102 
FXUS62 KGSP 160707
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
307 AM EDT Sun Oct 16 2022

.SYNOPSIS...
Warm temperatures and a quick round of showers for some of the area 
will end the weekend ahead of a strong cold front moving into the 
region Monday. The coldest air of the season so far will reach the 
area and bring about widespread freezing temperatures and frost for 
most of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 305 am EDT Sunday: IR satellite imagery shows a large shield 
of mid and high-level cloudiness streaming east from decaying 
convection over the middle Mississippi River Valley early this 
morning. The leading edge of this should thin a bit, but still 
expect an increasing mid/high cloud trend today given swift zonal 
flow aloft. This might cap maximum temperatures a touch under those 
supported by the warming thicknesses. Meanwhile, a weak and 
dissipating surface front remains stalled across western NC this 
morning. This boundary will further frontalyze as a much more potent 
cold front moves through the Ohio River Valley late in the day. 
Chance PoPs will build across northwest sections through the 
afternoon hours as very modest instability returns with recovering 
dewpoints ahead of the front. 

The upstream boundary will then quickly be on the move southeast 
tonight. Frontal circulations will combine with upper-level 
divergence near the right entrance region of a passing upper jetlet 
to force fairly solid likely to categorical shower coverage in 
northwest sections tonight. Indeed, the latest convection-allowing 
models all have robust coverage of showers and embedded 
thunderstorms, especially over western NC, from 03Z to 09Z. Surface-
based instability should be limited to a few hundred J/kg of SBCAPE 
just ahead of the approaching front, with 850 to 500 mb lapse rates 
generally near 6.5 deg C/km. Deep-layer bulk shear will likely reach 
40 to 50 kt along the northern Blue Ridge by midnight, and a 35+ kt 
low-level jet could transit east along the I-40 corridor through the 
early morning hours. Most of the better HREF updraft helicity 
streaks are west and north of the forecast area, but convection may 
need to be monitored with the approaching frontal zone into the 
overnight hours. The current Day 1 Marginal severe thunderstorm risk 
looks well-placed. Coverage may wane as the boundary moves southeast 
across the region and ongoing activity encounters drier profiles and 
lessening nocturnal instability. Anticipate our final night of warm 
mins for a while, with temperatures mostly in the 50s. Fog could 
become a problem in the NC mountains by daybreak with continued low-
level moisture.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 230 AM Sunday: A strong upper trough across the Great Lakes 
region will extend into the CWA on Monday. As the trough and 
associated low in Canada strengthen, heights should continue to fall 
throughout the region. A strong cold front will sweep across the 
area Monday morning into the afternoon, with plenty of cold air 
behind it. Backing winds will inject much colder and drier air 
throughout the forecast period and beyond. Any showers from prior to 
the front should rapidly taper off Monday morning with slight chance 
PoPs in the far western portion of the western Carolina mountains. 
High temperatures on Monday ahead of the FROPA will rise well above 
climo, with upper 70s in the Piedmont and upper 60s in the western 
Carolina mountains. As more CAA descends into the CWA, temperatures 
will steadily decline and the first widespread freeze and frost 
event is expected. Monday night temperatures dip below freezing in 
the mountains and bottom out in the 20s, with mixed 30s and 40s for 
the Piedmont. Even colder temperatures are forecasted for the entire 
region Tuesday and Wednesday night, with widespread 20s and 30s. A 
freeze watch is likely later today for Monday night. Frost is not 
expected Monday night as higher winds should prevent it from 
forming. However, more widespread frost is anticipated.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 230 AM Sunday: Continuing with the short term forecast, 
freezing temperatures are expected to again be widespread through 
the CWA, ranging from the 20s to 30s. Widespread frost is expected 
Wednesday night throughout the majority of the area as colder 
temperatures settle into the region. Thursday night temperatures 
will begin to rebound, but frost is likely in the northeastern 
portion of the CWA. As the upper trough and associated low across 
the Northeast begins to lift, surface winds returns to a 
southwesterly flow on Thursday and allows for warmer air to move 
into the area. High pressure will build back into the region through 
the rest of the forecast period. Dry conditions will persist as GFS 
and ECMWF model guidance suggest deep subsidence aloft and minimal 
PWAT values. Daytime temperatures should start to rise back to near 
climo and be indicative of the fall weather season. Overnight 
temperatures will not warm as quickly, however will rise above 
freezing for the remainder of the forecast period. As for any fire 
weather concerns, RH values will continue to be lower, teetering in 
the 30s, in the SE portion of the CWA. Despite the RH values, light 
winds throughout the week should keep any critical fire weather 
thresholds from being met.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR conditions will generally continue 
through the period with mainly mid and high-level clouds increasing 
from the west today and lowering through the VFR range this evening. 
Cannot rule out some brief valley fog around daybreak this morning, 
but increasing high clouds will limit the potential. Surface winds 
will remain generally locked in from the SW today through tonight, 
except for mostly NW into the French Broad Valley at KAVL. Low end 
gusts will be possible once again today, especially in the Upstate 
where mixing may be a touch deeper. Shower chances will increase 
from the northwest late today into tonight with the approaching, 
vigorous cold front. Will confine any PROB30 mentions for now to the 
NC TAF sites for the last few hours of the current period. Cannot 
rule out some thunder at the western NC sites, but with low 
confidence at present. Fog may pose a problem late tonight across 
the mountains and at KAVL.

Outlook: Showers will move east on Monday, with breezy conditions 
and rapid drying post fropa. Cool and dry high pressure will build 
into the region through the week. 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...CP
NEAR TERM...HG
SHORT TERM...CP
LONG TERM...CP
AVIATION...HG