North Charleston, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

142
FXUS62 KCHS 132343
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
743 PM EDT Mon Jul 13 2026

.WHAT HAS CHANGED...
The Aviation Section has been updated for the 00Z TAF issuance.

&&

.KEY MESSAGES...
- 1) Rounds of showers and thunderstorms are expected to impact
  southeast Georgia and southeast South Carolina through
  Tuesday. Locally heavy rainfall will be the primary concern,
  and isolated flash flooding will be possible. Also, a few
  strong to marginally severe storms could occur with damaging
  wind gusts.

- 2) Near-normal temperatures are expected to return end of
  this week and warming into the weekend.

- 3) Minor coastal flooding is likely for portions of the
  southeast South Carolina coast with the evening high tide
  cycles through Wednesday.

&&

.DISCUSSION...
KEY MESSAGE 1: Rounds of showers and thunderstorms are expected
to impact southeast Georgia and southeast South Carolina
through Tuesday. Locally heavy rainfall will be the primary
concern, and isolated flash flooding will be possible. Also, a
few strong to marginally severe storms could occur with damaging
wind gusts.

Through tonight: Aloft, the forecast area will sit within the
influence of a mid-level trough and just to the east of a
developing closed low (albeit weak). At the surface, a weak
boundary will sit west to east across the area, perhaps more
across southeast SC. This setup should provide a focus for
shower and thunderstorm development this afternoon within an
environment of precipitable water values solidly in the 2.1-2.25
inch range. Hi-res model solutions show a good bit of variance
in possible solutions, but the general consensus is for
development to first take place across southeast GA and perhaps
closer to the coast. Then with time through the evening and into
the overnight, convection could steadily shift more inland as
it is driven by subtle cyclonic flow around a weak area of low
pressure that develops to the west. Rainfall amounts will likely
be highly spatially variable due to the convective nature of
development. But, there is support in the HREF for pockets of
1-3 inches to be common along with isolated pockets of 3-5
inches possible. The HREF 3-hour rainfall probabilities suggest
a widespread 70% or greater chance of 1 inch or more just about
everywhere, and 30-50% probabilities of 3 inches or more favored
for inland areas away from the coastal corridor. The exact
placement of the heaviest areas of rain are difficult to pin
point, as mesoscale boundary interactions will have a lot to do
with that. The entire forecast area remains in WPC`s Slight Risk
in the Day 1 Excessive Rainfall Outlook. This makes sense given
the residual wet conditions from the last few days, and the
potential for intense rainfall this afternoon and into tonight.
Current thinking is that as convection shifts inland with time,
we should see most of the rain potential end for the forecast
area through the overnight hours. Also of note, though the
environment doesn`t look particularly support of severe
thunderstorms, we could still see a few strong to marginally
severe storms. Instability should be a bit weaker and we
certainly don`t have much mid-level dry air available. But, we
could see sufficient updraft enhancement near boundary
interactions to produce a wet microburst threat.

Tuesday: The aforementioned boundary should sink a bit to the
south which would also shift the focus and threat for heavy rain
a bit south as well. However, the environment will remain very
moist and thunderstorm activity is expected just about
everywhere. It is hard to put much confidence in narrowing down
the location of the greatest threat for locally heavy rain. So,
the entire forecast area remains within WPC`s Marginal Risk in
the Day 2 Excessive Rainfall Outlook. The HREF produces similar
3-hour probabilities as today, with the entire area in the 70%
or greater area for 1 inch or more and support for 30-50%
chances of 3 inches or greater (perhaps focused a bit more on
southeast GA). So we will have to watch for locally heavy rain
as well as another risk of an isolated strong to marginally
severe storm.

KEY MESSAGE 2: Near-normal temperatures are expected to return
end of this week and warming into the weekend.

A nice reprieve from the heat of the last week with broad
troughing over the eastern US cuts off into a upper low through
the remainder of the week. At the surface a subtle "cool" front
will be stalled just south of our area come Tuesday into
Wednesday. While this really wont usher in significantly cooler
temperatures, the combination of the weak upper low to our west
and light surface convergence along the boundary zone will
likely provide increased cloud and storm coverage through
Wednesday keeping temperatures more seasonable. By the weekend,
the upper low will have drifted westward towards the Mississippi
Valley allowing for upper ridging to try and nose into the deep
south and the weak boundary to mix out. While this should dry
us out, it will also result in a gradual warmup into the weekend
with the return of heat indices in the triple digits once
again.

KEY MESSAGE 3: Minor coastal flooding is likely for portions of
the southeast South Carolina coast with the evening high tide
cycles through Wednesday.

Astronomical influences including the lunar perigee (7/13) and
the new moon cycle (7/14) will combine to produce elevated tide
levels through at least the middle of the week. The evening high
tide cycle will be the most elevated each day. Though winds
won`t be particularly strong or supportive of large tidal
departures, minor coastal flooding will be likely especially for
Charleston and coastal Colleton counties. Coastal Flood
Advisories could be needed each evening.

Upcoming evening high tide (~8pm): The astronomical high tide
this evening is 6.57 ft MLLW meaning we need a departure of 0.43
ft to reach 7 ft MLLW and the minor coastal flooding threshold
at Charleston. At the preceding low tide, the departure is
between 0.5-0.6 ft and our local tide forecast tool suggests a
high tide around 7.2-7.3 ft MLLW. Therefore, a Coastal Flood
Advisory has been issued for Charleston and coastal Colleton
counties for the 6-10pm time period.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
The period begins VFR, then guidance is consistent in
indicating lower cigs developing overnight at all terminals.
There are hints of brief reductions to IFR, but MVFR looks to be
most prevalent. Cigs could linger until around mid-day before
improving to VFR. Another round of showers and thunderstorms
will be possible again on Tuesday, so have opted for a PROB30
for now.

Extended Aviation Outlook: Shower and thunderstorm coverage,
along with risks of associated restrictions, will remain
elevated through Tuesday.

&&

.MARINE...
Today through Wednesday: A weak cold front will continue to
slip through the region from north to south today and into
Tuesday, yielding variable winds. This front is expected to
increase the shower and thunderstorm activity over the waters,
with isolated to scattered thunderstorms becoming strong to
severe, primarily during the late afternoon and evening hours.
The front is expected to remain just off to our south of
Wednesday, though chances for thunderstorms will continue.
Outside of thunderstorms, marine conditions are expected to
remain well below Small Craft Advisory criteria.

Wednesday - Sunday: West-southwesterly surface flow is expected
to develop Wednesday and remain into the weekend, with
continued sub Small Craft Advisory criteria. Winds may briefly
increase to near Small Craft Advisory criteria by Saturday into
Sunday as the surface gradient tightens.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory until 10 PM EDT this evening for SCZ149-
     150.
MARINE...None.

&&

$$