634
FXUS62 KJAX 171720
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
120 PM EDT Fri May 17 2024

...New AVIATION...

.UPDATE...
Issued at 939 AM EDT Fri May 17 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

Strong thunderstorms have moved onshore from the Gulf this
morning, gradually weakening as they move eastward. Light rain
will be present over much of the area for the next few hours, with
thunderstorm potential continuing for the next hour or so over
Marion county.

Conditions still look favorable for another round of strong to
isolated severe thunderstorms over southeast Georgia moving in
from the northwest this evening. The main hazard will be gusty
winds, although locally heavy rainfall and an isolated tornado
cannot be ruled out. Timing for this round of thunderstorms looks
to be about 5PM-11PM.

&&

.NEAR TERM...Today and Tonight...

A broad, thick shield of cloud cover associated with a severe squall
line well to the west will overspread the region this morning. This
should limit fog potential for most of the area. The severe squall,
though intense at the time of this discussion, will decay as it
tracks eastward into the stable airmass situated across northeast
FL. A few remnant light showers and sprinkles may accompany the
mostly cloudy skies but thunderstorm chances will be near nil this
morning.

The cloudy conditions will hamper heating some while warm southerly
flow attempts to compensate. End result will be for temps to rise to
the mid/upper 80s in southeast GA and upper 80s and low 90s in
northeast and north-central FL today.

Late this evening and tonight, a weak surface low will track just to
the northeast across GA and drag an attendant warm front across the
entire area. The moist and unstable airmass that will follow behind
it will set the stage for an active period of weather through the
day Saturday; however, there is potential for a few bouts of
isolated to scattered convection across southeast GA late tonight as
a lagging shortwave ejects northeastward. Forecast soundings and the
latest HREF instability progs suggest the potential for strong,
possibly severe storms, storms. That said, there is lingering
uncertainty regarding evolution of the convection and whether
storms (if they develop far enough south) will be surface-based or
elevated. SPC has kept a Marginal Risk for the interior portions
of southeast GA and extended south into the Suwannee Valley to
account for the uncertainty.

Given the moisture surge behind the warm front, lows will be more
mild tonight and generally read in the low 70s. Otherwise, if winds
subside enough, patchy inland fog may develop across portions of NE
FL late tonight.

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)

Saturday, a compact southern stream trough over the mid MS valley
will shift east along the OH and TN river valleys during the day
with embedded shortwave energy running through the base of the
trough from the Gulf coast into the southeast states. The trough
will support a weak surface low with a trailing cold front that
will move eastward across the deep south states. Southwest low
level flow will yield moisture levels over the area between 1.60
and 1.80 inches, beyond the 75th percentile and should support
healthy rainfall rates with rounds of showers and storms that will
spread northeast from the FL panhandle along inland SE GA early
and then inch farther east through much of the area Saturday
afternoon. A band of scattered to numerous Storms will likewise
arrive by the early afternoon inland and mid to late afternoon
over locations closer to the coast. The storm prediction center
has a Slight risk (category 2 out of 5) for isolated severe storm
potential for areas in SE GA, the Suwanee Valley and locations
along and north of I-10 as strong 0-6km bulk shear values 50-60
knots will be coincident within a divergent nose of an approaching
250 mb jet streak and will help create a threat for gusty winds
approaching 60 mph with more intense cells. Mostly cloudy skies
will remain over SE GA and trend towards partly cloudy over NE FL
where highs will be warmer into the low 90s with isolated mid 90s
possible along I-95 corridor south of Jacksonville into the
southern St Johns basin as southwest winds pin the Atlantic
seabreeze to the immediate NE FL coast.

Saturday night will be moist and muggy with scattered to numerous
showers and T`storms continuing due to unstable southwest flow
ahead of the cold front still dragging through south GA overnight.
Lows will be in the low 70s over NE FL and the upper 60s over SE
GA with light southwest winds under mostly cloudy skies.

Sunday, the mid level trough will extend from the Mid Atlantic
coast southwest into the southern Appalachian and shift south and
east into the Carolinas into south GA through the day. This will
slowly drag the cold front north to south through our area with
scattered to numerous showers and T`storms. Strong to potentially
severe thunderstorms will again be in play as cooler mid level
temperatures from the core of the trough overlapping strong
surface heating will create a threat for gusty winds and large
hail as storms form along the cold frontal boundary and the pinned
Atlantic seabreeze. Mostly cloudy skies ahead of and partly
cloudy to mostly sunny skies behind the boundary with light
southwest winds shifting to more westerly late in the afternoon
over SE GA and then into NE FL by evening. Highs will be less warm
and closer to normal for most areas save for the St Johns river
basin where highs will reach in the upper 80s to near 90 as there
will be more time before the frontal passage.

Sunday night, as the cold front finally sinks south of the area,
light westerly winds will shift northwesterly.

&&

.LONG TERM...(Monday through Thursday)

A drier pattern will resume over the region during next week as a
compact cut off mid/upper level trough slowly exits off of the
southeast coast as ridging aloft forms over the northeast states
and then builds from the southwest Gulf towards the region
midweek. Isolated to scattered onshore convergent showers may
pinwheel on the backside of a weak surface low as it slowly moves
north and east away from the coast into the western Atlantic while
modest high pressure wedges south from the Mid Atlantic coast.
North to northeast winds will keep daytime highs on the cooler
side Monday and Tuesday with low to mid 80s near the coast and
upper 80s well inland towards I-75 in NE FL and US 441 in SE GA
under partly cloudy skies Monday and mostly sunny skies Tuesday.
As mid to upper ridging builds into the area from the Southwest
Gulf of Mexico, highs will climb into the low to mid 90s by
Thursday with weak surface high pressure over the region allowing
light winds and development of Atlantic and Gulf seabreezes to
drift inland with no showers or storms expected until Thursday as
moisture levels finally creep up towards average for late May.

&&

.AVIATION...
(18Z TAFS)
Issued at 120 PM EDT Fri May 17 2024

VFR conditions should persist through the evening for all of the
TAF sites, with remaining rain chances for SSI later this evening.
Tonight around 08-09Z, MVFR ceilings will move in from the west
impacting the inland sites, confidence was too low to extend those
MVFR cigs to the coastal sites (SSI, SGJ, CRG). Tomorrow, vicinity
thunderstorms have been placed in the SSI TAF beginning at 16Z,
however storms will likely impact the Duval sites after this TAF
period.

&&

.MARINE...
Issued at 337 AM EDT Fri May 17 2024

Weak high pressure will linger today before a weak area of low
pressure lifts to the north tonight, dragging a warm into the
waters from the west. A slow moving cold front trailing the low
will gradually push across the water late Saturday through Sunday,
renewing chances for thunderstorms. Winds will turn northerly as
high pressure wedges against a low pressure situated northeast of
the waters early next week. High pressure builds directly over the
waters during the middle part of next week.

Rip Currents: Low surf and weak flow, turning offshore through
Saturday, will keep a low risk for rip currents at area beaches
over the next couple of days.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  73  87  69  86 /  40  80  60  50
SSI  74  90  70  86 /  30  50  60  50
JAX  73  93  70  88 /  10  50  50  60
SGJ  73  93  71  88 /   0  40  50  60
GNV  71  91  70  86 /   0  60  60  70
OCF  73  92  72  86 /   0  50  60  80

&&

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

$$