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000
FXUS62 KGSP 221730
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
130 PM EDT Mon Apr 22 2024

.SYNOPSIS...
High pressure over the Carolinas brings warmer weather on
Tuesday with dry conditions persisting over the area. Warm
temperatures will linger through the workweek despite a weak cold
front tracking across the western Carolinas on Wednesday. This front
may lead to rain showers Tuesday night into Wednesday, especially
over the immediate Tennessee Border.

&&

.NEAR TERM /THROUGH TONIGHT/...
Noon Update...The fcst remains in great shape since the previous
update. Still expect reduced warming due to llvl CAA with highs in
the mid to upper 60s east of the mtns and l60s mtn valleys.

Otherwise, an upper wave moving east across the fcst area at
daybreak is expected to close off into a compact upper low over
the Coastal Plain of NC this afternoon...far enough east to not
have much of an affect on the fcst area beyond veering the flow
around more northerly. Sunny sky can be expected for the balance of
the day, which should allow for a nice rebound in the high temps
on the order of 7-10 degrees compared to Sunday. There is some
minor concern about the afternoon RH, which is forecast to drop
to around 30 pct, but it is not the best situation for dewpoint
mixing out. The upper low moves offshore tonight and a weakening sfc
high will move over the srn Appalachians by Tuesday morning. This
should set us up for a decent radiational cooling night, with low
temps about ten degrees below normal. This raises the possibility
of frost development after midnight. As the fcst is constructed,
only a patchy frost mention is supported over the nrn foothills of
NC because the dewpoint remains too high, so no Frost Advisory will
be issued. Be on the lookout for it, though, because a small change
in the fcst later today could point toward more frost potential.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 200 AM EDT Monday: Surface high pressure sets up shop over
the southeastern CONUS Tuesday as heights recover following the
departing shortwave trough. Weak south-southwesterly WAA and 850
mb winds supporting a west-northwesterly downslope component will
allow the airmass to modify as the surface high gradually shifts
offshore. Afternoon highs will return back to near-normal values
under partly to mostly sunny skies. A stout shortwave trough with
an attendant frontal boundary will slide across the Northern Great
Plains and into the Great Lakes region by Tuesday. The trailing
front will encroach the region Tuesday night and is forecasted to
produce showers along the front over the NC/TN border just before
daybreak Wednesday. Otherwise, the front will push into the region
under a mostly moisture starved environment. Increased clouds
and continued south-southwesterly flow will allow overnight lows
Tuesday to uptick back to near-normal values. Timing discrepancies
occur with the timing of the fropa on Wednesday amongst the model
guidance. As of now, the latest trends indicate the front won`t
make a clean sweep until late Wednesday evening. In this case, the
models are picking up on some form of QPF response along the front
with PWAT values surpassing 1.00" across the CLT Metro, Upstate SC,
and northeast GA during peak heating. Confidence isn`t the best in
this scenario, but due to back to back trends per model guidance,
decided to go with a mentionable PoP for portions of the Piedmont
zones. Afternoon highs on Wednesday are expected to run a few ticks
above normal. Dry air entrainment will filter in Wednesday night
as the front slips south of the CFWA and continental surface high
settles over the Great Lakes region. Overnight lows on Wednesday
will continue to run near climo, with a light north-northeasterly
breeze.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 315 AM EDT Monday: The short-term frontal boundary is expected
to stall across the Deep South and Southeast, but south of the
CFWA. As a result, surface high pressure over the Great Lakes will
remain in control Thursday and Friday as the front remains south of
the area and the surface high shifts across the northeastern CONUS
and eventually offshore the Northeast Coast by Friday. Temperatures
will run at or slightly below normal Thursday and Friday due to a
persistent northerly component. A digging upper trough will traverse
across the Four Corners region and into the High Plains by Friday,
inducing surface cyclogenesis across the central CONUS. In this
case, the stalled boundary will gain warm frontal activation and
eventually lift north of the CFWA the end of the workweek. Model
guidance are consistent with the overall synoptic pattern over
the region as an upper ridge develops over the Eastern Seaboard,
while the CFWA resides under a warm sector regime. In this case,
expect temperatures to rise a category or two above normal by
D6/D7. Uncertainty still resides with precip potential, but most
of any precip will develop to our north and west, but not enough of
a spark over the CFWA to maintain mentionable PoPs in the extended
forecast period at this time outside of the immediate TN border.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Fair weather thru the TAF period as high
pressure aided by upper ridging builds in from the west. This will
promote deep layered dry air and VFR conds. Surface winds outside
the mtns will remain n/ly to ne/ly today, then shift sw/ly on Tue.
At KAVL expect nw/ly flow thru this evening, becoming ssw/ly after
the inversion break Tue morning.

Outlook: Dry VFR conditions will continue thru Tuesday night as high
pressure builds over the region from the west. A cold front will
approach and lay down across the region Wednesday, which could bring
flight restrictions. Temporary drying returns Thursday, followed by
another moist weather system on Friday.

&&

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

&&

$$

SYNOPSIS...CAC
NEAR TERM...PM/SBK
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...SBK