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450 
FXUS62 KJAX 080028
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
828 PM EDT Wed Apr 7 2021

.UPDATE...

East coast seabreeze has made it about mid-way through the
FL Peninsula and Gulf coast seabreeze has made it north to the
FL-GA line as seen in local wind observations and satellite
observations. Now that we've lost that insolation for the night,
those winds will settle down for the night over the next few
hours, becoming light and variable. Patchy fog development is 
possible west of the FL I-75 corridor late tonight/early Thursday
morning.

&&

.AVIATION...
[Through 00Z Friday]

VFR conditions through the period. Light and variable winds
through the early morning hours becoming southwest around 5-10
knots around 15Z with an onshore seabreeze bringing south-
southeasterly winds to SSI and SGJ around 17Z.

&&

.PREV DISCUSSION [521 PM EDT]...

.NEAR TERM [Through Tonight]...

High pressure at the surface is positioned over the southern 
half of the Florida peninsula near Lake Okeechobee with mid to 
upper level ridging stretching north from the NE Gulf of Mexico 
up the west side of the Appalachian mountains into the eastern 
Great Lakes. This feature is allowing subsidence over the region 
to continue dry conditions and deflecting shortwave energy, higher
moisture content, and showers well NW of the region over the TN 
Valley ahead of a surface cold front over the southern plains 
states. With surface high pressure to our south, a light southwest
low level flow has allowed the seabreezes to intrude inland with 
the Gulf coast sea breeze more dominant today as it nears I-75 
due to the low level SW flow while the Atlantic seabreeze remains 
east of I-95. The warmest temperatures this afternoon have been 
between the seabreezes with values in the mid 80s and cooler in 
areas affected by the seabreezes into the upper 70s to near 80 
degrees.

Tonight, mostly clear skies will give way to increasing high 
and mid level clouds from the west with light south winds. patchy
fog is possible over the suwannee river valley of NE FL where 
the Gulf coast seabreeze increased surface moisture and stable 
high pressure pattern will be in place. Low temperatures overnight
will be around normal values in the lower to mid 50s.


.SHORT TERM [Thursday Through Friday Night]...

Ridging aloft will over the east coast of the U.S. on Thursday 
and then move just off the coast over the western Atlantic 
waters on Friday as a closed shortwave trough rotates eastward 
from the plains states into the mid MS Valley and then pivots 
northward into the western Great Lakes. Underneath the shortwave, 
a prefrontal trough will progress eastward into the deep south on 
Thursday with showers pushing east into GA, but the dry airmass 
and ridging aloft will keep most shower activity west of the area.
However, a belt of higher moisture with PWATs between 1.2 and 1.5
inches will advect into the area late Thursday night into Friday 
over SE GA with scattered showers and an isolated thunderstorm 
possible as mid level shortwave energy moves over the region which
will help to enhance lift. Some of the heavier showers may bring 
some locally heavy rainfall amounts for area near and north of the
Altamaha and Ocmulgee river basins. Meanwhile, much of of NE FL 
will remain drier with only isolated showers possible aided by 
weak seabreeze convergence.

Highs on Thursday will be above seasonal values by about 5-10 
degrees in the mid 80s inland and the upper 70s to around 80 at 
the beaches thanks to the Atlantic seabreeze will be pinned close 
to the coast thanks to prevailing low level SW flow. Similar highs
are expected on Friday except for areas north of Waycross where 
additional clouds, showers, and isolated storms will keep values 
rising only to around 80 degrees. Friday's low temperatures will 
be just above normal in the upper 50s to near 60 degrees over NE 
FL and SE GA.


.LONG TERM [Saturday Through Wednesday]...

Saturday, a strong positively tilted shortwave will emerge from 
the Rocky mountains into western NE and KS and dive ESE towards 
the MID MS Valley region as the downstream closed shortwave lifts 
northward from near Lake Superior into Canada. Ridging over the 
Bahamas will allow southwest flow over our region, but low level
southerly flow over the Peninsula will keep moisture levels from 
rising until late in the day. A cold front will move into the 
deep south and approach our area. The greatest chance for showers
and storms will be Saturday evening into early Sunday morning as 
a wave of convection runs ahead of the front. The biggest threat 
may be with squall line of storms that may bring a threat of 
strong wind gusts into the late night and early morning hours of 
Sunday. Deep shear will be lacking with values toppling out only
in the 35-40 knots range, with only 25-30 knots of low level 
shear and CAPE values around 5000-100 J/KG confined more to the 
western portion of the area. The cold front will slow down as it 
approaches the FL/GA state line and scattered storms are possible
with diurnal heating Sunday afternoon before the cold front sags 
south of the area late Sunday night. 

Monday into Wednesday, Weak high pressure will move just north 
of the region with drier candidness under mostly sunny skies with
light northwest winds as the cold front should depart farther 
south of the area as the GFS and ECMWF have come into better 
agreement this afternoon. The high will move over the area on 
Tuesday and then east into the western Atlantic waters near the 
Bahamas as a another cold front approaches from the west with 
isolated shower coverage expected on Wednesday.

Temperatures will be above normal on Saturday, near normal on 
Sunday due to more clouds and shower activity and then return 
to above normal values Monday through Wednesday.


.MARINE...

High pressure will prevail to the southeast through Thursday, then
to the east Friday into Saturday. A series of frontal boundaries
will move southeast across region Saturday afternoon through 
Sunday, with rounds of showers and thunderstorms expected over the
waters. Elevated winds and seas could lead to Small Craft Exercise
Caution conditions late Saturday night into early Sunday. Weak 
high pressure will build early next week, with a cold front moving
southeast across area late Tuesday into Wednesday.

Rip Currents: Low risk of Rip currents for NE FL and SE GA
beaches.


.FIRE WEATHER...Dry conditions will continue with high pressure 
near the region into Thursday with a gradual increase in RH 
levels into Friday. High dispersions are expected Thursday 
afternoon over Southeast Georgia and on Friday over Northeast 
Florida areas as surface and transport winds increase from the 
southwest.

&&

.PRELIMINARY POINT TEMPS/POPS...

AMG  53  81  60  79  59 /   0  10  40  50  20 
SSI  58  78  62  77  63 /   0   0  20  30  20 
JAX  56  85  60  83  63 /   0   0  20  20  10 
SGJ  58  81  61  80  64 /   0   0  10  20  10 
GNV  53  84  57  85  60 /   0   0  10  20  10 
OCF  53  85  58  87  61 /   0   0  10  10   0 

&&

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