730
FXUS62 KCAE 291816 CCA
AFDCAE

Area Forecast Discussion...CORRECTED
National Weather Service Columbia SC
216 PM EDT Sat Jun 29 2024

.SYNOPSIS...
Hot and humid conditions continue through the weekend. Afternoon
and evening rain and storm chances increase Sunday afternoon
and evening as a frontal boundary moves into the area. The cold
front is expected to bring slightly cooler and drier conditions
to start off the work week, but building high pressure will
allow the return of temperatures near the century mark by mid-
week.

&&

.NEAR TERM /THROUGH TONIGHT/...

KEY MESSAGES:
- Warm and humid again, showers and thunderstorms expected mainly
  south and east of I-20 this afternoon and evening.
- Heat index values pushing into the mid 100`s in many spots.

A modestly unstable environment continues to develop across the
Midlands and CSRA this afternoon. PWAT`s have climbed to near 2.0"
and ML CAPE is rising to around 1000 J/kg by mid-afternoon. Some
showers have pushed into the CSRA as of 18z, but lightning has
been very isolated thus far. Hi-res guidance was a bit late with
this initial initiation, but the overall progression, timing, and
behavior of convection so far is following obs and showers-storms
will spread eastward along the I-20 corridor and points eastward
this afternoon. The severe threat looks to remain relatively low,
in line with the last couple days, as we lack any sort of forcing
mechanism, deep layer shear, or truly impressive thermodynamics.
So a strong- severe thunderstorm is possible, again mainly in the
CSRA and southern Midlands, but confidence is very low.


&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...

KEY MESSAGES:
- Heat Advisory in effect Sunday afternoon and early evening.
  Not as hot on Monday with a front entering the region.

Sunday and Sunday night...Broad upper trough developing in the
northeast CONUS and Mid Atlantic region. The upper ridge over
the area will weaken with northwest flow aloft over SC. A weak
cold front will move toward the region late in the day. Moisture
will increase through the day with southwesterly low- level
flow. Strong moisture flux expected with precipitable increasing
to 2 inches or even higher ahead of the front. Models soundings
suggest deep moisture. This will result in hot and muggy
conditions by early afternoon. Heat indices in the 105-110 range
are expected with high temperatures in the mid to upper 90s. So
a heat advisory has been posted. So, as the front approaches,
the air mass will become moderately unstable with ML CAPE
1500-2000 J/kg. CAM models are suggesting a few isolated showers
in the morning, followed by scattered to numerous showers and
thunderstorms late afternoon into the evening as a short wave
trough approaches in northwest flow aloft. Highest pops appears
to be across the north Midlands into the Pee Dee where lift is
maximized due to approaching short wave and divergence aloft.
Deep shear near the NC/SC border is only 20 knots but can`t rule
out a severe pulse storm anywhere due to strong heating and
moist conditions. Moist downburst wind gusts main threat. Muggy
conditions overnight with showers diminishing but lingering as
the front moves slowly to the southeast.

Monday and Monday night...Although the deterministic pop
guidance is suggesting low pops on Monday, the front is expected
to stall near the area. The ensembles are suggesting relatively
high pops, actually categorical across the southeast CWA
through the day with lower/chance pops to the north. The air
mass will likely remain weakly unstable and quite moist.
Temperatures should be cooler with considerable clouds at least
through the morning with some clearing northwest.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...

KEY MESSAGES:
- Brief break from excessive heat on Tuesday before the heat
  and humidity return later in the week.
-Dry conditions may lead to increased fire danger mid to late
 week.

The front should push a little further south on Tuesday with
much drier air filtering into the central Midlands. Precipitable
water expected to fall below 1 inch across a good portion of the
area. So, a brief respite from the summer heat and humidity can
be expected. With the front near the Savannah River area, kept
chance pops there, but chance of rain should decrease by
afternoon. Ensembles show high pressure building aloft again
over the Southeast U.S. during the latter half of the week with
temperatures once again well above normal. Moisture will slowly
increase across the region through the period. Convective
activity should be mostly limited to near the sea breeze front
and small scale atmospheric interactions. Below normal rainfall
during the past month has led to dry vegetation which increases
the risk of fire starts, especially with upcoming Independence
Day celebrations. Another front may approach the area by next
weekend with an increase in showers/thunderstorms. But overall
the period appears mainly dry and increasingly hot by mid to
late week.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR conditions generally expected through the period.

Some showers and isolated thunderstorms are currently moving
through AGS and DNL, with some brief associated restrictions
likely through roughly 20z. Lightning has continued to remain
fairly limited in any of this convection, but this will likely
increase through the afternoon. These will continue to shift east
over the afternoon, likely moving into CAE, CUB, and OGB by 20z.
Given the coverage and timing uncertainties, went with a VCTS
group at these sites from 20z through 00z. Winds this afternoon
will remain fairly light, mainly out of the south, with gusts to
10-12 knots. Not expecting fog or stratus overnight tonight into
Sunday. Confidence is fairly high in restrictions on Sunday as a
front approaches.


EXTENDED AVIATION OUTLOOK...Widespread showers and thunderstorms
likely Sunday afternoon and evening. Chances of rain in the
afternoon and evening continue Monday and Tuesday, with stratus
and fog in the mornings.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Heat Advisory from 2 PM to 6 PM EDT Sunday for SCZ016-018-
     020>022-025>031-035-037-038-041-116-135>137.
GA...Heat Advisory from 2 PM to 6 PM EDT Sunday for GAZ040-063>065-
     077.

&&

$$