Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 280435

Area Forecast Discussion
National Weather Service Jacksonville FL
1135 PM EST Mon Nov 27 2023

...New AVIATION...

Issued at 847 PM EST Mon Nov 27 2023

For the latest NE FL and SE GA Daily Key Messages please visit:

Evening surface analysis depicts strengthening high pressure (1027
millibars) centered over central and eastern Texas, with a
reinforcing trough sweeping southeastward across the Deep South.
Aloft...deep troughing over Hudson Bay, Canada and the Great Lakes
region was creating a nearly 175 knot jet streak at 250 millibars
(around 35,000 feet) across the Tennessee Valley and the southern
Appalachians to the south of this trough, with these strong winds
quickly advecting a cirrostratus shield across Texas and the lower
Mississippi Valley downstream of a weak shortwave that was
migrating across the Rio Grande Valley. Mostly thin cirrus was
gradually increasing from southwest to northeast across our
region, while thicker cirrostratus was noted across the northeast
Gulf of Mexico. A brief lull in surface wind speeds ahead of the
approaching reinforcing trough and thinner cirrus was allowing
temperatures at 01Z to fall through the 40s across inland
southeast GA and along the Interstate 10 corridor in the Suwannee
Valley and northeast FL, ranging to the mid and upper 50s along
the northeast FL coast. Dewpoints ranged from the upper 30s and
lower 40s across inland southeast GA to around 50 across north
central FL.

The powerful jet jet streak up at flight level will push eastward
across the southern Appalachians this evening, the Carolinas
overnight, and will then push offshore of the Carolina coast by
Tuesday afternoon. Meanwhile, a reinforcing low level trough will
cross our region during the predawn and early morning hours on
Tuesday, resulting in a gradually tightening local pressure
gradient. Light west-northwesterly winds and fair to partly cloudy
skies are expected through midnight, followed by thickening
cirrostratus and a light northwesterly breeze of 5-10 mph
developing after midnight. Increasing cloud cover aloft and the
northwesterly breeze should prevent frost formation at inland
locations early on Tuesday morning despite cold air advection,
with lows ranging from the upper 30s for inland locations along
and north of the I-10 corridor to the low and mid 40s for north
central FL and coastal locations.

Thick cirrostratus cloud cover early on Tuesday morning will thin
during the late morning and afternoon hours from west to east as
the aforementioned jet streak moves offshore, with a much drier
low level air mass also advecting into our region in the wake of
the reinforcing low level trough that will pass through north
central FL during the morning hours. Sunshine during the mid to
late afternoon hours will be countered by cold air advection,
keeping highs generally in the 55-60 degree range area-wide.
Breezy northwesterly winds during the late morning and early
afternoon hours will diminish before sunset as our local pressure
gradient loosens, setting the stage for the first widespread frost
and freeze event of the season for inland southeast GA, the
Suwannee Valley, and the I-10 corridor west of downtown
Jacksonville late on Tuesday night and early on Wednesday morning.


(06Z TAFS)
Issued at 1135 PM EST Mon Nov 27 2023

VFR conditions next 24 hrs which just some high cloudiness Today
that should clear out in the evening. Northwest winds 8-12kts
Today, decreasing to 4-6kts in the evening.


Issued at 847 PM EST Mon Nov 27 2023

High pressure centered over Texas will gradually build eastward on
Tuesday and Wednesday, becoming centered directly over our local
waters on Wednesday night. Breezy northwesterly winds will prevail
locally through Tuesday afternoon before shifting to northerly on
Tuesday night, with speeds then diminishing by midweek. Small
Craft should exercise Caution both near shore and offshore through
Tuesday morning, with speeds then expected to diminish near shore
on Tuesday afternoon and offshore by Tuesday evening. Seas of 3-5
feet will prevail both near shore and offshore tonight, with seas
diminishing to 2-4 feet near shore on Tuesday.

High pressure will then shift offshore of the Carolina coast on
Thursday, with winds briefly becoming onshore before shifting to
southerly on Friday as low pressure shifts northeastward from
Texas and across the Ozarks before weakening over the Tennessee
Valley. Seas of 2-4 feet will prevail both near shore and offshore
from Tuesday night through Friday. Showers and possibly a few
thunderstorms are expected from Friday through the weekend as a
warm front lifts northward from the Florida peninsula. This storm
system`s cold front will then move across our local waters early
next week.

Rip Currents: Breezy offshore winds and a fading northeasterly
ocean swell should result in a low rip current risk at all area
beaches on Tuesday and Wednesday. A lower-end moderate risk may
materialize by Thursday at the northeast Florida beaches as
another northeasterly ocean swell arrives and combines with
onshore winds.


Issued at 847 PM EST Mon Nov 27 2023

A much drier air mass will plunge over our region on Tuesday and
Wednesday, with minimum relative humidity values falling to the
30-35 percent range by Tuesday afternoon at most inland locations.
Breezy northwesterly transport winds and clearing skies on Tuesday
afternoon will create good daytime dispersion values across inland
southeast GA, with fair values forecast elsewhere. Minimum
relative humidity values will plummet to near critical thresholds
at all inland locations on Wednesday afternoon, with diminishing
northwesterly transport winds resulting in poor daytime
dispersion values area-wide. Transport winds will then shift to
southeasterly by Thursday afternoon, but continued light speeds
will generally result in another day of poor daytime dispersion
values. A drier air mass will linger across inland southeast GA on
Thursday, but minimum relative humidity values will remain above
critical thresholds.


Issued at 847 PM EST Mon Nov 27 2023

Record low temperatures at our designated climate sites on
Wednesday and Thursday mornings:

                    Nov 29      Nov 30
Jacksonville       30 (1959)   26 (1959)
Gainesville        28 (1959)   22 (1959)
Alma, GA           22 (1938)   22 (1955)
Craig Airport      34 (1988)   32 (1979)


AMG  59  37  57  30 / MMM   0   0   0
SSI  62  41  57  39 / MMM   0   0   0
JAX  61  39  58  32 / MMM   0   0   0
SGJ  66  44  58  40 / MMM   0   0   0
GNV  65  41  58  33 / MMM   0   0   0
OCF  67  42  59  35 / MMM   0   0   0


FL...Freeze Watch from late Tuesday night through Wednesday morning
     for FLZ020-021-023-024-122-222.

GA...Freeze Watch from late Tuesday night through Wednesday morning
     for GAZ132>136-149-151>153-162-163-165-250-264-350-364.


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