457
FXUS62 KGSP 221925
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
225 PM EST Wed Jan 22 2025

.SYNOPSIS...
Arctic high pressure slowly weakens through the end of the work
week. The air mass will gradually modify by this weekend with
temperatures returning to around normal along with a return of
precipitation chances Sunday night and Monday morning. Dry and above
normal temperatures expected through the middle of next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Key Messages:

1) Dry conditions remain today with cold air still in place across
the region.

As of 150 PM EST Wednesday: A much quieter start to the near term as
the system that brought snow departs from the coastline. Behind it,
clear skies for the afternoon and into the evening hours.
Synoptically, the upper winds go rather flat before the back end of
the upper trough swings toward the area into Thursday. Light winds
continue today and become calm overnight for areas east of the
mountains. Cold air remains in place, but because the winds are
anticipated to be light to calm, wind chills are not looking to be
an issue. So, not as cold as last night. By Thursday, a dry frontal
boundary approaches the area and clouds return. Given the lack of
moisture in this Arctic air mass, this should pass uneventfully. No
precipitation is anticipated during the near term. Temperatures
tonight reaching the teens and lower 20s. For Thursday, the warming
trend begins as daytime highs for most of the area rise well above
freezing. Most of the Upstate could reach the low 40s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 150 PM Wednesday: A short wave crosses the area Friday taking
the upper trough with it. Zonal flow sets up for Saturday. The short
wave pushes a weak front across the area Friday with high pressure
building in on Saturday. There will be an increase in low level
moisture across the mountains Thursday night into Friday, along with
northwesterly flow and CAA. This will lead to clouds but uncertain
whether moisture or orographic lift will be enough for snow showers.
All the guidance differs on PoP and timing, so have limited the
mention to flurries for now. Otherwise, dry and mostly clear
conditions expected across the area. Lows will be nearly steady 10
to 15 degrees below normal. Highs around 10 degrees below normal
Friday rise to around 5 degrees below normal Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 210 PM Wednesday: Zonal flow remains over the area Sunday with
split flow developing Monday as a weak northern stream system brings
a shallow trough back to the eastern US. Another short wave drops
through the trough Tuesday but remains north of the area. A flat
ridge moves in Wednesday as a southern stream low pressure system
moves from the west coast to the 4 Corners region. At the surface,
high pressure slides east Sunday as a weak cold front drops into the
area by Monday then slowly moves south Tuesday and Wednesday. A weak
weave of low pressure moves along the front. The models agree on
this overall scenario. The difference is in the amount of moisture
associated with the front. The ECMWF is dry with little to no
precip. The GFS is the wettest with precip moving in Sunday night
and out of the area by Monday afternoon. The Canadian is in between
with precip, just not as much as the GFS. Have gone with the
guidance blend given the uncertainty. This means chance PoP is
limited to Sunday night and Monday morning. Thermal profiles would
suggest some wintry precip is possible, mainly for the mountains.
Any amounts are highly uncertain, especially since the ECMWF is dry.
Highs will be around normal Sunday and Monday and above normal
Tuesday and Wednesday. Lows below normal Sunday morning, bounce
around near normal the rest of the period.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR conditions prevail through the TAF
period.High pressure returns to the area and keeps skies SKC. No
vsby/cig restrictions anticipated as well. This afternoon, winds
toggle NE/SE before becoming calm this evening and overnight east of
the mountains. KAVL swings back NW/N after 14z Thursday, but remains
light. KCLT also toggles NE before becoming calm overnight and
coming back up out of the SW after daybreak. All in all, light to
calm winds and no restrictions.

Outlook: VFR conditions prevail as broad high pressure builds back
over the region today and lingers through the weekend.

&&

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

&&

$$

SYNOPSIS...RWH
NEAR TERM...CP
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...CP