299
FXUS62 KILM 051759
AFDILM

Area Forecast Discussion
National Weather Service Wilmington NC
159 PM EDT Sat Jul 5 2025

.SYNOPSIS...
Tropical Storm Chantal will approach the South Carolina coast
tonight, strengthening into a tropical storm before landfall.
The largest impact on the Carolinas will be locally heavy
rainfall with potential for isolated flooding tonight through
Sunday and strong rip currents and dangerous surf. Unsettled
weather returns during the middle of next week after a brief
break in widespread activity late Monday into Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
New christened but still poorly organized Chantal centered east
of GA coast. Sat imagery shows some westerly shear that will
relax with time this period, the shearing come from an upper low
to the storm`s west, but this feature will begin to retrograde.
From there steering flow will be able to impart a slow
northerly motion (the storm currently meandering with poorly
defined initial motion) which will naturally mean a steady
deterioration in conditions late today and moreso tonight into
Sunday. For all of the specifics including a plethora of
graphics check out our webpage (www.weather.gov/ilm) or for our
Chantal-specific briefing at www.weather.gov/briefing.

Our current QPF forecast paints a max of 4-6" along and south
of the NC/SC state line, remaining east of I-95. Raised a Flash
Flood Watch for areas that included the areas of highest
rainfall. Probabilistic guidance of amounts exceeding 6" are
nearly nil so flooding may only be localized and handled with a
warning or two. With most of the rain falling on a Saturday
night of a holiday weekend in a heavily populated and touristy
area that is the Grand Strand felt that some extra notice was
prudent. Current forecast would have moderate to occasionally
heavy rainfall continue through the period, with much of this
hinging upon the storm`s eventual uncertain path (some guidance
trending much slower, which was also a last minute nudge
supportive of the Flood Watch).

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Impacts from Chantal will be ongoing at the start of the period
over portions of southeastern NC. The main concerns during this
time would be heavy rain and the potential for localized
flooding. Urban areas along the coast have the highest chance of
seeing heavy rainfall, but any communities along the coast
should be paying close attention to our rainfall forecast.

Chantal moves off to the north and east of our area on Monday
and leaves a warm and humid air mass in its wake. Models show
that Chantal will be slow to progress out of the CWA, so
flooding could remain a concern through a good chunk of Monday.
Flood Watch continues through Monday due to this potential.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Moisture continues to pool across the eastern Carolinas on
Tuesday, but weak subsidence as Chantal exits to the northeast
should limit convective coverage to isolated or widely scattered
storms. If any convection does develop, weak steering flow and
saturated soils could quickly produce localized flooding,
especially in the hardest hit areas.

Weak troughing over the central US and a broad shortwave over
the mid Mississippi River Valley will promote SW flow across the
southeastern US later this week. Amble moisture transport and
solid mid level lapse rates should encourage widespread showers
and thunderstorms each afternoon. The main trough axis
approaches on Friday which should denote the peak in activity.

The forecast gets a bit unclear next weekend in a chaotic upper
level pattern and weak surface flow. There does not appear to
be any significant form of dry air advection during this time,
so while PoPs decrease, we should still see scattered diurnally
driven convection.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Chantal to dictate the forecast with lowered flight categories
for most of the period, save for a near term lack of cloudiness
due to some sinking air on the western periphery of the storm,
which still includes a leading line of heavier showers that will
lead to lowered VSBY and CIG before sunset. Thereafter from
east to west will be the true and widespread decline in both.
Thunder is tougher to diagnose...not normally characteristic of
tropical system but with this leading edge of sun almost
1500J/Kg of CAPE has developed. This window aside, thunder
should be the exception and not the rule with just rain
expected. The FM groups late in the period only address wind
direction change as the circulation approaches from the south.

Extended Outlook... Sub-VFR conditions expected through Sunday
night due to low ceilings as tropical low moves onshore across
SC. Intermittent flight restrictions possible Monday through
Wednesday due to daytime convection and potential early morning
fog/stratus.

&&

.MARINE...
Through Sunday... TS Chantal still showing slow/erratic
movement. As the mid level low to its west retrogrades tonight
the system should move to the northward. This will also relax
the shear and the wind field should increase and/or become
slightly more symmetric. Expect a deterioration of both wind and
seas through the period. TS Warning now in effect for all
waters.

Sunday Night through Wednesday... Swells from Chantal will be
just offshore overnight and gradually lifting northward with the
center of the storm. SC offshore waters will gradually see
conditions begin to improve Sunday night into Monday as
southeasterly swell becomes a bit more tame and mixed with a
long period easterly swell of around 1 foot. Better conditions
on Monday with the disturbed sea transitioning to the summer
baseline of SE and E swell. Tuesday and Wednesday will see
predominately SE swell (2-3 feet at around 7 seconds and 1 foot
around 15 seconds). Showers and thunderstorms see a brief
minimum on Monday evening and early Tuesday before better
coverage during the middle of next week.

&&

.TIDES/COASTAL FLOODING...
Other - Rip Currents: Increasing south-southeasterly fresh
swell with wave periods averaging 7-8 seconds will feed onto the
beaches today in advance Tropical Depression Three. This wave
group should produce a high risk of rip currents at most area
beaches. Conditions should deteriorate further Sunday as the
tropical system approaches landfall on the southern South
Carolina coast when breaking wave heights in the surf zone could
approach 6 feet south of Cape Fear. A High Surf Advisory is now
in effect.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Tropical Storm Warning for NCZ106-108-110.
     Flood Watch through Monday evening for NCZ099-109-110.
     High Risk for Rip Currents until 8 PM EDT this evening for NCZ106-
     108.
     Beach Hazards Statement until 8 PM EDT this evening for NCZ110.
     High Surf Advisory from 6 AM to 8 PM EDT Sunday for NCZ110.
SC...Tropical Storm Warning for SCZ054>056-058.
     Flood Watch through Monday evening for SCZ054-058-059.
     High Risk for Rip Currents until 8 PM EDT this evening for SCZ054-
     056.
     High Surf Advisory until 8 PM EDT Sunday for SCZ054-056.
MARINE...Tropical Storm Warning for AMZ250-252-254-256.
&&

$$

SYNOPSIS...ILM
NEAR TERM...MBB
SHORT TERM...21
LONG TERM...21
AVIATION...MBB
MARINE...MBB/21
TIDES/COASTAL FLOODING...ILM