873
FXUS62 KGSP 011755
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
155 PM EDT Sat Jun 1 2024

.SYNOPSIS...
Dry high pressure moves off the Carolina coast on Sunday with
warming temperatures and increasing moisture. A typical summer
pattern will return during the first half of the week with daily
afternoon thunderstorm chances. Showers and thunderstorms will
likely increase in coverage for Wednesday and Thursday as a cold
front approaches our area.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 9:55 AM Saturday...The better cirrus coverage is currently
moving east of the I-77 corridor as a much broader cloud shield
and associated showers gradually approach the western Carolinas
from the west. Based on the latest near-term guidance and linger-
ing cirrus coverage, I lowered high temps a bit for today.

Otherwise, upper level ridging will shift east today as a shortwave
upper trof advances east overnight. Still expect mainly upper clouds
thru the day today, which will have an impact on lowering sfc temps
even as the sfc flow picks pick a more s/ly component. Highs will
likely hold a cat or so below normal levels. Still a dry sfc layer
as upper subs will be slow to erode, thus expect low RH thru the
afternoon period.

Forcing ahead of the upper s/w reaches the NC mtns late afternoon,
yet moisture advect off the Atl will take some time for the low
levels to saturate across the FA. The latest op models show the best
timing of llvl moist transport aft midnight, however, sct showers
are probable across the NC mtns before that. More widespread precip
will occur overnight, but with limited instability and meager mlvl
LRs, deeper cells with high rainfall rates will be hard to develop.
The upslope regions of the NC mtns will receive the higher precip
amts with arnd three quarters of an inch or so, while anticipate
only arnd a quarter inch east thru daybreak Sun. Mins Sat night will
be held right arnd normal due to reduced heating during the daytime
Sat and increasing column moisture.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 227 AM Saturday: Surface high pressure shifting offshore will
allow for winds to shift to out of the south/southeast with onshore
flow ushering moisture back into the region. At the same time, a
shortwave trough will be lifting through the Ohio Valley and into
the Appalachians. Showers will likely already be ongoing Sunday
morning across the mountains with this activity expected to expand
east across the Upstate and into the Foothills/Piedmont through the
day. A few thunderstorms will also be possible during the afternoon
to early evening hours. Cloud cover and coverage of precipitation
will likely keep temperatures below average for another day with
afternoon highs generally in the low to upper 70s. By Monday, the
upper trough will have lifted across New England leaving behind a
nebulously forced pattern. Weak westerlies will extend from the
Southern Plains into the southeast states with a couple weak
embedded shortwave perturbations. This will foster diurnally driven
scattered afternoon showers and thunderstorms with afternoon high
temperatures rebounding into the low to mid 80s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 234 AM Saturday: A weakly forced summer pattern will continue
Tuesday as temperatures continue to warm with another round of
scattered diurnal convection. Heading into mid week, an intense
Pacific jet over British Columbia and Washington state will help
carve out a potent negatively tilted trough over the Northern Plains
into the Great Lakes region. While the strongest large scale height
falls will remain displaced north of the area, some degree of
increased forcing will likely exist across the Southern Appalachians
Wednesday into Thursday. This will result in a noticeable uptick in
coverage of showers and thunderstorms on Wednesday across much of
the area. An associated cold front will also approach the area
Thursday into Friday. Severe weather chances still appear low
through the period given poor thermodynamic profiles with
tall/skinny CAPE profiles and near moist adiabatic lapse rates.
Guidance beings to diverge, however, with exact timing of the front
and evolution of the synoptic wave. Most solutions close off a large
upper low, but show considerable spread as to when/where this
occurs. Regardless, another seasonably dry and cool airmass will
eventually spill into the area by next weekend.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Expect VFR conditions to continue thru
the 18z period at all taf sites except at KAVL and KAND, where
cigs are expected to drop below VFR towards the end of the period
late tomorrow morning. The other terminals could see some lower
cigs by that time, but more than likely they will remain low-end
VFR thru the period. Otherwise, VFR clouds will gradually lower
tonight and early Sunday with sct showers approaching the area by
that time. I have PROB30s for shra at all sites beginning Sunday
morning and PROB30s for tsra by the early afternoon once some in-
stability is present. Winds should continue to favor a SLY to SELY
direction thru the period, becoming weaker later tonight and then
picking back up moderately by the early afternoon tomorrow.

Outlook: Diurnal shower and thunderstorm chances will linger thru
the middle of next week.

&&

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

&&

$$

SYNOPSIS...TW
NEAR TERM...JPT/SBK
SHORT TERM...TW
LONG TERM...TW
AVIATION...JPT