Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus62 kilm 221721 
afdilm

Area forecast discussion
National Weather Service Wilmington NC
121 PM EDT sun Sep 22 2019

Synopsis...
temperatures will gradually warm through early this week. Jerry
will pass well offshore into mid week, while a weak cold front
drops into the Carolinas. The weather will become Summer-like
late week, with unseasonably warm and humid conditions.

&&

Update...
essentially a copy of this time yesterday with slightly higher
dewpoints as the boundary layer slowly modifies. We have Max
temperatures just a degree or two above yesterday's values with
current trends looking good.

&&

Near term /through Monday/...
surface high pressure weakly extended over the area will retreat
seaward today, bringing about a veering but light wind profile,
from southeast to S to SW, today through tonight. The frail return
flow will raise dewpoints several degrees the next couple days,
with strong temperature climbs into the middle 80s inland this
afternoon under unabated radiation. Max-ts a few degrees warmer
Monday, as it appears an element of down-slope low-level wind
flow will be present, offering an added layer of adiabatic
warming, to already warm air under mainly sunny skies.

A few afternoon cumulus are expected today, a little moreso Monday,
but moisture remains too shallow to introduce a chance of measurable
rainfall. The weak pressure gradient about the area the next few
days will result in light winds, and recent 10-meter wind model
output, shows 7 knots or less through Monday, aside from slight sea
breeze enhancement near shore in afternoon, as land temps exceed
SSTs.

&&

Short term /Monday night through Tuesday night/...
mid to upper trough swinging across the Great Lakes Mon night
into tues will push a cold front through the Carolinas. This
front will lose substance as it comes against ridge extending up
across the southeast Continental U.S.. moisture profiles and soundings do
show an increase in moisture through the column between 4k and
10k ft, enough to support some passing clouds, overnight into
up through daybreak, but enough dry air and subsidence aloft
should keep any shwrs at Bay. Front will be exiting off the
coast through tues morning, with winds shifting around from SW
to a more northwest to north direction, but very light. At the same time,
Jerry will be passing well off to the east, up around Atlantic
ridge. Weak high pressure will build in behind front through
tues as weakened boundary shifts farther south. Aside for some
cu tues aftn, front should move through unnoticed. Temps will be
in the mid to upper 80s tues, with lows in the mid 60s Mon night
and tues night.

&&

Long term /Wednesday through Saturday/...
mid to upper ridge gets suppressed farther south on Wed with a
minor perturbation possibly providing enough support for clouds
and a stray shwr Wed aftn. GFS has been showing weak wave of low
pressure along lingering front to the south and increasing
moisture as flow comes back around to the south as high pressure
off shore begins to dominate. The ridge builds back over the
southeast in force thurs into the weekend with 500 mb heights rising
up to 595 dem over the Carolinas Fri into Sat. This will help
to push temps well above normal and keep any convection at Bay.
Therefore only chc of pcp should be on Wed aftn, although the
GFS is hinting at another front or trough dropping south on Fri.
Otherwise a warm and more humid air mass in place with temps
soaring up around 90 away from the beaches with some morning fog
possible and aftn cu mixing with the sunshine. Warm nights
expected with temps closer to 70.

&&

Aviation /18z Sunday through Friday/...
a ridge of high pressure with dry conditions through the column will
continue to support no restrictions. The ridge will lose its
influence across the area during Monday with a weak trough expected
to develop across the inland Carolinas. Light onshore wind with the
sea breeze will be calm to light/variable overnight. More of a
southerly component expected by Monday afternoon with the ridge
shifting farther east.

Extended outlook...VFR, except localized to patchy fog during
the early mornings through the middle of the week.

&&

Marine...
a favorable marine period for small craft, as very little wind-sea
present in the wave spectrum, only a little wind-chop inshore during
the afternoons today and Monday, as a weak sea breeze circulation
fires up for several hours. Weak long period swell waves will be
sustained, as what is left of Humberto's backswell fades, and
becomes replaced by Jerry's long-period wave energy. This will
result in seas about 3 feet every 14 seconds or so by late Monday,
all in swell, which may produce standing wave turbulence in area
inlets during an outgoing tide, at times. Wind-seas and wind-waves
to remain minimal this period with no tstms over the 0-20nm
waters.

A weak and dry front will approach from the northwest Mon
night into tues while Jerry passes by well east of the waters.
This should kick S-SW winds up a bit late Mon and should swing
winds around to a more off shore direction on tues. High
pressure will shift just east of the local waters and dominate
Wed through the remainder of the week with southerly winds
around 10 to 15 kts. Seas will increase up to 3 to 4 ft Mon
night into tues. Overall expect seas in the 2 to 4 ft range with
longer period southeast swells mixing in.

&&

Ilm watches/warnings/advisories...
SC...none.
NC...none.
Marine...none.

&&

$$
Synopsis...ilm
update...shk
near term...mjc

National Weather Service Glossary of Abbreviations