Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 161612

Area Forecast Discussion
National Weather Service Wilmington NC
1110 AM EST Sat Dec 16 2017

High pressure will build across the Carolinas today and shift
offshore later today thru Sunday. Below normal temperatures will
continue today and tonight. A cold front will move into the area and
stall Mon thru Mon night. Hit or miss showers will occur from early
Mon thru Mon night with amounts generally less than one tenth of an
inch. Low pressure from the Gulf coast states will push across the
area Wed thru Thu with a chance for substantial rainfall. High
pressure will follow for the late week period.


As of 915 AM Saturday...Weak confluent flow aloft will persist
across the Eastern U.S. with surface high pressure across the area
through tonight. Other than patchy high cloudiness, skies will be
mostly clear through the period. Below normal temperatures will
continue through tonight as well with highs today in the lower to
mid 50s, and lows at or just below freezing away from the coast
tonight. Light winds with a weak pressure gradient across the area.


As of 345 AM Saturday...Low amplitude ridging aloft, with the
ridge axis extending north across the FA from the Bahamas, will
persist thru this period. A mid-level s/w trough ejected from the
Desert SW early Sunday, will track to the NE remaining well north of
the FA as it passes by. At the same time de-amplifying as it gets
absorbed in the mean flow by late Sun. The southern branch of the
jet stream will dominate the local area, keeping any cold air or
outbreaks well north of the FA this period.
Sunday will be a mostly sunny early with increasing mid and
upper level clouds by afternoon. Low level cloudiness will
become more persistent late Sunday night thru Tue as a cold
front drops south and stalls as it becomes parallel with the
upper flow oriented from the ENE to WSW across the FA. Will
indicate low chance for isolated to widely scattered light
showers to break out early Monday morning and continuing thru
Mon Night. As for temps, stayed close to a consensus of avbl Mos
Guidance as a start followed by the addition of a few degrees
especially for maxes Sun and Mon.


As of 300 PM Friday...On Monday the 12 UTC runs of the ECMWF
and GFS are showing a trough/cutoff low south of the 4 corners
area of the great southwest. The models begin to diverge and by
Tuesday the GFS is faster pulling the cutoff low to the east. By
Wednesday morning the GFS has dissipated this wave and it has
this feature accelerating to the east coast in the zonal flow.
The ECMWF still has a cutoff over the Oklahoma and Arkansas
border and the model weakens and dissipates this features as if
has moves off the east coast. Therefore confidence in the
extended forecast is not high.

The GFS models continue to show a warming trend through Tuesday
before moving a cold front through the area between Tuesday and
Wednesday and bringing down a shot of cooler temperatures, but
the ECMWF keeps the shot of colder air farther north. So the
forecast will side with the model blend and this will bring in
cooler temperatures for Wednesday.

Rainfall chances looks to be the best on Monday into Tuesday
with the favoring of the GFS solution stronger southern energy
out of the southwest and pulling the cutoff low out quicker.
With the the west-southwest flow remaining over the region
expect to see small chances of rain Wednesday through Thursday.


As of 18Z...High confidence for VFR conditions through most of the
forecast period. High pressure centered to our west will give us
light northerly flow with moderate subsidence. Other than jet
cirrus, little to no clouds are expected. There may be some light
fog around sunrise, but it should not be much of a problem. Sunday,
light southerly flow with increasing clouds at the end of the
forecast period.

Extended Outlook...Sunday VFR.  Unsettled weather Monday through
Thursday morning as a near stationary front moves in and out of the


As of 915 AM Saturday...A surface ridge axis aligned along the
Carolina coastal plains will maintain light northerly flow across
the adjacent waters. Light and variable winds expected tonight
as high pressure shifts farther east. Seas will be 2-3 ft today,
and subside to 1-2 ft tonight.

As of 345 AM Saturday...Rather docile wind and sea conditions
Sunday that will likely persist thru Monday with only a few
knots of wind added and up to 1 foot for significant seas.
Center of high pressure overhead early Sunday with a variable
wind direction under 10 kt, will push offshore late Sunday
resulting in a brief southerly return flow. An approaching cold
front will produce SW to W flow at 15 kt or less Mon thru Mon
night due to a slight tightening of the sfc pg. The front will
stall oriented ENE to WSW across the local waters in the
vicinity of Cape Fear late Mon thru Mon night. Winds W to WNW
north of the stalled front and SW-WSW south of the front.
Significant seas will run 1 to 2 ft Sun thru Sun night and
2 to occasionally 3 ft Mon thru Mon night. An easterly 1 foot, 9
to 10 second period ground swell will dominate the local waters
Sun thru Sun night. Wind induced waves at 3 to 5 second periods,
Mon thru Mon night may become the more dominant player in the
sig. seas.

As of 3 PM Friday..An unsettled period for the marine forecast
with west to southwest flow on Monday into Tuesday with a cold
front pushing across the waters later Tuesday into Wednesday.
Will have to watch if small craft conditions develop after the
cold frontal passage but otherwise expect seas of 2 to 4 feet.





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