246
FXUS62 KCAE 010951
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
551 AM EDT Tue Jul 1 2025

.SYNOPSIS...
A bit cooler with widespread showers and storms Tuesday and
Wednesday. Rain will be moderate to heavy at times. Temperatures
recover to near average Thursday through the weekend with
isolated chances for afternoon storms.

&&

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

- Increasing moisture and instability should lead to increased
chances of convection.
- Isolated storms could become strong to severe with a damaging
  wind threat and locally heavy rainfall.

Morning analysis shows an upper trough over the upper Midwest digging
southeastward towards the Ohio Valley while the upper ridge remains
over the central Atlantic ridging into the Carolinas. At the
surface, the Bermuda high remains strong with a moist southerly flow
across the forecast area with satellite derived PWATs ranging from
1.7 to 1.9 inches while a cold front was pushing into the OH/MS
Valleys.

The front will continue to shift eastward today, driven by the
eastward moving upper trough, but should remain west of the forecast
area through tonight. Ahead of the front, atmospheric moisture will
begin pooling across the Piedmont region of the Carolinas with lee
side troughing and PWATs are expected to slowly rise to at or above
2 inches by this evening across the forecast area. Forecast
instability is expected to be higher than the last couple of days,
despite relatively poor mid level lapse rates, leading to tall
skinny CAPE profiles with MLCAPE values around 1500-2000 J/kg. Wind
shear will also be a bit better than previous days but generally in
the 15-20 knot range so widespread organized convection is not
expected. Scattered to numerous thunderstorms are expected to
develop by early to mid afternoon as convective temperatures are
reached. SPC/WPC has the western half of the forecast area outlooked
in a marginal risk of severe weather and excessive rainfall,
respectively, which seems reasonable given the forecast
instability/shear parameters today. Better coverage is expected
across the western Midlands this afternoon and evening, closer to
the increasing upper support and weak height falls but chances of
storms expected area wide.

Convection is expected to linger into the evening hours particularly
across the western part of the area as the frontal boundary
approaches from the west but intensity should wane by late evening.
Widespread cloud cover overnight should limit radiational cooling
and expect lows to be in the lower 70s.

&&

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

- Widespread showers and storms continuing Wednesday with
  marginal flash flood risk in the southeastern area.

Upper trough will be shifting through the area Wednesday with a
cold front to the west, although HiRes guidance indicates there
will likely be a lull in shower or storm activity in the
morning with a capping inversion in place and notably, forcing
not looking quite as strong with the latest guidance. Still with
HREF mean showing PWATs above 2 inches and increasing low level
convergence, widespread showers and storms expected to develop
by the afternoon, with the heaviest rain favoring the eastern
portion of the forecast area where synoptic forcing will be
strongest in the afternoon. Similar to Tuesday, the pattern
supports a marginal flash flood threat with the southeasternmost
tier of counties in a marginal risk ERO from WPC. The limiting
factor will be storm motion with steering flow likely to exceed
10 knots. This will prevent widespread flash flooding issues but
rain will still be locally heavy at times. A bit cooler
Wednesday with widespread clouds and increased rain chances with
highs in the mid to upper 80s.

As the front moves offshore, drier air will work into the area
for Thursday with upper ridging beginning to build over the
central CONUS. Upper heights recover with blended guidance
favoring near normal temperatures. Forecast soundings indicate
significant moisture remaining in place below 10kft as humidity
remains high. With the front expected to stall near the coast of
SC, some uncertainty as to whether or not we could get shower or
storm development in the southeastern portion of the forecast
area.

&&

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

- Drier with seasonably hot conditions. Moisture begins to
  recover by the end of the weekend and into next week.

Global ensembles have trended drier in the extended, both in
deep layer moisture and also in the low levels as upper ridging
strengthens to the west of the area and northwest flow
develops. LREF indicates a relatively high probability (around
50 to 70%) of PWATs remaining below an inch and a half Friday
and Saturday before a gradual moisture increase with the latest
GEFS mean showing PWATs returning to near normal through the end
of the period. Seasonably hot conditions with the ridge
building to the west, although with this added dry air LREF mean
soundings show strong mixing, leading to a slight break from
the significant humidity earlier in the week. Worth mentioning
the the National Hurricane Center is monitoring the potential
for low pressure to develop along the front as it stalls
offshore and has a 20% chance of tropical or subtropical
development but even if there is development, impacts to our
area would likely be limited.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
Widespread IFR cig into mid morning then improving by late
morning with scattered afternoon showers and storms expected.

Stratus clouds with cigs around 4-7kft have overspread the
terminals. This stratus deck should begin to diminish and
transition to a cumulus VFR deck by late morning(14-16z) into
afternoon. Chances of afternoon storms appear a bit higher today
with increased atmospheric moisture and weakening upper ridge
as an upper trough and associated cold front approach from the
west. Winds should continue to be from the south today with some
possible gusts around 15 knots. Possible stratus returns
tonight with abundant moisture in place.

EXTENDED AVIATION OUTLOOK...Patchy low clouds and/or ground fog
possible each night along with diurnally favored showers and
thunderstorms.

&&

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

&&

$$