Sumter, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

494
FXUS62 KCAE 211948
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
248 PM EST Thu Nov 21 2024

.SYNOPSIS...
A drier and colder airmass will settle across the region into
the weekend. Gusty winds are expected once again this morning
and into the afternoon hours, with gusts of 30-40 mph possible.
Dry weather continues this weekend, with slowly rebounding
temperatures across the area.

&&

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

- Colder and drier air continues to settle into the region.
- Strong and gusty winds will remain into this evening.
- Freezing temperatures expected over the northern Midlands
  tonight.

Clear skies across the region this afternoon as a potent cold
front has moved offshore. Much drier air has filtered into the
region, evident in dewpoints in the 20s to around 30 and
satellite PWAT estimates around 0.25". The synoptic setup boasts
a well-developed low pressure system across the Mid-Atlantic and
New England regions. Both strong low level winds (VWP speeds of
30-40 kts at 1.5-2kft MSL) and a tight pressure gradient over
the area are generating gusty west winds, generally between 15
and 20 mph with gusts around 30 mph. Its possible we still could
see some higher gusts this afternoon or this evening, and so the
Lake Wind Advisory remains in effect through 7 PM EST. Cold
advection has kept temperatures cool despite abundant sunshine.
Highs so far this afternoon have reached the upper 50s or 60 in
a few locales.

Though windspeeds and gusts will diminish some overnight, we`re
still expecting speeds around 10 mph to continue much of the
night. This will continue to bring cold air into the region,
though the potential of the cold air may be tempered some by the
winds keeping things mixed. In terms of temperatures, there is
still a large area of greater than 50% probability of less than
33 degrees for lows tonight across the northern Midlands from
the NBM. Other guidance didn`t make the forecast much clearer,
with lows generally ranging from 31 to 35 degrees across the
same areas. While the impacts are not likely to be widespread or
long-lived, still felt that as one of our coldest nights so far
this season, an upgrade from the Freeze Watch to a Freeze
Warning was supported. The rest of the forecast area should fall
into the middle 30s. Frost is possible, but should be limited
with max RH values of 65 to 75 percent, reflective of our very
dry environment.

&&

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

- Cooler Friday with breezy conditions possible into Friday   night.
- Temperatures rebound slightly on Saturday, but frost remains
possible late Saturday night.

Strong upper low and associated surface low pressure system over the
Northeast are expected to gradually shift eastward through the short
term period. Upper ridging and surface high pressure slowly move in
from the west as well. As a result, there will likely be a fairly
strong pressure gradient on Friday, leading to breezy northwest to
west winds in the afternoon. However, with the low pulling away
somewhat, the gradient and winds are expected to be a bit weaker
than Thursday. The downsloping winds bring another sunny day to the
area, which will aid in good mixing as well, resulting in gusts in
the 20-30 mph range.
The highest gusts are anticipated in the northern portions of the
forecast area. Conditions remain borderline on the need for a Lake
Wind Advisory Friday evening, so we`ll keep monitoring for the need
to issue one, but will wait at least until the current Lake Wind
Advisory expires. With the ridging edging further eastward,
temperatures rebound slightly on Saturday and winds continue to
subside.

Overnight lows are expected to be on the chilly side both Friday and
Saturday nights. There is some uncertainty of just how cold we`ll
get Friday night, but there is potential for a few spots to see hit
the freezing mark early Saturday morning. The main factors that
would prevent locations from hitting the freezing mark are that
ridging is expected to bring in slightly higher heights, thus warmer
air, and winds are not expected to become calm overnight, limiting
the radiational cooling factor. While still chilly, lows Saturday
night are forecast to be slightly warmer than Friday night.

&&

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

- Gradually warming but dry pattern into early next week.
- A bit more unsettled weather possible by midweek.

Confidence remains high that dry conditions and a gradual warming
trend continue into the first half of the work week as both
deterministic and ensemble model solutions are in good agreement
that upper ridging and surface high pressure move over the area.
Uncertainty creeps back into the forecast for Thanksgiving and the
end of the week as a trough and surface frontal boundary approach
the region.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR is forecast for the entire period.

Dry airmass over the area will keep skies clear and negate any
threat for reduced VSBYs. Biggest issue through the period will be
the winds and associated gusts. West winds of 10-15 kts with gusts
of 20-30 knots are expected into this evening. Gusts then diminish
but sustained speeds remain elevated overnight around 10 kts.
West/northwest winds increase again on Friday at 10-15 kts with
gusts of 20-25 kts, so perhaps slightly weaker compared to today.

EXTENDED AVIATION OUTLOOK...Strong and gusty winds expected again on
Friday with gusts in excess of 25 knots possible. Otherwise, no
significant aviation impacts expected through the weekend.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Lake Wind Advisory until 7 PM EST this evening for SCZ016-018-
     020>022-025>031-035-037-038-041-115-116-135>137.
     Freeze Warning from 3 AM to 9 AM EST Friday for SCZ016-020>022-
     029-115-116.
GA...Lake Wind Advisory until 7 PM EST this evening for GAZ040-
     063>065-077.

&&

$$