Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 220558
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
1259 AM EST Thu Feb 22 2018

.SYNOPSIS...
Bermuda high pressure will remain anchored offshore through
Sunday. Springlike weather with unseasonably warm temperatures
will continue until a cold front arrives Monday morning. This
front should bring a shot of rain to the area, followed by
temperatures returning to near normal for the middle of next
week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 930 PM Wednesday...Persistence the rule tonight as Bermuda
ridge remains anchored offshore producing warm S/SE winds into
the eastern Carolinas. There is very little change from this
time last night, and another very warm night is expected with
mins dropping only to around 60 tonight after record highs
today. For reference, the average HIGHS for this week are just a
degree or two over 60, more indication of how warm this air
mass truly is.

Concern tonight will again be the development of fog and sea fog
across the area. Latest VWP from LTX shows lighter winds than
last night, and nearly all available guidance suggests fog
developing in the next few hours and becoming widespread and
potentially dense overnight. The overnight crew will need to
monitor for a dense fog advisory, but have added areas of fog to
all locations, starting first at the coast and spreading inland
from there. Previous discussion from 300 PM Below:

As of 300 PM Wednesday...Anomalously strong upper ridge north
of the Bahamas, impinging the US SE Coast, will circulate air
whose temperatures are 18-22 degrees F above normal tonight and
Thursday, reflecting an early May climatology.

Nocturnal showers dotting the ocean, may take a swipe at the NE
SC coast and Cape Fear region overnight into early Thursday,
but this could hardly be described accurately as a `rain-event`,
isolated at best.

Fog appears poised to debut again tonight, higher confidence
over land than water, since gradually, we are seeing SSTs rise
inshore. Probability of a Dense Fog Advisory, is higher than
`no` Dense Fog Advisory overnight. Have included sea fog over
the waters, with coastal zones fog/mist impacts tonight and
Thursday morning, persistence in the forecast playing a large
role, as the pattern continues similarly.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...The main feature through the short
term period will continue to be the strong and persistent mid
level ridge off the southeast coast. The ridge does get pushed a
little further south by the end of the period but will still
yield primary influence across our CWA. At the surface high
pressure remains in control as well as a weak cold front
emanating from the activity out to the west currently will push
only to the NC/VA border late Friday. As for temperatures, the
MAV continues to advertise much warmer numbers as opposed to the
MET and leaned more in favor of the warmer readings.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM Wednesday...The record-breaking upper level ridge
should retrograde back into the Gulf of Mexico and across
Florida by Saturday. An upper disturbance across the Plains
states should damp out as it moves east into the ridge Sunday
and Monday, but should still knock heights down enough to allow
deep moisture pulled off the western Gulf of Mexico to reach
the area Sunday night through Monday.

Bermuda high pressure at the surface will remain off the
Carolina coast through Sunday while continuing to advect an
unseasonably warm and humid airmass into the area. A few record
high temperatures will be possible again Saturday and Sunday.
Sunday`s record high of 79 in Florence looks particularly
breakable.

The strong subsidence inversion associated with the upper ridge
should rise to around 9000 feet AGL on Saturday, high enough to
allow some pretty substantial cumulus to develop beneath the
cap aloft. I`ve put a slight chance of showers in the forecast
inland. By Sunday, increasing moisture ahead the front and the
disappearance of the subsidence inversion should spread these
showers chances down to the coast as well. The front itself
should cross the area Monday morning, finally pushing the
tropical airmass out of the area. Long-range models show rain
chances peaking behind the front Monday morning as a ~12 hour
period of isentropic lift overrunning the frontal surface
develops aloft. Once the front pushes down into Georgia the
drier, cooler air from the north should become deep enough to
dry our weather back out, with more seasonable temperatures
expected for Tuesday and Wednesday.

It`s interesting to note that the tremendous negative temperature
departures we rang up in early January (15-25 degrees below
normal for seven consecutive days) will almost be cancelled out
by the exceptional warmth we`re experiencing now (February
20-25). Since December`s temperatures averaged near normal, it`s
likely the meteorological winter of 2017-2018 will go down in
the record books as "near normal" for average temperature...
despite the roller coaster ride we`ve been on seeming anything
but normal!

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
As of 06Z...Fog developing across the area will lead the way to LIFR
vsbys in fog with vertical vsbys up to 200 to 300 ft mainly between
07z and 13z. Shortly after sunrise LIFR fog will lift, and IFR/MVFR
vsbys and cigs will improver by 15z across most terminals, leaving
some mainly VFR strato cu across the area this afternoon with plenty
of dry air and subsidence through the mid levels. Soundings show
potential for some SCT to BKN clouds between 3500 and 5k this
afternoon. A light southerly return flow up to 5 to 10 kts in the
aftn will persist as Bermuda High remains in place.

Extended Outlook...Morning IFR/BR possible through Sat am. Showers
and MVFR conditions possible Sunday through Monday, drying Tuesday.

&&

.MARINE...
NEAR TERM /THROUGH THURSDAY/...
As of 1000 PM Wednesday...No significant changes this evening as
forecast remains on track. A persistence forecast looks
reasonable with 3ft/7sec swell continuing to produce 2-4 ft
seas. Latest beach cams show some fog increasing at the
immediate coast, and expect sea fog to gradually increase in
coverage overnight. Not sure a dense fog advisory will be
needed, but will need to be monitored overnight. Previous
discussion below:

As of 300 PM Wednesday...Primary hazard remains potential for
fog overnight, as diurnal cooling boosts RH over the sea, and
mild moist flow continues to spread from the south. A `Marine
Dense Fog Advisory` may be needed tonight and Thursday morning.

Steady light southerly flow overnight 12 kt or less, as the sea
breeze weakens in early evening. Thursday changes are small,
but look for wave periods to stretch out to 9 seconds, resulting
less steepness, but count on 3 ft seas at a minimum, and up to
4 ft offshore. No TSTMS this period, but isolated showers should
be expected.

SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 300 PM Wednesday...Little change in the offing for the
coastal waters forecast. Surface high pressure off the southeast
coast will continue to drive winds from the south around ten
knots or so. Significant seas will be 2-3 feet with a few four
footers possible on occasion across the outer waters.

LONG TERM /SATURDAY THROUGH MONDAY/...
As of 300 PM Wednesday...Unseasonably well-defined Bermuda high
pressure will maintain a south-southwesterly wind across the
waters Saturday and Sunday. The approach of a cold front from
the west Sunday should accelerate winds to around 20 knots
during the day. There`s at least a chance conditions could
reach Small Craft Advisory criteria. The front should finally
cross the area early Monday morning with a shift to northerly
winds. Weak high pressure to our north is expected to push the
front down into Florida Monday night.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$

NEAR TERM...MJC/JDW
SHORT TERM...SHK
LONG TERM...TRA
AVIATION...RGZ



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