St. Andrews, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

992
FXUS62 KCAE 230026
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
826 PM EDT Sun Jun 22 2025

.SYNOPSIS...
Upper ridging establishes itself over the eastern CONUS
bringing an early week warming trend. Hot and humid conditions,
and dangerous heat index values, are expected during the mid-
week period under the continued influence of the upper ridge.
Rain chances increase later in the week as ridging should begin
to break down.

&&

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

-  None

Mostly clear skies tonight under upper level ridging. No
additional shower development is likely due to subsidence.
Temperatures will remain warm through the night with lows only
reaching into the low to mid 70s. With crossover temperatures in
the mid to upper 60s we do not expect fog to be a problem.

&&

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

- Heat continues to build into the region with near Heat
  Advisory Heat Indices Tuesday and Wednesday.

The center of the strong upper level ridge will shift over the Mid-
Atlantic Monday. NAEFS mean indicates that 500mb heights will be
near the climatological max for this time of year for both Monday
and Tuesday as heat continues to build over the forecast area.
Temperatures rise as a result into the mid to upper 90s with heat
indices rising into the triple digits. Confidence is relatively high
that heat indices stay below heat advisory criteria but HREF
indicate 30 to 40 percent probability of heat indices 105F or
greater, so we will likely be close. Surface high pressure just off
the coast will also help to promote broad subsidence over the area
which will limit convective chances, although a shower or two
remains possible but most of the area remains dry.

Tuesday, heat is expected to continue to build in with slightly
higher chances to reach heat advisory criteria Tuesday or Wednesday
(although still not a lock). Tuesday and Wednesday will likely be
the hottest days of the period, with a slight increase in moisture
expected as well. Both days are highlighted in the EC Extreme
Forecast Index with values greater than 0.8 across the entire area
which indicates a high temperature anomaly with highs likely near
triple digits. Blended guidance typically struggles in keeping dew
points too high in these anomalously hot events which is why there
remains a question as to whether a heat advisory will be needed.
GEFS has also indicated a bit higher PWATs compared to early runs
Tuesday and Wednesday and possibly some weaknesses in the ridge.
This may allow for some convection to develop either day, although
confidence remains low.

&&

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

- Upper ridging may begin to break down during the extended,
  with an increase chance for afternoon and evening convection.

GEFS and EC ensemble mean trends have been showing a weakening
in upper level riding over the last several runs over the
forecast area. This will likely lead to highs a few degrees
cooler for the end of the week and into the weekend, although
blended guidance still favors highs above average with heat
indices near 100F. Not much of a relief from the heat by any
means but likely will not need a heat advisory in the extended.
LREF probabilities indicate a around 50 percent chance for PWATs
to exceed 1.8 inches Thursday and Friday with higher
probabilities for the weekend. This, along with weakening in the
ridge will lead to chances for diurnal showers and storms each
day in the extended forecast.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected through the TAF period at this
time.

High pressure continues to fill into the region with any
lingering cumulus beginning to diminish and winds that have
become light out of the southeast generally. Overnight tonight,
winds become light and variable to calm with mostly clear skies
outside of some passing cirrus. While some patchy fog cannot be
ruled out near the normal fog prone sites of AGS/OGB, confidence
is too low to add mention into the TAF at this time (around 20-30%).
Some stratus may develop into the Coastal Plain, but the bulk
of model guidance shows this remaining south of the terminals at
this time. As high pressure builds a bit north of the forecast
area, winds in the morning start variable around 5 kts before
becoming a bit more southeasterly to south- southeasterly after
18-20z. Mostly clear skies are expected through the end of the
TAF period with only FEW cumulus and cirrus during the afternoon
and into the evening tomorrow.

EXTENDED AVIATION OUTLOOK...Next week looks to be on the drier
side with minimal restrictions expected at this time.

&&

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

&&

$$