653
FXUS62 KCAE 240007
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
807 PM EDT Mon Jun 23 2025

.SYNOPSIS...
Hot and humid conditions, with dangerous heat index values, are
expected during the next few days under the continued influence
of a strong upper ridge. Rain chances increase mid to late week
as ridging begins to break down.

&&

.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
Key Message(s):

-  Above normal temperatures tonight

Warm weather continues tonight with lows only dropping into the
mid 70s. Skies will be mostly clear with no rain expected. Fog
is unlikely except for the typical fog prone locations near
rivers and creeks.

&&

.SHORT TERM /7 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Key Message(s):

- Heat Advisory in Effect for Tuesday. Hot and Humid Wednesday.

- Scattered Showers and Storms Wednesday. A few storms may
  produce damaging wind gusts.

Upper level ridging will be centered just to the north of the area
with 500mb heights approaching 3 standard deviations above normal
indicating highly anomalous heat settling over the forecast area.
Guidance has been relatively consistent in high temperatures for
Tuesday with highs expected to be around 100F. Some spread remains
on dew point evolution into the afternoon but typically in these
days where temperatures are well above average, hi resolution
guidance is able to better capture the degree of mixing associated
with drier air being brought to the surface. As a result, have gone
a bit below blended guidance for dew points which matches the
observations from the previous couple days. This still brings heat
indices across the area from 105 to around 108F during the afternoon
tomorrow. As a result, a Heat Advisory is in place for the entire
forecast area for Tuesday. Is the potential for a coastal trough to
set up tomorrow with HREF mean PWATs increasing near the coast to
around 1.8 inches. Still think through most of the area, subsidence
will dominant preventing showers and storms from developing but
cannot rule out some convection in the far eastern area late
tomorrow. Low temperatures Tuesday night remain warm with blended
guidance in the mid 70s.

Wednesday may be a bit more complicated forecast as guidance is
coming into agreement of an upper disturbance moving into the
Bahamas which would cause weakening in the upper ridge over the Mid
Atlantic. While above average heights will still favor a hot day,
GEFS probabilities of PWATs increasing to above 2 inches is around
40 percent. With this weakening of the ridge, increasing
probabilities of thunderstorms developing over the area Wednesday
afternoon into Wednesday evening. Forecast soundings show high
probability of strong destabilization across the area with limited
shear but strong low level mixing. As a result, potential for any
storms to produce damaging wind gusts and potentially some hail,
although temperatures once again near 100F will make it difficult
for large hail to reach the surface. Have opted to hold off on
extending the heat advisory into Wednesday but it may be needed as
well as temperatures may be slightly lower but low level moisture
slightly higher.

&&

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

- Seasonably hot and humid with afternoon showers and storms.

A more typical summertime pattern is expected in the extended
forecast with NAEFS mean indicating that 850mb temperatures will
be less than one standard deviation above normal. While ensemble
guidance indicates slightly lower moisture Thursday and Friday,
by next weekend, LREF shows a high probability of PWATs greater
than 1.8 inches (60-70%). With the overall synoptic pattern
likely becoming more zonal, broad subsidence will no longer be
over the area which will allow diurnally driven storms to form.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected through the TAF period.

The upper ridge remains in place through much of the TAF period
with diurnal cumulus diminishing this evening, giving way to
mostly clear skies overnight and into Tuesday morning. Winds
are light, generally out of the southeast to south, but should
become light and variable to calm overnight. While a brief
window of fog (around 1 hour or less) for our more prone sites
at AGS/OGB cannot be ruled out toward daybreak, confidence is
fairly low (around 20%) in this occurring and thus I have left
mention out of the TAF. Winds will pick back up to 5-7 knots
after 14-16z, but are expected to remain fairly variable much of
the TAF period before becoming perhaps a bit more easterly to
southeasterly late in the day. Some more scattered cumulus and
passing high clouds will be possible during the afternoon and
through the end of the TAF period. Some high res models suggest
enough moisture may be in the region for a couple showers/storms
mainly in the eastern Midlands during the afternoon but
coverage would be limited and confidence in these forming is low
at this time.

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 to 8 PM EDT Tuesday for SCZ016-018-
     020>022-025>031-035-037-038-041-115-116-135>137.
GA...Heat Advisory from 1 PM to 8 PM EDT Tuesday for GAZ040-063>065-
     077.

&&

$$