Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 170801

Area Forecast Discussion
National Weather Service Jacksonville FL
301 AM EST Sun Dec 17 2017


.NEAR TERM...Today and Tonight...

Synopsis...Moderating temperatures back to above climo values
with increasing moisture across the area bringing more cloud
cover, a low chance of inland showers, and late night fog tonight.

Mean layer ridging will be in the control of the area with a mean
trough upstream over the western tier of the country. This broad
synoptic pattern will keep deepest moisture and forcing WNW of the
region and bring a warming trend under the upper ridge. At the
surface, high pressure over the Carolina Atlantic coast early this
morning will shift ESE through tonight centering offshore of the
Fl Atlantic coast with a ridge axis extending across central
Florida by 12Z Monday morning. As the ridge swings southward, a
warm front will lift northward from south Florida this morning to
north of the Altamaha River basin this afternoon. Shallow moisture
pooling and lift along the warm front could spark a few inland
showers generally west of the Highway 301 corridor this afternoon.
Dry conditions expected toward the Atlantic coast and southward
toward Palatka and Ocala where subsidence will be stronger near
the low level ridge axis as it builds across central Florida.
Surface winds will veer from ENE this morning to the SE through
the afternoon, becoming southerly tonight which will not only warm
temperatures but also increase low level moisture. Abundant cloud
cover will blanket much of SE GA near the lingering front and
over the top of the upper level ridge tonight where a low chance
of a shower will be possible generally from Douglas toward Jesup
northward, while less high clouds and stronger low level
subsidence over NE FL tonight favors fog potential. Included
patchy fog for SE GA with areas of fog/patchy dense mentioned for
NE FL south of I-10 corridor.

After a chilly morning with lows in the mid to upper 30s across
parts of SE GA to low/mid 40s NE FL, temperatures will moderate
above climo values with highs in the upper 60s to low 70s as low
level winds swing around the SE through the day and upper ridge
persists aloft. Tonight, mild minimum temperatures in the mid to
upper 50s are expected, with fog expected across much of the area.

.SHORT TERM /Monday and Tuesday/...

Mild conditions will prevail with temperatures well above normal
for most of the area, despite partly to mostly cloudy skies.
Light southerly winds will prevail as high pressure dominates the
area. A very strong upper high will be over Cuba with ridging
stretching northward across our region. A quasi-stationary warm
front will be positioned just northwest of our area and this
boundary will be the primary focus for the best chance of rainfall
which should remain west and northwest of our area on Monday.

Nevertheless, an increase in deep layer moisture in association
with an upper shortwave trough embedded in the fast moving flow
around the northwest periphery of the large high aloft over Cuba
will support a low chance of a few light to moderate showers north
of Interstate 10 on Monday. The best rain chances (40-50%) will
be across our northern zones near the Altamaha River basin.
Rainfall amounts should be generally light.

Conditions will be favorable for an advective fog/stratus layer
moving into our western zones Monday night. Have added areas of
fog in that area for now.

Tuesday should remain primarily dry and very mild with near record
temps possible across portions of the area.

.LONG TERM /Wednesday through Saturday/...

Ridging will primarily remain the dominant feature with rather mild
conditions continuing into next weekend. A low pressure system
will track east northeastward from the southern plains Tuesday
night and is expected to pass north of our area on Wednesday. The
ECMWF continues to be persistent with this solution. This track would
keep the more widespread rainfall northwest and north of our
area. A weak trailing cold front, however, will move into
southeast Georgia and bring a chance for a few showers to our area
Wednesday afternoon through late Wednesday night. The best rain
chances with this system (50-60%) will be across our northern

Ridging will begin to amplify again over the region in the wake
of this system Thursday through Saturday with mild and mainly dry
conditions prevailing.



VFR conditions through 00Z. Mid and high clouds will pass over the
area today as winds veer from ENE to SE into the afternoon with
speeds 10 kts or less. Tonight (Sun night) conditions become more
favorable for restrictions due to both stratus and fog. 00Z SREF
model guidance indicating highest potential for restrictions near
SGJ with IFR probabilities at about 20%.



Surface high pressure will build southeast from offshore of the
Carolina Atlantic coast today to offshore of the Florida Atlantic
coast through Tuesday. A cold front will approach the local waters
late Wednesday with an increase in offshore flow preceding the
front with the potential for marginal exercise caution conditions
over the outer waters. Winds shift onshore trailing the front
Thursday as high pressure builds NE of the waters and a coastal
trough develops offshore of the FL Atlantic coast, but surge not
expected to meet headline criteria.

Rip Currents: Low risk today and Monday.


AMG  69  57  73  60 /  20  20  40  10
SSI  64  57  71  61 /   0   0  20  10
JAX  71  58  79  60 /   0  10  20   0
SGJ  70  59  77  61 /   0   0  10   0
GNV  75  57  80  57 /  10  10  10   0
OCF  76  57  80  57 /   0   0  10   0




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