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000
FXUS62 KGSP 060727
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
327 AM EDT Thu May 6 2021

.SYNOPSIS...
High pressure builds into the area today ushering in cooler and
drier conditions. A reinforcing cold front crosses the area Friday,
keeping below normal temperatures and mostly dry condtions into
the weekend. A low pressure system approaching from the west will
increase shower and thunderstorm chances late Sunday into early
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 315 AM EDT Thursday: Quiet across the region at this early
hour. Satellite imagery shows some lingering stratocu moving away
to the east of the Charlotte metro area, and some in the upslope
areas near the TN border. Cold advection from the NW is filtering
into the forecast area behind the cold front and will provide the
area with low temps dropping to near-normal values.

A broad mid/upper trof will affect the region through the
next 24 hours, with weak sfc high pressure moving past to the
north. Within this broad regime, two short waves will drop down
across the region. The first one arrives this afternoon and induces
weak lee cyclogenesis over the Carolinas. Interestingly enough,
the convergence to the northwest of this feature helps to trigger
isolated showers over the northern Upstate in the afternoon, which
is a development shown by several of the convection-allowing
models. We will add a slight chance of showers through late
afternoon. Temps will remain about a category or so below normal
today as the cold trof moves in. The follow-up wave will approach
tonight. This wave should trigger a linear MCS over wrn KY/west TN
that may make a run at the mtns this evening, but all indications
are that it will fade away before reaching this far east. Instead,
the passage of the short wave trof axis will bring the flow around
to something more northwesterly and that will force some precip in
the upslope areas along the TN border toward daybreak on Friday. Low
temps will also be below normal, but were bumped up a degree or two,
which should preclude any frost/freeze concerns over the mtns.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 245 AM EDT Thursday: A vort max will exit east of the area
during the day Friday, as a deep longwave trough begins to lift NE
toward the Northeast Coast. Gusty NW winds are expected Friday, with
about 30 kt of 850 MB flow and CAA. Some moisture will lingering
along the TN border to support isolated showers, with perhaps an
uptick Friday night. But overall, Friday looks dry, and depending on
fuel moistures, could be a fire wx concern as gusty winds combine
with low RH. Temps will be about 8 deg below normal under mostly
sunny skies. Min temps will be 5-8 deg below normal Friday night.

Upper flow continues to flatten out atop the region Saturday thru
Saturday night, resulting in a deep-layer westerly flow aloft. A
low pressure system will begin to develop over the Central Plains,
and this may activate a warm front across the TN Valley to the
Southern Appalachians. A few showers may affect the NC mountains
near the TN border, but overall, just an increase in cloudiness
is expected. Temps will rebound a couple of categories, so still
a few deg below normal for highs, but remain slightly above normal
Saturday night with strong low-level WAA atop the forecast area.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 300 AM EDT Thursday: The 00z suite of deterministic guidance
shows better than average agreement for the medium range, and
showing some decent run-to-run consistency. A fairly fast, split
flow pattern sets up across the CONUS for the first half of next
week. A southern stream shortwave will eject out of the Four
Corners region and track across the Plains to the Ohio Valley
Sunday into Monday. An associated sfc low pressure system will
reach the Central Appalachians by 12z Monday. So a warm SWLY flow
ahead of this low will set up atop the forecast area, and result
in above normal temps Sunday and Sunday night. PoPs will begin to
creep in late Sunday night, but overall, it looks dry.

The low will drag a cold front thru the area Monday, bringing a
round of showers and possibly a few tstms. The front loses some
oomph as it lays over in a more E-W in orientation, and instability
still doesn`t look that impressive. Still, with decent shear in
the area, we could see a non-zero severe threat on Monday. Temps
will be near normal.

It now looks like Tuesday should be a dry day, as the model
consensus has the front push all the way thru the area and a
fairly strong high pressure system builds in to our north. While
the QPF response is dry, the models do keep a fair amount of 850
mb RH. So could see lingering stratocu well into the day. That,
in addition to cool thicknesses behind the front should keep temps
a few deg below normal.

Models are also in better agreement on another southern stream
trough ejecting into the Plains, while strong confluent upper
flow sets up along the East Coast. This could be a good setup for
a classic or hybrid CAD for Wednesday. PoPs have been bumped up
into the solid chc range, and temps are held 8-12 deg below normal.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR through the period. Still some high based
stratocu lingering around KCLT, but a ceiling is not expected. The
low clouds also continue to linger over the mtns, so KAVL could be
in and out of a low cloud VFR ceiling for the next few hours. For
today, only high clouds are expected. Wind will be N to NE into
the middle of the day, but a lee trof should develop that will
bring the wind direction around to WSW. Around sunset, the wind
should come back around to NW.

Outlook: Predominately VFR conditions are expected thru the
weekend. The next system to bring restrictions is looking like it
will arrive on Monday of next week.

Confidence Table...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High 100%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:

www.weather.gov/gsp/aviation

&&

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

&&

$$
SYNOPSIS...ARK
NEAR TERM...PM
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM