Area Forecast Discussion
Issued by NWS Wilmington, NC
FXUS62 KILM 252330
Area Forecast Discussion
National Weather Service Wilmington NC
730 PM EDT Tue Apr 25 2017
A slow moving storm system will continue to lift northeast
farther away from the area through mid week as weak high
pressure eases in from the Atlantic. Look for improving
conditions, with a warming and drying trend. A weak cold front
will nearly dissipate as it moves across the area Thursday
night. Bermuda high pressure will dominate the weather Friday
through the weekend with early summer-like conditions. A few
locations away from the coast, may break the 90 degree mark this
weekend. Another cold front will move through Monday with high
pressure returning on Tuesday.
.NEAR TERM /THROUGH WEDNESDAY/...
As of 730 PM Tuesday...Last few sprinkles moving across our
coastal counties and will be offshore shortly. Still
anticipating a dry overnight period. Previous discussion follows
from this afternoon:
Upper low tracking north over the Pamlico and Albemarle Sounds
of Eastern North Carolina will reach just offshore of New
England Wednesday afternoon. This will mark a transition in the
low level wind flow as the system releases its grip locally,
allowing SFC-H8 winds to become SW by the late afternoon
Wednesday. Concurrently, mid-level drying will continue to press
down to 6-7 KFT on Wednesday, shutting down precipitation
chances, although diurnal cumulus appears to be a good bet. As
late spring thickness values snap back in place in wake of the
upper cold pool, look for a mammoth warm up Wednesday into the
upper 70s to lower 80s across NE SC and SE NC away from the
beaches. Consequently, in terms of sensible weather, Wednesday
will bring a return to an early summer- like feel to the area
and this will trend beyond Wednesday. Partial clearing overnight
and a flattening pressure gradient from west to east will allow
for patches and banks of fog and mist to develop after midnight
favored inland, and aided by still wet ground.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 300 PM Tuesday...Low pressure system will be heading
farther off to the northeast starting off near the Long Island
Coast Wed eve. A SW to S return flow will develop between high
pressure easing in from the Atlantic and a cold front
approaching the Carolinas by Thurs. Overall, there will be weak
ridging aloft with plenty of dry air through the mid levels
above h7 with moisture confined to the sfc and very low level of
the atmosphere. This moisture rich air near the surface will
maintain dewpoint temps in the 60s and above normal temps.
A lighter southerly breeze will increase as the gradient
tightens with the approach of a cold front on Thurs. Moisture
will pool ahead of the front with pcp water values reaching up
to 1.75 inches by midnight Thurs night, but with loss of heating
and upper level support displaced well west and northwest of
area, do not expect much forcing other than convergence along
the front to produce some shwrs and possibly an iso tstm Thurs
night. Expect some localized diurnal cu to develop Thurs aftn
mainly associated with sea breeze front but should be limited in
growth due to subsidence and dry air aloft. Therefore expect
main shwr activity to come Thurs night as front weakens and
nearly dissipates as it moves over the eastern Carolinas.
Bermuda High begins to dominate again by Fri morning.
Temps Wed night will be in the low to mid 60s leading to max
temps into the mid 80s on Thurs. Continued WAA and increased
cloud cover will maintain temps in the mid 60s to near 70 on
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 300 PM Tuesday...Period begins with remains of weak front
pushing off the coast under ridging aloft. Boundary lacks
moisture by the time it reaches the area and the bulk of the
dynamics shifts off to the north. Cannot rule out an isolated
sea breeze shower in the wake of the front Fri afternoon but the
lack of mid level moisture suggests coverage would be minimal
at best. Surface and mid level ridging will be the dominant
features through the weekend. The 5h ridge axis is just offshore
and a slow but steady increase in moisture as flow aloft
becomes more southwesterly opens up the possibility of sea
breeze/diurnal convection, especially Sun afternoon and evening.
Temperatures will be above to well above climo with potential
for 90 degree readings inland.
Next system winds up over the central CONUS early next week, lifting
from the plains on Sun to the Great Lakes on Mon. Warm advection
ahead of the front will maintain temps above climo through Mon. Cold
front trailing the low moves into the area later Mon preceded by
convection. Best dynamics pass well north of the area but there will
be a narrow band of deeper moisture along with low level convergence
and a strengthening low level jet. Also potential for some PVA
depending on timing of any shortwave rotating around the base of the
trough. Surface high and broad troughing aloft Tue contribute to
deep westerly flow, drying the region out but with a cooler air mass
building in temps will be slightly below climo as the period
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 00Z...Tricky forecast regarding cigs for the overnight
period for ILM, with confidence not as high as usual that CIG
category will drop to IFR around midnight or so and continue
until around daybreak. Do not see cigs below 3.5kft for our
other coastal terminals overnight, but again confidence not high
that we could descend below this level. Better confidence in IFR
early morning fog for FLO/LBT. Continued mixing should keep fog
from the coastal terminals.
Extended outlook...VFR expected from Wednesday afternoon through
NEAR TERM /THROUGH WEDNESDAY/...
As of 730 PM Tuesday...Have allowed Small Craft Advisory to
expire as latest obs show seas now back down in the 3 to 5 ft
range with winds of 10 to 15 kts. Previous discussion follows
from this afternoon:
Sea heights still relatively large and in recovery mode from SE
waves of 4-6 feet every 10 seconds over the 0- 20 NM waters, a
bit smaller into the South Carolina shores. As a result a Small
Craft Advisory remains posted the NC waters until 5 PM this
afternoon at which point most significant waves within 20 NM
should subside below 6 feet. Offshore winds of 15 KT with
occasional gusts to 20 KT can be expected into evening before
easing overnight to 10-15 KT. As a result the wind-wave portion
of the spectrum will decreases choppiness into early Wednesday.
A few marine showers are possible north of Cape Fear this
evening but isolated. Expect slowly diminishing SE swell Wed but
an increase in SW wind-waves later in the day as both the sea
breeze and return synoptic wind flow gear up to moderate
SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 300 PM Tuesday...Bermuda High will build westward Wed
night into Thurs as a cold front approaches the Carolinas from
the west. Southerly winds in between these two systems will run
about 10 to 15 kts Wed night into early Thurs with an increase
as gradient tightens as cold front moves east through late
Thurs. May see winds up to 15 to 20 kts out of the south, but
the front weakens as it reaches the waters with Bermuda High
dominating again by Fri morning.
LONG TERM /FRIDAY THROUGH SunDAY/...
As of 300 PM Tuesday...High pressure will be the dominant
feature through the period with south to southwest flow in
place. Speeds will be on the low end of the 10 to 15 kt range
early in the period but increase to a solid 15 kt Sun as
gradient becomes a little more defined. Seas mostly 2 to 3 ft
early in the period will experience an upward trend late in
response to increasing southwest flow.