Area Forecast Discussion
Issued by NWS Wilmington, NC-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS62 KILM 271858
Area Forecast Discussion
National Weather Service Wilmington NC
258 PM EDT Thu Apr 27 2017
High pressure offshore will bring a warming and drying trend
late this week through the weekend. A weakening cold front will
bring a few showers or a thunderstorm tonight inland and early
Friday at the coast. A stronger frontal system will bring a chance
of rain late Monday and early Tuesday. Another storm system may
impact the region with a soaking rain next Thursday.
.NEAR TERM /THROUGH FRIDAY/...
As of 230 PM Thursday...The NSSL 4KM WRF and the HRRR models
depict similar schemes, in edging a broken line of showers and
possibly an isolated TSTM along and west of I-95 in SC 9-10 PM
tonight followed by convective weakening due to diurnal cooling
and waning low-level convergence as lower tropospheric winds
veer slightly more to SW vs S late tonight. A frail cold front
if we can even use the word cold, will wash out on approach to
the the coast overnight. No wind-shift and in fact, dewpoints
along the coast will rise to near 70 deg into early Friday. A
scarcity of moisture aloft will render substantial rain an
improbability but an isolated shower near the coast early Friday
cannot be written off entirely given the rich low-level
moisture stream from the SW.
A sea breeze shower Friday could pop because the sea breeze
circulation itself will be moderately strong with low-level
heating on the uptick tomorrow. Again however we see that dry
air aloft will limit shower coverage and strength, and only
isolated showers were painted in along the coastal interior
Friday afternoon. Maximums Friday near 90 over the deeper
interior and upper and mid 80s most everywhere else, coolest
eastern zones, given a marine influence brought about by a
southerly wind flow versus southwest.
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 300 PM Thursday...Bermuda High will take hold of the area
with ridging all the way up through the mid and upper levels.
This will maintain a deep southerly return flow with very mild
summer-like weather. Plenty of dry air and subsidence through
the mid levels will maintain a cap on convection although
shallow low level moisture will be quite rich. Overnight winds
should prevent fog, but sounding data shows potential for a few
hours of saturated column up to 1500 ft or so and greater
potential Sat night into Sun morning. Therefore may see some
stratus around overnight but will dissipate as sun rises Sat
morning. Should also see some cu develop right along sea breeze
boundary as it pushes inland Sat aftn. Temps will run about 10
to 15 degrees above normal with plenty of sunshine on Sat. Both
Fri night and Sat night lows will near or around 70 degrees with
daytime highs soaring through the 80s to around 90 in many
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 300 PM Thursday...Western Atlantic High Pressure will maintain
deep southerly flow on Sun. Although a shower along the seabreeze
can`t be ruled out, subsidence on the periphery of the ridge should
keep afternoon convection to a minimum, except along the inflection
point, will keep POPs out of the forecast at this time.
Surface and mid level ridge will weaken and drift east Mon, allowing
a cold front to approach from the W. Low pressure and associated
strong dynamics and upper level support will be well dislocated from
the Carolinas as a cold front moves across the area Mon night. This
suggests convection weakening as it moves into the eastern
Carolinas. Current timing brings the likelihood for showers and
thunderstorms later Mon and Mon night.
As the front moves off the coast Tue morning, high pressure along
the Gulf Coast will slide east and then offshore to our S during
Wed. This should bring a dry period. Deep low pressure will move out
of the mid south and Gulf coast states Wed, lifting slowly to the
NE. Its associated cold front will move into the Southeast states
Thu-Thu night, bringing the risk for robust thunderstorms.&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
As of 18Z...Mainly VFR conditions through this afternoon. A
weak cold front will make it`s closest approach from the west
tonight and early Fri before washing out altogether during
Friday near the coast. MVFR conditions possible this evening
thru the overnight period. Will indicate VCTS or VCSH during
that time span. Ceilings may lower to MVFR or isolated IFR.
Winds will start out SSW 5 to 10 kt and increase to S 10 to 15
kt with g20 kt this afternoon and evening. The higher gusts will
occur across the coastal terminals due to an active sea breeze.
Thursday 12z-18z VCSH mainly near the coast with SCT-BKN040
inland and MVFR cigs close to the coast.
Extended outlook...VFR through Sunday. Periods of IFR/MVFR in
convection late Monday into early Tuesday.
NEAR TERM /THROUGH FRIDAY/...
As of 230 PM Thursday...Not ideal marine conditions with 20 KT
SW gusts likely tonight and on Friday, but with seas holding
mainly at 3-4 feet, and 5 footers confined to the extreme outer
portion, no advisories or caution statements are planned at this
time. An isolated marine shower is possible early Friday from
pre-dawn through the day Friday but TSTMS not expected due to
dry air aloft. The wave spectrum will be shared by SE waves 2
feet every 7-8 seconds, and a moderate to strong S-SSW chop of
2-3 every 4-6 seconds, thus a bit bumpy due to the frisky winds.
Gusts in excess of 20 KT possible Friday afternoon due to a
strong sea breeze overlapped on the synoptic winds, and if 25 KT
gusts are frequent enough, a brief Advisory may be required.
SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 300 PM Thursday...Southerly return flow will persist
around the periphery of the Bermuda High which will keep a
stronghold on the local waters through the period. Winds will
run 10 to 15 kt with gusts to 20 to 25 kt possible especially
the nearshore waters during the afternoon sea breeze. Seas will
run 2 to 4 ft, but may see some 5 fters in outer waters.
LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 300 PM Thursday...Western Atlantic High Pressure will
bring increasing S winds ahead of a cold front. S winds Sun and
Sun night will be increasing to 15 to 20 kt. Seas will increase
to 4 to 6 ft by early Mon morning.
S to SW wind speeds will increase further Mon and Mon night, up to
20 to 25 kt as seas build to 5 to 8 ft. Then in the wake of the
front Tue, developing offshore winds will trend lower. The offshore
trajectories will knock seas down and we should drop below Small
Craft Advisory levels by Tue eve.
SC...Coastal Flood Advisory from 8 PM to 10 PM EDT this evening for
NC...Coastal Flood Advisory from 8 PM to 10 PM EDT this evening for
Coastal Flood Advisory from 9 PM this evening to 1 AM EDT
Friday for NCZ107.