437
FXUS62 KILM 210716
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
316 AM EDT Tue Jul 21 2026

.WHAT HAS CHANGED...
Discussions updated. Heat Advisory in effect for much of the area
today. Moderate risk for rip currents at all area beaches.

While only isolated showers are storms are expected today based on
the broader pattern, there is low to moderate confidence that the
favorably-timed arrival of a moisture plume from T.S. Bertha could
provide a more supportive environment for the sea breeze to produce
scattered showers and storms from around midday into this
afternoon.

&&

.KEY MESSAGES...
1) Hot weather continues through Wednesday with another Heat
Advisory possible.

2) Highest chances for rain arrive with a strong cold front during
mid to late week, including a risk for flash flooding.

3) A period of enhanced winds and seas will occur through midweek as
a strong cold front drops down from the north, creating hazardous
conditions for small craft.

&&

KEY MESSAGE 1...Hot weather continues through Wednesday with
another Heat Advisory possible.

For today, low to moderate confidence exists that the passage of a
moisture plume associated with T.S. Bertha during this morning into
the early afternoon will result in the sea breeze becoming active by
around midday, producing scattered showers and storms which would
prevent many areas from reaching Heat Advisory criteria.
However, if convection remains isolated or doesn`t materialize,
the moisture plume should support reaching a 105F or greater
heat index for 2+ hours across the advisory area. Meanwhile, the
western tier of counties is expected to remain on the periphery
of this moisture plume, with lower dew points expected to mix
down during the afternoon as drier air filters in aloft.

The region will remain sandwiched between mid-upper troughing to the
north and the closed mid-upper low associated with T.S Bertha to the
south, leaving a weak ridge axis in between. Temperatures in the low-
mid troposphere are forecast to hold at similar levels to those
observed over the weekend, supporting continued above-normal
temperatures and heat indices breaching 100F. The extent of
cloudiness and showers/storms will affect whether some areas reach
heat indices of 105F, but it appears additional Heat Advisories are
possible until a cold front settles into the area on Thursday.
Until then, coverage of showers/storms should remain isolated
through Wednesday.

KEY MESSAGE 2...Highest chances for rain arrive with a strong cold
front during mid to late week, including a risk for flash flooding.

As a moisture plume associated with T.S. Bertha passes through the
area today, low to moderate confidence exists that this will reduce
dry air and subsidence enough in the low-mid troposphere to support
an active sea breeze with scattered showers and storms developing
around midday and lifting northeastward through the afternoon. With
pwats rising from ~1.7-1.8" to 2.1-2.2" and low to mid-level flow
largely parallel to the sea breeze, heavy rainfall and training
thunderstorms capable of producing localized flash flooding in low-
lying and poor drainage areas would be the main hazard if more than
the typical isolated pop-up storms materialize.

Otherwise, if remnant dry air and subsidence win out, isolated
showers and storms remain a possibility through Wednesday along the
sea breeze and any convergence zones that happen to form inland. An
isolated strong to damaging wind gust cannot be ruled out if a storm
can take advantage of steep low-level lapse rates combined with a
heavy, water-loaded downdraft. Something to watch is the progression
of showers and storms to the north, which could send outflow into
our northern tier of counties (Pender through Marlboro) and produce
areas of heavy showers and storms.

As troughing becomes reinforced over the eastern CONUS during
midweek, a stronger cold front is progged to push slowly southward
into the area on Thursday or Thursday night before stalling. This
front, accompanied by occasional mid-level shortwaves helping to
enhance lift, is likely to result in periods of scattered to
numerous heavy showers and storms into this weekend. The primary
threat this setup will bring is flash flooding from heavy storms
backbuilding and/or tracking over the same area multiple times.

KEY MESSAGE 3...A period of enhanced winds and seas will occur
through midweek as a strong cold front drops down from the north,
creating hazardous conditions for small craft.

See marine discussion below.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
Shower/storm activity looks to stay to our north tonight with no
impacts expected to terminals. S/SW winds will remain strong tonight
with no fog formation expected however some stratus is starting be
observed at coastal terminals. This will have to be monitored to see
if it pushes far enough inland to impact KFLO/KLBT, but coverage
might be too low by that point. Clearing should occur by daybreak.
Headed into Tuesday winds will pick start gusting +20 kts after
sunrise with strongest winds expected at coastal terminals with the
afternoon sea breeze ~15-17Z, gusts ~30 kts  out of the south
possible. There could be the threat of brief IFR/MVFR with any
storms that are able to develop in the afternoon but there`s
uncertainty around coverage at this time. Coverage may be better
along the sea breeze than we have seen for the past couple days as
moisture from the Gulf system comes up from the SW, eroding some of
the dry low levels around midday. If this trend continues will add
PROB30s for terminals. Strong SW winds will continue into Tuesday
night with an increase in gustiness possible after sunset,
particularly for inland terminals, as the PG increases.

Extended Forecast...Potential for brief MVFR/IFR from storms will
gradually increase beginning Wednesday and remain possible through
Saturday, mainly in the afternoon and evening. More solid
restrictions may arrive Thursday with a frontal passage bringing the
potential for IFR CIGs.

&&

.MARINE...
Tuesday through Sunday...Steady south to southwest winds are
expected through midweek with daily enhancements nearshore due to
the sea breeze. An approaching cold front will help tighten the
pressure gradient from Tuesday afternoon into Wednesday night,
resulting in a Small Craft Advisory with winds and seas firmly above
criteria. Winds diminish overnight Wednesday into Thursday as a cold
front drifts in from the north and stalls along or inland of the
coast. Guidance now suggests the front may not push through the
waters until Saturday night or Sunday, but its presence near the
coast can result in changeable wind directions as at least one weak
wave of low pressure ripples along the boundary.

Seas around 2 to 4 ft early today will rise to 4 to 6 ft by this
evening, remaining elevated through late Wednesday. Seas will
diminish to 2 to 4 ft on Thursday as winds weaken. Marine conditions
should remain below any thresholds with lower winds and seas as the
cold front remains in vicinity. However, periods of scattered to
numerous showers and storms are anticipated due to the front,
resulting in hazardous conditions for small craft in and near
thunderstorms through this weekend.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for NCZ087-096-099-105>110.
     Beach Hazards Statement through this evening for NCZ106-108.
     High Risk for Rip Currents through this evening for NCZ106-108-110.
SC...Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for SCZ017-024-033-054-058-059.
     Beach Hazards Statement through this evening for SCZ054-056.
     High Risk for Rip Currents through this evening for SCZ054-056.
MARINE...Small Craft Advisory from 11 AM this morning to 10 PM EDT
     Wednesday for AMZ250-252-254-256.

&&

$$

WHAT HAS CHANGED...ABW
KEY MESSAGES...ABW
DISCUSSION...ABW
AVIATION...LEW
MARINE...ABW