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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 181623
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1126 AM EST Tue Feb 18 2020

.SYNOPSIS...
A warm front will move north across the area this afternoon
before dissipating, followed by a cold frontal overnight. Wet
period through Thursday night, with brief reprieve possible Wed
afternoon. Low pressure develops along stalled offshore front
Thursday before moving northeastward, with increasing chance for
frozen precipitation Thursday night through Friday morning,
particularly for southeast NC. Cold Canadian high pressure will
follow late Friday into the weekend.

&&

.UPDATE...
No major changes with this update. Rain currently at our SW
border and will move across the area late this morning/early
afternoon.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Sfc high ridging across the FA from the Northeast will
weaken considerably allowing a weak warm front to lift across
the area this aftn before dissipating altogether. Models
indicate temps today thru tonight will remain above normal, 1 to
2 categories above the norm. However, short-lived, as a rather
strong cold front will suppress southward tonight and Wed,
passing across and south of the FA before stalling by late Wed.
Pcpn will mainly be convective or showery today into tonight,
then become more stratiform once the cold front pushes south of
the CWA early Wed. Could see a brief stoppage of the pcpn late
Wed aftn and night with skies remaining variably cloudy. QPF
this morning thru Wed sunset will run one half to three quarters
of an inch. Did not include any thunder due to limited Cape.
Tonights lows will actually be close to Wed max temps, due to
the decent CAA after the CFP Wed morning.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Cold front moves through during the late afternoon on
Wednesday leading to a brief period of dwindling precip
chances. Mid-level clouds are likely to linger overnight. SFC
northeasterly winds will advect colder air and overcome the mid-
level cloudiness and temperatures are likely to fall into the
low 40s by morning. During the day on Thursday, a low pressure
system will develop along the cold front to the south at the
intersection of the cold air and the Gulf Stream. Winds out of
the NE will increase and lead to strong cold air advection
keeping temperatures in the 40s for the duration of the day. The
low pressure will mature along the coastal trough and rain will
spread south to north across the area on Thursday, increasing
in intensity during the afternoon via isentropic lift.

Overnight Thursday, rain will spread northward as the low
pressure moves off to the north and northeast from its genesis
near the coast of GA. Given the run-to-run and model-to-model
consistency of the location and strength of the high pressure
supplying cold air, chances are we will have an air mass capable
of producing wintry weather in place. Moisture continues to be
the limiting factor in this scenario for those pulling for light
snow across the area. The GFS continues to show a secondary low
form along the cold front associated with a trailing upper-
level jet streak ahead of the longwave trough. The latest change
with the GFS is its slightly more northward track. This is
significant because it allows the low to pull in more cold air
via a tighter pressure gradient along the Carolina coast and
allows moisture to hug the coast producing a better chance of
wintry precip. The ECMWF has a single low pressure system pushed
slightly to the south as compared to the GFS, further away from
the US east coast. This would lead to limited moisture
associated with the system and lower chance of snowfall.
Available moisture within each model solution continues to
change from run-to- run with more variation than we would like
to see at this stage. As a result, have continued with the rain
to rain and snow to all snow Thursday night into Friday morning.
Currently, don`t expect any significant accumulation outside of
what would be indistinguishable from a heavy frost on grassy
and elevated surfaces.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Low pressure moves away from the coast on Friday with cold
air continuing to surge southward into our area. Temperatures
will struggle to reach the mid-40s as a result and cloudy skies
early will become a full compliment of sunshine by early
afternoon. Given the cold air advection during the day,
decreasing winds toward sunset, and clear skies, those with
agricultural concerns should be concerned with low temperatures
Saturday morning. Currently shooting for lows in the mid 20s but
if light snow accumulations become a reality on Friday morning,
we could even colder lows in a few spots. High pressure moves
overhead on Saturday and modifies a bit. Near normal conditions
under clear skies on Saturday. High moves offshore during the
day on Sunday and light southerly winds return, bringing warmer
temperatures and increased moisture. On Monday, global models
show the development of a low pressure system over the southern
plains making its way through the Southeast US through Monday
night. This would lead to increased southerly winds, much warmer
temperatures, and potential for widespread rainfall. A lot
could change with this scenario, so have gone with a chance of
rain at the moment.

&&

.AVIATION /15Z TUESDAY THROUGH SUNDAY/...
Another in a series of weather systems moving into the region this
afternoon, fueled by the subtropical jet. Look for deteriorating
conditions later today, with precipitation moving in from the
southwest. By evening, look for widespread IFR/LIFR, with rain and
warm air advection. IFR ceilings will likely hang in there a good
portion of the day on Wednesday.

Extended Outlook...MVFR/IFR conditions expected Wed Night thru
Fri morning. This a result of weak waves of low pressure moving
ENE along a stalled front across the Carolinas. Improving to
dominate VFR Fri into Sat as low pressure pulls away followed
by strong cold and dry Canadian high pressure.

&&

.MARINE...
Today thru Wed:
Decided to hoist the SCA in conjunction with the passage of the
cold front during Wed. Around noon for NC Waters and close to
sunset for the SC Waters. Have the SCA going thru Sat morning.

Winds today will be a function of a warm front that lifts across
the waters by this aftn. Winds will veer from the NE-E this
morning to SSW-SW this aftn and continue thru tonight. Speeds
generally under 15 kt. And seas 3 ft or less and primarily a
function of an ESE swell at 8 to 9 second periods. Sea fog
potential is not as clear cut given sfc dewpoints after the WFP
only reach the upper 50s to around 60 at it`s peak.

The CFP will occur Wed morning followed by a short delay in the
cold surge to late Wed morning for the NC Waters and close to
sunset Wed for the SC Waters. Winds will become NE 15 to 25 kt
once the sfc pg tightens after the CFP. Seas will build as a
result with 4 to 6 second wind driven waves becoming the
dominant input to the sig. seas.

Wed night thru Sat:
Cold front will pass through the area on Wednesday night and
park itself to the south. After the front moves through the
area, high pressure will build into the area briefly. Winds will
increase to 15- 20 knots overnight with gusts near 25 knots
setting up very likely Small Craft Advisory conditions. Low
pressure will develop along this front during the day on
Thursday spreading rain from south to north beginning during the
early morning hours. NE winds will continue to increase;
currently expecting winds out of the NE at 20- 25 knots
increasing to 25-30 knots through Thursday night. Wind waves of
6-8 feet will develop by Friday morning as the low intensifies
and moves off to the north and east. As the low quickly exits
the picture during the day on Friday, expect conditions to
rapidly improve. By Saturday morning, winds should become 10-15
knots and seas falling to their typical 2-4 feet. High pressure
overhead during the day on Saturday will provide quiet weather
and a pleasant day for mariners.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory from 6 PM Wednesday to 6 AM EST Saturday
     for AMZ254-256.
     Small Craft Advisory from noon Wednesday to 6 AM EST Saturday
     for AMZ250-252.

&&

$$

SYNOPSIS...VAO
UPDATE...VAO
NEAR TERM...DCH
SHORT TERM...21
LONG TERM...21
AVIATION...43
MARINE...DCH/21