100
FXUS62 KCAE 080757
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
357 AM EDT Mon Jul 8 2024

.SYNOPSIS...
Abundant moisture combined with an unstable air mass should
support scattered to numerous showers and thunderstorms
for each afternoon and evening through much of the week. Above
normal temperatures are expected again, with Heat Index values
above 100 each day through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key message(s)

- Slow moving storms/potential for isolated flash flooding.
-Heat index near 105 degrees.

Convection is diminishing across the area early this morning.
Radar at 07z is showing some light showers in the northern Midlands
associated with mesoscale vortex feature. Expect pops to decrease
through mid morning. Upper level heights rise a bit today which
could be a limiting factor for afternoon convection.
However, the air mass will remain quite moist today with soundings
indicating a deep "warm Layer" and moderate long thin CAPE, 1500-
2500 J/kg surface based as temperatures rise into the low 90s.
Precipitable water remains above 2 inches, perhaps around 2.25
inches, with higher moisture to the east near the coastal plain.
This is about 130-140 % of normal, above the 99.5 percentile for
this time of year (NAEFS). There is a weak diffuse frontal boundary
across the area, probably setting up/remaining near the SC Piedmont.
Trigger appears to be lacking other than low level convergence
possibly near the frontal boundary or in the east associated with a
weak seabreeze. CAM models suggest convective coverage will be much
less than yesterday evening with a focus in the east where moisture
is a little deeper. Went with chance pops all areas mainly this
afternoon and evening. The main threat will be locally heavy rain
and potential for flash flooding. Heat index values near 105 degrees
before any convection. Muggy again tonight with lows in the mid to
upper 70s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Key Message(s):

- Anomalously high atmospheric moisture
- Scattered to numerous showers and thunderstorms.
- Isolated Flash Flooding threat continues

The remnants of Beryl will be lifting northeastward through the
Mississippi Valley into the western Ohio Valley on Tuesday with
a slight weakening of the upper ridge over the southeast states
while another closed low over the western Atlantic moves
southwestward toward the Florida coast. Copious amounts of
moisture remain over the forecast area this period with PWATs
well above 2 inches aided by persistent south to southwesterly
low level flow. Expect continued diurnally based afternoon and
evening convection each day possibly favoring the southeast
Midlands and CSRA where an active sea breeze pushes inland late
in the afternoon into evening hours. The NBM pops continue to be
quite high given a lack of upper forcing or features to trigger
convection so have generally high chance pops each day with
likely pops in the southeast Midlands and CSRA on Tuesday and
mainly southeast Midlands on Wednesday. Temperatures are
expected to be slightly above normal with highs expected in the
mid 90s which will combine with high dewpoints to result in heat
index values between 100-105 degrees. Overall severe threat
appears low but cannot totally rule out an isolated strong to
severe storm capable of damaging wind gusts but isolated flash
flooding should continue to be the primary concern given
excessive atmospheric moisture and continued weak shear leading
to slow storm motion and possible training of storms with very
efficient rain rates.

&&

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

- Some drier air briefly moves into the region
- Lower chances of rain over the weekend
- Heat indices over 100 degrees continues

Somewhat of a change in the weather pattern during this period
with some drier air working into the region providing lower rain
chances. The remnants of Beryl which become absorbed by the
upper trough midweek should be lifting into the Great Lakes on
Thursday while a weak frontal boundary shifts eastward into the
Carolina Piedmont. PWATs drop below 2 inches for the first time
in a while on Thursday and the combination of drier air and
upper ridging should result in lower pops in the chance range,
favoring the eastern Midlands where the higher PWATs will
reside. A weak surface low may develop along the boundary on
Friday over our area promoting some moisture advection off the
Atlantic across the Pee Dee region and expect slightly higher
pops with a gradient from the Pee Dee to lower pops in the CSRA.


Ensembles are in reasonable agreement showing positive 500mb
height anomalies over the weekend as the 500mb flow becomes more
zonal which should continue to favor lower atmospheric moisture
with PWATs near normal at values below 2 inches. This should
result in a fairly typical summer like pattern with isolated to
scattered diurnal convection with daytime heating in the absence
of upper level features. Temperatures are expected to be above
normal in the mid to possibly upper 90s on Thursday followed by
near normal high temperatures in the lower to mid 90s into the
weekend.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Restrictions early this morning with showers moving to the east
of the terminals and low clouds/patchy fog toward morning.

Deep moisture across the area this morning with a weak diffuse
frontal boundary near the area. Showers are moving to the east
of the terminals at 06z, and visibilities likely to improve.
However, Satellite and observations indicating patchy areas of
MVFR ceilings developing. Guidance is suggesting MVFR ceilings
will develop closer to 12z and continue through about 14z.
There is some potential for IFR ceilings but confidence lower.
Expect VFR by 15z with scattered to broken cumulus through the
day. Scattered showers and thunderstorms are expected this
afternoon, especially after 19z. Winds will be light and
variable through the period.

EXTENDED AVIATION OUTLOOK...Restrictions possible in diurnally
driven showers and thunderstorms each day as well as early
morning fog and stratus.

&&

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

&&

$$