Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 080303

Area Forecast Discussion
National Weather Service Wilmington NC
1003 PM EST Wed Dec 7 2016

Dry and seasonable weather will continue through Thursday as
high pressure weakens across the Carolinas. A cold front will
move through later on Thursday, ushering in the coldest
temperatures of the season for the first part of the weekend. A
warming trend will follow Sunday into Monday ahead of the next
cold front. Expect seasonable and dry weather Tuesday as high
pressure builds in behind front. Another frontal system will
affect the area during the middle of next week.


As of 945 PM Wednesday...A deck of low to mid clouds is moving
in from the SW and that will put a damper on the rather steep
downward plunge in temperatures that occurred this evening.
Other than that see no changes to the forecast for the overnight
period. Previous discussion from this afternoon follows:

A break-through sparkling afternoon after several days of slate
overcast. Plenty clouds lurk W through SW of the forecast area,
and this is the direction from which winds in the boundary
layer to 850 MB will be trending overnight into early Thursday.
Consequently, we expect an intrusion/increase in clouds into NE
SC and SE NC tonight. The backing wind regime is being spurred
by the approach of a cold front, behind which brings a cold rush
of air after the `near term` time period. All factors
considered it appears our minimums will dip into the low and
middle 40s in the pre-dawn hours, potentially leveling off into
daybreak as clouds impact long-wave radiation escape.


As of 300 PM Wednesday...Overwhelming headline for the THU/FRI
period is `Old Man Winter Dips His Toes into the Carolinas`, as
the leading edge of a bubble of Arctic born air infiltrates late
on Thursday. Widespread sub-freezing 20s will greet SE NC and
NE SC daybreak Saturday as this high settles nearly overhead.
Even with cold air advection breezes Thursday night, temps well
inland may fall below freezing. A brief deepening of column
moisture Thursday into the afternoon could provoke or motivate
a few showers to form just ahead or along the cold front late
THU with support from low-level convergence and diffluence
aloft. Dewpoints and moisture remain limited and no thunder or
appreciable rainfall is anticipated. Since the front arrives
later in the day, and a downsloping W wind will precede this
surface boundary, look for mild temperatures well in the 60s
Thursday, before the northern door swings open wide and brings
a talked-about chill to the area. Wind chill values will bottom
out very early Saturday in the upper teens to lower 20s.


AS OF 300 PM Wednesday...A chilly start to the long term period.
with the coldest air of the season overhead with temps down in
the 20s to start the day. Deep CAA will wane through the day
with diminishing winds and plenty of early December sunshine as
the center of high pressure migrates over the Carolinas. But
after such a cold start to the day and this cold dense air mass
over the area, the temps will only reach into the 40s.

The air mass will modify as GFS shows a slow but steady rise in
850 temps from close to -8c very early Sat morning up to +8 by
Mon aftn. Light northerly winds will begin to swing around to
the NE and E through early Sunday and eventually a warmer and
moister southerly return flow will develop later in the day as
high pressure shifts farther off shore. This will allow dewpoint
temps to recover from the teens to 20s Sat into Sun up to mid
40s by Sun night. Sunshine will be plentiful once again on
Sunday with WAA kicking temps back up into the 50s.

A broad mid to upper trough will move east from the central
CONUS pushing next cold front through the area on Monday. Decent LLJ
will tap into enough Atlantic and Gulf moisture to bring values
up from a quarter of an inch on Saturday to nearly 1.25 inches
on Monday ahead of front. Overall expect increasing clouds and
potential for showers Sunday night through Monday. The ECMWF
continues to be slower with this system, but either way, expect
good chc of pcp on Monday before front makes its way off shore
by Mon night. Warm and moist advection will keep overnight lows
Mon close to what the high temperature was just a day before.
Monday will be the warmest with temps well into the 60s, but
readings will be dampened by the clouds and pcp. Cooler and
drier high pressure will move in behind front for Tues, but may
see another system affect the area again already by Wed. Temps
following cold front late Monday will be closer to normal...with
mid to upper 50s for highs Tues and Wed.


As of 00z...Confidence is rather low with regards to ceilings and
visibilities overnight. A weak frontal boundary is in place with
some decent low level moisture moving in about six hours from now.
Think this will be mainly a MVFR situation with a sprinkle possible.
Mainly westerly flow on Thursday with a continued chance of an MVFR

Extended Outlook...VFR.


As of 945 PM Wednesday...Latest obs show seas remain benign in
the 2 ft range with very light and variable winds. Forecast
remains on track with no changes. Previous discussion from this
afternoon follows:

A window of manageable marine conditions on tap this evening as
weak high pressure settles in, offering N winds 10 KT or less
tonight tending to W 5-10 KT early Thursday. Seas of 2-4 feet
overnight...highest offshore, will be comprised of S waves 2-3
feet every 7 seconds, and E-SE waves 1-2 feet every 8-10
seconds. No TSTMS or restrictions to VSBY overnight.

As of 300 PM Wednesday...Deteriorating marine conditions the
main headline this period as a powerful blast of cold air late
on Thursday through Friday brings gusty N winds of 20-25 KT and
choppy steep waves. Gusts to 30 KT will be common across the
outer and slightly milder offshore waters. A Small Craft
Advisory will be needed for this Arctic High in wake of a cold
frontal passage late in the day Thursday. Offshore navigation is
discouraged for small craft Thursday night and Friday, and with
the season comes the potential for hypothermia in the event of
an overboard situation. The Advisory will be likely be issued
overnight, but will allow another model run as to glean more
accurate timing of the event.

As OF 300 PM Wednesday...Northerly winds 10 to 15 kts early
Saturday will will diminish as they veer around through the
weekend become NE to E by Sunday as high pressure moves nearly
overhead before shifting further east off the Mid Atlantic coast
on Sunday. Seas will diminish as well through the weekend as
the high pressure shifts closer overhead Sat night and then off
the Mid Atlantic coast on Sunday. Seas near 3 ft Sat morning
will be down less than 2 ft Sat night through Sun morning as
winds become very light and more variable. By late Sun into Mon
winds will increase out of the SE to S pushing seas rapidly back
up possibly into SCA thresholds by Monday. A cold front will
move through the waters late Monday producing a veering of winds
to the W-NW up near 15 kts.





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