222
FXUS62 KJAX 121149
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
749 AM EDT Wed Mar 12 2025

...New UPDATE...

.UPDATE...
Issued at 748 AM EDT Wed Mar 12 2025

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

Sunny and warmer today as high pressure builds over the area.
Inland temperatures will top out near 80 while an afternoon
sea breeze keeps coastal locales in the mid 70s. Fog potential
increases tonight, with dense fog probabilities increase near and
west of the I-75 corridor of the Suwannee River Valley.

&&

.NEAR TERM...
Issued at 325 AM EDT Wed Mar 12 2025

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

Dry high pressure continues over the area today, shifting east
off the Atlantic coast in the evening hours. This surface high
pressure will bring beautiful clear skies and daytime highs in the
upper 70s to low 80s. Overnight, low temperatures will get into
the upper 40s inland with coastal temperatures staying slightly
warmer. Dense to patchy fog is expected to develop over inland
locations late this evening into Thursday morning mainly along and
west of I-75.

&&

.SHORT TERM...
(Thursday through Friday night)
Issued at 325 AM EDT Wed Mar 12 2025

Upper troughing migrating across the lower Mississippi Valley and
the Ozarks on Wednesday night will pivot east-northeastward across
the Tennessee Valley and the southeastern states on Thursday, with
this trough filling slightly as it pushes off the southeastern
seaboard on Thursday night. Meanwhile, weak surface ridging centered
near Bermuda will extend its axis southwestward across the FL
peninsula. Low level southwesterly flow will advect fog and low
stratus ceilings northeastward from Apalachee Bay and the Gulf
during the predawn hours on Thursday ahead of the approaching upper
trough, with dense fog expected to overspread much of our area
during the predawn hours on Thursday, possibly reaching the I-95
corridor towards or shortly after sunrise. Fog and low stratus
ceilings will then dissipate by the mid-morning hours. Warm air
advection will offset gradually increasing afternoon cloud cover
from the west, resulting in highs climbing to the mid and upper 70s
inland, with an afternoon sea breeze developing at coastal
locations that will likely remained pinned along or east of the
I-95 corridor late in the afternoon. This sea breeze will keep
coastal highs in the lower 70s for coastal northeast FL and
around 70 for coastal southeast GA.

Moisture levels will rebound above 1 inch across western portions
of the Suwannee Valley and inland portions of southeast GA during
the late afternoon and early evening hours as much colder
temperatures aloft associated with the upper trough provide an
increasingly unstable atmosphere. Higher moisture levels just west
of our area should keep the threat for strong to severe thunderstorms
confined to AL/FL panhandle/Southwest GA, but widely scattered
showers and embedded thunderstorms will likely enter inland southeast
GA and western portions of the Suwannee Valley during the late
afternoon and evening hours before this convection weakens and
dissipates before midnight as it encounters a lingering dry air mass,
with measurable rainfall currently not expected to reach the I-95
corridor on Thursday evening. Skies should then clear out during the
predawn and early morning hours, with radiational cooling before
sunrise allowing lows to fall to the 50s area-wide.

Flat ridging aloft will build into our area on Friday as a potent
trough pivots across the southern Plains states. A dry and subsident
air mass will prevail across our area in the wake of the departing
upper trough from Thursday night, and weak low level flow will allow
for earlier sea breeze development on Friday afternoon. High altitude
cloudiness may thicken during the afternoon hours, especially across
southeast GA, with filtered sunshine otherwise boosting highs to the
lower 80s inland, while the inland moving sea breeze keeps highs in
the 70s for locations east of I-95. Low level southerly flow will
then begin to strengthen on Friday night, possibly resulting in fog
and low stratus development across much of our area towards sunrise
on Saturday. Warm air advection will keep lows in the upper 50s for
most inland locations, ranging to the lower 60s for coastal
northeast FL.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 325 AM EDT Wed Mar 12 2025

Ridging aloft over the FL peninsula on Saturday will deflect a
potent shortwave trough northeastward across the Upper Midwest
and western Great Lakes states. However, a digging longwave
trough in the wake of this lead shortwave will drive a strong
cold front into the southeastern states on Sunday, with this
front crossing our region on Sunday night and Monday. Our
local pressure gradient will tighten well in advance of this
storm system on Saturday, with breezy southerly winds and
filtered sunshine allowing highs to soar to the mid and
possibly upper 80s at inland locations, with a slightly
south-southeasterly component to the surface winds keeping
coastal highs in the mid to upper 70s.

A robust low level jet will enter interior southeast GA and
western portions of the Suwannee Valley after midnight on
Saturday night. Ongoing strong to severe thunderstorms ahead
of the approaching strong cold front should move further away
from upper support and approaching longwave troughing, but
showers and thunderstorms are likely to overspread areas west
of Waycross and Lake City before sunrise on Sunday. Long-term
model guidance is a little better agreement in bringing
widespread convection across our region on Sunday and Sunday
night, with the potential for strong to severe thunderstorms
for coastal southeast GA, northeast and north central FL on
Sunday afternoon and early evening as the robust low level
jet traverses the rest of our area. Coverage of strong to
severe storms will likely depend on how much heating can
take place ahead of the approaching strong cold front, which
could be limited by morning convection that will likely be
impacting inland southeast GA and the Suwannee Valley, where
highs will likely be held to the 70s. 80s are possible
elsewhere if breaks in the cloud cover materialize ahead of
the approaching front.

Convection could linger into at least Monday morning for
north central and coastal northeast FL as a deep, but
progressive upper trough moves across our area. A cooler and
drier air mass will then advect into our region in the wake
of this cold frontal passage on Monday night and Tuesday.
Lows on Monday night should fall to the low and mid 40s
inland, with 40s again expected on Tuesday night. Near to
slightly below average highs early next week will then
rebound back towards 80 degrees at inland locations towards
midweek as heights aloft again rise downstream of another
storm system that will be emerging over the Plains states.

&&

.AVIATION...
(12Z TAFS)
Issued at 727 AM EDT Wed Mar 12 2025

VFR conditions through 06z under light WSW winds 5-8 kts. Winds
back S to SE at SSI and SGJ into the afternoon with a weak sea
breeze. Fog risk increases after 06z tonight through 12z
Thursday morning, with the highest confidence of restrictions
of MVFR at VQQ and GNV, with increasing chances of IFR at
GNV after 08z and potentially LIFR by 12z.

&&

.MARINE...
Issued at 325 AM EDT Wed Mar 12 2025

High pressure builds eastward across the Florida peninsula,
shifting east into the Atlantic by the evening hours. The high
extends across central Florida into Thursday as a weak front
approaches from the west and begins to stall across south Georgia.
This front will lift northward as a warm front late Friday into
Saturday, as a stronger frontal system approaches from the west.
Small Craft Advisory conditions develop Saturday as southerly
winds increase with the approach of the next front. Showers and
storms preceded the frontal passage Sunday, then the front slowly
settles south of the local waters through early Monday.

Rip Currents: Moderate risk of rip currents at all area beaches
today through Friday due to easterly swells.

&&

.FIRE WEATHER...
Issued at 325 AM EDT Wed Mar 12 2025

Light west-northwesterly transport winds this morning will shift to
southwesterly this afternoon, with gradually increasing speeds
expected through sunset. A dry air mass will result in minimum
relative humidity values approaching critical thresholds this
afternoon at inland locations, with a weak sea breeze keeping
coastal humidity values higher this afternoon. Gradually
strengthening transport speeds today will create good daytime
dispersion values at inland locations, while fair values prevail at
coastal locations. Southwesterly surface and transport winds will
continue on Thursday, with gradually strengthening speeds during
the afternoon hours again yielding good daytime dispersion values
inland, with the afternoon sea breeze keeping values fair at
coastal locations. Transport winds will shift to a more easterly
direction on Friday morning, followed by winds shifting to
southeasterly by early afternoon and then southerly by late
afternoon well inland. Elevated mixing heights on Friday will
create good to marginally high daytime dispersion values at inland
locations, with fair values at coastal locations, where onshore
surface winds will prevail throughout the day.

&&

.HYDROLOGY...
Issued at 217 PM EDT Tue Mar 11 2025

St Marys River at Macclenny is forecast to reach Moderate
flooding.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  80  48  75  53 /   0   0  20  40
SSI  71  51  69  55 /   0   0   0  10
JAX  80  48  77  52 /   0   0  10  10
SGJ  74  50  72  56 /   0   0   0   0
GNV  80  47  77  53 /   0   0  10  10
OCF  80  48  76  52 /   0   0   0  10

&&

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

$$