Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 241720
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
120 PM EDT Sun Mar 24 2024

.SYNOPSIS...
Dry and cool high pressure will persist across the area through
early Tuesday before a rainy cold front crosses the area late
Tuesday into Thursday.  Dry and warmer weather returns Friday
through the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1135 AM EDT Sunday: For the late morning update, a few minor
changes were made to dewpoint and RH values. So far, the daytime
mixing is on track with the forecast, but wanted to bump the RH a
tad lower to account for the extremely dry mid-level that could mix
down into the BL. Winds are starting to turn more ENE outside the
mountains. A few low end gusts are being recorded in the eastern
portion of the CWA, but should diminish later this evening.

Otherwise...today will be a dry one.  Upstream soundings over
the upper Mid-Atlantic reveal a layer of incredibly dry air just
above the surface, which will advect into the Carolinas today.
With nothing to hinder daytime heating from the moment the sun
rises, ensemble soundings depict the development of a mixed layer
across the area by mid-morning, and it won`t take long to start
tapping into that dry air aloft and mix it down to the surface.
Consequently, went with the lower quartile of dewpoint guidance
for this afternoon, resulting in widespread critical RHs across
most of the forecast area.  The saving grace for fire weather
will be the lack of stronger winds; with flow getting increasingly
anemic throughout the day, afternoon RH minima will coincide with
relatively weak 20ft winds, putting us below Fire Danger criteria
for all zones.  High temperatures will climb into the mid/upper
50s across NC, and may approach 60 in the Upstate and NE GA,
especially along the Savannah River.

Winds will slowly turn east before getting increasingly light this
evening and tonight.  Temperatures for much of the NC Piedmont
will fall to near or below freezing.  For zones with high enough
confidence in freezing temperatures, a Freeze Warning has been
issued; for those zones along the NC-SC border, where confidence is
lower, a Frost Advisory was issued, as winds should be light enough
that at least patchy frost seems likely.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 155 AM Sunday...An upper level ridge axis shifts across the
area Mon/Tue while stg high pressure ridges down the east coast
ahead of an incoming cold front. Model soundings still indicate a
lowering subsidence inversion, down to 2Kft, and a dry mixed layer
below that. This will lead to low RH values in the afternoon, but
likely not as dry as Sun. Cloud cover increases atop the sfc wedge
and the combination of llvl CAA and less heating will hold high
temps arnd 60 F east of the mtns and m50s mtn valleys. Thus, shallow
vertical mixing will not lower td/s greatly leading to RH values in
the u20s to arnd 30 percent range. Also with lower wind speeds, the
meteorological conds don`t support the need for fire-wx products
attm. An upstream h5 s/w brings an active cold front the east TN
Tues morning and this will interact with a sfc wedge leading to
widespread rainfall by the evening and overnight into Wed.
Instability is meager ahead of this system, yet added thunder across
the NC mtns Tue evening as upslope forcing could help produce a few
embedded tstms. Highs Tue will also hold around 8 degrees below
normal with a moist sfc wedge persisting. Mins will not drop off
each night in this environment as lows are held a few degrees abv
normal Mon night and 6-10 degrees abv normal Tue night.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 220 AM Sunday...A cold front continues to slowly push east of
the FA Wed and the atmos remains unsettled into the overnight as an
upper trof crosses from the west. The current timing consensus of
sfc convg favors the eastern zones for the best chance rain and have
kept PoPs in the mid chance range across the I-77 corridor thru the
evening. Rain chances go down to low early Thu across all areas as a
nrn stream sfc high builds in which may also bring enuf cold air for
a period of high elevation -snsh before the deeper moisture pushes
east. The synoptic setup Thu evening is still a little uncertain
tho, as the ECMWF and the CMC models produce a sfc wave on the coastal
front possibly bringing -shra back to the ern zones. The QPF trends
on this scenario have decreased however, so have not made sigfnt
adj/s to the grids. The pattern becomes dry with a large upstream
ridge developing across the central CONUS Fri, which will maintain
warming sfc hipres over the FA into Sat. High temps begin the period
arnd or a little below normal and by Sat expect max temps in the
m70s non/mtns and l70 mtn valleys. Mins will generally be held a few
degrees abv normal each morning with patchy/areas of frost possible
Thu night due to clearing skies and calm winds.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: VFR conditions will prevail at all terminals
through the TAF period. High clouds start to move into the area from
the west after 22z, but should remain around the BKN/FEW240 mark.
Upper clouds will increase overnight and stick around through Monday
morning. Dry conditions should help minimize any low-end clouds as
well. Winds will continue with an easterly direction, with KCLT
remaining just north of east. Wind gusts should start to diminish
this evening for all sites outside the mountains. KAVL could have
low-end gusts toward the end of the forecast period, but confidence
is low. Overall, fairly calm and quiet TAF period.


Outlook: Rain chances and possible restrictions return Tuesday into
Wednesday as a cold front moves in. Lingering showers could keep
restrictions in place through Thursday.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Freeze Warning from midnight tonight to 9 AM EDT Monday for
     NCZ035>037-056-057-069-072-502-504-506.
     Frost Advisory from midnight tonight to 9 AM EDT Monday for
     NCZ068-070-071-082-507>510.
SC...None.

&&

$$

SYNOPSIS...SBK
NEAR TERM...CP/MPR
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...CP


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