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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 241855
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
255 PM EDT Tue May 24 2022

.SYNOPSIS...
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Cool high pressure over New England will ridge down into our area
through Wednesday.  Low pressure over northern Texas will strengthen
as it moves northeast toward the Great Lakes with a cold front
approaching our region from the west. The coverage of showers and
storms will increase Wednesday night through Thursday night ahead of
the approaching cold front.  The front crosses our area on Friday
with dry high pressure moving into our region for the weekend and
early next week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH WEDNESDAY/...
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As of 2:30pm EDT Tuesday: Surface low responsible in part
for severe weather yesterday is now well east of the area, leaving
behind complex, though relatively low impact weather for the next 24
hours.  Aloft, a modest shortwave in advance of the next synoptic
trough swings northeastward tonight and is expected to give some
showers this afternoon and tonight.  At the surface, winds are
light, but become more northeasterly this afternoon behind the
surface low as a cold-air damming episode commences with a wedge
front pushing across the entire area tonight.  Some surface CAPE is
analyzed from observations early this afternoon, with northeasterly
CAD flow eliminating CAPE behind the wedge front.  Showers are
expected later this afternoon and evening as upper shortwave comes
into play, but convection will be commencing as CAPE is in continual
decline as front advances.  This will create a somewhat narrow time
and area for thunder from around 10pm to midnight, mostly over the
western mountains southward.

Currently, radar is clear, with showers expected to develop from
southwest to northeast after 5pm.  Areal average rainfall amounts
through Wednesday morning will be light at a few tenths of an inch,
though some isolated areas will receive more and many areas and
areas in the eastern half of the CWA won`t get any rain in this
period.  Clouds have become scattered to broken with ceilings rising
from low morning values.  CAD will bring overcast and low ceilings
by morning, along with northeast winds of 5 to 10 kts throughout the
day on Wednesday.  High temperatures will also be subdued tomorrow
due to CAD/clouds, and reduced later today over northeast parts of
the CWA that are already seeing northeast flow.  None of the usual
model blends reduced temperatures enough behind the wedge front, and
made more manual adjustments to forecast temperatures than usual.
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&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
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As of 115 PM EDT Tuesday: An active pattern will return for the
short term period of the forecast. A mid level ridge will be in
place along the Southeast coast through the period, while a
trough/possible closed low moves from the southern plains across the
Ohio and Tennessee Valleys. At the surface, a cold front will move
across the area on Friday.

Expect areas of showers and thunderstorms each period. While much of
the rain will be beneficial after the recent dry spell, locally
heavy areas of rain may develop especially in the upslope areas of
the southern Appalachians. Model instability and wind profiles also
suggest that there will be some risk of severe thunderstorms from
Thursday afternoon through early Friday.
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&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
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As of 115 PM EDT Tuesday: The system impacting the short term period
will have moved off the coast by the weekend, with conditions drying
out as a result. Mid level ridging will develop across the region
with with strengthening of this feature indicated by early next week
over the Ohio Valley. This scenario would lead to warmer
temperatures early next week, with highs potentially climbing into
the lower 90s in the Piedmont on Tuesday.
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&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
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At KCLT and elsewhere:  Northeast winds are becoming established in
the wake of surface low that crossed the area last night.  This will
begin a period of cold-air damming with lowered CIGS expected at all
TAF sites tonight and Wednesday. Winds Wednesday will be
northeasterly around 5 to 10 kts and gustless. Currently, Ceilings
of 1 to 3 kft have mostly scattered. Forecast soundings have CIGS in
decline after dark this evening, reaching IFR levels by daybreak.
Some weak shortwaves in advance of next trough may support some
scattered showers this afternoon and tonight, mostly southwest of
the KCLT and KHKY areas.  Surface-based instability is marginal, and
is wiped-out as wedge boundary advances from the northeast,
resulting in little temporal overlap between rain and CAPE.  Most
likely areas for any thunder are KAVL to KAND for a few hours this
evening.

Outlook: Persistent moisture and cold air damming will keep
precipitation and restrictions in the picture Wednesday into
Thursday. Another cold front will arrive from the west late
week. Nocturnal fog/stratus will be possible as well, especially
where rain has recently fallen.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...DEO
NEAR TERM...WJM
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...WJM