116
FXUS62 KCAE 161821
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
221 PM EDT Mon Sep 16 2024

.SYNOPSIS...
Low pressure moving onshore will spread rain along with breezy
conditions across mainly the central and north Midlands through
tonight. Locally heavy rain possible in the north Midlands and
Pee Dee tonight. The low pressure area will continue to weaken
and remain across the western Carolinas through Wednesday.
Linger showers and seasonable temperatures expected through
midweek. Drier weather expected by the weekend.

&&

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

- Potential Tropical Cyclone 8 brings potential for locally
  heavy rain along the North Carolina border.
- Lake Wind Advisory remains in effect through 2 AM.

Potential Tropical Cyclone (PTC) 8 continues to churn near the
coast or just on shore around the NC/SC border. Latest guidance
has PTC 8 moving somewhere along or near the NC/SC border as it
heads west northwest. Rainfall associated with PTC 8 is
spreading westward into the PeeDee and northern Midlands this
afternoon; however, the heaviest rain has been staying out of
the forecast area at this time. That said, some pockets of heavy
rain are possible this afternoon and evening, mainly in
Chesterfield and Lancaster Counties. Due to the potential for
flash flooding concerns in the Charlotte metro area, did go
ahead with a Flash Flood Watch for the northern panhandle of
Lancaster County from 8 tonight through 8 am on Tuesday. Upwards
of 3" of rain is possible there. Flash flood guidance is pretty
high elsewhere, so don`t think a watch was warranted for
anywhere else. There will likely be a fairly sharp gradient with
rainfall amounts due to some dry air being entrained into the
system. Areas to the north could see 2-3", while areas around
Columbia are forecast to see around 0.5" or so, and locations
such as Augusta and Orangeburg might not get any rain (or very
little). There also remains a decently strong pressure gradient
between the center of PTC 8 and a surface high over the
Northeast, which is bringing some gusty winds to the area. Winds
are anticipated to gust up to 35 mph at times generally north
of the I- 26 corridor, with an isolated gust higher than that
possible. Therefore, have kept the Lake Wind Advisory going
through 2 AM. Winds and rainfall intensity are anticipated to
diminish late tonight or early tomorrow morning. Temperatures
overnight are expected to be in the mid 60s for the most part.

&&

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

- Lingering showers both days more likely focused in the north
  Midlands and Piedmont

- Cooler than normal temperatures in the north Midlands/Piedmont
  Tuesday then warming Wednesday

Vertically stacked/slowly filling mature low pressure system
will be near the area, probably in the western Carolinas into
Wednesday. Lingering diurnally driven showers expected to focus
in the Piedmont and north Midlands Tuesday where moisture and
lift more evident. In-situ shallow wedge conditions with
isentropic lift expected in the SC Upstate into the
Piedmont/extreme north Midlands with ridge to the north
extending into the western Carolinas and surface low/front
across the Midlands. Drier air may advect into the southern
Midlands/CSRA but in general expect precipitable water values to
remain above 1.5 inches. Upper low remains over the area
Wednesday, moving slowly east. There may be an increase in
moisture in weak south 850mb flow. Coupled with short waves
rotating around low, lift appears sufficient for scattered
showers mainly in the afternoon as diabatic heating increases
leading to weak instability. Isolated thunderstorms possible
mainly Wednesday with weak instability noted. Stayed near the
NBM mean temps. Wide range of temperatures Tuesday with mid 70s
north to mid 80s south. Temperatures warmer Wednesday into the
low to mid 80s across the area. Overnight lows both nights in
the low to mid 60s.

&&

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

-Trending drier for the weekend.

Model ensembles in pretty good agreement with upper trough
taking on positive tilt and moving to the SC coast by late
Friday into the weekend. Moisture becoming more limited and
surface high building into the area. Diurnally driven showers
expected to be more isolated and focused near the coast.
Temperatures appear seasonable then maybe slightly cooler than
normal by next week.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Generally MVFR conditions become IFR overnight before improving
again after daybreak.

Generally MVFR cigs continue at CAE, CUB, and OGB through about
06z, then IFR cigs are anticipated, which is later than
previously forecast. A few passing showers may lower vis at CAE
and CUB over the next few hours. More steady rain is then
expected to move over those terminals. Confidence has decreased
that OGB will see shower activity, so only have VCSH there for
now. The chance for showers over or near AGS and DNL is too low
to include in the TAF for now. North winds gusting to around 25
kts are expected through around 23z before transitioning to
northwest winds. Winds are expected to continue veering
counterclockwise and diminishing as PTC 8 passes to the east and
north.


EXTENDED AVIATION OUTLOOK...Drier air will push into the region
this week lowering rain chances. However lingering moisture
leaves the door open for early morning restrictions.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Lake Wind Advisory until 2 AM EDT Tuesday for SCZ016-020>022-
     027>029-031-037-038-115-116-135>137.
     Flood Watch from 8 PM EDT this evening through Tuesday morning
     for SCZ115.
GA...None.

&&

$$