891
FXUS62 KCAE 031846
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
246 PM EDT Wed Jul 3 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 through Sunday.
Atmospheric moisture remains high through the long term
supporting a chance of rain each day.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):
- Low-level Moisture increasing tonight

Strong upper level ridge extending from southeast TX northeast
across the Deep South to SC. At the surface, a pressure ridge
centered off the coast of the Mid Atlantic and New England extends
into the Carolinas and Georgia. Satellite and observations confirm
that drier air remains across the area at the moment with higher
moisture confined to the coastal SC and GA. Strong subsidence across
the area is leading to higher temps this afternoon than yesterday,
low to mid 90s. The surface ridge will shift east tonight and the
low-level moisture will increase, especially in the SC Piedmont
where south/south-westerly flow will be a little stronger around
ridge. Expect precipitable water to rise above 1.6-1.7 inches
overnight. Skies mainly clear overnight although some patchy stratus
may develop toward daybreak due to increase in low-level moisture.
Guidance temps consistent with lows in the low to mid 70s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Key Message(s):
- Heat Index values up to 110 possible Friday. A Heat Advisory may
be needed.

Upper level ridging will build over the Forecast Area (FA) during
the short term as low level moisture increases through southerly
flow. The main concern for the period will be Friday afternoon where
Heat Index values should reach the 105 to 110 range. With PWAT
values increasing to near 2 inches on Friday and upper ridging over
the FA there should be sufficient heat and moisture to raise
heat-related illness concerns and may prompt a Heat Advisory.
Thursday afternoon appears too dry to meet criteria with
afternoon dewpoints mixing into the 60s.

Showers are unlikely Thursday due to a drier airmass and warm temps
aloft. However we can`t rule out an isolated shower or weak
storm in the afternoon. A low number of HREF and SREF members
have convective precipitation on Thursday afternoon. On Friday,
with temperatures reaching near 100 degrees, closer to the
convective temperature, and PWAT values from 1.75 to 2 inches,
we are more likely to see isolated or widely scattered storms.
Forecast soundings show a tall, skinny CAPE profile indicating
limited potential for severe weather.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Key Message(s):
- Increased risk of heat-related illnesses this weekend
- A Heat Advisory may be needed Saturday and Sunday

Moisture continues to increase through the weekend with hot and
humid conditions expected through early next week. Heat Index
values on Saturday and Sunday of around 110 degrees are
possible. Considering non-environmental factors of being a
holiday weekend and increased exposure, the risk of heat-related
illnesses could be higher than normal. A Heat Advisory may be
needed for Saturday and Sunday. However the possibility for
decent convective coverage does limit confidence in reaching
criteria.

Ridging should remain over the Southeast despite an upper
trough expected to move through the Great Lakes region Friday
and into northern New England on Saturday. A frontal boundary,
associated with the trough, will approach the Southeast with
significant moisture pooling over our FA. This pattern supports
increasing rain chances in the long term with PWAT values
slightly above normal. The upper ridge may limit widespread
convection, but we should see a chance of rain each day through
the extended. The highest rain chances may be Sat and Sun with
the weak frontal boundary in the vicinity before it becomes
diffuse early next week. Isolated strong or severe storms are
possible as afternoon CAPE values increase due to the
higher moisture. Near or above normal PWAT values continue
through the end of the forecast period supporting climatological
rain chances through the long term.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR expected through 06z.

The region is under high pressure. Satellite is showing scattered to
broken cumulus clouds extending from the coastal area of SC
southwest to the Savannah River. Fewer clouds in central SC where
the air mass is a little drier. This should continue through the
afternoon, then cumulus will dissipate after sunset. Winds
variable but favoring east-southeast through the afternoon.
Low-level moisture is expected to increase late tonight which
may lead to areas of stratus with MVFR/IFR conditions near 12z
Thursday. The higher probability of stratus appears to be near
the AGS/DNL and OGB terminals. Will add tempo MVFR at those
terminals 09z-13z. Lower clouds mixing out by 15z with scattered
cumulus developing into the afternoon and south-southwest winds
around 5 knots.

EXTENDED AVIATION OUTLOOK...Moisture and
potential for afternoon showers and thunderstorms and associated
restrictions returns through Monday.

&&

.FIRE WEATHER...
Key messages(s):
-Increased Fire Danger.
-Rainfall probabilities increasing over the weekend.

Increased fire danger during the Independence Day Holiday week, with
temperatures well above normal values. Scattered afternoon and
evening thunderstorms, especially by the weekend may aid current dry
conditions.

&&

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

&&

$$