Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 231030
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
530 AM EST Wed Jan 23 2019

.SYNOPSIS...
High pressure will shift off shore bringing a considerable
warmup today. Gusty showers will accompany a cold front
that will cross the area Thursday morning. High pressure will
build in from the northwest late in the week. The high will
shift south of the area early next week. Temperatures near
to slightly below normal into the weekend will start warming
early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 3 AM Wednesday...Latest sfc analysis shows 1035 mb high
pressure centered just off the VA/NC coast with 1007 mb low pressure
over MO. The high pushes farther offshore today allowing for onshore
flow to continue over the local area. Lowered rain chances for this
morning due to the strength of the high and weak forcing for ascent.
There will be some increasing warm air advection through the day
while a warm front moves northward and with moisture profiles
somewhat increasing through the day, maintained a slight chance-
chance of a shower especially over western areas. Temps noticeably
warmer than the last couple days...highs in the low/mid 60s.

For tonight, maintained low chance PoPs out ahead of the approaching
cold front with continued meager forcing. Best chance of rain is
between 09-15Z Thursday in association with the cold front and
potent mid-level shortwave trough. Rainfall totals up to around an
inch possible area-wide. Also expect gusty winds out ahead of the
front, from both the gradient winds and moreso any convective
elements/showers, due to a 70-80 kt low-level jet. Will mention
gusts to 30-40 mph in the HWO.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 3 AM Wednesday...Cold front will be in the region as the
period begins, likely with showers ongoing as well as the
possibility of an isolated thunderstorm along the coast.
Although the event looks to be a typical high shear low CAPE
setup, the timing is not at all favorable. The front will be
crossing the area during the time of lowest CAPE with only a
strong low level jet to aid forcing. Additionally both the GFS
and ECMWF are showing signs of convection along the FL Gulf
Coast, something that typically hinders convection across
coastal Carolina. At this point do not anticipate any severe
weather, but something to keep an eye on. Cold advection lags
the front and Thu afternoon will likely end up mild with gusty
west winds. Might even see some clearing before the sun sets.

Cold air arrives Thu night as high pressure builds in from the
northwest. Thickness and 850 temps rapidly drop, with the later
dropping as much as 8 degrees C in 12 hours. Mixing will help keep
lows overnight near climo Fri morning despite clearing skies and
deep dry air. High continues to build in from the west Fri into Fri
night keeping temperatures near to below climo despite plenty of sun
in the afternoon. Precipitable water drops under 0.30" with forecast
soundings showing a bit of a subsidence inversion. Boundary layer
winds weaken and become more easterly Fri night as the center of the
high moves closer to the region. Winds may not go completely calm,
especially along the coast, but radiational cooling should be able
to have some effect. Lows will likely end up below climo with temps
ending up in the mid to upper 20s for much of the area.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 3 AM Wednesday...Mid-level trough will remain over the eastern
CONUS through the period, with the axis remaining west of the area
into next week.

-Temperatures will be near to below climo through the weekend,
trending slightly above next week.

-West to northwest flow aloft will prevent any meaningful moisture
return, precipitable water will be at or below 0.60" through the
period.

-Low pressure will pass well off the coast early next week as
 another low passes northwest of the area. This low may move a
 cold front and increased rain chances into the area late Tue.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
As of 12Z...High pressure will shift offshore today, with southerly
flow returning. Could be some tricky stratus/fog that could set up
around sunrise, but kept things minimal at this time. A coastal
trough sets up this afternoon with a slight chance of showers.
Tonight, a cold front approaches rather rapidly from the west.
Southerly winds ahead of the front will increase, with gusts to 25
kts expected after midnight. Convection will enter our western
terminals by 08Z, reaching the coast at the end of the forecast
period.

Extended Outlook...MVFR overnight Wednesday into Thursday due to
showers and a passing cold front. VFR Friday through Sunday.

&&

.MARINE...
NEAR TERM /THROUGH TUESDAY/...
As of 3 AM Wednesday...Sub-Small Craft Advisory conditions daytime
today with high pressure just off to the NE. Expect 10-20 kt SE
winds with 3-5 ft seas. Winds and seas then ramp up tonight ahead of
an approaching cold front. Converted the gale watch to a warning,
from 06Z-18Z Thursday, with frequent gusts up to 35-40 kt expected
due to a 70-80 kt low-level jet despite cool SSTs. Seas up to 8-11
ft. Chances for sea fog not high enough to include mention in the
forecast attm.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 3 AM Wednesday...Gale Warning ongoing at the start of the
period will transition to a Small Craft Advisory as cold front
pushes east of the waters and westerly flow develops. Gradient
starts to relax Thu afternoon with west flow becoming northwest
Thu night as colder air arrives. Northwest winds around 15 kt
Thu night drop to around 10 kt Fri and Fri night, becoming north
and then northeast as they slowly weaken. Double digit seas are
expected prior to the passage of the cold front. Once offshore
flow develops seas will start to diminish, but seas are likely
to remain over 6 ft into Fri morning. Seas 3 to 5 ft on Fri
slowly subside ending up 2 to 3 ft by the end of the period.

LONG TERM /SATURDAY THROUGH SUNDAY/...
As of 3 AM Wednesday...Surface high over or just south of the
waters at the start of the period will gradually shift
southeast. Weak gradient will keep winds light into Sun before
more defined gradient leads to increasing west-northwest flow.
Late in the period the highs moves farther south and light west
or even southwest winds may develop. Speeds under 10 kt during
the period along with varying direction will keep seas 2 to 3 ft
Sat and 2 ft or less on Sun.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...Coastal Flood Advisory from 10 AM this morning to 2 PM EST
     this afternoon for NCZ107.
MARINE...Gale Warning from 1 AM to 1 PM EST Thursday for AMZ250-252-254-
     256.

&&

$$

NEAR TERM...MAS
SHORT TERM...III
LONG TERM...III
AVIATION...43


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