946 
FXUS62 KJAX 161351
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
951 AM EDT Sun Oct 16 2022

...ISOLATED SEVERE THUNDERSTORM POTENTIAL MONDAY AFTERNOON AND 
EVENING...
...New UPDATE, MARINE...

.UPDATE...
Issued at 945 AM EDT Sun Oct 16 2022

Tranquil and warmer than normal conditions expected once again 
today under the influence of low level ridging, which is gradually
progressing east-southeasterly today. Highs will be in the mid 
and upper 80s this afternoon. 

Tonight, as ridging shifts east of the region flow will shift south 
southwesterly ahead of an approaching front. This will usher in Gulf 
moisture and enhance the potential for patchy fog and low stratus 
tonight beneath an increasing cirrus shield. Due to the increase in 
moisture, lows will be noticeable warmer and range in the low to 
mid 60s.&&

.SYNOPSIS...
Issued at 515 AM EDT Sun Oct 16 2022

Early morning surface analysis depicts high pressure (1020 
millibars) centered over the Deep South. Meanwhile, a series of 
cold fronts were progressing across the Upper Midwest, the Plains 
States, and the Tennessee Valley, with strong high pressure (1034 
millibars) building southeastward from the Canadian Rockies and 
Prairies towards the Dakotas and northern Rockies. Aloft...dry 
west- northwesterly flow prevails locally at the base of a broad 
trough that remains in place over the eastern half of the nation. 
Otherwise, a potent shortwave trough diving southward from Hudson 
Bay, Canada, was poised to sharpen the trough over the Upper 
Midwest and Great Lakes region, while stout ridging was building 
over the Pacific Northwest. A few wisps of cirrus were invading 
our skies from the northwest, with decoupling winds otherwise 
promoting radiational cooling. Temperatures at 09Z were generally 
in the 50s at inland locations, ranging to the lower 60s across 
north central FL and also along the immediate coast. Dewpoints 
ranged from 50-55 at inland locations and around 60 at the 
northeast FL coast and in north central FL. 

&&

.NEAR TERM...
(through Tonight)
Issued at 515 AM EDT Sun Oct 16 2022

High pressure will gradually weaken as it slides eastward today,
reaching the South Carolina coast this afternoon and then moving
offshore by early evening. A dry air mass will linger across our
area today, with thin cirrus clouds occasionally moving overhead,
while a few patches of marine stratocumulus begin to advect
onshore towards sunset for locations south of St. Augustine.
Plenty of sunshine will boost highs to the upper 80s for inland
locations west of Interstate 95, while the afternoon Atlantic sea
breeze keeps coastal highs in the low to mid 80s.

Meanwhile, a powerful shortwave trough will dive southward from
the western shores of Hudson Bay, Canada, towards Lake Superior
and the U.S. border late this afternoon and tonight. This feature
will sharpen the long wave trough that remains in place over the
eastern half of the nation, which will strengthen and propel a
cold front into the southeastern states by the predawn hours on
Monday. Low level winds will veer to southeasterly this evening
and then southerly overnight. Increasing low level moisture should
result in low stratus ceilings and patchy to areas of locally
dense fog formation during the predawn hours on Monday at inland
locations. Increasing cloud cover and warm air advection will keep
lows in the 60s area-wide. 

&&

.SHORT TERM...
(Monday through Tuesday night)
Issued at 515 AM EDT Sun Oct 16 2022

Deep troughing over the Great Lakes region early on Monday will
continue to sharpen and will dig southward through the Ohio and
Tennessee Valleys by Tuesday afternoon, creating fast westerly
flow over our region. This feature will drive a strong cold front
across the southeastern states on Monday and Monday night, with
this front moving south of our area and across the I-4 corridor in
the FL peninsula by noon on Tuesday. A ribbon of deeper moisture
will pool ahead of this front, with PWAT values increasing to 1.5 -
1.75 inches, resulting in scattered showers and isolated
thunderstorms developing by Monday afternoon over inland 
southeast GA and the Suwannee Valley as the front approaches the 
Altamaha/Ocmulgee/Alapaha Rivers. A 100-knot jet streak at 250 
millibars (around 35,000 feet) will become positioned across 
northern AL and GA on Monday afternoon and evening, enhancing lift
and divergence over our area. Model soundings depict 
strengthening westerly speed shear over our region by Monday 
afternoon and evening, with bulk shear values approaching 50-60 
knots. Instability will become sufficient for a few strong or even
isolated severe thunderstorms across our area, mainly for 
locations southeast of Alma, as ML CAPE values increase to the 
500-1,000 j/kg range. The primary threat within stronger storms 
that develop on Monday afternoon and evening will be strong wind 
gusts of 40-60 mph. Model soundings depict generally poor lapse 
rates and only modest shear in the low levels, which should negate
the threat for hail or tornadoes. 

Following morning low stratus and locally dense fog at inland
locations early on Monday, multi-layered cloudiness will quickly
increase area-wide. Breezy southwesterly winds will still allow
highs to climb to the mid 80s at most locations. Shower coverage
will diminish from northwest to southeast across southeast GA
after midnight, with chances for showers continuing along the
front through around sunrise on Tuesday along the I-10 corridor.
Cool air advection in the wake of the front will allow lows to
fall into the 50s across inland southeast GA and the western
Suwannee Valley, with 60s expected elsewhere. 

The aforementioned jet streak will strengthen over the
southeastern states on Tuesday, which should keep plenty of post-
frontal cloud cover in place through the early afternoon before a
much colder and drier air mass then plunges southeastward by
Tuesday evening. Highs on Tuesday will range from the upper 60s
over inland southeast GA to the upper 70s in north central FL,
where cold air advection will not arrive until almost sunset.
Skies will then clear across the rest of our region on Tuesday
night, with breezy northwesterly winds continuing throughout the
night at coastal locations, and a light breeze adding to the chill
at inland locations. Lows will plunge to the upper 30s across
inland southeast GA and the northern Suwannee Valley, with wind
chill values approaching freezing by sunrise for locations north
of Waycross. Lows elsewhere will fall to the low and mid 40s
inland and the upper 40s to lower 50s at coastal locations.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 515 AM EDT Sun Oct 16 2022

Deep troughing will pivot across the eastern third of the nation
on Wednesday, with reinforcing shortwave troughs diving across the
southeastern states late this week. Cold high pressure will dive
southward across the Plains states on Tuesday and Wednesday and
will then weaken as it builds over the southeastern states by
Thursday. Breezy northerly winds on Wednesday will keep strong
cold air advection in place locally, and highs will only reach the
mid to upper 60s area-wide, despite full sunshine. These values
will generally be 10-15 degrees below late October climatology.
Breezy northerly winds will prevail at coastal locations through
Wednesday evening, followed by decoupling winds at inland
locations overnight, which will set the stage for the coldest
night of the Fall season thus far. Lows will fall to the mid 30s
for inland locations north of Waycross and also over the far
western Suwannee Valley by early Thursday morning, where patchy
frost will be possible. Lows elsewhere at inland locations will
fall to the upper 30s to lower 40s, while a chilly northerly 
breeze holds lows to the 45-50 degree range along the immediate
Atlantic coast.

A very dry air mass and plenty of sunshine will allow for a slow
warming trend to take shape by Thursday afternoon, as highs climb
slightly to the upper 60s and lower 70s throughout our region.
Another cold night is expected Thursday night as winds again
decouple inland, where lows will generally fall to the 40-45
degree range. A persistent northerly breeze will keep coastal lows
in the 50-55 degree range. Coastal troughing should then take
shape by Friday and Friday night over our adjacent Atlantic waters
as high pressure weakens over the Deep South. Highs will slowly
rebound to the 70-75 degree range on Friday, with a more
noticeable warming trend by Friday night, as lows fall to the
upper 40s and lower 50s inland, while an onshore breeze keeps
coastal lows in the 55-60 degree range. Rising heights aloft next
weekend should allow highs to reach the mid and upper 70s inland,
while the coastal trough and onshore winds keep highs in the lower
70s for locations along and east of I-95. A few showers may also
begin to advect onshore next weekend along the northeast FL
coastal counties.

&&

.AVIATION...
(12Z TAFS)
Issued at 759 AM EDT Sun Oct 16 2022

Prevailing VFR conditions are anticipated through the majority of
the forecast period with increasing cirrus through the evening 
and overnight. Under the influence of high pressure, winds will be
light and variable this morning before a weak sea breeze develops
this afternoon. Winds will shift southeasterly this evening and 
veer southwesterly overnight ahead of an approaching cold front. 
Increasing moisture on southerly flow tonight will enhance chances
for patchy low stratus which may result in occasional IFR 
conditions at inland terminals around daybreak Monday. Held off on
any direct mentions of IFR for this cycle but will reevaluate 
potential once the latest guidance arrives this morning.

&&

.MARINE...
Issued at 945 AM EDT Sun Oct 16 2022

High pressure will dominate the weather pattern until a cold front 
approaches the region Monday evening and eventually passing across 
area waters Tuesday morning. Breezy offshore winds will develop 
ahead of the front on Monday and shift northwesterly Tuesday behind 
it. Winds will shift northeasterly and onshore by Thursday as high 
pressure builds from the west and then to the north during the 
latter half of next week. 

Behind the front, wind may approach Small Craft Advisory levels.
The much colder airmass pushing across the waters will offer a
situation where frequent, strong (20-30 knots) gusts are possible
through Tuesday.

Rip Currents: Moderate risk today decreasing to Low risk on Monday 
with offshore flow developing.

&&

.FIRE WEATHER...
Issued at 515 AM EDT Sun Oct 16 2022

A very dry air mass will persist at inland locations today, with
minimum values briefly approaching critical thresholds this 
afternoon across inland southeast Georgia and the Suwannee Valley.
Transport winds will become westerly across southeast Georgia 
this morning, while easterly transport winds are expected for 
locations south of the Interstate 10 corridor. Speeds will remain 
light, resulting in low daytime dispersion values at most 
locations today. Transport winds will then shift to southwesterly 
overnight across southeast Georgia and southerly elsewhere, with 
winds strengthening by the late morning hours on Monday. Surface 
and transport winds will shift to west-southwesterly by Monday 
afternoon across southeast Georgia and south-southwesterly across 
northeast and north central FL. Breezy conditions for locations 
north of the I-10 corridor will result in good dispersion values, 
while fair to poor values prevail for locations south of I-10, 
where speeds will be lighter.

Surface and transport winds will shift to northwesterly and will 
become breezy on Tuesday, ushering in a much drier air mass by 
Tuesday afternoon, with humidity values crashing to near critical 
thresholds for locations along and north of I-10. 

&&

.HYDROLOGY...
Issued at 515 AM EDT Sun Oct 16 2022

Water levels will continue to reach minor flood levels within the
St. Johns River basin from Lake George northward to around Palatka
during times of high tide through at least early Tuesday. A
Coastal Flood Advisory will remain in place for these locations in
eastern Putnam County. Water levels will generally remain just 
below flood stage for locations north of Palatka to downtown 
Jacksonville along the St. Johns River during times of high tide
through at least early Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  87  61  84  55 /   0   0  20  20 
SSI  82  67  83  63 /   0   0  40  40 
JAX  85  63  85  63 /   0   0  40  50 
SGJ  84  68  85  68 /   0   0  40  40 
GNV  88  64  85  63 /   0   0  40  30 
OCF  88  65  84  65 /   0   0  30  30 

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 6 AM EDT Tuesday for FLZ137.

GA...None.
&&

$$