Area Forecast Discussion
Issued by NWS Wilmington, NC-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KILM 220538
Area Forecast Discussion
National Weather Service Wilmington NC
138 AM EDT Sat Apr 22 2017
-- Changed Discussion --High pressure will remain offshore and extending back into the
Carolinas today. A slow moving cold front will sink south into
the area late tonight before stalling near the NC/SC border
through early next week. A complex storm system will develop
along this boundary and bring thunderstorms and potentially
heavy rainfall through late Monday. This system will lift away
from the area Tuesday with a return to seasonable and dry
weather by the middle of next week.
-- End Changed Discussion --
.NEAR TERM /THROUGH TONIGHT/...
As of 915 PM Friday...The main change made for this update was
to decrease the cloudiness coverage tonight into Sat. Latest sat
imagery trends and rh model time height displays across the FA
indicate diurnal driven cu will dissipate leaving only thin
cirrus aloft. Any convective debris clouds from upstream will
remain north of the FA. Tightened sfc pg and the nocturnal low
level jet overnight, will combine to keep winds active thruout
the night and preventing any fog development. This will also
result in elevated min temps for tonight with widespread 60s
across the FA.
As of 300 PM Friday...It`s practically a summertime pattern
this afternoon with Bermuda High Pressure offshore and a
unseasonably warm airmass in place. Officially we hit 88
here in Wilmington just before the seabreeze arrived, our
warmest temperature of the year so far! A strong seabreeze
circulation is developing with winds at the beaches expected
to gust to 25-30 mph over the next few hours. Cumulus clouds
developing along the seabreeze front and inland near the
Piedmont Trough have struggled to overcome dry mid-level air
observed in this morning`s 12Z soundings from MHX and CHS.
Where natural convergence is maximized along the Piedmont
Trough, a few showers could develop from Darlington and
Bennettsville across Lumberton in the next few hours but
coverage is likely be less only 20 percent.
Much like last night a hefty low level jet should develop
this evening with 1000 foot wind speeds increasing to 25-30
knots. This should help keep the boundary layer stirred up
enough that lows will remain quite warm for April: 63-65 inland
with upper 60s near the coast.
Another warm day is expected Saturday. Differences from today
include winds not quite as dominated by westerly low and mid
level flow, however dry air aloft still appears to be in place.
I have placed 20 PoPs in the forecast along the seabreeze and
in the northern half of the Pee Dee region as dewpoints should
be a few degrees higher which may help the afternoon cumulus to
have a bit more luck combating the dry air aloft. Highs should
again rise well into the 80s away from the beaches.
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 300 PM Friday...Anomalously strong upper low will
but cutting across TN Saturday night with surface low only
slightly ahead/east of the mid level system. The position of the
leading front associated with the surface wave is and has been
poorly agreed upon by various model guidance, the GFS being the
far south outlier. The boundary may well end up bifurcating the
area north-south by Sunday morning. Wind and temperature
forecast have been adjusted accordingly. With only low level
forcing in place precip amounts look to be light and will be
overrunning stratiform rain north of the boundary and shallow
convection south of it. On Sunday height falls will help to
strengthen the low level jet and thus the overrunning north of
the boundary. Similarly the coverage of rain south of the front
will increase though with much lighter amounts expected. Sunday
night the upper low dives even further south and the system
occludes overhead or south of the area...impressive for late
April. The period should end with a healthy amount of rainfall
area-wide likely in the 1-2 inch range.
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 300 PM Friday...The extended period will be active early
on as a closed mid level low moves across the interior southeast
then up along the east coast Tuesday. As for Wednesday through
Friday mid level ridging will develop across the southeast as
deep troughing develops out west.
The aforementioned mid level cyclone will be located in central
Georgia at the beginning of the period with an occluded surface
cyclone just off the South Carolina coast. Both features
move to the north and by Tuesday morning the surface feature
should be near Cape Hatteras with the mid level feature not too
far behind. We continue to advertise likely to categorical pops
for Monday trending downward Tuesday. Normally the words cutoff
and late April are associated with an appreciable risk of severe
weather but the wind fields don`t look overly impressive at
least from a speed standpoint with 30 knots dispersed kinda
diffusely at 850mb. Still a cold core system during late April
could pose a hail threat. The remainder of the week should be
dry with above normal temperatures trending even higher as time
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --As of 06Z...VFR forecast through the valid period. High pressure
offshore will keep a cold front to the north at bay, but increased
moisture this aftn will permit at least SCT aftn diurnal CU at VFR
levels. A few showers and even isolated tstms are possible, mostly
along the sea breeze, but are not expected to impact any of the
terminals. SW winds will remain above 5 kts through daybreak, and
then increased to 10-15 kts, with gusts over 20 kts likely at the
coastal terminals behind the sea breeze. A local backing to the S/SW
is also forecast at ILM/CRE/MYR this aftn. Winds will ease slowly
after dark, and the aforementioned cold front will begin to sag
southward. Guidance has sped up the timing of this fropa, but will
likely still not see a wind shift or any showers across NC terminals
until just beyond this valid period. However, VFR cigs will slowly
develop from north to south overnight tonight.
Extended outlook...MVFR/IFR cigs possible late Saturday night
into Sunday. Periods of MVFR and IFR are likely Sunday and
Monday in showers and thunderstorms. VFR re-developing on
-- End Changed Discussion --
NEAR TERM /Tonight through Saturday/...
As of 915 PM Friday...Active SW winds expected tonight thru Sat.
A tightened sfc pg across the area waters well ahead of a cold
front, will keep SW winds active across the waters tonight thru
Sat. , located across central VA at the moment, will continue
across the area waters tonight thru Sat. A low level 20 to 30
kt SW jet is expected again over the area waters tonight. With
SSTS having climbed to around 70, some of those hier winds aloft
may work their down to the ocean sfc as gusts. Significant seas
will generally run 2 to 4 ft with 3 to 5 ft not entirely out of
the question during Saturday. This may result in the issuance of
a SCEC if this trend continues. A decaying easterly pseudo
swell at 7 to 8 second periods tonight will give way to the 3
to 5 second period wind waves as the dominate player in the seas
As of 300 PM Friday...High pressure centered about 500 miles
east of the Florida east coast will move very little through
Saturday. A cold front currently extending from West Virginia to
the Maryland coast will slip as far south as the northern Outer
Banks by late Saturday afternoon. Our weather will continue to
be influenced most strongly by the high offshore in a summerlike
pattern that will feature another strong seabreeze circulation
Locally-generated wind waves will dominate the wave spectrum
tonight into Saturday. There will be also a pair of 8 second
east and southeast swells pushing across the coastal waters but
with amplitudes much less than the short period wind chop.
SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 300 PM Friday...Boundary will be slipping south into or
across the area as Saturday night progresses. The position and
movement of this boundary is highly uncertain as it is poorly
agreed upon between various guidance. So not only is the wind
shift line uncertain but so too is the areal coverage of the
stronger pre- frontal SW flow regime. These details will likely
become more clear in future forecast iterations. These
uncertainties will translate into the latter part of the period
as well. Low pressure bearing down on the area from the west
will try to push the boundary northward but the system as a
whole will be translating southward. Overall winds will remain
below any advisory or even cautionary thresholds and the late
period main marine threat may end up visibility restrictions due
to moderate rainfall.
LONG TERM /MONDAY THROUGH TUESDAY/...
As of 300 PM Friday...A complex storm system will move up the coast
Monday and Tuesday and with the nature of the storm and the extended
time frame, confidence is low for this forecast. Initially the
waters should see a southeast flow. This flow will transition to
northeast by Monday evening and turn more offshore Tuesday. As of
now, speeds should remain below flag criteria but an extended period
of somewhat churned up seas may allow heights to eclipse six feet.
Both elements should subside considerably Wednesday.
-- Changed Discussion --SC...Beach Hazards Statement from 7 AM EDT this morning through
this evening for SCZ054-056.
NC...Beach Hazards Statement from 7 AM EDT this morning through
this evening for NCZ106-108-110.
-- End Changed Discussion --