National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 211103
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
603 AM EST Fri Feb 21 2020

.SYNOPSIS...
Low pressure offshore from the Carolina coasts this morning
will further intensify as it accelerates away from the mainland
this afternoon through Sat. Any ongoing light snow early this
morning will quickly end by mid-morning. Cold and dry Canadian
high pressure will build in and dominate this weekend. A warm
front will lift across the area early Mon bringing milder
temperatures thru Tue. A cold front will push across the region
late Tue with cold and dry high pressure following for the mid-
week period.

&&

.NEAR TERM /THROUGH SATURDAY/...
This update will remove Marlboro and Dillon Counties from the
Winter Wx Adv with the remaining NC Counties untouched. Will
issue a SPS for all locations not in the Winter WX Adv for ice
covered roadways, walkways and etc. Temps are right at 32
degrees and may drop 1 or 2 more degrees by sunrise. Decent CAA
this morning will slow the diurnal rise of temperatures back
above freezing, with guidance suggesting by the mid daytime
morning hrs.

The back edge of the pcpn shield extends from Elizabethtown,
Bladen County, to Myrtle Beach. The back edge will slide off the
Carolina Coasts altogether by or just after daybreak. A couple
of tenths of an inch of additional snowfall remains possible
for Pender and northern New Hanover Counties. Elsewhere, a trace
to no additional snow accumulation. Black Ice will be hit hard
within the various statements that WFO ILM issues this morning.

The intensifying Gale(Storm?) Low with Storm Gusts, up to 50+
kts just offshore from the NC Coastline, will continue to
accelerate ENE, away from the U.S. mainland today. The tightened
sfc pg combined with CAA surge will keep winds brisk across the
FA today with wind chill readings in the upper teens well
inland this morning, and the low to mid 20s closer to the
coast. The positive tilted mid-level trof pushes off the
Southeast Coast by sunset. This will allow the 1035+ mb sfc
high to migrate east to the Carolinas late tonight with it`s
center becoming sprawled across the Eastern Carolinas by Sat
night. Max temps today will run in the upper 30s across
locations that received measurable snowfall and elsewhere in
the lower 40s. For tonights lows, will highlight the low to mid
20s and that includes an active N to NE wind to prevent temps
from bottoming out altogether with progged dewpoints in the
teens. Sat max temps will see a 10+ degree change to the milder
side with 50 to 55 degree readings.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
The short term period will see very quiet conditions
after a long period of unsettled weather. The mid level pattern
will continue to relax as arctic high pressure moves overhead
then makes the transition offshore. Temperatures will not
necessarily be a prelude to spring as lows Sunday morning will
be at or below freezing once again only recovering to the middle
to upper 50s Sunday afternoon. A return flow setting up keeps
lows Monday morning somewhat above freezing.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
An active southern stream will bring pops back in the
picture rather quickly later Monday as low pressure ejecting
across the southwest moves into the midwest. We have likely to
even categorical pops in place but I have a feeling this system
may weaken in time like most following this pattern this season.
Beyond this even more uncertainty as a digging trough to the
west seems to keep the baroclinic zone parked over the coast
with a period or two of unsettled conditions. Global guidance is
in agreement on moving this system out near weeks end with
another round of possibly freezing temperatures.

&&

.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
Flurries coming to an end across the area as dry air surges
southward. Northerly winds will increase in intensity this afternoon
as the BL develops and a few gusts to 20-25 knots. Skies will clear
quickly this morning with some areas in SC already seeing the mid-
level deck scour out. VFR this afternoon as winds decrease overnight
as high pressure moves overhead.

Extended Outlook...VFR will persist through the weekend as cold,
dry Canadian high pressure prevails. Flight restrictions will
likely return on Monday.

&&

.MARINE...
Today thru Sat:
N to NNE Winds across the area waters remain solidly in Gales
with sustained 30-35 kt and frequent gusts at 40 to 45 kt.

Gale Warning remains active across all waters. Latest winds and
seas are close to their peaks with this deepening low. With
Storm Force gusts, 50+ kt, having been recorded offshore at the
Onslow Bay Outer Buoy 41064. Across the ILM Coastal Waters,
plenty of gusts in the 40 to 45 kt range with 41037, just
offshore from Wrightsville Beach having recorded a 47 kt gust,
just shy of Storm conditions.

MOS Guidance from both the NAM and GFS for our local buoys
indicate winds to peak thru daybreak followed by a slow
diminishing trend, below Gale force late in the day. The
tightened sfc pg and the cold surge will continue combine to
keep winds at SCA thresholds well into tonight. The high`s
center will approach the Eastern Carolinas during Sat and as a
result, the sfc pg will relax and the CAA will have become
neutral. Winds will further lower to 10-15 kt. Significant seas
will peak thru midday, with up to 12 to 14 ft just offshore and
beyond the ILM coastal waters from Onslow Bay south across the
outer Frying Pan Shoals. The northerly component in the wind
field has limited the fetch for which waves to build upon, but
given the high Gale and low Storm Force wind gusts, seas have
become quite monumental with periods at just 8 seconds. That is
major league wind chop!!! Seas will initially drop once wind
speeds lower today but then will follow a slow subsiding trend
with back waves or swell from the departing low affecting the
waters Sat.

Sat Night thru Tue:
ALight wind fields will be in place for the first day or so of
the short and long term marine periods. A northerly component
will remain for a day or so before the transition to a return
flow develops late Sunday and becomes more pronounced Monday.
Winds will peak at 15-20 knots late Monday into Tuesday from the
southwest ahead of the next system. This boundary never moves
across according to the latest projections but the southwest
flow does lose some zest. Finally a system late in the work week
will turn the winds offshore and seemingly with some authority.
Significant seas will be modest early on with a range of 2-3
feet ramping up with the winds into possibly small craft
criteria Tuesday and again late in the period with the offshore
flow.

&&

.TIDES/COASTAL FLOODING...
Have placed the NC beaches in a Coastal Flood Advisory that runs
thru 8 am this morning. The latest Johnny Mercer Pier tide
forecast has levels reaching just shy of 6.5 ft MLLW at the 549
am high tide this morning. This level breaches the 6.0 ft MLLW
threshold for minor coastal flooding to occur. The SC beaches
will remain just below minor coastal flood thresholds via latest
Springmaid Pier tidal data.

The Lower Cape Fear River from Wilmington south has also been
included in a Coastal Flood Adv for river levels to reach 5.9
ft MLLW. This forecast level is above the Minor coastal Flood
threshold of 5.5 ft MLLW. High tide will occur around 8am at
the river gage near downtown Wilmington. Minor flooding will
occur up to 3 hrs centered at the time of high tide.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...Winter Weather Advisory until 10 AM EST this morning for
     NCZ087-096-099-105>107-109.
     Coastal Flood Advisory until 8 AM EST this morning for NCZ106-
     108-110.
     Coastal Flood Advisory until 10 AM EST this morning for NCZ107.
MARINE...Gale Warning until 6 PM EST this evening for AMZ250-252-254-
     256.

&&

$$

SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...21
MARINE...DCH/SHK
TIDES/COASTAL FLOODING...ILM