Sumter, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

536
FXUS62 KCAE 231938
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
238 PM EST Sat Nov 23 2024

.SYNOPSIS...
A dry, cool but moderating air mass will remain across the
region through the weekend. A cold front with limited moisture
will move through the area Tuesday with perhaps a few isolated
light showers. A stronger cold front will move through the area
Thursday night with scattered to numerous showers. Temperatures
will warm to above normal until Friday as the stronger cold front
pushes offshore.

&&

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

- Continued dry and cool today with highs around 60 degrees.

- Areas of frost possible tonight across the entire CWA.

The upper pattern consists of northwesterly flow aloft as flat
ridging approaches from the west. Associated surface high
continues to move east towards the FA during the near term. This
will keep the region dry and on the cooler side with limited
cloudiness. Afternoon temperatures are on track to reach the
lower to mid 60s. For tonight, the combination of light winds
and mainly clear skies will promote widespread radiational
cooling. Blended the NBM 5 percent into the forecast to account
for the temperature bias shown the the guidance. This resulted
in overnight temperatures in the lower 30s in parts of the
Northern Midlands and lower to mid 30s elsewhere. While
widespread subfreezing temperatures are not forecast in counties
remaining in our frost/freeze program, there is the potential
for areas of frost in those counties. With this in mind, have
hoisted a Frost Advisory on Sunday morning for our remaining
counties, in coordination with WFO Charleston. In addition to
the frost potential, would not be surprised if areas of steam
fog develop along area rivers are lakes towards daybreak.

&&

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

- Dry with temperatures continuing to moderate through Monday.

Sunday and Sunday night...Upper level flow becomes more zonal
with short wave ridging over the area. Surface ridge over the
area Sunday morning shifts to the southeast in the afternoon.
The air mass remains quite dry. Low-level flow more westerly
and weak warm advection noted. With weak ridging over the area
continued subsidence. Highs in the mid 60s. Seasonable cool
Sunday night with lows near 40.

Monday...the upper level flow becoming more amplified Monday as
a trough moves east across the Plains toward the Mississippi
Valley. Low-level flow becoming more south-westerly and warm
advection will continue. This trough will push a weak cold front
toward the area Monday night. Modest increase in low-level
moisture with precipitable water near 1.00 inch by Tuesday
morning. A few sprinkles or light showers possible in the
Piedmont toward morning as the front approaches but moisture and
lift appears limited. High temps around 70 and warmer at night
with increasing clouds, lows in the mid 50s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Key Message(s):

- Warm Tuesday with temperatures near normal mid to late week.
- More unsettled weather towards the end of the forecast period,
  including Thanksgiving.

The ensembles and latest deterministic guidance continue to
show the weak cold front moving through the area Tuesday
morning. The models appears to be a little drier this run and
overall do not expect much in the way of qpf with this first
front. Precipitable water briefly increases to around 1.30
inches in the morning but westerly low level flow will limit
moisture flux. Lift appears weak along front and dowslope
developing quickly. So lowered pops slightly from previous
forecast but can`t rule out a few sprinkles or a brief light
shower in the morning, mainly northwest. Afternoon temperatures
above normal.

Ensembles show zonal flow or short wave ridging over the area
through Wednesday with dry conditions and temperatures slightly
above normal. The ensembles show amplified pattern late in the
week as an anomalously deep upper trough extends from the Great
Lakes and Ohio Valley south to the lower Mississippi Valley.
This trough will push a stronger cold front through the area
Thursday night and eventually lead to strong coastal low
pressure in the northeastern U.S. Strong moisture flux ahead of
the front Thanksgiving Day and short wave energy
support numerous showers as the front moves through the area.
Below normal temperatures expected behind the front Friday into
the weekend.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR Conditions Continue....

Very quiet weather continues during the TAF period. Winds will
generally be out of the northwest at or under 10 knots this
afternoon, becoming light or even calm at times tonight. Only
possible hazard will be any radiation fog that drifts over our
sensors at OGB and especially AGS. This could result in brief
visibility reductions but confidence is not high enough to
warrant its inclusion in the TAFs. The favorable conditions
continue into Sunday.

EXTENDED AVIATION OUTLOOK...No significant aviation impacts
expected.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Frost Advisory from 4 AM to 8 AM EST Sunday for SCZ018-025-026-
     030-035-037-038-041-135>137.
GA...Frost Advisory from 4 AM to 8 AM EST Sunday for GAZ040-063>065-
     077.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...