Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 212330
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
630 PM EST Wed Feb 21 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 300 PM Wednesday...80 degrees reached at ILM, eclipsing a
maximum temperature record today of 78 set in 2014. Cool SSE
winds off the ocean at the `Grand Strand` may thwart a record
high at CRE of 76 set 65 years ago in 1953. FLO though, within
tenths of a degree in tying a record high of 81 in 1997.
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.

Have indicated isolated, brief, low-topped showers along the
I-95 lane, late this afternoon and early evening tracking to
NNE. Enough low-level instability and convergence is present,
but moisture aloft terribly lacking. 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 /00Z THURSDAY THROUGH TUESDAY/...
As of 00Z...Southerly flow around Bermuda high pressure will
continue to prime the low-levels with moisture, and conditions
overnight will once again favor widespread dense fog. Confidence
is fairly high in IFR conditions developing after midnight,
with tempo LIFR before the fog lifts by late morning.

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

&&

.MARINE...
NEAR TERM /THROUGH THURSDAY/...
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.

`Fresh Swell` or `Mature Wind-Seas`, you could select either,
in describing the dominant wave energy fanning ashore currently,
and tonight, SE waves 3-4 feet every 7 seconds offshore, 2-3 ft
inshore. 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.

&&

$$
SYNOPSIS...TRA
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...TRA
AVIATION...CRM



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