846
FXUS62 KCAE 212334
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
734 PM EDT Tue May 21 2024

.SYNOPSIS...
High pressure will dominate the region through early Thursday
keeping fair and dry conditions in place along with warming
temperatures. A frontal boundary will approach the region
Thursday night and Friday and is expected to stall just north
of the area resulting in chances of showers and thunderstorms
Friday through next weekend.

&&

.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
Weak high pressure remains in place over the area this evening.
Only forecast issue will the the chances for ground fog
overnight. The best chances will be in the eastern Midlands and
southern CSRA where the dew points are a bit higher, and also
along rivers and lakes where local moisture values are a bit
higher.

&&

.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
High confidence in a fairly quiet period through Friday as
guidance is in good agreement on the expected pattern. Upper
level ridging is forecast to be centered across the southeastern
US by Wednesday morning, with deep troughing settling into the
OH Valley. Ensembles & operational models push the axis of this
ridge offshore by Thursday evening, with more zonal flow
emerging on its heels. The ridging will keep us warm, dry, and
sunny on Wednesday. Highs are likely to be in the low 90s during
the afternoon, with only a few clouds. A strong mid-level
inversion looks to settle in with subsidence beneath the
ridging, so chances of rain are near zero. Clear skies and lows
in the low 60s are expected Wednesday night. The zonal flow is
forecast to take over on Thursday at the same time as we begin
to see an increase in low-level moisture across the forecast
area. Surface theta-e is forecast to climb to 340-345k across
the area on the western side of the surface high across the
Atlantic, increase potential instability. However, it still
looks like a strong cap will remain in place and keep storms at
bay for most of the area. The GFS/NAM/LREF suite of members do
show a weak shortwave trough approaching by Thursday evening.
Thinking that this could break the cap in the northern FA and
spark an isolated to scattered storm across that area. Bumped
PoPs up to slight chance as a result of this. LREF probabilities
of >0.01" of rain in the period are 20-30%, which support the
idea that, while not widespread, some precip is definitely
possible with this shortwave. Highs will likely be in the lower
90s on Thursday, with overnight lows in the upper 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Fairly high confidence in the general pattern in the long term.
LREF member means and operational models are in fairly good
agreement showing zonal flow continuing through early next
week, with multiple robust shortwaves progressing through the
flow in the long term period. At the surface, rich BL moisture
characterized by high theta-e, PWs 125-130% of normal, and
dewpoints in the upper 60s to around 70 will be in place. This
is forecast to all sit southward of a slow moving surface front
that should approach on Friday and become diffuse or weak around
the area into the weekend. Combine all of this with seasonally
warm temps in the low 90s and the stage is set for a fitting
start to the summer season and Memorial Day Weekend. So look for
highs to be 90-95F each day through early next week, with
chances for storms each afternoon as well. Given the strength of
some of these shortwaves combined with the rich low-level
moisture that is expected and there is a chance that strong
storms become a possibility each afternoon. The mesoscale
details will be important, so stay abreast of the forecast
especially if you have outdoor plans this weekend. For what its
worth, the CSU ML Probabilities are showing elevated severe
probabilities at this range on Sat/Sun/Mon, so it will be worth
watching this weekend. A more developed system and front look
likely to push in and through the region by the middle of next
week, which could cool us down if the front actually
materializes.

&&

.AVIATION /00Z TUESDAY THROUGH SUNDAY/...
High confidence in VFR conditions all terminals through 06z
then expect predawn visibility/ceiling restrictions in patchy
fog primarily at OGB and AGS. Confidence is higher for
restrictions at OGB.

High pressure remains in place across the region with a
relatively dry air mass in place. However, low level winds
overnight shift more southeasterly and may allow for some weak
onshore flow possibly leading to early morning fog/stratus over
the Coastal Plain. Guidance continues to suggest LIFR conditions
possible at OGB prior to dawn...08z-12z. The cross-over
temperature is higher at that terminal suggesting an increased
threat for fog. HRRR also supports MVFR/IFR at AGS. Brief MVFR
fog possible at CAE and CUB but overall NBM visibility
probabilities much lower than at OGB. Winds will be light and
variable overnight but favor a southeast direction. With the
ridge axis shifting east Wednesday, expect winds from a south-
southwest direction through the day less than 10 knots. High
clouds will be increasing from the west mainly in the afternoon
as the upper ridge weakens.

EXTENDED AVIATION OUTLOOK...No significant flight restrictions
are currently anticipated through Thursday outside of brief
morning fog. Low probability of restrictions during the late
week period into the weekend from afternoon and evening
convection.

&&

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

&&

$$