Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 111905
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
205 PM EST Mon Dec 11 2017

...BRIEF REBOUND IN TEMPERATURES TONIGHT & TUESDAY...

.NEAR TERM...Surface high pressure across the Gulf of Mexico was edging
farther south as an approaching cold front was diving southeast toward
the mid MS River Valley. Sunny skies prevailed across the forecast
area this afternoon under WNW winds 5-10 mph which will progressively
back WSW into this evening as the ridge shifts farther south and
the trough approaches. High temperatures will top out near 60
degrees.

A warmer night tonight by about 5-10 deg across the forecast area
due to warmer SW flow off of the Gulf ahead of the approaching
cold front. The coolest spot across the area is expected to be the
Suwannee River Valley where lighter winds and mostly clear skies
are expected...and advertised patchy frost and shallow ground fog
there tonight as temperatures fall into the upper 30s to near 40.
Farther south toward Gainesville and Ocala, expect some passing
low cumulus clouds after midnight through Tue morning ahead of
the front which will keep min temperatures tonight more mild in
the lower 40s, and elevated winds across inland SE GA will keep
min temps more mild with lows in the low 40s tonight also. Toward
the St. Johns River basin and Atlantic coast mins tonight will
fall into the mid to upper 40s.

Tuesday the dry cold front (meaning no rainfall expected) will
press southeast across SE GA in the morning then across NE Fl
through the afternoon. The biggest weather impact from this
approaching front will be windy conditions developing by mid-
morning. WSW winds will increase to near 15 mph by midday across
much of the forecast area with gusts of 25-30 mph due to a strong
pressure gradient with the passing cold front. Given the timing of
the frontal passage in the morning across SE GA, daytime highs
will only range near 60 once again, while parts of NE FL from
roughly St Augustine toward Ocala will near 70 degrees ahead of
the cold front. A few passing low and high clouds will bring
mostly sunny to partly cloudy skies across parts of NE FL while
prevailing mostly sunny skies are expected over SE GA. Cold and
dry air advection will ensure trailing the surface cold front from
NW to SE through the day.

.SHORT TERM...Tuesday night Through Thursday...

An upper level short wave trough will remain entrenched along the
eastern CONUS with a series of impulses dropping southward and a
few clipper systems moving across the Great Lakes and New England
through the period. The primary impacts this far south will be a
series of dry cold frontal passages which will really be
noticeable due to the increasing winds and cold air advection in
their wake. An inland freeze is expected again Tuesday night, with
wind chills in the 20s. After this a series of quick systems can
be expected with slight moderation of the temperatures and
humidity ahead of them and cooling/drying behind them.

.LONG TERM...Thursday night Through Monday...

Continued reinforcing of the upper trough will occur on Thursday
night and Friday but this one will drop far enough south to pick
up some Gulf moisture for our next shot of precipitation. This
front will sweep across the are on Friday with a developing
northeaster off Cape Cod. Over the weekend surface high pressure
will move directly over the area with some moderation in the
temperatures. By Monday the high will pull offshore with another
reinforcing shortwave digging south and a frontal system racing
across the area during the day.

&&

.AVIATION...

Prevailing VFR through 06Z tonight. There is a low probability of
shallow MVFR mist at GNV after 08Z tonight. A dry cold front will
approach from the NW late tonight into early Tue with increasing
winds. Included wind shear for only SSI early Tue morning around
11Z due to approach of a 950 mb (about 2 kft agl) jet of 35-40
kts. VFR conditions expected Tue after 13Z under windy westerly
winds with gusts 20-30 kts as front shifts southward across the
forecast area through the day.

&&

.MARINE...

Westerly winds near 10 kts prevailed over the waters this
afternoon with combined seas 3 ft or less. Winds will increase
through this evening as they back more WSW ahead of approaching
dry cold front that will cross the waters NW to SE through Tuesday
afternoon. Winds will increase to advisory levels tonight for all
legs and raised an advisory with the potential for a few
infrequent gale force gusts over the outer waters through late Tue
afternoon. Offshore NW flow will remain elevated at SCA levels Tue
night, then winds and seas will begin to subside to exercise
caution levels through Wed as the pressure gradient relaxes as
high pressure builds over the Gulf Coast region. This ridge will
build SSE through Thu in advance of yet another cold front
expected to cross the waters late Fri or Sat with a low chance of
rainfall with the potential for marginal advisory conditions over
the outer waters.

Rip Currents: Low risk today. Moderate risk highlighted for
Tuesday.

&&

.FIRE WEATHER...

High daytime dispersions Tuesday with dry cold front pressing
across the area. Rainfall not expected. Freeze and frost likely
again Tuesday night and potentially Wednesday night inland.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  40  59  30  51 /   0   0   0   0
SSI  48  63  36  52 /   0   0   0   0
JAX  43  66  34  54 /   0   0   0   0
SGJ  46  69  36  55 /   0   0   0   0
GNV  41  68  32  55 /   0   0   0   0
OCF  40  70  34  57 /   0   0   0   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory from 11 PM this evening to 2 PM 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 from 11 PM this evening to 7 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.

&&

$$

Enyedi/Sandrik/McGinnis


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