Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 102005
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
305 PM EST Sun Dec 10 2017

...FREEZE WARNING TONIGHT FOR MOST OF THE AREA WITH HARD FREEZE
WARNING TONIGHT FOR PORTIONS OF THE SUWANNEE RIVER VALLEY...

.NEAR TERM...This afternoon through Monday...

Deep trough will continue over the eastern CONUS which will continue
dry conditions and below normal temperatures. A broad surface
ridge axis extended from the TX to FL Gulf Coast, while a weak low
and mid level trough was shifting SSE across the mid MS River
Valley. Offshore flow prevailed this afternoon under sunny skies
with temperatures topping out near 50 across SE GA to lower 50s
across NE FL.

Tonight the low level ridge will strengthen eastward as the
aforementioned low and mid level trough axis shifts eastward toward
the Atlantic coast.
Although subtle, the resultant pressure gradient between this surface
ridge and the trough axis north of the local area will influence
where the coldest temperatures settle tonight. The surface ridge
axis is expected to extended across the Suwannee River Valley
under which near calm winds and cold,dry air drainage are
expected. This morning the low reach 28 in Live Oak with some
rural locations falling to 26-28 across the Suwannee River Valley,
with occasional surface winds of 2-5 mph. Tonight under the ridge
axis and with drier air in place, anticipate further cooling and
trended a degree or two lower than MOS guidance across these zones
which resulted in minimum temperatures and durations meeting Hard
Freeze conditions for our western tier Suwannee Valley zones.
Elsewhere, freezing temperatures of 27-32 degrees are expected,
even across rural portions of St. Johns and Flagler counties
between I-95 and the St. Johns River basin, but for a brief
duration of less than 2 hours expected at this time and thus
freeze warning was not extended for these areas. Frost potential
is tricky tonight given dry air advection resulting in lower dew
pt depressions. At this time continued with patchy to areas of
frost, and refrained from a Frost Advisory for areas not covered
in a Freeze Warning given the dry air advection tonight.

After a cold start, temperatures Monday will rebound by about 7-10
degrees warmer than today`s highs as surface winds back WSW in
advance of yet another but deeper low and mid level trough axis
approaching from the NW which as the ridge across the Gulf Coast
region retreats southward. Sunny skies will prevail as
temperatures warm into the lower 60s.

.SHORT TERM...Monday night through Wednesday night...Temperatures
will not be as cold Monday night as surface ridge shifts south of
the area. Cool readings still expected with low temperatures Monday
night in the upper 30s inland to the low/mid 40s coast. A dry
clipper system will push a cold front across the area on Tuesday.
Temperatures will be a few degrees above average across ne Fl as
winds become westerly ahead of the front. Se Ga will be cooler as
the front will push through during the morning hours with cold air
advection by afternoon. Temperatures will be below normal Tuesday
night through Wednesday night as dry high pressure builds into the
area. An inland light freeze will be possible Tuesday and Wednesday
nights.

.LONG TERM...Thursday through Sunday...Sw winds ahead of another
cold front will bring temperatures back to normal levels on
Thursday. Models differ greatly with frontal passage late week.
GFS/GEFS show a cold front pushing through Thursday night that is
faster and drier than the ECMWF/EPS which develops a Gulf low and is
slower and much wetter. Due to high uncertainty will go with
consensus pops/temps with a chance for rain Friday and Friday night.

&&

.AVIATION...VFR conditions.

&&

.MARINE...

Small craft exercise caution due to WNW winds 15-20 kts this
afternoon, then no headlines tonight under offshore flow 10-15 kts
and combined seas 4 ft or less. Surface high pressure will extend
across the Gulf Coast region and north Florida through early
Monday, then the high will shift south as a dry cold front
approaches from the northwest Monday night. This front will push
south of the local waters Tuesday, trailed by another increase in
winds through Wednesday with advisory conditions probable. Winds
and seas will gradually subside Wed night into Thu as high
pressure builds farther east across the Gulf of Mexico.

Rip Currents: Low risk through Monday under offshore flow.

&&

.FIRE WEATHER...Afternoon relative humidity values on Monday will
be near critical values across parts of ne Fl(upper 20s)...but
winds will be light with fuel moisture levels high.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  28  61  38  59 /   0   0   0   0
SSI  34  59  45  62 /   0   0   0   0
JAX  30  61  41  66 /   0   0   0   0
SGJ  34  60  44  67 /   0   0   0   0
GNV  28  62  38  67 /   0   0   0   0
OCF  29  62  40  70 /   0   0   0   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Freeze Warning from 1 AM to 9 AM EST Monday for Alachua-Baker-
     Bradford-Clay-Inland Duval-Inland Nassau-Marion-Putnam-
     Union.

     Hard Freeze Warning from 1 AM to 9 AM EST Monday for Columbia-
     Gilchrist-Hamilton-Suwannee.

GA...Freeze Warning from 1 AM to 9 AM EST Monday for Appling-
Atkinson-     Bacon-Brantley-Charlton-Clinch-Coastal Camden-Coastal
Glynn-     Coffee-Inland Camden-Inland Glynn-Jeff Davis-Pierce-Ware-
    Wayne.

     Hard Freeze Warning from 1 AM to 9 AM EST Monday for Echols.

AM...None.
&&

$$

Enyedi/Zibura/Corless



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