469
FXUS62 KILM 181732
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
132 PM EDT Fri Jul 18 2025

.SYNOPSIS...
Hot and humid weather will persist through Monday as Bermuda
High Pressure maintains a southwesterly wind across the
Carolinas. A cold front arriving Monday could bring increasing
coverage of showers and thunderstorms, followed by slightly
cooler weather Tuesday and Wednesday. Heat could return late
next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
Cu fields have begun to show signs of life early this afternoon and
should lead to widely scattered showers/tstms through the late
afternoon and early evening. HREF indicates convective activity will
trail off after 02Z. Overnight min temps will only fall to the mid
70s, except upper 70s at the beaches as surface high pressure off
the SE coast maintains warm and moist SW flow across the area.
Synoptic features Saturday remain largely unchanged from today as a
ridge continues to dominate across the SE CONUS. Guidance continues
to point to widespread mid 90s Saturday, and combined with
mid/upper 70s dewpoints, will necessitate another CWA-wide Heat
Advisory. The heat index will likely touch 110 degrees in a few
locations Saturday afternoon, but only for an hour or two,
therefore not requiring an Extreme Heat Warning. The mid-level
ridge will keep weak ripples in the westerly flow aloft just to
our north, along with better chances for tstms. Across our CWA,
PoPs Saturday will generally range from 20% across NE SC to 40%
across SE NC.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
A 500 mb ridge centered over the Florida Gulf Coast on Saturday
Night should retrograde to the lower Mississippi Valley by late
Monday. Hot temperatures and high dewpoints should continue
across the Carolinas Sunday, likely necessitating another day
of Heat Advisories with afternoon heat indices expected to reach
105-108 degrees. Sunday`s seabreeze front and the Piedmont
Trough inland should be triggers for isolated showers and
thunderstorms within an airmass with 2000-3000 J/kg CAPE but
with relatively dry mid level humidity.

By Monday the upper ridge should retrograde far enough to allow
northwesterly mid and upper level flow to develop over the
Carolinas. In addition, an upper trough swinging through New
England should help push a surface cold front southward into the
Carolinas during the day. High temperatures on Monday should
again reach the mid 90s with high humidity, likely triggering
yet another Heat Advisory. Enhanced low level convergence as
the front meets the afternoon seabreeze plus impulses arriving
within the northwest flow aloft should help to develop clusters
of showers and thunderstorms Monday afternoon into Monday night.
While we`re not in a Day 4 convective outlook from SPC, it`s
possible strong/gusty winds could develop in association with
these storms. The cold front should gradually work its way
offshore Monday night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The upper ridge should poke north over the Mississippi River
Valley Tuesday through Thursday, perhaps settling back toward
the Gulf Coast again by Friday. Low level northeast flow should
bring slightly cooler air into the Carolinas Tuesday and
Wednesday with highs anticipated to reach 85-90 both days with
maximum heat indices only in the 90s. Uncertainties as to how
far south the front makes it before stalls means I`ll have to
keep a chance of showers and thunderstorms in the forecast
Tuesday despite the GFS showing the arrival of a drier and much
more stable airmass.

The front should gradually wash out just off the Southeast
coast Wednesday into Thursday as the Bermuda High strengthens
offshore. This should gradually veer our surface winds from
northeast to a southerly direction with humidity creeping back
up each day. By Friday it`s possible we`ll have a return to the
same airmass we`re in now with temperatures in the 90s and heat
indices creeping back up to the 105 trigger for Heat Advisories.

Note: although the 12z operational GFS shows a low developing
from the old front and moving onshore Thursday, there is no
support for this solution among the 12z GFS ensembles at this
time.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Widely scattered showers/tstms moving into the Pee Dee region and NE
SC may impact KFLO/KLBT/KMYR/KCRE over the next few hours with MVFR
cig/vis and potential wind gusts to 30 kt. Convection will wane
after 02Z and should remain quiet overnight. Isolated showers/tstms
will begin to pop up by 16Z or so Saturday, but confidence too low
to include if TAFs at this stage.

&&

.MARINE...
Through Saturday...SW flow will persist through Saturday between
surface high pressure off the SE coast and a weak Piedmont trough
across the inland Carolinas. Wind speeds will be on the order of 10-
15 kts with occasional gusts to 20 kts, particularly this
afternoon and again Saturday afternoon as the gradient tightens
up a bit. Shower/tstm chances remain relatively low this
afternoon and overnight, and will tick up a bit north of Cape
Fear late Saturday due to proximity to the westerly flow aloft
and associated weak shortwave energy crossing NC.

Saturday night through Tuesday...Bermuda High Pressure offshore
will maintain a humid southwest wind across the Carolinas
Saturday night through Monday. A cold front should arrive at the
beaches during the day Monday, however Monday`s daytime
seabreeze should be strong enough to keep the front from
initially pushing out across the coastal waters. We will need to
watch Monday afternoon and Monday night closely for the
development of clusters of gusty thunderstorms which could bring
impacts for mariners. The front itself should finally push
offshore Monday night with northeasterly wind expected to
develop Tuesday into Wednesday. Confidence on the speed of these
northeast winds is not particularly high - the 12z GFS model
has a stronger high building over coastal New England by the
middle of next week and shows our NE winds averaging 20 knots
while the 12z Canadian and 00z ECMWF are in the 10-15 kt range.

There should be a small 8 second southeast swell with us through the
entire forecast period. Dominant waves, however, will consist
of a 5 second southerly wind wave Saturday night through Monday,
then a 5-6 second northeasterly wind wave Tuesday into
Wednesday. Combined seas should average 2-4 feet -- although
higher seas could develop Tuesday and Wednesday if the GFS model
is correct with its higher wind speeds.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Heat Advisory until 8 PM EDT this evening for NCZ087-096-099-
     105>110.
SC...Heat Advisory until 8 PM EDT this evening for SCZ017-023-024-
     032-033-039-054>056-058-059.
MARINE...None.

&&

$$

SYNOPSIS...TRA
NEAR TERM...CRM
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...CRM
MARINE...ILM