000
FXUS62 KGSP 260309
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1009 PM EST Tue Jan 25 2022

.SYNOPSIS...
Dry and colder Canadian high pressure settles across the region
Wednesday into Friday. A low pressure system moves up the Atlantic
coast Saturday as a cold front crosses the area from the northwest.
High pressure returns behind the low into the first half of next
week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 10 pm EST: No changes of note have been made on the regularly
scheduled late evening update. The latest surface analysis depicts a
cold front just southeast of I-85 that continues to push slowly
southeast across the GA/SC Piedmont. The near term models continue
to indicate a narrow band of shallow upglide around 850 mb over the
frontal zone overnight. This will probably be sufficient to produce
some cloud cover, but not enough for any precipitation overnight as
the boundary layer dries out from the north. IR satellite imagery
also shows modest low-level northwest flow upslope moisture near the
spine of the southern Appalachians. However, cloud top temperatures
are running minus 2 to minus 6 C and the moisture is probably too
shallow to wring out any light snow near the Tennessee border. The
developing clouds may keep minimum temperatures from crashing
overnight and forecast mins will be held near to slightly above
climo in most areas despite the weak cold advection.

Sprawling high pressure will build from the Midwest to the central
Appalachians through Wednesday, with a surface ridge nosing soutward
into our region and keeping thicknesses on the cool side. Expect
afternoon highs to only reach the lower 40s in the northern Piedmont
and mtn valleys Wednesday, while the GA/SC zones will top out in the
upper 40s to near 50.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 155 pm Tuesday: Below normal temps will turn in the wake of
the cold front for the early part of the short term, with good
radiational cooling conditions likely yielding min temps 5-10
degrees below climo Wed night. Temps will likely average around 5
degrees below normal for the duration of the period.

The next weather of note (really the only weather of note for the
next 7 days) for our forecast area still looks to occur during the
Fri/Fri night time frame, when a series of strong speed maxima
originating from western North America are expected to carve out a
deep/progressive upper trough across the East by the end of Friday.
There remains a strong consensus in operational model guidance that
the evolution of this feature to a neutral/negative tilt, and
resultant coastal "bombogenesis" will occur too far east for
significant precip to occur over our area. However, most guidance
sources also suggest some potential for light precip to develop
within an area of frontogenetical forcing west of the developing
cyclone Fri night, while ingredients also appear favorable for
accumulating NW flow snow showers across the mountains late Fri into
early Saturday. So, while a light snow event is still very possible,
esp across the mountains and across eastern portions of the CWA,
confidence is steadily increasing that a more significant event is
unlikely to occur.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 215 pm Tuesday: Very cold weather is anticipated for the start
of the extended period, with strong cold air advection in the wake of
the East Coast bomb expected to yield temps a solid 10-15 degrees
below climo through Sat night. Conditions will then steadily
moderate through early next week in response to a changing large
scale pattern favoring a western trough/developing East Coast ridge.
That being the case, temps are expected to warm to around normal by
Day 7/next Tuesday. Otherwise, dry/uneventful weather can be
expected through the period.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Expecting VFR conditions through the period,
although a few MVFR-level cloud bases could flirt with KAVL
overnight given the upvalley flow and shallow moisture to the west.
With the passing cold front settling southeast of the TAF sites,
surface winds will turn to NE at all sites overnight, with NW flow
and low-end cold advection gusts at KAVL. Weak upglide aloft will
produce a VFR stratus/stratocumulus field through the nighttime
hours, but the drying boundary layer should preclude any
restrictions. Steady NE flow will continue through Wednesday with
stratus and stratocumulus slowly dissipating with time as profiles
dry.

Outlook: Dry high pressure remains over the area through Thursday.
Flight restrictions may develop Friday into Friday night as a moist
low pressure system develops near the coast. Dry high pressure will
return over the weekend.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$
SYNOPSIS...DEO
NEAR TERM...HG/Wimberley
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...HG/Wimberley

NWS GSP Office Area Forecast Discussion