968 
FXUS62 KGSP 160305
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1105 PM EDT Sat Oct 15 2022

.SYNOPSIS...
A weekend warm-up continues for the region as high pressure 
builds across the area ahead of a strong cold front. This strong 
cold front arrives from Kentucky and Tennessee then crosses our 
region on Monday. Much colder air will descend into the area 
bringing the coldest air of the season through the middle of the 
week.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of 1035 PM EDT Saturday: As expected, the area of sct showers 
over NE Tennessee fizzled out as it approached the NC border a
few hours ago. I'm not expecting any additional shower activity
thru the overnight/morning with cloud cover gradually increasing
from the NW Sunday morning. The mostly clear skies and relatively 
low dewpts should allow for good radiational cooling, although 
the pressure gradient may remain sufficient to support areas of 
weak mixing across the Piedmont. The potential is there again
for the sheltered mtn valleys to crater shortly before sunrise. 
Thus, low temps are fcst right around climatology across much of 
the Piedmont and Foothills, and below climo across the valleys. 

Otherwise, a long wave trof over the east will sharpen thru the 
near-term period as a strong speed max digs into the western Great 
Lakes toward the end of the period. This will activate an associated 
baroclinic zone from the southern Great Plains into the Tennessee 
Valley Sunday afternoon and evening. In the interim, another round 
of mostly token chance PoPs are carried across our northern and 
western zones to account for the potential for showers and perhaps 
a thunderstorm or two before the front arrives. Otherwise, high temps 
are expected to be even warmer than Saturday, with values about 6 
to 10 degrees above climo over most areas.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
As of 115 PM Saturday: Broad upper low will bring rapid height falls
into the area through the short term as an attendant cold front 
encroaches the region from the northwest Sunday night. A stout upper 
jetlet and southwesterly flow through the lower half of the 
troposphere will align with the main frontal zone ahead of the cold 
front Sunday night into Monday morning. This should allow for 
scattered showers with a few rumbles of thunder possible with 
elevated instability being indicated in profiles. The cold front is 
expected to slip through the CFWA by Monday afternoon, but if 
guidance tries to push the forward progression back any slower, 
instability may uptick and allow for at least scattered or a broken 
line of convection east of the mountains Monday afternoon due to the 
fropa occurring at peak heating. The best chance would be along and 
east of I-77, but as of now, the cold front is forecasted to 
instigate a fropa before peak heating of the day and thus, should 
lower convective chances and keep PoPs in the forecast until 
daybreak Monday. The best upper forcing will also shift into the 
eastern Carolinas by peak heating as well, which will reduce 
convective chances even more. 

Strong CAA will filter in behind the front as heights continue
to fall and a stout Canadian surface high dips into the central
CONUS. Expect gusty northwesterly winds and colder temperatures as a 
result, especially over the mountains Monday night into Tuesday as 
the area enters a true post-frontal regime. Temperatures will remain 
above normal Sunday night as extensive cloud cover and precip will 
be over the CFWA, while temperatures Monday manage to reach near-
normal values, just ahead of the cold front. Temperatures take a 
very cold turn as lows Monday night drop to around 10 degrees F 
below normal as strong CAA and decent radiational cooling conditions 
settle over the region. Expect freeze conditions to prevail over the 
mountains, while frost advisories will be likely along the I-40 
corridor and north and west of the I-85 corridor Monday night. 
Despite dry conditions and mostly sunny skies, expect max 
temperatures on Tuesday to be 12-18 degrees F below normal, feeling 
more like late November/early December than mid-October as broad 
upper troughiness and CAA remains over the eastern CONUS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 215 PM Saturday: Upper troughiness over the eastern CONUS
will continue to deepen through the middle part of the week. Expect
height falls to continue through Wednesday, which will allow our
temperatures to remain 12-18 degrees F below normal for highs
and lows through Wednesday night. Expect widespread freeze in the
mountains and foothills, while locations in the northern Upstate and
along the I-40 corridor will flirt with the freezing mark. Elsewhere
will likely experience frosty conditions Tuesday and Wednesday
night, which essentially puts an end to the growing season for
the year. The base of the trough axis should move across the area
Wednesday into Wednesday night.This should allow for the airmass
to gradually modify through the end of the period as broad high
pressure sets up shop over the CFWA through the end of the work
week. Temperatures will remain a few degrees below normal through
Friday night. Model guidance have picked up on a cutoff low from the
base of the trough as it dips the low into Florida and eventually
meander off of the Southeast coast through D7. This could fetch
moisture back into the region, but would mostly stay confined to
the Coastal Plains. Expect dry conditions through the medium range.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR conditions are expected to persist 
thru the 00z taf period. With moisture increasing, the potential 
for fog will be higher in the mtn valleys Sunday morning, yet 
fog still appears most likely in the valleys west of KAVL (if 
it actually materializes). Otherwise, high clouds will increase
thru the day tomorrow, with KAVL and KCLT likely going bkn by
the end of the taf period. In addition, I included a PROB30 for 
SHRA at KAVL and KHKY for the last few hours of the period, but 
held off on any mention of precip for the other taf sites for 
the time being. Winds will be light tonight/overnight and continue
to favor a SWLY direction at most sites. They will pick up again 
out of the SW by late morning and remain SWLY thru the day. The
only exception will be KAVL, where winds will favor more of a 
NWLY direction tomorrow.    

Outlook: There will be an uptick in shower chances from the NW 
Sunday evening and early Monday along with the arrival of the next 
cold front. Frost/freeze conditions could impact operations each 
morning from Tuesday onward, but with VFR conditions still likely
at most sites.

&&

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

&&

$$
SYNOPSIS...DEO
NEAR TERM...JPT
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...JPT