Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 212045
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
345 PM EST Sat Jan 21 2017

.SYNOPSIS...
A warm front over the NC/SC border will lift north through
tonight as low pressure moves up into the Carolinas. A more
complex and potent storm system will affect the Carolinas Sunday
into Monday with potential for severe weather during Sunday
afternoon and evening. Total rainfall amounts today through
Monday should amount to one to three inches. This storm system
will slowly depart through Monday leaving high pressure for
Tuesday and Wednesday. The next cold front will move across the
area on Thursday. Much colder weather will follow Friday and
into next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Saturday...Sfc winds coming around to the SE to S
most places and will see a deep warm and moist S-SW flow across
the area by tonight as warm front lifts north. Models continue
to show a sfc low moving along this boundary as a shortwave
tracks up from the SW. As the low exits off to the north
a line of convection will move E-NE through SC. The warm front
boundary will get a slight push south again as low pulls off to
the NE but it looks like it should be aligned closer to the
VA/NC border by Sun morning leaving our forecast area well
entrenched in a warm and moist air mass overnight. The best
shortwave energy will move across the area this afternoon
through this evening with better chc of thunderstorms and
showers with heavier rain. Strongest convection to the southeast
will weaken as it moves toward the area but could see some
stronger storms reach the area into this evening. Best chc of
convection with heavy rain and gusty winds will be between 4
and 8pm over northeast SC, but overall expect weakening with
time.

Expect a break in pcp overnight with another period of low
stratus and fog with temps and dewpoints remaining near 60.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 300 PM Saturday...SPC latest forecast continues to keep
slight risk over northern fringe of forecast area and enhanced
risk elsewhere for Sunday. Therefore we are still looking at an
active late day on Sunday with potential for damaging winds and
potential for tornadoes.

Similar to Sat morning, areas of fog will start out the morning
and low pressure will be lifting off to the N-NE off the VA
coast. This will swing boundary back around but should be just
north of local forecast area Sun morning as potent storm system
tracks up from the southwest. The parent low will be stacked
over the lower Mississippi Valley Sun morning and will track
slowly east to northeast through Sun into Monday. Strong upper
level energy will rotate around this system into the southeast
through late Sunday. Although some pcp will brush over the area
through Sun morning, the main threat of stronger convection and
heavier rain will come later in the day on Sunday as the upper
low shifts east over the Carolinas. It looks like the brunt of
the convection will reach the eastern Carolinas between 6p and
midnight. The models differ in terms of exact location of low
and timing and therefore will keep a wider window for now. The
position of the low will be key in terms of potential for
tornadoes, but either way, the enhanced upper level support will
produce potential for strong to severe storms storms with
damaging winds. Gearing up for a high shear, low cape event with
main threat Sun evening. LLJ cranks up to 50 to 60 kts running
right up through the tip of Cape Fear around 7 to 10 pm. Pcp
water reaches up close to 1.7 inches at this time with CAPE
values up 500 to 800 j/kg through late Sun evening.

This potent low will move slowly off to the E-NE reaching the VA
coast Mon evening. The cold front extending south will push
well east of the FA late Sunday night into early Monday. Some dry
air will wrap around the back end into the Carolinas through
Mon morning but stacked low will drift across VA and off the VA
Cape by Tuesday daybreak. Enough moisture will continue to wrap around
maintaining a good deal of clouds along with a low end pcp
chances. The 850 temps will drop from 13c Sun aftn down to 5 to
6 c by Mon aftn as cooler air makes its way in on the back end.
This will bring temps down a good 5 to 10 degrees on Monday but
still keeping well above normal temps for this time of year.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 300 PM Saturday...A regime change signaled by a strong cold
front Thursday will separate the extended into two distinct seasons.
Ahead of this front, Tue-Thu, continued above to well above normal
temperatures are forecast. Tuesday is likely the coolest day of this
stretch behind Monday`s cold front, but temps will still reach into
the 60s, above normal for late-January. Thereafter, 500mb ridging
blossoms up the Southeast coast while high pressure moves into the
western Atlantic. This will create dry weather and lots of sunshine
Wednesday with temps soaring towards 70 once again. Another warm day
is forecast Thursday, but a cold front along the leading edge of a
deepening mid-level trough will bring a chance for showers, followed
by much colder air for Friday. Temps crash quickly behind this front
as a significant trough sets up across the eastern CONUS. While the
latter half of the period will be dry, this trough will be
periodically reinforced so temps will get cooler each day into the
wknd, and by Saturday could be several degrees below climo. This
cold air looks to remain locked in for quite a while, persisting
even beyond this extended.


&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 18Z...Difficult flight conditions as periods of IFR and
MVFR prevail this TAF cycle. The onshore flow will also plague
coastal terminals at times with VSBYS < 1/2 NM. -RA/SHRA also in
the mix 22Z-02Z, then again Sunday AFT 14Z. Winds mainly SSE-SSW
this period at speeds of 11KT or less.

Extended outlook...Thunderstorms are expected on Sunday
with IFR conditions possible. There is potential for strong to
severe thunderstorms Sunday afternoon into the evening.

Monday thru Wednesday, MVFR to mainly VFR conditions expected.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
As of 300 PM Saturday...Dense Fog Advisory issued for all
waters for areas of fog with vsbys less than a mile. SCA for all
coastal waters beginning at 6 am Sunday and persisting thru 6
pm Tuesday.

A sfc frontal boundary will move back north as a warm front as
low pressure tracks up into the Carolinas through this evening.
Winds to the north of this boundary will shift from E-SE to
S-SW and south of the boundary the winds will be S to SW. Winds
10 kts or so will pick up to 10 to 20 kt overnight into Sunday
morning as southerly winds increase ahead of next system. This
southerly push will drive seas from 2 to 3 ft this afternoon up
tp 3 to 5 ft by Sun morning.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 300 PM Saturday...Strong SCA conditions through the period
as a potent low pressure system moves across the Carolinas and
up to the VA coast by Mon night. Increasing SW winds ahead of
this system on Sunday will reach up to 20 to 30 kts. This strong
southerly push will drive seas rapidly up to SCA thresholds
through the morning and possibly as high as 7 to 9 ft by Sun
night. Winds will begin to veer to the W-SW through the day on
Monday which will help to lower the heights near shore but still
expect seas up to 6 to 8 ft through much of the day on Monday
in SW winds up to 20 to 30 kts. Winds will continue to veer with
strong off shore westerly winds by Tues morning keeping the
highest seas in the outer waters but strong winds will persist
through the period with SCA conditions throughout.

LONG TERM /TUESDAY THROUGH THURSDAY/...
As of 300 PM Saturday...Cold fronts moving across the water bookend
the period. The first will be offshore Tuesday morning, leaving
gusty W/NW winds of 20-25 kts, easing slowly to 10-15 kts while
backing to the W/SW by Wednesday morning. An SCA from Monday may
linger into Tuesday morning for these winds and 4-6 ft seas, before
falling to 2-4 ft by Wednesday morning. Brief ridging creates SW
winds increasing to 15-20 kts during Wed and into Thu, before
another cold front crosses with a wind shift to the W/NW at the end
of the period. Wave heights will build again to 3-5 ft late
Wednesday into Thursday before falling behind Thursday`s cold front,
but no further statements or headlines are anticipated.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Dense Fog Advisory until 6 AM EST Sunday for AMZ250-252-254-
     256.
     Small Craft Advisory from 6 AM Sunday to 6 PM EST Tuesday for
     AMZ250-252-254-256.

&&

$$
NEAR TERM...RGZ
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...MJC/DRH


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