-- Discussion containing changed information from previous version are highlighted. --
610
FXUS62 KCAE 221803
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
203 PM EDT Wed May 22 2024

.SYNOPSIS...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Satellite imagery shows the evidence of increased moisture over
the region with widespread fair weather cumulus over much of
the southeast. PWATs have slowly risen through the day to around
1 inch in the western Midlands and CSRA. Temperatures continue
to climb through the 80s and should top out in the upper 80s to
near 90 degrees.

Tonight: Diurnal cumulus should dissipate quickly with sunset
but deeper convection to our west along an approaching frontal
boundary should provide some higher clouds which move east over
the region tonight. Low level flow has become more south to
southwesterly, losing the component off the Atlantic so think
the fog/stratus risk is a bit lower than last night. Overnight
lows could be impacted by the higher cloud cover as well as a 25
knot low level jet preventing ideal radiational cooling and
expect lows in the mid 60s.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
VFR conditions generally expected during this forecast period.

Afternoon cumulus remains VFR and should dissipate with sunset,
although some higher clouds to the west should move over the
region tonight into Thursday. While overall moisture has
increased the low level flow has shifted more south to
southwesterly ending the onshore fetch so think the stratus/fog
threat is diminished and this is supported by the lack of
fog/stratus shown by any guidance. There is also a 25 knot low
level jet that should disrupt the boundary layer enough to keep
a light wind overnight and also reduce the risk of fog,
therefore only have a tempo group for MVFR vsbys at prone
OGB/AGS. Winds should pick back up from the southwest around 6
to 10 knots by 14z.

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

&&

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

&&

$$