314
FXUS62 KCAE 191651
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
1251 PM EDT Thu Sep 19 2024

.SYNOPSIS...
Isolated to scattered showers and thunderstorms expected
this afternoon, with highest coverage in the eastern Midlands.
Moisture appears more limited on Friday as high pressure
build south from New England over the weekend into early next
week. Dry and warm conditions through Sunday, then more
seasonable early to mid week.

&&

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

- Isolated to scattered showers and thunderstorms today mainly
  in the east Midlands

The long wave upper trough has finally moved off the Eastern
Seaboard. Still some weak short waves rotating through the
trough providing some lift across eastern SC. Considerable
stratus and fog this morning is dissipating at 16z, and
temperatures are quickly rising through the upper 70s to around
80 degrees. Precipitable water is decreasing across the area
especially in the west Midlands and Piedmont where values around
now around 1.5 inches. Precipitable water values are higher in
the east, 1.6-1.7 inches based on satellite analysis. Cumulus
development is noted in the visible satellite south and east of
the decaying stratus field in the north Midlands. Cumulus is
more enhanced in the east. Models suggest weak to moderate
instability this afternoon, similar to yesterday with Surface
based CAPE 1000-1500 J/jg. Expect widely scattered showers maybe
a thunderstorm focused in the east Midlands this afternoon.
Showers should diminish early in the evening. Any rainfall
should be limited in qpf and brief. Max temps today appear on
track with low to mid 80s across the region with extensive low
clouds diminishing. High low-level moisture remains across the
area tonight. Clearing aloft may result in fog tonight. The HRRR
suggests the central and north Midlands/Pee Dee for fog late
tonight and early Friday morning. This potential fog has
support from the NBM. Overnight lows in the mid 60s appears on
track.

&&

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

- A drying and warming trend into this weekend.

A weak upper level trough slowly lifts offshore on Friday and
is replaced by northwest flow aloft this weekend. Precipitable
water levels range from 1.25 to 1.5 inches despite the
increasing subsidence and drying aloft.

The region is at the tail end of the pulse convection season,
therefore an isolated diurnal shower or two cannot be ruled out
given the low level moisture and shortwave troughs moving down the
backside of the departing upper level trough. The best chance for an
isolated shower is on Friday with lesser chances this weekend.

Temperatures will warm with increasing H5 heights to 5 to 10 degrees
above late September climatology. Any precipitation with the
isolated showers should be less than one tenth of an inch.

&&

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

- Warm and dry weather expected to start the fall season.

The deterministic and probabilistic ensembles models depict above
normal H5 heights building into the Southeast U.S. from the Gulf of
Mexico into the middle of next week. This should lead to dry weather
and above normal temperatures.

The models diverge on solutions by next Wednesday with the handling
of an upper level trough over the Ohio River Valley. There could a
be a chance of showers Wednesday and Thursday. The models also
differ on the timing and trajectory of a potential tropical system
moving into the Gulf of Mexico at the end of the forecast
period.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...

VFR conditions expected through 06z. Ceiling and visibility
restrictions possible toward 12z Friday.

High pressure will be building in from the north with drier air
aloft spreading into the area. Ceilings are improving across
the area and becoming VFR. Low- level moisture remains high and
expect scattered to broken strato-cumulus across the area
through the afternoon then dissipating/scattering out around
00z. Winds light from the north-northeast. A few widely
scattered showers or thunderstorms are possible this afternoon
but should stay east of the terminals, closer to the Coastal
Plain. Guidance is suggesting ceiling and visibility
restrictions late tonight with fog developing across the north
Midlands after 06z then developing into the central SC toward
12z Friday. Low clouds/fog expected to lift by 14z Friday.

Extended Aviation Outlook...Drier air over the region will
limit the chance of restrictions through the weekend before
moisture begins to increase early next week.

&&

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

&&

$$