Area Forecast Discussion Issued by NWS Greer, SC
000
FXUS62 KGSP 191034
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
634 AM EDT Tue Mar 19 2024
.SYNOPSIS...
Drier and cool conditions continue today as Canadian high pressure
moves over the Southeast. Warmer temperatures return Wednesday
into Thursday with continued dry weather. A low pressure system
will bring cooler temperatures and rain back on Friday, with rain
chances potentially lingering into Saturday morning. High pressure
should build back in from the northwest to salvage the second half
of the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 630 AM EDT Tuesday: No major changes were needed as the
forecast remains on track. Temps in the Freeze Warning are still on
track to drop below freezing prior to sunrise, with some locations
already at or below freezing as of 630 AM. Wind chills this morning
are in the upper teens to low 20s across the mountains and the low
to mid 20s east of the mountains. Higher elevations in the NC
mountains are seeing wind chills from the single digits to below
zero. Cloud cover continues along the northern NC/TN border this
morning, but clear skies persist elsewhere. Cloud cover will
continue decreasing through daybreak along the NC/TN border,
becoming sunny by mid-morning. Wind gusts will linger across the
mountains this morning, but should gradually decrease in speed as
the pressure gradient relaxes. Since the growing season has already
started in the SC Upstate, portions of NE GA, and the southern NC
Foothills and Piedmont, the Freeze Warning remains in place for
these locations through 10 AM. After this time, temps will be above
freezing in these locations.
It will remain dry and cool again today, with breezy winds returning
this afternoon. Although gusts will not be as strong as yesterday,
abundant insolation will lead to minimum RH values falling below 25%
across the forecast area today. In coordination with land managers
and neighboring forecast offices, an SPS for Increased Fire Danger
was issued for all of western North Carolina and northeast Georgia
for this afternoon and evening. See the fire weather discussion
below for more details. Winds will start out NW this morning,
turning SW (east of the mountains) and W/WNW (across the mountains)
by this afternoon. Highs this afternoon will end up 3 to 8 degrees
below climo. Breeze winds will remain across the mountains through
the overnight hours, while winds east of the mountains will
gradually diminish during the early overnight hours. Although clear
skies will remain in place tonight, lows will be around 5-10 degrees
warmer than lows this morning.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 206 AM EDT Tuesday: The middle part of the week continues
to look quiet for the most part. A broad low amplitude mid/upper
trof over the east half of the United States will slowly fill
on Wednesday. The air mass over the Southeast modifies quickly
as heights rise, with temperatures rebounding back to five
degrees above normal for Wednesday afternoon, while keeping the
RH relatively low. That gives us one more day with much of the
area east of the mountains getting down into the 25-30 percent
range, but wind should not be significant. One final reinforcing
cold front should cross the region from the NW Wednesday evening,
but the upstream air mass is not nearly as cold as the previous
one. Low temps should be close to normal Wednesday night and
the highs on Thursday will only drop back 3-5 degrees compared to
Wednesday with increased cloud cover, thus still on the warm side of
normal. Changes should start happening on Thursday and into Thursday
night as a srn stream system comes out over the southern Plains,
building a downstream ridge over the Carolinas, which supports
an elongated sfc high from Quebec to the Mid-Atlantic Coast by
daybreak Friday. Moisture associated with the low approach from
the west will begin to spread over the region in the overnight
hours, with isentropic lift forcing the development of some light
rain which may reach the ground before sunrise. The increased cloud
cover should keep low temps above normal, and above freezing across
the mtns as the precip begins.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 330 AM EDT Tuesday: By daybreak on Friday, all the players
should be on stage for hybrid cold air damming to develop across
the western Carolinas and northeast Georgia, with a 1032 mb high
sliding off the Mid-Atlantic coast in the morning and improving
moist isentropic upglide and weak mid/upper forcing doing their part
to spread light precip across the region from the southwest ahead
of the upper trof moving across the lower MS Valley region. Precip
chances quickly ramp up to likely by afternoon, helping to lock in
the wedge air mass east of the mtns, while an almost Miller-B type
low organizes to our southwest. For temps, we will undercut the
NBM by several degrees, which should keep the high temps on Friday
afternoon well below normal and not getting out of the low/mid 50s
outside the mtns. Fcst soundings over the mtns suggest a snow level
perhaps making it down to about 7k feet at some point, so a few
wet snowflakes won`t be ruled out on the tall peaks, but this will
not be included at this time. A few embedded thunderstorms could
develop over the southeastern fringe, but fortunately the wedge
will preclude any severe storms owing to the lack of sfc-based
buoyancy, which is good because shear will be strong. A low level
jet feature should translate east across the region Friday night
and take most of the rain with it before daybreak Saturday as a
sfc low strengthens off the Southeast Coast, but the operational
models keep the sfc low in close enough proximity early in the day
to suggest that precip could easily linger well into the morning,
while taking well into the afternoon to drain the wedge. That
makes the temp forecast for Saturday really low confidence. The
low should move away late in the day and high pressure builds in
from the west to dry us out Saturday night.
The remainder of the medium range should be fairly quiet even as
the pattern remains progressive. An upper ridge in the nrn stream
will support a large sfc high ridging down across the region for
Sunday into Monday. Meanwhile, a deep mid/upper trof moving across
the southwestern United States will help develop an increasingly
SW flow aloft, though moisture and warm advection will be slow to
return. The rest fcst will be kept dry with a slow warming trend.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR and dry through the 06Z TAF forecast
period thanks to high pressure. Low VFR cloud cover is noted along
the northern NC/TN border this morning, with clear skies in place
elsewhere. This cloud cover will gradually decrease through
daybreak, becoming clear. Clear skies are expected everywhere the
rest of the TAF period. Wind gusts have tapered off across the
terminals this morning. However, KAVL should see intermittent gusts
linger through this morning before tapering off. Some guidance keeps
gusts around at KAVL through early this afternoon, but confidence on
this is low. Winds are mostly NW this morning and will gradually
turning SW (east of mountains) and W/WNW (across the mountains)
early this afternoon. Wind gusts return this afternoon so have low-
end gusts mentioned across the terminals, with the exception of
KAVL. Gusts should linger across the SC terminals through late
tonight, while gusts at KCLT and KHKY should taper off by this
evening. Low-level wind shear may develop at KAVL late tonight into
daybreak Wednesday, but with this being towards the end of the
forecast period, confidence is low on this potential.
Outlook: VFR conditions will linger through mid-week. A low pressure
system will bring rain and associated restrictions Friday into early
Saturday.
&&
.FIRE WEATHER...
Fire weather concerns return again this afternoon and early evening
with forecast minimum RH values falling into the teens and lower
20s, and with forecast wind gusts ranging from 20 to 30 mph across
the western Carolinas and northeast Georgia. In coordination with
land managers and neighboring forecast offices, an SPS` for
Increased Fire Danger was issued for all of western North Carolina
and northeast Georgia for today. An SPS for Increased Fire Danger
was not issued for the SC zones as fuel moisture values are running
high. Winds will start out NW early this morning before gradually
turning SW (east of the mountains) and W/WNW (across the mountains)
this afternoon.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Increased Fire Danger from 11 AM EDT this morning through this
evening for GAZ010-017-018-026-028-029.
Freeze Warning until 10 AM EDT this morning for GAZ018-026-028-
029.
NC...Increased Fire Danger from 11 AM EDT this morning through this
evening for NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510.
Freeze Warning until 10 AM EDT this morning for NCZ068>072-082-
508-510.
SC...Freeze Warning until 10 AM EDT this morning for SCZ008>014-019-
104>109.
&&
$$
SYNOPSIS...AR/PM
NEAR TERM...AR
SHORT TERM...PM
LONG TERM...PM
AVIATION...AR
FIRE WEATHER...AR