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417
FXUS62 KGSP 240250
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1050 PM EDT Thu May 23 2024

.SYNOPSIS...
Temperatures will remain several degrees above normal each
day through Monday as humid subtropical air remains over the
Southeast. Chances for showers and thunderstorms will remain higher
than normal, with some chance lingering each night. A cold front
passing late Monday will bring cooler and drier conditions in the
middle of next week.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
As of 10:25 PM EDT Thursday: Widely sct showers with a few weak,
embedded thunderstorms continue to linger over our fcst area late
tonight. As we head into the overnight, this activity should con-
tinue to diminish as any lingering sfc-based instability dwindles
and the weak upper shortwave energy moves further east. Once the
convection exits the area overnight, gradually clearing skies
should permit some amount fog development. With dewpts remaining
elevated thru the overnight and winds going light to calm across
the area, it`s looking more likely that fog could become more
widespread than previously anticipated. Low temps Friday morning
should be very similar to Thursday and remain about 4 to 6 degrees
above climatology.

Otherwise, we will remain under broad/flat upper ridging thru
the period. Weak, embedded upper shortwave energy is expected
to translate over our fcst area again Friday afternoon/evening
and will provide at least some amount of upper level support for
convection. Fog should sct out fairly quickly tomorrow morning
giving way to another partly cloudy day. Profiles will once again
support some afternoon convection, with most of the near-term
guidance producing about 1000 to 1500 J/kg of sbCAPE and roughly
20 to 30 kts of bulk shear. Consequently, some thunderstorms could
become severe and produce strong downbursts and/or damaging hail.
SPC currently has most of our CWA in a Marginal Risk Area for svr
convection for Fri. Based on the latest fcst profiles, this still
seems reasonable despite the fact that the latest CAMs continue
to struggle with the timing and location of convective development
thru the afternoon and evening.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
As of 150 PM Thu: A short wave ridge builds over the area Saturday
then slides east on Sunday as a short wave trough crosses the area.
Any surface frontal features will be weak and likely remain north
and west of the area. A weak lee trough seems to be the dominant
surface feature if there is any. Convection should diminish Friday
evening with isolated showers possibly lingering overnight. Diurnal
convection returns Saturday, but the coverage while favoring the
mountains, remains somewhat questionable, especially over the
Upstate and NE GA given the ridge building in. That said, where
storms do form, isolated severe storms with damaging downbursts
would be possible given moderate instability, low shear, and mid
level dry air. Isolated heavy rainfall would also be possible.
Convection should taper off quickly Saturday evening.

Coverage on Sunday should be greater, still favoring the mountains.
The atmos could become very unstable with shear increasing to around
40 kts. This could lead to a more organized severe storm threat
adding large hail to the damaging wind potential. There is still
some uncertainty, so this will need to be monitored. Lows around 5
degrees above normal and highs 5 to 10 degrees above normal both
days.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 220 PM Thu: A phasing short wave digs a trough over the
eastern CONUS and crosses the area Monday night. The trough remains
in place as another phasing short wave moves through on Wednesday.
NW flow aloft will be over the area Thursday. A cold front will
slowly move toward the area Monday and across the area Monday night.
The front may stall near the area Tuesday before a weaker cold front
crosses the area Wednesday. Likely to good chance PoP expected
Monday with the front. Lower chance PoP expected Tuesday with
moisture along the stalled front, with only isolated mountain
showers with the Wednesday front. Some severe storms and heavy
rainfall will be possible with the Monday front. Much lower chance
of either Tuesday. Thursday looks to be dry. Temps start out above
normal on Monday falling to near normal by Thursday.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Expect sct showers and thunderstorms to
linger across the area thru late tonight and into the overnight.
I have TEMPOs for tsra at all taf sites thru roughly 04z tonight,
with mostly just showers expected to linger after that. I kept a
mention of MVFR visby at KCLT and the Upstate terminals and IFR
visby at KAVL and KHKY owing to the elevated dewpts and rain from
earlier. It remains difficult to determine if things will clear out
enough overnight to permit any widespread low stratus development,
but IFR stratus is certainly not out of the question. For the time
being, I kept any lower clouds sct thru the morning hours. Winds
will continue to favor a SW direction for most of the period and
should go light and vrb to calm overnight at most sites. Expect
less coverage of showers and storms on Friday, but at least some
convection still appears likely. This is handled with PROB30s for
tsra beginning around 18z and running thru the end of the period
tomorrow evening. The evolution of any convection tomorrow remains
difficult to predict, thus confidence on timing and/or location
remains low.

Outlook: A unsettled pattern will linger thru the weekend and into
early next week, allowing for diurnal shower and thunderstorm chances
each day and fog development each night/morning.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...JPT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JPT