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000
FXUS62 KGSP 190149
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
949 PM EDT Thu Apr 18 2024

.SYNOPSIS...
Showers and thunderstorms are possible Friday as a cold front
crosses the area, but unseasonably warm weather continues through
Saturday.  Below-normal temperatures and widespread light rain is
expected Sunday with cool but drier weather on Monday. Drier and
warmer weather will return to the area Tuesday through Thursday
of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 935 PM Thursday: A series of short wave troughs will push a
cold front across the TN and OH Valleys overnight. Guidance agrees
that mid/high clouds will continue to steadily thicken, with lower
clouds increasing toward daybreak. The 00Z run of the HRRR has
backed off considerably on the potential for pre-sunrise/pre-frontal
convection impacting the CWA...with more of a focus on late morning
(and keeping it confined to the mountains at that.) PoPs have
therefore been lowered across western areas, with likelies confined
to a sliver along the TN/NC border. A strong storm or two can`t be
ruled out across the far west toward sunrise, but a combination of
modest nocturnal instability and unimpressive shear parameters
should preclude a severe storm threat. QPF doesn`t look especially
heavy either, although some moderate amounts are possible. Min temps
will be around 10 degrees above normal.

Convection is expected to reignites during the afternoon as the cold
front itself moves in from the west. Indeed, the trend toward less
coverage of morning convection suggests better potential for
redevelopment during the afternoon. Best coverage will be over NC
and the central and eastern Upstate, with isolated coverage over the
Upper Savannah River valley. An isolated severe storm or two will be
possible with moderate CAPE and shear developing. Right now, it
doesn`t look to be especially organized even with the front moving
in. Again, some moderate QPF is possible but significant coverage of
heavy rainfall is unlikely. Highs will be a little tricky given the
clouds and potentially two rounds of convection. For now, have highs
around 10 degrees above normal.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 200 PM EDT Thursday: A cold front will be draped across the
center of the forecast area early Friday evening before gradually
pushing south and east Friday night into daybreak morning. CAMs show
the potential for lingering isolated convection through late Friday
evening, so have chance PoPs in place through late Friday night
across the western and eastern zones. The SPC Day 2 Severe Wx
Outlook has the western Carolinas in Marginal Risk for isolated
strong to severe storms, thus a few strong to severe storms will be
possible through the evening hours. The main potential impacts with
any storm that manages to become severe will be large hail and
damaging wind gusts. Lows Friday night will end up around 12-15
degrees above climo thanks to increasing cloud cover and convection.

The cold front will be located just south of the forecast area on
Saturday, which may allow additional isolated convection to develop
during the afternoon and evening hours. Have chance PoPs in place
again on Saturday to account for this potential, but the NAMnest
shows mostly dry conditions. Thus, confidence on PoPs for Saturday
is low. The severe weather threat looks to be lower on Saturday, but
we cannot not rule out an isolated strong storm or two if convection
manages to develop. Despite cloud cover lingering on Saturday, highs
will be around 4-8 degrees above climo across most locations.
However, the NC/TN border will likely see highs a few to several
degrees below climo behind the cold front.

The front will stall across the Gulf Coast Saturday night into
Sunday while sfc high pressure gradually builds into the central
CONUS leading to much cooler temperatures. Meanwhile, upper
shortwaves will track across the Southeast Saturday night into
Sunday leading to gradually increasing rain chances. Could not rule
out some isolated thunderstorms Saturday evening thanks to lingering
instability. However, thunder is not expected on Sunday thanks to in-
situ CAD leading to a more stable airmass. Have chance PoPs Saturday
night with likely to categorical PoPs on Sunday. Lows Saturday night
will end up around 4-7 degrees above climo, with highs on Sunday
ending up around 10-13 degrees below climo.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 230 PM EDT Thursday: Rain chances will linger through Sunday
evening before gradually tapering off overnight as the upper
shortwaves push east of the western Carolinas. Thus, have chance
PoPs in place through late Sunday night across the forecast area.
Lows Sunday night will end up near climo to a few degrees below
climo despite lingering cloud cover. The aforementioned sfc high in
the short term will gradually push into the eastern CONUS Monday
into Tuesday leading to drier conditions. CAD looks to linger
through Monday before gradually dissipating Monday night into early
Tuesday. This will lead to another round of below climo temps, ~7-11
degrees, Monday afternoon. Highs on Tuesday will be noticeably
warmer thanks to the sfc high being directly overhead the Carolinas
and leading to S/SSW`ly flow. Lows Monday night will end up a few
degrees below climo thanks to mostly clear skies. Lows Tuesday night
will end up a few degrees above climo ahead of an approaching cold
front. A cold front looks to track across the western Carolinas
overnight Tuesday into Wednesday, mainly leading to increased cloud
cover, especially along the western North Carolina mountains. Rain
chances also look to return with this front, but should remain
confined to the western North Carolina mountains. Thus, capped PoPs
to slight chance for now across these zones. Both highs and lows on
Wednesday will end up a few degrees above climo. Dry high pressure
will build back into the region behind the departing front Wednesday
night into Thursday leading to drier conditions and slightly cooler
temps.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: VFR conditions are expected to predominate
through this TAF period. Chances for showers and perhaps some TS
will increase ahead of a cold front toward daybreak Friday,
especially across western areas. Prob30s are included at all sites
except KCLT during the morning. While -SHRA is advertised at most
sites, -TSRA is included in the Prob30 at KAND. Convection is
expected to push east of the Terminal Forecast Area during the late
morning/early afternoon. However, conditions may become favorable
for redevelopment of scattered activity later in the afternoon, and
most sites get a second Prob30 for -TSRA during the afternoon. Winds
will generally be light/vrbl overnight...perhaps favoring a light
S/SW component at some sites. Winds will then increase from the SW
at 5-10 kts during the daylight hours Friday.

Outlook: As a cold front sags south across the area, another round
of convection is possible Saturday, mainly during the afternoon.
Rain and possibly isolated thunderstorms are expected to develop
north of the front on Sunday, likely resulting in restrictions for
at least the southern part of the area. Drier conditions return
Monday, continuing into Tuesday.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...JDL/RWH
SHORT TERM...AR
LONG TERM...AR
AVIATION...JDL