National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS62 KGSP 210602
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
202 AM EDT Sun Apr 21 2024

.SYNOPSIS...
Much cooler temperatures and widespread light rain is expected
overnight into Sunday with drier weather returning by Monday. Warmer
weather returns by Tuesday and continues through the workweek.

&&

.NEAR TERM /THROUGH TODAY/...
As of 150 AM EDT Sunday: Radar shows the leading edge of an
area of showers, with embedded thunderstorms, moving into the
southwestern part of the fcst area. The atmosphere once again defies
expectations with the cloud to ground lightning detected west of
Anderson. Precip probs have been modified accordingly and thunder
added to the forecast in the Savannah R valley. That`s it for now,
other than tweaks to the temp/dewpt trends.

Otherwise, the eastern periphery of sprawling sfc high pressure will
continue to gradually expand eastward and into our area. At the same
time, rain chances will gradually ramp up from the south overnight
and into Sunday morning as an in-situ CAD develops and isentropic
ascent increases. Low temps overnight should be a couple degrees
above climo outside of the mtns thanks to increasing clouds and
rain, and a few degrees below climo over the mtns thanks to per-
sistent NLY flow. Light to moderate showers are expected to linger
thru much of the day on Sunday before gradually tapering off from
west to east early Sunday evening. Still not expecting any thunder-
storms with these showers thanks to the CAD regime and its lack of
instability. In addition, QPF amounts should be low-end with most
of our CWA expected to get no more than a half inch or so. Thanks
to the CAD regime, highs on Sunday will end our recent streak of
above-normal temps, with values 15 to 20 degrees below climo.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
As of 200 AM EDT Sunday: Shortwave trough will be in the midst
of shifting across the CFWA, while surface high propagates
eastward from the Lower/Mid MS Valley on Monday. In this case,
cool north-northwesterly low-level flow and colder air aloft will
keep temperatures ~10 degrees below normal for afternoon highs,
with mostly sunny skies. The aforementioned surface high will set
up shop over the CFWA by Monday night and set the stage for good
radiational cooling conditions across the region. With light winds,
tight dewpoint depressions, and temperatures remaining 6-10 degrees
below normal, expect areas of frost to develop, mainly in the
southern/central NC mountains and locations along and north of I-40
(active growing zones). A Frost Advisory may be needed for these
zones Monday night, especially if trends continue to run cooler per
model guidance. Airmass will begin to modify Tuesday as the surface
high slips offshore the Southeast Coast and weak southwesterly
WAA filters into the area. Factor in rising heights and afternoon
highs will return to near-normal values for most locations. Stout
shortwave trough with an attendant frontal boundary will begin to
encroach from the northwest. The front is forecasted to be near
the TN/NC border by daybreak Wednesday. The parent low and better
forcing will reside well to the north and east of the CFWA, while
the front moves into a moisture starved environment. As a result,
only able to muster up slight chance PoPs along the immediate TN
border. Otherwise, overnight lows Monday will rebound and return
to near-normals values.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 115 PM EDT Saturday: A mid level trough will move from the
Great Lakes into the Northeast for the middle of the week. This will
push a weak and mainly dry cold front into the area on Wednesday.
Mid level heights will quickly rebound from this trough for Thursday
and Friday. Another system will impact the area late in the week
with some showers possible by Friday, mainly in North Carolina.
Temperatures for the middle to end of the week should be pretty
close to climo.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Starting out VFR, but this will quickly go
downhill as rain spreads northeast across the region through the
pre-dawn hours. It may take an hour or two for the rain to bring the
vis/ceiling down to where an MVFR restriction forms, but a downward
progression looks like a good bet. Expect nearly all places to be at
least MVFR by sunrise to mid-morning. Once the steady precip moves
in, the latest guidance is quite pessimistic with its IFR stratus
deck lingering through much of the day. I`m not yet convinced of the
IFR and have kept most places prevailing MVFR for the time being,
and will continually evaluate. Wind should remain NE through the
daytime. The rain will get carried off to the east in the late
afternoon and early evening, and when that happens, expect the
vis/ceiling to recover gradually. Most places end the period VFR.

Outlook: Dry, VFR conditions continue Monday as high pressure
builds over the region from the west.

&&

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

&&

$$

SYNOPSIS...SCW
NEAR TERM...JPT/PM
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...PM