191
FXUS62 KILM 230109
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
909 PM EDT Sun Jun 22 2025

.SYNOPSIS...
A strong mid and upper ridge will build in over the eastern
United States through midweek with a significant warming trend.
Hot afternoon temperatures combined with high humidity will
create dangerous heat through much of the upcoming week. Do not
expect much in the way of relief from showers or thunderstorms
during the week.

&&

.UPDATE...
Sfc and Upper High centered over the Mid-Appalachian Mountains
will drive this forecast this period. Cirrus over the Eastern
flank of the high, will swing onshore within the upper
anticyclonic flow and across the FA overnight into daylight Mon.
This moisture will continue to scour out as it moves to and
across the FA leaving just FEW/SCT thin cirrus, with
occasional opaque patches. GFSLAMP guidance not nearly as
profound with low stratus and/or ground fog like the previous 2
nights. As a result, no changes needed to the wx and sky
conditions overnight. Some tweaking of hrly temps/dewpoints but
no categorical changes. Winds will become offshore in direction
overnight, nearly a land breeze along the immediate coast,
going into daylight Mon morning.

&&

.NEAR TERM /THROUGH MONDAY/...
Deep, strong ridge over the Eastern US today will only get stronger
Monday, with 500mb heights increasing to almost 600 dam centered
over the Mid-Atlantic Monday afternoon. After near normal lows
Monday morning in the low 70s, temperatures will soar into the mid
to upper 90s Monday. There is a low chance (about 15%) that some
areas near I-95 could reach 100F Monday afternoon. Combined with
dewpoints around 70F, have issued a Heat Advisory for majority of
the CWA starting Monday morning for forecasted heat indices around
105F during the day (with exception of Williamsburg and Georgetown
counties as well as the immediate coastline). Monday will be the
first day of a prolonged stretch of hot and humid weather (see
short/long term discussions). Subsidence from the ridge will keep
pops out of the near term forecast.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Hot weather will continue as strong ridging in the mid to upper
levels continues to build over the region. ECMWF now shows the
peak of heights in the mid levels at 599 dam just to our north
late Mon. The one influence we will need to watch out for is an
upper low which nudges westward from the Atlantic trying to push
the ridge inland a bit more. This could help to lower H5
heights just enough to keep the temps a few degrees less hot
heading into midweek. With that being said, that could influence
the issuance of any extreme heat products, but overall, it will
be a hot and humid week ahead with dangerous prolonged heat. The
strong subsidence and dry air should keep convection at bay, but
cannot rule out a stray shower. Looks like weak boundary tries
to drop down late Mon into early Tues and could see some clouds
or a brief wind shift associated with this and maybe this
boundary will initiate some convection in central Carolinas, but
not confident about this as we have such strong ridging and
subsidence aloft.

Overnight temps in the mid 70s will not provide much relief
from the high heat expected during the day on Tues. The high
heat with daytime highs well into the 90s to near 100 will
combine with high humidity to produce heat index values greater
than 105 and possibly pushing Extreme Heat Warning criteria of
110. For now, we have a Extreme Heat Watch in effect for midweek
for the potential of extreme heat and high humidity.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Hot weather will continue but may see temps trending slowly
downward as the mid to upper ridge weakens through the week. The
center of the ridge aloft gets pushed slightly westward as an
upper low tracks down the Southeast coast. The ECMWF shows it
splitting the ridge in two over the region while the GFS shows
it riding by to the south of the ridge but weakening the ridge
overall. Exactly how this plays out will remain to be seen, but
for now, expect continued warm and moist southerly flow around
sfc high pressure over the Atlantic and limited convective
potential most days. As the ridge weakens would expect the sea
breeze to become a little more active. Overall, temps will run
well above normal, into the 90s to near 100 inland on Wed with
heat index values topping 105 in parts of the area. A slight
trend downward in the heat will come Thurs into the weekend.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
High confidence in VFR conditions through the 00Z TAF cycle as
high pressure sfc and aloft prevails. Atm column a bit drier
than yesterday at this time along with a convective lid in place
as subsidence aloft from the high suppresses any convection that
tries to boil up from the FEW/SCT Cu this evening and again
during daylight Mon, otherwise SCT250 from cirrus dropping down
then onshore from the N thru NE. GFSLAMP guidance suggests a
much rosier picture for the overnight, meaning the low stratus
and/or ground fog will be much lower in coverage, if any at all.
All terminals will observe southerly winds AOB 6 kt at the
start, becoming W-NW AOB 5 kt by daybreak Mon. Will observe an
active sea breeze develop around 16z with winds backing to S
around 10 kt at the coastal terminals. Sea breeze will progress
to the inland terminals by 22Z with winds backing to the S
around 6 kt.

Extended Outlook...Predominantly VFR through mid week as strong
high pressure surface and aloft puts a lid on most convective
development.

&&

.MARINE...
Through Monday...Strengthening ridge over the eastern US will
maintain south-southwest winds around 10 kts over the local coastal
waters through Monday (with sea breeze enhancement near the coast in
the afternoon/evening). Seas around 2 ft from persisting 8 sec SE
swell and weak wind wave mixed in.

Monday night through Friday...Initially, southerly return flow
will continue around sfc high off the Southeast coast. Winds may
shift to a more W-NW direction Mon night into Tues or become
more variable, as the high gets suppressed farther south and a
weak sfc boundary drops south into the waters. By Wed, Bermuda
high will dominate again with increasing and persistent southerly
winds returning for several days ahead. Seas will be less than 3
ft to start, but should increase into next weekend in persistent
and increasing southerly winds. A longer period SE swell will
continue to mix in.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory from 10 AM Monday to 10 AM EDT Tuesday for
     NCZ087-096-099-105-107-109.
     Extreme Heat Watch from Tuesday morning through Wednesday
     evening for NCZ087-096-099-105>110.
SC...Heat Advisory from 10 AM Monday to 10 AM EDT Tuesday for
     SCZ017-023-024-032-033-058-059.
     Extreme Heat Watch from Tuesday morning through Wednesday
     evening for SCZ017-023-024-032-033-039-054>056-058-059.
MARINE...None.

&&

$$

SYNOPSIS...ILM
UPDATE...DCH
NEAR TERM...VAO
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DCH
MARINE...ILM/RGZ/VAO