000
FXUS62 KGSP 220249
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1049 PM EDT Sun Apr 21 2024

.SYNOPSIS...
Much cooler temperatures and widespread rain will continue the rest
of today before drier conditions return tonight into Monday as high
pressure builds into the region. Warmer weather returns on Tuesday
with dry conditions persisting over the area. Warm temperatures will
linger through the workweek despite a weak cold front tracking
across the western Carolinas on Wednesday. This front may lead to
rain showers along the Tennessee border Tuesday night into
Wednesday.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 10:15 PM EDT Sunday: Since the last update the rain showers
have moved off the coast, although within the past hour or so a
narrow band of light precip has developed over our NE Georgia and
southern Upstate zones. This is likely in response to the base of
the upper trof approaching our area from NW. Regardless, this acti-
vity should dissipate over the next few hrs as the better upper
support moves east. We`ve seen a decent amount of clearing across
our area this evening, however another fairly broad band of mid and
high level clouds have been filling in across the NC mtns over the
past few hrs, likely as a result of an uptick in low-level moisture
within the NWLY flow. It`s doubtful that it will produce any addi-
tional showers though. As previously mentioned, widespread frost is
not expected to develop over the NC mtns largely due to the elevated
N/NW winds. Nonetheless, a Frost Advisory was issued for Graham,
Swain, and Macon counties from 2am to 9am Monday morning as winds
will likely be weaker over those zones, especially in the sheltered
valleys.

Otherwise, heights will steadily fall thru the period as a robust
southern stream upper trof dives SE and over our area on Monday.
At the sfc, a moist sfc boundary and its associated low will move
off the Atlantic Coast overnight and thru the day on Monday. At the
same time, broad high pressure will continue to gradually push into
our area from the west and is expected to be centered just to our
west by the end of the period late Monday. As for the sensible wx,
we should remain dry on Monday with any lingering cloud cover even-
tually moving east of our area Monday morning. Under ample sunshine,
temperatures will rebound significantly from Sunday, however falling
heights and a persistent NLY to NELY low-lvl flow should keep highs
about 8 to 12 degrees below climatology. In addition, RH values may
approach critical thresholds for a few hours in the aftn, however
with the recent rainfall fuel moistures should be relatively high.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 110 PM EDT Sunday: Dry sfc high pressure will linger over the
Southeast Monday night into Tuesday leading to continued dry weather
and mostly clear skies. Great radiational cooling conditions as well
as light winds may allow for some patchy frost development Monday
night into daybreak Tuesday across portions of the NC Foothills and
northern NC Piedmont. However, lows Monday night look borderline at
best (despite being several degrees below climo) for frost
development in these areas so confidence is low. Lows Monday night
will dip into the mid 30s across the mountains, with the upper 30s
to lower 40s expected elsewhere. Despite the colder temps across the
mountains, frost formation is not expected in the central/southern
NC mountains (where the growing season is active) as forecast
dewpoint depressions are too large at this time. Temps on Tuesday
will be noticeably warmer thanks to great insolation and S/SW winds.
Highs will climb into the lower 70s across east of the mountains and
across the mountain valleys. Despite the warmer temps, highs will
still end up a few degrees below climo.

A cold front will approach out of the NW Tuesday night allowing
cloud cover to increase across the northern half of the forecast
area. Increased cloud cover along with S/SW`ly flow remaining in
place ahead of the front, will lead to much warmer lows Tuesday
night. Thus, frost development is not expected to be a concern. Lows
should end up a few degrees above climo, ranging from the mid 40s to
lower 50s across the forecast area. The cold front will track across
the forecast area on Wednesday, allowing winds across the mountains
to turn NW`ly. Winds east of the mountains will turn W`ly.
Downsloping flow will allow highs on Wednesday to climb several
degrees warmer east of the mountains compared to Tuesday`s highs.
Thus, temps will remain a few degrees above climo Wednesday
afternoon. Rain showers may develop along the NC/TN border on
Wednesday thanks to the cold front, so have slight chance PoPs for
these locations.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 130 PM EDT Sunday: The aforementioned cold front will push
east of the western Carolinas Wednesday evening. High pressure will
build into the eastern CONUS Thursday into Friday, lingering over
the East Coast through the weekend. The latest global model guidance
is not in great agreement regarding on whether or not we will remain
dry during the long term forecast period and the GFS looks to be the
wetter solution compared to the 00Z ECMWF and 12Z Canadian. Thus,
confidence on PoPs will be low due to model disagreement. Went with
dry conditions Wednesday night into Thursday night and chance PoPs
across the western and northern zones (per global models) Friday
into the weekend. Lows will remain above normal through the period.
High temps start out a few degrees below climo on Friday, thanks to
increased cloud cover, becoming near climo on Saturday thanks to a
slight decrease in cloud cover and S`ly flow. Highs on Sunday look
to top out around 10 degrees above climo thanks to mostly sunny
skies and SW`ly flow.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Rain has moved east of our fcst area over
the past few hours as drier high pressure gradually spreads over
the area from the west. VFR clouds will continue to sct from west
to east this evening and early Monday. Expect most sites to go SKC
by the early afternoon with a few lingering high clouds. Winds will
remain NLY this evening thru early Monday with low-end gusts likely
at the Upstate terminals during the late morning and into the aftn.
They will veer to more NELY by the early aftn and eventually go light
and VRB to calm by the end of the period tomorrow evening. At KAVL,
winds will remain NWLY thru the period with moderate gusts weakening
overnight and then dropping off by the late morning.

Outlook: Expect dry, VFR conditions to continue thru Tuesday as high
pressure builds over the region from the west.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Frost Advisory from 2 AM to 9 AM EDT Monday for NCZ051-058-062.
SC...None.

&&

$$

SYNOPSIS...AR
NEAR TERM...JPT
SHORT TERM...AR
LONG TERM...AR
AVIATION...JPT