541
FXUS62 KCAE 171026
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
626 AM EDT Thu Jul 17 2025

.SYNOPSIS...
Upper level ridging returns for the remainder of the week and
this weekend. This will allow for above normal temperatures,
muggy conditions, and isolated to scattered showers and storms
each afternoon.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- Above normal temperatures with isolated showers/storms

Ridging builds over the area today which will largely suppress
convective development and allow temperatures a few degrees
warmer than the past few days. Subsidence beneath the ridge
favors a mainly dry forecast with just a few isolated showers or
thunderstorms possible in the afternoon. The HREF shows the
lowest convective coverage in the past few days adding
confidence to the forecast. Highs will be in the mid 90s.
Afternoon dewpoints will likely drop to the low 70s or lower
despite NBM forecast values of the mid to upper 70s. This will
keep Heat Index values around or just over 100, below advisory
criteria.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Key message(s):

- Isolated to scattered showers/storms each afternoon.

- Temperatures begin to warm to round out the week and for the
  start of the weekend with heat indices exceeding 100F.

Upper ridging and weak surface high pressure begin to slowly
slide into the region from the east during the short term
period, bringing a warming trend to end the week and for the
start of the weekend. 850mb and 700mb temperatures approach the
NAEFS 90th percentile by Saturday while low level flow generally
remains out of the southwest each day. This should allow
temperatures to reach into the mid to upper 90s each day with
heat indices likely exceeding 100F, though they are expected to
remain just below Heat Advisory criteria at this with Saturday
being the most likely day to near it. PWAT`s remain near
climatological average Friday before slightly increasing into
Saturday as the periphery of the upper ridge begins to slowly
advect deeper Gulf moisture into the Southeast. Some lingering
possible subsidence as seen in forecast soundings may limit
convective coverage Friday afternoon to be a bit more isolated
with MLCAPE being around 1000 J/kg, but moisture that will be
slowly increasing could yield convection that is a bit more
scattered Saturday afternoon and evening with similar
instability parameters.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Key message(s):

- Hot and muggy conditions to end the weekend and to start the
  week.

- Scattered convection is expected Sunday before increased
  coverage will be possible during the early week.

The main change into the extended is that the upper ridge will
become a bit more suppressed and displaced toward the west than
previously shown Sunday through Tuesday as a upper trough slides
into the Great Lakes region and down into the Mid Atlantic. The upper
ridge will help continue to advect deep Gulf moisture from the
remnants of the low currently riding along the Gulf Coast into the
Southeast, raising PWAT`s to between 120-130% of normal as shown in
both of the EC Ensemble and GEFS mean solutions. This should bring
more scattered chances for mainly diurnal showers/storms Sunday but
increased PoP`s then seem reasonable both Monday and Tuesday as the
upper trough may reach near the northern FA and some shortwave
energy may work its way in. There is some indication also that a
diffuse frontal boundary could near the area by Monday afternoon,
possibly lingering into Tuesday. Weak upper ridging and surface high
pressure then look to work in for the mid-week, bringing more
typical diurnal convection.

The bigger story Sunday and Monday is continued hot/humid
conditions with above normal temperatures and heat indices that
could possibly near Heat Advisory criteria each day. The biggest
limitation on this, especially Monday, is the coverage of
convection may limit afternoon temperatures and thus this will
continue to be monitored. Temperatures are then expected to
return to more seasonable levels into the mid week.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Mainly VFR Conditions Through the Period

A few area of low stratus have developed early this morning.
This will lead to brief periods of MVFR or possibly IFR ceilings
at the TAF sites prior to 14Z when VFR conditions will return.

Expect S/SSW winds through the day around the same speeds as
the previous day. Ridging aloft will work to suppress convective
development today. CAMs show lower storm coverage than the past
few days. Therefore we have kept any mention of showers/storms
out of the TAFs for the time being. Light S winds may stay up
into the evening going calm late tonight.

EXTENDED AVIATION OUTLOOK...Typical seasonal restrictions
continue with daily convection and patchy early morning
fog/stratus possible through Sunday. Rain chances increase early
next week ahead of an approaching surface boundary.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.

&&

$$