244
FXUS62 KCAE 240740
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
340 AM EDT Tue Jun 24 2025

.SYNOPSIS...
Hot and humid conditions, with dangerous heat index values, are
expected through Wednesday under the continued influence of a
strong upper ridge. Rain chances increase for the mid to late
week as ridging begins to break down. A few thunderstorms may
become strong to severe on Wednesday.

&&

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

-  Dangerous Heat Today
-  Heat Advisory in Effect
-  Heat Index Values 104-109

Conditions will be very favorable for dangerous heat today as a very
strong upper ridge becomes centered just north of the region. At the
surface, a ridge axis will extend westward into the area from the
Atlantic, but as the day progresses a coastal trough will develop
and shift inland.

The anomalous heights aloft and associated strong subsidence will be
the primary driver of the heat today. Model guidance is all in
fairly good agreement indicating high temperatures within a degree
or two of 100. The forecast dew point is usually not handled well by
the global models in these scenarios as they typically run too high,
but looking at some of the high resolution guidance and observations
from Monday, don`t see much reason for dew point values to drop
below the upper 60s during peak heating. As a result, heat index
values should range from about 104-109, justifying a Heat Advisory
across the area.

Skies will start the day sunny, but then diurnal cumulus is
expected to develop this afternoon. The majority of the CAMs
show limited to no convection today, however it should be noted
that a couple of models show convection firing along the coastal
trough, so cannot rule out at least the possibility of storms
near the Pee Dee and eastern Midlands late this afternoon/early
this evening.

Skies should clear this evening, with another mild night expected
with lows in the mid 70s.


&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Key Message(s):

- Continued hot and Humid Wednesday with dangerous heat index
  values near criteria.

- Showers and thunderstorms develop during the afternoon and
  evening hours. A few thunderstorms may become severe producing
  damaging wind gusts.

Upper ridge will be positioned to our northwest at the start of
the day with an upper low located near the Bahamas. The low
undercuts the ridge on Wednesday, causing a shift in our weather
pattern. While the ridge will be breaking down, another hot and
humid day is expected with forecast highs around 100 degrees.
Held off on extending the Heat Advisory into Wednesday as the
locations most likely to see heat index values around criteria
are also the ones most likely to see convective development
first. ML guidance continues to highlight the threat for severe
weather on Wednesday and the SPC has responded to this trend by
upgrading the Midlands to a Slight (2/5) risk for severe
weather in their Day 2 SWO. The 00Z HRRR shows convective
initiation during the mid-afternoon across the northern Midlands
and Pee Dee, gradually spreading south as the day goes on. This
will be a high CAPE, low shear situation where the severe risk
is almost exclusively driven by the threat for damaging winds.
Modeled soundings show stout low-level lapse rates and a strong
inverted-V signature in addition to 3000-4000 J/kg of CAPE and
mid-level dry air associated with the weakening ridge. There is
the potential for this to be a significant severe event with
high microburst potential.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Message(s):

- Typical summertime pattern with near to slightly above normal
  temperatures and daily chances for showers and thunderstorms.

The upper low continues to break down the ridge across the
region on Thursday putting an end to the strong subsidence over
the FA. This means that while daytime temperatures should return
to more seasonal values, the threat for afternoon and evening
convection also returns. Withe the aforementioned upper low in
the area, a few stronger thunderstorms could develop again on
Thursday, though ML guidance shifts the main threat to our west.
The Day 3 SPC SWO places our northern and western counties in a
Marginal (1/5) risk for severe weather with damaging winds once
again being the primary threat. With the loss of any large
scale triggers Friday and into the weekend, the overall severe
threat should be low. However, any pulse thunderstorm could
briefly become strong to severe under the right conditions with
localized impacts.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected through the TAF period.

Clear skies and some low level moisture could contribute to the
formation of patchy fog at KAGS this morning, with some guidance now
suggesting reduced visibilities possible toward daybreak. As a
result have included a tempo group from 08-12Z for fog reducing
visibilities to MVFR levels, although cannot rule out a brief period
of IFR or lower visibilities. Otherwise, VFR conditions will prevail
at the terminals through the forecast period.

Scattered to broken cumulus is expected this afternoon due to
diurnal heating, but any ceilings would remain VFR. Winds should
increase to only 5-7 kt this afternoon, with directions more N-NE
through early afternoon, then veering E-SE late this afternoon.
Strong subsidence over the area should generally prevent any
showers/thunderstorms from developing, but if they do the eastern
Midlands look more favorable due to the proximity of a coastal
trough.

EXTENDED AVIATION OUTLOOK...Rain chances increasing some Wednesday
and beyond that may lead to brief restrictions if a terminal sees a
shower/storm.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Heat Advisory from 1 PM this afternoon to 8 PM EDT this
     evening for SCZ016-018-020>022-025>031-035-037-038-041-
     115-116-135>137.
GA...Heat Advisory from 1 PM this afternoon to 8 PM EDT this
     evening for GAZ040-063>065-077.

&&

$$