104
FXUS62 KCAE 112357
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
757 PM EDT Sun Aug 11 2024

.SYNOPSIS...
Hot temperatures and high humidity have led to triple digit
heat indices again today for many locations. Scattered
afternoon and evening thunderstorms are also likely, with
isolated flash flooding and a strong to severe storm or two
possible. Temperatures cool off slightly this week with daily
chances of afternoon showers and thunderstorms continuing.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Key Message(s):

- Isolated flash flooding and thunderstorm potential tonight

Forecast remains largely on track across the FA this evening.
Earlier shortwave that sparked scattered to numerous
thunderstorms across the central and eastern Midlands earlier
this afternoon has pushed east and out of the FA at this point.
Another shortwave upstream from the carolinas is expected to
continue to provide at least weak lift as we get into the
overnight hours, with CAMs consistently showing enough lift and
instability to support convection across the northern half of
the forecast area for much of the night. The next real batch
isn`t forecast to develop until before or just after 06z
tonight. There is quite a bit of uncertainty regarding this
given that there is ongoing convection across GSP`s eastern
counties. However, given that storms really were not long
lasting, thinking more convection is certainly possible tonight
and have continued PoPs in the northern half of the FA as a
result. Temps will be fairly similar to what they have been -
generally mid 70s across the area.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Key Message(s):

- Showers and thunderstorms expected across the eastern half of
  the forecast area on Monday
- Increasing chances of showers and thunderstorms Tuesday

Zonal upper level flow will persist over the CONUS through much
of the short term with some amplification noted late Tuesday and
Tuesday night as ridging builds over the central US and weak
troughing over the eastern US. At the surface the weak and
diffuse boundary will be over the eastern Midlands on Monday
continuing to act as a focusing mechanism. Instability will
again be moderate to strong Monday afternoon with pwat values
remaining in the 2.0 to 2.2 inch range over the central and
eastern Midlands. This will again make for showers and
thunderstorms during the afternoon and evening with much of the
anticipated activity along and south of I-20. Wind gusts will be
the main threat for severe thunderstorms as DCAPE values will
again push toward 1000 J/Kg. The other concern remains the
potential for locally heavy rainfall combining with already
saturated or nearly saturated soils. WPC has much of the central
and eastern Midlands in a marginal risk of excessive rainfall
and with the anticipated convective coverage this seems
reasonable. With sunset expect much of the activity to dissipate
however with the instability and remaining outflow boundaries a
few cells could develop into the early overnight hours. High
temperatures Monday will range from the mid to upper 80s in the
far northern Midlands to the low 90s in the southern Midlands
and CSRA. Lows Monday night will be in the low to mid 70s.

On Tuesday the pattern begins to shift as the upper levels
amplify over the central and eastern US which will put the area
under NW flow aloft. Although this will be ushering some drier
air into the area models are indicating a short wave which will
be moving through the northern portions of the forecast area
which should trigger convection once again for the afternoon and
evening hours. Much will depend on the location of the short
wave as it moves through the region however with slightly drier
air aloft DCAPE values during the afternoon will be rising to
over 1000 J/Kg producing a wind threat from thunderstorms. With
the lower pwat values Tuesday afternoon around 1.8-1.9 inches
the threat of locally heavy rainfall will be slightly lower.
High temperatures Tuesday afternoon will again be in the upper
80s north to low 90s south with overnight lows in the upper 60s
to lower 70s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Key Message(s):

- Slightly cooler temperatures but seasonably dry weather
  expected throughout the middle part of the week.

The upper level pattern amplification will continue as the ridge
builds over the central US with the trough digging along the
Atlantic Coast. This will keep the forecast area under
northwesterly flow and drier conditions for Wednesday and
Thursday. By late in the week low pressure will be marching into
the western Great Lakes with a frontal boundary extending into
the central Gulf States. This system is expected to slow as it
reaches the Great Lakes with the frontal boundary lingering over
the SE US through the weekend. This will once again bring
showers and thunderstorms back into the area however with the
trough over the eastern US and expected cloud cover temperatures
will be slightly lower. Afternoon high temperatures will be
slightly below normal in the mid to upper 80s.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
Generally VFR conditions expected outside diurnally driven
thunderstorms and early morning stratus/fog.

Convection has diminished across the area at 23z with mainly
mid and high debris clouds across the area. There is upstream
convection in the Upstate SC at the moment but think these
showers will weaken as the move southeast toward the CAE/CUB
terminals. With shallow low-level moisture, near calm winds
overnight and decreasing high clouds, fog may develop toward
morning. Guidance is hitting the central Midlands SC with
stratus. Will mention a period of restrictions, possibly LIFR/IFR
during the pre- dawn areas with conditions improving by 14z
Monday. A stationary front remains across the area Monday. As
the air mass becomes moderately to strongly unstable in the
afternoon, scattered thunderstorms are expected to develop near
the front. Winds will be variable 5 to 10 knots.

EXTENDED AVIATION OUTLOOK...Afternoon and evening convection
and associate restrictions will be possible through Friday.
Early morning fog and stratus could occur, especially at fog-
prone AGS/OGB.

&&

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

&&

$$