069
FXUS62 KCAE 270744
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
344 AM EDT Mon May 27 2024

.SYNOPSIS...
A cold front will move through the area tonight. Scattered
strong thunderstorms are expected ahead of the front today with
temperatures remaining above normal. More seasonable
temperatures and drier conditions are expected behind the front
through mid to late week as a high pressure area builds in from
the upper Mississippi Valley.

&&

.NEAR TERM /THROUGH TONIGHT/...
The focus for today remains centered around the MCS moving
through the TN Valley at this time and its potential impact on
the environment later this morning into early afternoon before
another round of convection is expected as a cold front
approaches from the west. The ongoing MCS is forecast to cross
the mtns during the predawn hours and gradually decay as it
moves into the Midlands, but it should be noted that the hi-res
guidance has struggled with the timing of this feature with even
the updating HRRR still lagging behind the actual speed of it.
This means the MCS could move into our area earlier and
dissipate earlier which may allow for the atmosphere to recover
more and destabilize.

Hi-res CAM guidance shows generally scattered convection
developing with locations being a bit different but a focus in
the CSRA early afternoon. Convection is likely to initiate on
whatever outflow boundary is left behind from the decaying
morning convection and possible differential heating boundary
created by debris clouds, so even 12 hours out there is limited
confidence in where and when convection will initiate. However,
the environment should be rich in moisture with ensemble PWATs
around 130-150 percent of normal with values around 1.6-1.8
inches this afternoon ahead of the approaching front. This may
support an isolated flood threat if there is training of storms.
Forecast soundings indicate a bit of a capping inversion albeit
weak, and increasing upper support in the form of shortwave
energy should help convection develop during the afternoon in an
increasingly unstable environment, assuming the morning MCS
does not disrupt this process. Hi-res guidance suggests MLCAPE
values over 1000 J/kg with 25-30 knots of deep layer shear
supporting scattered convection that may try to organize a bit.

SPC continues to outlook the forecast area in a slight risk for
day with damaging wind gusts as the primary threat. Convection
should shift eastward and dissipate over our area by 03z as
850mb winds shift more west to northwesterly as the trough axis
shifts over the region with the cold front pushing through the
region late tonight. Temperatures today are challenging and
dependent on how much cloud cover exists through the day but
will continue to advertise another warm day with highs ranging
from the mid 80s western Midlands and upper CSRA to the lower
90s in the eastern Midlands. Overnight lows expected to range
from the mid 60s west to around 70 east as the cooler and drier
air behind the front reaches the western Midlands during the
predawn hours.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A drier atmosphere moves in behind the departing front for Tuesday
and Tuesday night with slight height rises and zonal flow aloft. The
upper level trough to our north will remain quasistationary, however
a lack of forcing and PW values falling below 1" by midday should
keep things dry. Highs Tuesday afternoon will still be in the upper
80s to low 90s with little in the way of cloud cover. Overnight lows
will be more seasonable in the low to mid 60s.

Little change in our sensible weather for Wednesday, except for some
additional drying with PW values closer to 0.6"-0.7". Highs a few
degrees cooler than Tuesday in the mid to upper 80s with nighttime
lows in the low 60s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Broad upper trough generally remains to our north mid to late week
as multiple disturbances rotate through the flow. The first
discrepancy comes Thursday with the GFS bringing a shortwave through
the southern stream and bringing a few showers to the CSRA while the
EC remains dry. Friday, a weak but generally dry front will push
through the area from the north. Behind that, high pressure will
build in from the west as upper ridging replaces the trough that
will finally move offshore for the weekend. Boundary layer flow
becomes a bit more onshore by Sunday with some indication that
moisture flux will be increasing. However, the GEFS mean keeps PW
values around 0.75" through Sunday, with some increase toward about
1" Sunday night. Given some uncertainties late in the forecast
period, kept close to NBM guidance which keeps us dry through
Saturday before bringing in a slight chance of showers/storms on
Sunday.

Dewpoints remain in the 50s in the extended period while
temperatures will be in the low to mid 80s Thursday and Friday,
which is near to or slightly below normal for late May. A few more
degrees of warming follow for the weekend with high pressure ridging
down the eastern seaboard. Overnight temperatures also get a
reprieve with lows in the upper 50s and low 60s during this
time.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR conditions generally expected through the 24 hr forecast
period with the exception of restrictions in scattered
convection.

Satellite showing mostly clear skies across the region early
this morning but a convective complex is moving into the TN
Valley and will approach our area after sunrise bringing
increasing clouds and possible showers or thunderstorms if it
holds together over the mountains with limited confidence.

25-30 knot low level jet is keeping surface winds up around 5 to
7 knots out of the south through daybreak then winds increase to
around 10 knots and become gusty late morning through the
afternoon as a cold front approaches by this evening. It is
unclear whether or not the convection arriving after sunrise
will hold together but there is high confidence in increasing
clouds mid morning with this feature and possibly some MVFR cigs
at AGS/DNL so included a tempo group to cover that from 11z-15z.
Another round of convection is expected this afternoon ahead of
the approaching cold front but there is uncertainty given how
the morning decaying convection impacts the environment to
support afternoon convection, which appears to be scattered at
this time, therefore carried VCSH for now until confidence
increases for impacts at the terminals. Winds should diminish
with sunset to around 5 knots from the southwest. The boundary
layer remains well mixed overnight so fog is not expected.

EXTENDED AVIATION OUTLOOK...Restrictions possible Monday evening
in scattered thunderstorms as a cold front moves through the
area. Otherwise, significant restrictions not expected.

&&

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

&&

$$