Areal Flood Advisory 77, NWS Columbia, SC

Area Forecast Discussion
National Weather Service Columbia SC
1251 PM EDT Wed Sep 8 2021

.SYNOPSIS...
Ample moisture and instability across the area will result in
afternoon and evening showers and thunderstorms today. A cold
front will move through Thursday, with drier conditions
returning Friday lasting into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
The axis of an upper level trough will be west of the area
today. This will provide some support for convection over the
forecast area, possibly enhanced by shortwave energy at times.
The surface front associated with the upper trough will remain
to our NW through the near term, but a prefrontal convergence
zone will trigger thunderstorm development in the afternoon.
PWAT values near 2 inches will also support showers and
thunderstorms. Given ample moisture, surface convergence and
weak upper level support, we expect numerous showers and
thunderstorms to develop this afternoon and linger into the
evening. However, the threat for severe weather appears low.
Boundary layer heating will be hampered by extensive cloud
cover, leading to a tall skinny CAPE profile. Mid level lapse
rates are weak as well. This setup would typically favor a
threat of isolated heavy rain but not widespread severe weather.
High temps today will be in the mid to upper 80s.

There will be a chance of rain throughout the night as the
surface front approaches the region. An upper level shortwave
may also increase the convective coverage outside of the
diurnally favored time period. The HREF ensemble members are
generally in agreement on keeping a few showers in the area even
though they differ in placement. With abundant moisture from
rainfall and mostly cloudy to overcast skies expected, lows
should be mild, near 70 degrees or in the low 70s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A trough and its associated cold front passes through the
region on Thursday. These features should keep the disturbance
in the Gulf of Mexico to our south and east limiting any
potential impacts. While the entire forecast area could see
showers and thunderstorms Thursday, PoPs decrease behind the
front from northwest to southeast meaning that the highest
rainfall amounts should be closer to the coast which will be the
last to clear out. Rainfall should end across our area by
Thursday evening. With unsettled weather in place during the
daytime hours, high temperatures should only manage to reach the
mid-eighties. Temperatures Thursday night will fall into the
lower to mid sixties. An extended period of dry weather begins
on Friday as the trough moves off the coast. Highs on Friday
should once again be in the mid-eighties with lows on Friday
night dropping into the lower sixties.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Dry conditions dominate the long term as ridging builds into
the region. Temperatures are expected to increase by a few
degrees each day with values reaching the lower nineties
regionwide on Monday. The moisture gradually increases during
the long term as well with muggy conditions returning early next
week. It appears that the rain chance will remain low until at
least mid-week.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Ample moisture, surface convergence and weak upper level
support will support numerous showers and thunderstorms this
afternoon. There's a moderate chance of thunderstorms and
associated restrictions at all terminals this afternoon and into
the early evening. Winds will generally be out of the south-
southwest, 5-7 knots with some gusty winds in any thunderstorms
that develop.

A few showers and thunderstorms should linger overnight as a
front approaches from the NW. At this point convective coverage
appears to be low enough to remove mention of VCTS for the
overnight period. Models are showing deteriorating cigs
overnight. Ample low level moisture and a 20 kt LLJ would tend
to point to a low ceiling threat rather than fog. Extended
periods of MVFR ceilings appear likely at all TAF sites but
confidence is not as high in seeing IFR or LIFR conditions.
These restrictions may continue through portions of Thursday
morning, near the end of the TAF period.

EXTENDED AVIATION OUTLOOK...Possible restrictions from early
morning fog/stratus and diurnal convection continue Thursday.
Drier air moves in Friday and for the weekend.

&&

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

&&

Hazardous Weather Outlook
National Weather Service Columbia SC
357 AM EDT Wed Sep 8 2021

GAZ040-063>065-077-SCZ016-018-020>022-025>031-035-037-038-041-115-
116-135>137-090800-
Lincoln-McDuffie-Columbia-Richmond-Burke-Chesterfield-McCormick-
Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-Richland-Lee-
Aiken-Sumter-Barnwell-Calhoun-Clarendon-Bamberg-Northern Lancaster-
Southern Lancaster-Northwestern Orangeburg-Central Orangeburg-
Southeastern Orangeburg-
357 AM EDT Wed Sep 8 2021

This Hazardous Weather Outlook is for the Midlands of South Carolina
and the Central Savannah River area of Georgia.

.DAY ONE...Today and tonight.

A few strong storms may be possible this afternoon along a weak
surface front. The main hazard would be strong wind gusts and
possibly some heavy rainfall.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service Columbia SC
145 PM EDT Wed Sep 8 2021

SCZ025-030-081830-
Aiken SC-Edgefield SC-
145 PM EDT Wed Sep 8 2021

...A strong thunderstorm will impact portions of southeastern
Edgefield and northwestern Aiken Counties through 230 PM EDT...

At 144 PM EDT, Doppler radar was tracking a strong thunderstorm over
Belvedere, moving northeast at 10 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Aiken, North Augusta, Aiken Mall, USC Aiken, Citizens Park, Aiken
Municipal Airport, Edgefield County Airport, Graniteville,
Burnettown, Trenton, Poverty Hill, Murphys Estates, Ninety Nine
Islands and Savannah Bluffs Heritage Preserve.

This includes the following highways...
 Interstate 20 in South Carolina between mile markers 0 and 25.
 Interstate 520 in South Carolina between mile markers 16 and 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3384 8174 3355 8152 3343 8191 3346 8193
      3349 8199 3350 8199 3356 8205 3358 8208
TIME...MOT...LOC 1744Z 246DEG 10KT 3356 8194

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

CJR