711
FXUS62 KCAE 041024
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
624 AM EDT Thu Jul 4 2024

.SYNOPSIS...
Moisture increases through the week and into the weekend with
isolated to scattered showers and thunderstorms possible each
afternoon. Above normal temperatures are expected and Heat
Index values around 110 are possible Friday into the weekend.
Atmospheric moisture remains high through the long term
supporting a chance of rain each day.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- Hot with heat indices between 100-105 this afternoon.

Water vapor imagery early this morning shows ridging aloft
continues to pivot across the area, driving northwesterly flow
aloft. PWAT`s are relatively low compared to points west of us,
between 1.5"-1.8", thanks to prior day`s easterly component
flow. PWAT`s and surface dew points will start to steadily climb
today as southerly low level flow develop with the ridge
shifting east. Regardless of moisture, another hot day is
expected with temps pushing 100F as mid-level dry air and broad
subsidence will allow for strong heating. The combination of
deep, dry mixing and mid-level capping should nearly any
convective activity this afternoon with the entire area less 15%
PoP`s.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
Key Message(s):

- Heat Indices as high as 110 degrees. A Heat Advisory may be
  needed.

- Increasing chances of showers and thunderstorms this weekend

Friday and Friday Night: The upper ridge will weaken a bit
across the Mid-Atlantic on Friday as a closed upper low moves
into the Great Lakes region. A frontal boundary will push into
the Appalachians but will remain well west of our area. Ahead of
the front, moisture will be pooling over western NC and Upstate
SC, with PWAT values at or above 2 inches, with slightly lower
PWATs over the Midlands around 1.8-1.9 inches. There is not much
in the way of upper forcing to aid in convective initiation so
expecting isolated to scattered diurnal convection to develop in
the afternoon, favoring the western Midlands and upper CSRA
closer to the deeper moisture. Instability is generally limited
with a skinny CAPE profile and some mid level capping that
should limit the severe threat.

High temperatures are forecast to be in the upper 90s to around
100 degrees, and this combined with dewpoints in the 70s should
be enough to yield possible heat advisory conditions with heat
indices as high as 110 degrees.

Saturday through Sunday night: The upper low moving through the
Great Lakes region will push eastward into New England on
Saturday with the southern extent of the shortwave energy and
upper forcing staying well to our north across the eastern Ohio
Valley and into the Mid-Atlantic through Saturday night.
However, the axis of high PWATs is forecast to shift into the
central Carolinas with operational models suggesting values as
high as 2.5 inches, while the LREF mean is slightly lower around
2.2 inches. Nevertheless, the combination of high temperatures
again in the upper 90s to near 100 degrees and increased
moisture should result in better chances of diurnal convection
and will carry likely pops on Saturday. Cannot rule out the
possibility of isolated severe storms with increased instability
compared to Friday, though wind shear remains weak with 0-6km
shear less than 20 knots.

The frontal boundary to our west pushes near the forecast but
is expected to stall over the western part of the area or just
to our west. This will serve as a focus for convection and
expect storms to linger into the evening hours in its vicinity
while it provides a locally heavy rain threat. Depending on the
timing of convection and cloud cover heat indices could approach
advisory criteria again, especially in the eastern Midlands.
Similar expectations for Sunday with very high atmospheric
moisture with PWATs at or above 2 inches expected with scattered
diurnal convection expected with the surface boundary near the
area. Temperatures should be a bit cooler given extensive cloud
cover and precipitation.

&&

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

- Heat Indices over 100 degrees

- Daily diurnal convection expected

Little change in the forecast thinking regarding this period.
Ensemble guidance continues to show positive 500mb height
anomalies over the southeastern states with the presence of a
persistent upper ridge in place while upper level troughing
remains over the center of the country. Abundant atmospheric
moisture remains in place with surface high pressure centered
over the western Atlantic with PWATs forecast to be at or above
2 inches. This should result in a typical summer regime with
daily diurnal showers and thunderstorms. Cannot rule out
isolated severe storms but do not currently see any signal for
widespread severe weather under the influence of upper ridging.

Temperatures during this period should be near to above normal
with highs in the low to mid 90s and lows in the low to mid 70s.
The combination of warm temperatures and dewpoints in the 70s
likely will result in continued heat indices over 100 degrees
next week.

&&

.AVIATION /10Z THURSDAY THROUGH MONDAY...
Some brief vsby restrictions at AGS this morning, VFR
conditions expected the rest of the TAF period.

High cirrus continues to move across the area, helping prevent
any low cloud cover or fog as of 11z. AGS is seeing its typical
sporadic morning vsby issues that will likely linger through
11-12z, but beyond that no other restrictions are expected
through the TAF period. Winds will pickup out of the south for
all sites mid- morning, 5-7 knots with some typical summer cu
field development between 4000-5000 ft. Some stratus is possible
Friday morning but confidence far too low for any mention in the
TAF`s yet.

EXTENDED AVIATION OUTLOOK...Increasing chances of showers and
thunderstorms and associated restrictions Friday through
Monday.

&&

.FIRE WEATHER...
Key messages(s):

-Hot and dry conditions continue through Independence Day.

-Rainfall probabilities increasing Friday through early next
 week.

Hot and dry conditions will continue through Independence Day
with increasing moisture and chances of showers and
thunderstorms Friday into early next week. Although there was
some rain late in the weekend and into early this week the hot
and dry conditions over the past few days and through Thursday
will generally minimize any improvement from the rain. Moisture
will begin increasing Thursday but rain chances will hold off
until Friday with scattered afternoon and evening thunderstorms
mainly along and north of I-20 then spreading eastward Saturday
into early next week. Temperatures will also be a concern with
afternoon highs in the upper 90s to around 100 which will push
heat index values to around 105 Thursday and 110 Friday and
Saturday.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
FIRE WEATHER...