570
FXUS62 KCAE 171840
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
240 PM EDT Fri May 17 2024

.SYNOPSIS...
Chances of showers and thunderstorms will increase this
afternoon as a weak system begins to slowly cross the region
with shower and thunderstorm 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 /THROUGH TONIGHT/...
Positive tilted upper trough over the central/southern Plains
will be moving east toward the Mississippi River overnight. Weak
surface low over the Gulf coast area will move northeast into
SC overnight. Southwest flow aloft continues across GA and SC
overnight ahead of trough. Deeper moisture axis over AL/west GA
this afternoon seen on water vapor will be shifting northeast
into SC by early this evening. Precipitable water is expected to
be > 1.75 inches, perhaps near 2 inches across the
CSRA/southern or eastern Midlands overnight. Convection at the
moment is focused across southern AL into south central Ga near
a stationary front. As the surface low moves northeast toward
the area, expect this front to lift north and showers should
spread northeast into the CSRA and the Midlands by early
evening. Mid level clouds have been considerable through the
morning and convective inhibition remains, but breaks in the
overcast developing across the central and north Midlands and
temperatures are rising into the lower 80s. Model soundings show
steepening low level lapse rates through the afternoon then
weakening. Expect at least some weak instability so chance
thunderstorms probability less threat later this evening. Weak
short wave trough triggers in southwest flow aloft along with
warm advection/increasing isentropic lift overnight should lead
to numerous showers. Think the focus will be in the CSRA and
south Midlands late afternoon and early evening with potential
for locally heavy rain/higher precipitable water. Light
precipitation to the north in mainly isentropic lift diminishing
overnight. Overnight lows in the mid to upper 60s/near 70.


&&

.SHORT TERM /SATURDAY 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 /18Z FRIDAY THROUGH WEDNESDAY/...
Restrictions developing by early evening as showers move into
the region.

VFR at the moment with mid level ceilings dominating. Moisture
will be increasing late this afternoon and overnight as weak low
pressure moves toward the area from the Gulf coast. Radar is
showing showers over central Ga. These showers will move
northeast into the region by early evening. guidance is
consistent with MVFR ceilings/visibility in showers this
evening and possible IFR ceilings by 06z. Focus for any heavy
rain during the 21z-04z period. Widely scattered/scattered
thunderstorms possible and think mainly from AGS/DNL to OGB but
confidence low at this time due to overall limited instability.
Showers dominate by mid evening and overnight as any
instability weakens but coverage increasing so restrictions in
visibility possible. MVFR conditions after 12z Saturday with a
few showers in the area. Winds have been light and variable this
afternoon, but favor light south to southwest.


EXTENDED AVIATION OUTLOOK...Increasing confidence in
restrictions in showers and thunderstorms continuing through
Sunday night.

&&

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

&&

$$