Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
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FXUS62 KILM 092020 CCA
Area Forecast Discussion
National Weather Service Wilmington NC
313 PM EST Fri Dec 9 2016
Arctic high pressure will bring in the coldest temperatures of
the year tonight through Saturday night. A warming trend will
occur on Sunday and continue through the mid week. A cold front
will approach from the plains and will move into the area
Tuesday and will remain in the area through Wednesday before a
second stronger cold front will bring below normal temperatures
back to the area on Thursday into next Friday.
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --As of 3 PM Friday...Temperatures presently 12-17 degrees cooler, RH
values 20-40 percent lower, and pressure values notably higher than
24 hour ago, as the eastern edge of a bubble of frigid air courses
westward toward the Carolinas. A wintry bite will greet daybreak
Saturday with temperatures bottoming out in the low and middle 20s,
with wind chills several degrees lower, as a slight north breeze
prevails. The clear sky will help long-wave radiation escape
tonight. Plants and pets will become vulnerable late tonight and
even outdoor exposed water pipes should be covered or insulated or
allowed to drip if the former actions cannot be taken.
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.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 3 PM Friday...The germane weather streaming headline this
period reads `Frigid Sunday Morning, Chance of Rain Sunday
Night and Early Monday`. Arctic high pressure entrenched over
the region dawn Sunday will migrate offshore Sunday afternoon.
Height falls aloft co-joined with a tenacious surface wedge
will result in coastal trough formation just off the beaches.
The associated low-level convergence will set off a few showers
as the trough impinges the coast and coastal interior Sunday
afternoon and night. The best chance of rain being Sunday late
night as the trough sharpens and the moisture advection accumulates.
Warm air advection will raise temperatures well above the threat of
frozen pcpn, but the evaporative cooling could keep maximums Sunday
below guidance values.
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM Friday...A comparison of the 500 mb flow between the
GFS and ECMWF both are vary similar with zonal west-
southwesterly flow over the southeast United States. In the
lower levels the models are showing return flow from the south
and southeast and the tail end of a coastal trough that had
developed the the south a few days earlier. In the larger
synoptic flow cold front from the plains is expect to move
across the forecast area late Monday night into early Tuesday.
Both the 12 UTC ECMWF and GFS are showing the cold front moving
off the coast and stalling to the south and east of the area.
Both are indicating that the surface low will now form a bit
farther off the coast. Uncertainty is high on the fronts final
location. There will be a chance of showers through Wednesday
with a lull expected Monday night. QPF values are not expected
to be extreme with this event.
A second cold front will push quickly through the forecast area
late Tuesday into Wednesday morning with another shot of colder
air later Thursday into Friday.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 18Z...High confidence in VFR through the valid period.
High pressure edging in from the west will become oriented
overhead on Saturday. This will continue clear sky conditions,
with slowly decreasing winds. Northerly winds will continue to
gust through sunset at around 15 kts, but will become light
after nightfall. A subtle veering in wind direction is forecast
Saturday, but with speeds less than 10 kts and continued SKC.
Extended Outlook...Showers possible Mon-Wed. Otherwise VFR.
-- Changed Discussion --NEAR TERM /THROUGH TONIGHT/...
As of 3 PM Friday...Cold but improving marine conditions for boat
navigation as both winds and seas lessen into Saturday. Small Craft
Advisories from earlier have been canceled as seas have settled to 2-
4 feet and wind gusts down to 20 KT offshore, with a little bit of
improvement into Saturday as a high pressure cell migrates closer to
the coast. The sea spectrum overnight will be comprised of NE waves
2-4 feet every 5 seconds and SE waves about 1 foot every 8 seconds.
with dampening shorter period waves into Saturday making things a
little safer. This is a good time to think about items onboard that
reduce the chance of hypothermia in the event of an overboard
situation as sea surface temperatures take a bit of a plunge this
weekend. No TSTMS or rain or restrictions to visibility expected
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 3 PM Friday...Main marine headline this weekend` Cold but no
Advisories expected Saturday, Deteriorating late Sunday`. As high
pressure nearly overhead Saturday migrates off the mid-atlantic
coast Sunday, a coastal trough will form near the Carolinas coast.
Due to increasing winds moreso east of the 20NM zone, waves will
build notably Sunday night to 4-6 feet and a Small Craft Advisory is
very possible then. This will be joined by occasional rain showers
reducing VSBY to 2-4 NM. In addition to this, its possible the warm
moist over the chilly inshore waters could spur a bit of marine fog
late Sunday night into early Monday.
LONG TERM /MONDAY THROUGH TUESDAY/...
As of 3 PM Friday...South-southwest winds of 10 to 15 knots will
start long term marine forecast ahead of a cold front that will push
off the coast late Monday and stall near or just south and east of
the coastal waters on Tuesday. Winds to the west of the will be from
the west and west-northwest at this time winds speeds are expected
to remain below 20 knots. No small craft condtions are expected.
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