland. A cool front moving in from the northwest
tonight will bring potential for t`storms, mainly at KSSI after
00z. Weakening of the front and the supporting disturbance will
lower t`storm chances across most of NE FL through the overnight
hours with VCSH more likely. No concern for fog or low stratus
given the continuation of light westerly winds around 4-8 kts and
mostly cloudy skies overnight. The front will slowly track south
toward central FL through Tuesday with skies clearing and winds
turning WNW in its wake.

&&

.MARINE...
Issued at 335 AM EDT Mon May 27 2024

West to southwest winds initially today but will shift to southeast
and south during the aftn at 10-15 kt. Seas remain low near 2 ft
per buoys but will rise up slightly later today as winds ramp up
further. Sustained sfc winds near 15 kt possible by evening, with
a weak cool front and upper level disturbance approaching from
the northwest. Some t-storm activity possible late tonight and on
Tuesday. The front will move south of the area by Wednesday but
will stall and become diffuse thereafter. Winds will be onshore
later in the week as high pressure ridge builds in from the north.

Rip Currents: A low-end moderate risk again today with surf possibly
a tad higher but overall little difference from yesterday. At
least initially, up to 3 wave groups noted in buoys this morning,
with a long period swell near 14 seconds that is very small. Low
risk is in place for southeast GA beaches. Longshore current
likely weak from the south. Similar conditions appear for
Tuesday.

&&

.HYDROLOGY...
Issued at 330 AM EDT Mon May 27 2024

Moderate river flooding is forecast end of the week on the Santa
Fe at Three Rivers Estates, just touching the moderate category.
The Satilla River basin remains in Minor Flood stage at Atkinson
(but coming down) and portions of the Suwannee are expected near
Minor Flood stage this week. Minor flooding will be possible
towards mid to late for the lower Santa Fe River near the gauge
at Hildreth.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  92  71  92  67 /  40  50  10  10
SSI  92  73  91  72 /  20  40  20  10
JAX  95  73  94  69 /  10  30  20  10
SGJ  94  73  93  72 /   0  20  30  10
GNV  92  72  93  67 /   0  30  30  10
OCF  93  72  93  70 /   0  20  40  10

&&

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

$$