Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 121853
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
153 PM EST Tue Dec 12 2017

.NEAR TERM /Tonight and Tomorrow/...

A dry cold front is currently moving through our area. Breezy
westerly winds 15 to 20 mph with gusts of 25 to 30 mph will
continue through the rest of the afternoon. A few peak gusts up
to around 35 mph will remain possible for a couple more hours.

Cold air advection will kick in late this afternoon and continue
through tonight. The models have come up a little on minimum
temperatures tonight. Northwest winds will stay up a bit for much
of the night and will likely not completely decouple. As a result,
freezing temps across our interior sections will be rather short
lived for a period right around the time of sunrise on Wednesday
morning. Although many inland locations will eventually reach the
freezing mark, widespread freezing temperatures longer than 2
hours are not expected. Therefore, we dropped the freeze watch
and decided against a freeze warning. Very dry air will also
steadily move into the region, so we are not expecting much in
the way of frost tonight, especially given that the winds will
not completely go calm.

High pressure over the panhandle of Florida early Wednesday
morning will move south during the day. Light southwesterly winds
will prevail. Despite full sunshine, temps will be on the cool
side with below normal max temps area-wide, especially across
southeast Georgia.

.SHORT TERM /Wednesday Night through Thursday Night/...

Wed night...Center of surface high pressure will reside over
north Florida with our region on the northern periphery of the
feature. Light west winds at the surface of 3 to 7 knots will be
decoupled from the 925mb winds which will be 40 to 45 knots SE GA
and 25 to 40 knots FL zones. There will be enough mixing to
preclude most areas from dipping to the freezing mark. Clear skies
should prevail overnight across southeast Georgia. Lows in the
mid to upper 30s at inland locations likely occurring right around
midnight, with coastal lows generally around lower 40s.

Thursday...SW to WSW wind will prevail Thursday as surface ridge
across south Florida tracks eastward. This should allow afternoon
high temps to warm into the lower 70s. The airmass will be
initially dry though some cloudiness and moisture advection in the
925-700 mb layer will move into areas south of I-10 to the
southern CWA by late afternoon from the Gulf of Mexico with a
strong upper level jet strengthening from TX into the Southeast
and encroaching SE US cold front. The attendant dry cold front
will migrate into central GA and AL by late Thursday. Periods of
mid and cirroform clouds will advect across our region from west
to east as the fast subtropical jet stream remains over our area.
Zonal flow aloft and west- southwest surface winds of 10-15 mph
during the afternoon hours will help temperatures rebound to near
climo, with low to mid 60s expected in southeast Georgia and mid
to upper 60s for northeast and north central Florida.

Thursday night...During Thursday night the high will shift further
east-southeast into the Atlantic as another short wave trough and
attendant but weakened cold front bisects the region near the FL/GA
border during the pre-dawn hours.  As a result...Mid and
high altitude cloudiness will increase during the evening hours
across north central and northeast Florida, with isolated light
showers possibly developing toward daybreak across north central
Florida and southern part of the Suwannee Valley. A dry low and mid
level air mass will prevail over southeast Georgia, where a
cirrus cloud shield should gradually thicken overnight. Increasing
cloudiness and light low level south to southwesterly winds will
result in above climo lows, with mid to upper 40s over inland
southeast Georgia and 50-55 expected elsewhere.

.LONG TERM /Friday through Tuesday/...
A potent shortwave trough will pivot eastward from the lower
Mississippi Valley across the Tennessee Valley and southeastern
states on Friday. The attendant cold front will move south through
the forecast area on Friday with feature moving through north
central Florida not until late in day or early evening. Rain
chances increase into the 20 to 30 percent SE GA Friday, and then
40 to 60 percent across NE FL as the front moves south through the
area. CAA will likely begin during the afternoon hours over
inland southeast Georgia, where highs will only reach the upper
50s to near 60, while highs elsewhere reach the mid to upper 60s.
The last shot of arctic air for the long- term period will plunge
over our region on Friday night as high pressure quickly builds
into the southeastern states. Cool high pressure will prevail over
the southeastern states on Saturday and will only slowly progress
eastward off the southeast U.S. coast by Saturday evening. Highs
on Saturday will only climb to the mid/upper 50s, except lower 60s
for north central Florida. Lows Saturday night will range from
the upper 30s/lower 40s inland to the mid/upper 40s at the coast.

The high will shift east into the Atlantic on Sunday.
Southwesterly flow aloft will develop and strengthen towards the
end of the weekend and early next week as the next shortwave
trough dives into the lower Mississippi Valley and southeastern
states. Dry weather should prevail through at least Sunday
evening, with highs on Sunday rebounding to the mid/upper 60s,
except lower 70s for north central Florida. Rain chances should
gradually increase from west to east from Sunday night through
early next week, with subtropical ridging in place over the
Bahamas and south Florida boosting highs into the low/mid 70s by
Monday, except perhaps upper 60s for inland southeast Georgia,
where cloudiness should be thicker. Milder Pacific air and zonal
flow aloft are progged towards the mid portions of next week, with
a minimal and brief cool-down possible by Tuesday in the wake of
the departing shortwave trough and associated cold front.

&&

.AVIATION...

VFR conditions will continue through this 24 hour TAF period.
Gusty winds from a westerly direction will continue this
afternoon. Much lighter winds tonight and tomorrow.

&&

.MARINE...

Small craft advisory conditions will continue until late tonight
into tomorrow morning. Westerly winds 20 to 25 knots this
afternoon will become northwesterly tonight behind a dry cold
front. An occasional gust up to around 35 knots is possible this
afternoon and evening. Winds will subside substantially on
Wednesday as high pressure builds in from the west. Winds will
back to the southwest and increase to SCEC levels, possibly SCA
levels, for a brief period Wednesday night into Thursday. Another
round of SCA conditions expected on Friday/Friday night as
offshore winds increase behind another cold front.

Rip Currents: Low Risk.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  32  54  37  62 /   0   0   0   0
SSI  35  54  43  64 /   0   0   0   0
JAX  35  57  39  67 /   0   0  10   0
SGJ  38  56  41  67 /   0   0  10  10
GNV  33  58  37  68 /   0   0  10  10
OCF  35  59  39  69 /   0   0  10  10

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory until 9 AM EST Wednesday for Waters from
     Altamaha Sound GA to Fernandina Beach FL from 20 to 60 NM-
     Waters from Fernandina Beach to St. Augustine FL from 20 to
     60 NM-Waters from St. Augustine to Flagler Beach FL from 20
     to 60 NM.

     Small Craft Advisory until 5 AM EST Wednesday for Coastal waters
     from Altamaha Sound to Fernandina Beach FL out 20 NM-
     Coastal waters from Fernandina Beach to St. Augustine FL
     out 20 NM-Coastal waters from St. Augustine to Flagler
     Beach FL out 20 NM.

&&

$$

Shuler/Cordero/



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