894 
FXUS62 KJAX 181140
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
740 AM EDT Fri Mar 18 2022

.AVIATION...
[Through 12Z Saturday]

Widespread dense fog locked in place at GNV/VQQ, with coastal TAF
sites of JAX/CRG/SSI/SGJ still on the edge of some brief LIFR
conds from 12-14Z. Fog lifts/dissipates between 14-15Z then VFR
through the rest of the day with daytime heating and S-SW winds
increasing to 10-12 knots, east coast sea breeze pushing inland
will trigger possible/brief VCTS at all TAF sites except for GNV 
in the 22-01Z time frame. Meanwhile latest Hi-Res models trying to
suggest weakening squall line pushing through SE GA and impacting
SSI from 00-06Z time frame and JAX metro TAF sites around 06Z but
low confidence in this scenario at this time. Medium confidence in
another round of low stratus/fog developing over inland NE FL and
tracking into GNV (LIFR conds) in the 07-09Z time frame and 
possibly reaching the JAX metro TAF sites (IFR conds) in the 
09-12Z time frame.

&&

.PREV DISCUSSION [616 AM EDT]...

.NEAR TERM [Through Tonight]...

Latest short-term, high resolution guidance indicates that dense
fog and low stratus ceilings may expand somewhat across inland
portions of southeast GA through around sunrise, with patchy fog
possibly developing along the I-95 corridor and coastal locations.
All guidance indicates that fog and low stratus will lift before
the mid-morning hours, with southerly winds resulting in warm air
advection this morning as skies clear.

The storm system currently over the southern Plains states will
accelerate northeastward towards the Great Lakes region by this
evening. Downstream of this feature, southwesterly flow aloft 
will strengthen this afternoon locally, with embedded shortwave
energy migrating across southeast GA early this evening. Meanwhile,
weak high pressure currently in place over southeast GA will 
shift offshore this morning, allowing for a developing warm front 
over the FL peninsula to lift northward this afternoon, reaching 
the I-10 corridor by sunset. This weather pattern will push the
squall line of strong to severe thunderstorms currently traversing
the lower Mississippi Valley eastward across the Deep South and
the FL panhandle this afternoon, with the squall line reaching the
Alapaha/Ocmulgee/upper Altamaha Rivers late this afternoon and
then weakening early this evening as activity moves southeast of
Waycross and across the Suwannee River along the I-10 corridor.
Bulk shear values of 40-45 knots and speeds around 50 knots in the
hail growth zone across southeast GA and northern portions of the
Suwannee Valley will support strong to isolated thunderstorms
within this squall line, and the Storm Prediction Center has
placed these locations within a marginal risk (level 1 out of 5)
for severe thunderstorm development through early this evening. 
Damaging wind gusts of 50-60 mph and hail of penny to quarter size
in diameter will be possible within embedded stronger activity 
along the squall line. Support aloft for the squall line will then
wane by the mid-evening hours. Plenty of sunshine will occur 
before this squall line approaches late this afternoon, and highs 
will soar to the low and mid 80s inland, with a few upper 80s 
possible for inland locations south of Gainesville. The Atlantic 
sea breeze will develop and move inland this afternoon, with 
isolated to widely scattered showers and possibly a few 
thunderstorms developing along this boundary near the I-95 
corridor from around St. Augustine southward late this afternoon 
through early this evening before activity shifts offshore.

The storm system will continue to shift northeastward towards the
Great Lakes region overnight, pushing the associated cold front
across the FL panhandle after midnight. This boundary may develop
another line of weaker convection ahead of it following the
passage of the early evening squall line. Locations south of the
I-10 corridor will continue to remain mostly dry. Warm air
advection and cloud cover ahead of the approaching cold front will
result in lows only falling to the mid and upper 60s area-wide.


.SHORT TERM [Saturday Through Sunday]...

A low pressure system tracking across the Great Lakes region on
Saturday will bring a trailing cold front across SE GA and NE FL.
The cold front will slowly approach the area from the west-
northwest, and gradually move southeast across the area throughout
the day on Saturday. Showers and thunderstorms are expected to
focus along the boundary. An upper level trough will swing across
the eastern US, and the base of the trough is expected to pass
near the FL/GA border Saturday afternoon and evening. A strong
upper level jet will accompany the trough, and the environment
will be favorable for strong to severe storm development. Any
severe storms that develop could cause locally damaging winds, and
possibly hail and/or an isolated tornado. The Storm Prediction
Center has issued a slight risk of severe thunderstorms for SE GA
and the Suwannee Valley north of I-10. 

As the trough progresses eastward, the frontal boundary will push
south of the area Saturday night and showers and storms will taper
off. A few lingering showers will be possible Sunday morning, but
the area will dry out by the afternoon and skies will clear as
high pressure builds over the Southeast US.  

Temperatures will be above average on Saturday with highs in the
upper 70s to middle 80s. As the frontal boundary moves south of
the area, temperatures will drop a bit and trend near normal.
Saturday night lows will be in the upper 40s and 50s, and Sunday
highs will be in the 70s. Sunday night temperatures will trend
slightly below normal as colder air filters in from the north with
lows in the middle 40s to middle 50s.


.LONG TERM [Monday Through Thursday]...

High pressure will shift to the north on Monday, then shift
offshore in to the western Atlantic on Tuesday. Dry weather is
expected Monday and Tuesday, then the next frontal system will
approach mid-week. Low pressure will track to the north across the
Mid-Atlantic region on Wednesday, and bring a trailing cold front
across the area Wednesday into Thursday. Showers and storms will
be possible both days.  

Temperatures will trend near normal early in the week, then
slightly above average mid-week. Temperatures are expected to
return to near normal towards the end of the week.


.MARINE...

A brief period of dense fog may be possible over the near shore 
waters from around St. Augustine northward early this morning. 
Otherwise, Atlantic high pressure will shift eastward today as a 
warm front develops over the Florida peninsula and lifts northward
well in advance of a cold front that will enter the southeastern 
states this evening. Seas of 3-5 feet will prevail both near shore
and offshore today, mainly due to a longer period east-
southeasterly ocean swell. 

A squall line of strong thunderstorms late this afternoon will 
weaken as it approaches the near shore waters early this evening. 
Southerly winds will strengthen to Caution levels of 15-20 knots 
tonight as the warm front lifts north of our local waters. Seas
offshore will build to 4-6 feet overnight. Another round of 
showers and possibly a few strong thunderstorms are expected along
the cold front on Saturday afternoon and evening, with 
strengthening northwesterly winds expected overnight in the wake 
of the frontal passage. High pressure will then build over the 
southeastern states on Sunday and will move offshore of the 
Carolina coast on Monday, resulting in strengthening onshore winds
and building seas early next week.

Rip Currents: A long period east-southeasterly ocean swell will
keep a moderate rip current risk in place at all area beaches
through at least Saturday.


.FIRE WEATHER...

A warm front will lift north across the area this afternoon, and a 
cold front will slowly move into the area on Saturday. Showers and 
storms will be possible this evening through Saturday. Winds will 
shift to northwesterly Saturday night as the front gradually pushes 
south of the area. The front will be to the south on Sunday, and high 
pressure will build into the region early next week. Another frontal 
system is expected to impact the area mid-week.


.HYDROLOGY...

Minor flooding will continue along most of the St. Marys River
during the next several days. Minor flooding along a majority of
the Santa Fe River will continue at most gauges upstream of Three
Rivers Estates through early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...

AMG  82  65  77  48  71 /  50  60  70  20   0 
SSI  76  66  80  54  72 /  30  40  60  40   0 
JAX  85  66  84  55  75 /  20  20  50  40  10 
SGJ  83  67  83  58  72 /  30  30  40  40  10 
GNV  86  66  83  56  76 /  20  20  40  30  10 
OCF  88  66  84  58  77 /  10  10  30  30  10 

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Dense Fog Advisory until 10 AM EDT this morning for Baker-
     Bradford-Central Marion-Eastern Alachua-Eastern Clay-
     Eastern Marion-Eastern Putnam-Gilchrist-Hamilton-Inland 
     Nassau-Northern Columbia-Southern Columbia-Suwannee-Trout 
     River-Union-Western Alachua-Western Clay-Western Duval-
     Western Marion-Western Putnam.

GA...Dense Fog Advisory until 10 AM EDT this morning for Appling-
     Atkinson-Bacon-Brantley-Clinch-Coffee-Echols-Inland Camden-
     Inland Glynn-Jeff Davis-Northeastern Charlton-Northern Ware-
     Pierce-Southern Ware-Wayne-Western Charlton.

AM...None.
&&