-- Discussion containing changed information from previous version are highlighted. --
717
FXUS62 KCAE 222310
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
710 PM EDT Wed May 22 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 near the
area resulting in chances of showers and thunderstorms Friday
and possibly Saturday. Another stronger system is expected
Sunday into early next week and continue the chances of
thunderstorms.

&&

.NEAR TERM /THROUGH THURSDAY/...
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The last convective free evening for a while is underway. Low
clouds are diminishing this evening as the sun sets, but cirrus
is starting to work its way into the CWA from the west. The high
clouds should remain thin through the night.

The other concern overnight is fog. The atmosphere looks like it
will be a bit more mixed tonight, so fog should only be patchy
at best and confined to the usual locations that are
particularly susceptible.
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&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
The quiet weather we have enjoyed over the past couple of days is
expected to quickly move into the rear view mirror as a more
active pattern begins unfolding. Guidance continues to show the
upper level ridge axis quickly pushing off the southeast coast
by Thursday morning. This is likely to occur as a deep shortwave
continues to shift into southeast Canada while another deep
trough digs into the central Rockies. Expecting the ridge to
flatten out both Thursday and Friday, with zonal flow becoming
dominant across the Carolinas and southeastern US. As this
occurs, a weak front is expected to slowly push southeastward,
with guidance showing this feature moving slightly faster over
the past several runs. This pushes it close to the area by
Thursday evening before settling across the area on Friday.

This is likely to create for some interesting weather beginning
Thursday evening. Models continue to indicate a fairly robust
shortwave trough emerging from the southern TN valley on Thursday
afternoon. Rich moisture is forecast to be across the area ahead of
this, but capping is likely to limit the aerial extent of showers
and storms to the northern tier of counties in our FA along the NC
border. Guidance has been routinely breaking the cap in this area
ahead of the shortwave. The wishy-washy front should settle into the
area on Friday, with more widespread chances for showers and
thunderstorms expected. Another strong shortwave within the zonal
flow is expected to approach the area during the day, with fairly
robust instability expected ahead of it. LREF members show >50%
chance of >1000 j/kg, with operational members backing this up.
Additionally, probability of >30 knots of shear is 50-60% as well,
indicating the potential for strong thunderstorms Friday afternoon.
CSU ML Probabilities are highlighting the whole area, so this is
something we need to keep an eye on. Highs on both days should be in
the upper 80s and lower 90s, with overnight lows in the upper 60s.
Friday`s highs are a bit less certain given the expectation for more
convection.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Active weather looks to continue into the long term as well,
especially towards the beginning of next week. Given that guidance
has trended towards a more amplified trough on Friday, shortwave
ridging looks more and more likely to develop on Saturday in the
wake of the departing shortwave. This will have pushed the front
back to the west, with rain chances decreasing compared to Friday.
Highs should still be quite warm - in the low 90s - as the front
really isn`t much of a front. Ridging will likely build again on
Sunday as a deep trough emerges over the central MS Valley.
Southerly flow will continue to advect rich moisture into the
region, but this is mainly to set us up for a potential severe
weather event early next week. Guidance is in good agreement that a
compact synoptic system will develop and push through the OH Valley
and Great Lakes, with a compact surface low and front pushing
eastward on Monday. Ahead of this, we will likely see warm
temperatures and high low level moisture, with dewpoints near 70F
expected. This is a good signal for a potential severe event as the
front approaches around the Monday evening timeframe. Still several
days away from this, but operational models and LREF members are in
decent agreement at least on Synoptic scale features and timing, so
it bears close watching in the coming days. CSU ML Probs are
elevated with this event as well. Front should push through sometime
late Monday and into Tuesday of next week, with drier and slightly
cooler air following behind it.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
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VFR conditions generally expected during this forecast period.

Cumulus will dissipate after sunset with high clouds spreading
over the area overnight. While overall moisture has increased,
the low level flow has shifted more south to southwesterly with
ridge along the coast. So stratus and fog threat has diminished.
The guidance is not showing any fog overnight. There is also a
15 to 20 knot low level jet that should result in a relatively
mixed boundary layer after 06z. Therefore, continued only a
tempo group for MVFR visibilities at fog prone OGB/AGS. Winds
should pick back up from the southwest around 6 to 10 knots by
14z with scattered cumulus.

EXTENDED AVIATION OUTLOOK...Low probability of restrictions
during the late week period into the weekend from afternoon and
evening convection.
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&&

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

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...