387
FXUS62 KCAE 180544
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
144 AM EDT Sat May 18 2024

.SYNOPSIS...
A few showers will be possible tonight with periods of showers
and thunderstorms expected today and into Saturday night. Rich
moisture across the region will keep rain chances likely
lingering into Sunday. Cooler and drier air moves in for Monday
and Tuesday with temperatures rebounding during the middle of
next week as another ridge moves in from the west.

&&

.NEAR TERM /UNTIL 7 AM THIS MORNING/...
2am Update: Scattered showers have developed across the Central
Midlands tonight but rainfall amounts have been very light.
Additional showers are approaching the CSRA and could also
bring some light rainfall amounts to our southern FA. The first
significant round of showers and thunderstorms for today is
currently moving into Alabama from Mississippi and should arrive
in our CWA towards daybreak. Slight Chance to Chance PoPs
gradually ramp up through 7am to account for this.

Previous Discussion: Positively tilted upper trough continues
to slowly progress through over the central/southern Plains
toward the Mississippi River Valley this evening. Southwest flow
aloft continues to usher in moisture with PWATs between 1.5"
and 1.7" and dewpoints in the mid to upper 60s. PW values are
expected to increase overnight to between 1.7" and 1.9", with a
few locations closer to 2" across the CSRA/southern or eastern
Midlands.

Ongoing convection to our south is progged to remain out of the area
tonight. However, weak short wave energy moving through the mid
level flow is expected to generate scattered showers across the area
amid increasing isentropic lift. The latest HRRR shows a reasonable
solution, with perhaps a bit of a stronger area of showers and
thunderstorms pushing through the CSRA around daybreak. Severe
threat remains low though brief heavy rainfall is possible.

Overcast skies and a well-mixed boundary layer keep overnight lows
quite mild, only falling into the mid to upper 60s/near 70. Low
dewpoint depressions may generate some reduced visibilities in and
near shower activity.

&&

.SHORT TERM /7 AM THIS MORNING THROUGH SUNDAY NIGHT/...
Positively tilted trough will continue to slowly push eastward
towards us and should be centered across the lower MS Valley by
tomorrow morning. Strong flow at 500 hPa is expected to create
strong shear profiles, and CAMs are generally showing some sort
of MCS structure to our southwest, but how far north this gets
and how fast it will be is in question. Generally, guidance has
struggled with speed and placement of convective structures like
this in recent weeks. So there is uncertainty about this, but
confidence is high that an MCS of some sort will be in central
GA at the start of this period. Ahead of this, rich moisture
should favor some instability, and given the shear in the
atmosphere, strong to marginally severe storms are again
possible depending on the location of this convection. Thinking
the best chance for this is in the southern FA, but timing and
severity is hard to piece together right now. Think it`ll be
approaching or through our FA by late morning, and if this
happens, it opens the door for some afternoon sunshine and
another round of thunderstorms in the central and northern FA.
While the strongest shear will be to our east, robust
instability is possible where we see sunshine tomorrow afternoon
so we`ll need to watch for strong strong storms along an
amorphous surface front across the northern part of SC. Highs
should generally be in the mid 80s but upper 80s are possible
for those that see more sunshine. Showers will probably hang
around into Saturday night as the trough approaches with lows in
the mid 60s expected. On Sunday, more showers and embedded
thunderstorms are possible as the trough approaches and pushes
over the region. Some uncertainty is present with where the
surface low and resultant convergence develops, adding some
overall uncertainty to rain coverage Sunday afternoon. But
confidence is high that we`ll see scattered to numerous showers
across much of the area, with highs in the upper 70s and low
80s. Showers should clear out on Sunday night as a back door
front pushes through and pushes low PW air into the area.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Confidence continues to remain fairly high in the long term
period. Cool and dry air is expected to remain in place on
Monday, with highs well below normal near 80s. Modification
quickly begins on Tuesday as high pressure shifts to our east
and ridging aloft begins to build. This should carry highs back
into the upper 80s and low 90s by Thursday. Another cold front
is forecast to approach by the Thur/Fri timeframe, with the
possibility of showers and thunderstorms in the afternoon in
association with that.

&&

.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
Ceilings Expected to Fall this Morning...

Scattered showers have developed near CAE/CUB tonight but
rainfall amounts have been very light and no restrictions are
currently being reported. Additional showers are approaching
the CSRA and could also bring some light rainfall to AGS/DNL and
eventually OGB. While ceilings remain in VFR tonight, guidance
remains bullish in dropping them to the IFR category prior to
daybreak. Amended TAFs to reflect the ceilings falling by 09Z.
An area of showers and isolated thunderstorms will approach the
terminals towards daybreak, likely resulting in a temporary
reduction in visibility. The ceilings should improve around
midday with a return to VFR conditions in the afternoon.
However, additional showers and thunderstorms will be possible
across the region later today. Maintaining VCSH after 21Z due to
low confidence in thunderstorm timing.

EXTENDED AVIATION OUTLOOK...Periodic restrictions from showers
and thunderstorms continue through Sunday night. Low ceilings
are also possible Sunday morning. Conditions should improve on
Monday.

&&

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

&&

$$