Area Forecast Discussion Issued by NWS Greer, SC
000
FXUS62 KGSP 130604
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
204 AM EDT Sat Apr 13 2024
.SYNOPSIS...
Drier air will filter into the region today, with sunny skies
and still gusty winds. Temps return to around normal today and
trend still warmer Sunday, remaining well above normal through at
least Thursday.
&&
.NEAR TERM /THROUGH TODAY/...
As of 130 AM: A channeled vort max surrounding upper trough
extends all the way back to around Lake Michigan. This is driving
a few showers across eastern KY/TN and now into some of the NC
mountains. Instability has diminished and so has shower coverage
over the last 90 minutes or so. Still can`t rule out a few sprinkles
across the mountains, or the foothills northeast of I-26. Based on
sfc temps and a couple of northern mtn webcams, higher elevations
may continue to see a rain-snow mix albeit not likely with any
additional accumulation. Coverage and intensity should continue
to wane thru daybreak, with clouds dissipating soon after. T/Td
remain on track for the morning following earlier tweaks.
Heights will rise as upper trough axis swings further east and
offshore by midday. The upstream ridge will be quite dry and
skies look to remain virtually clear through the day. The gradient
won`t be nearly as strong as yesterday, and low level winds will
be comparatively tame. Nonetheless, with flow remaining moderate
through the boundary layer, frequent gusts of seasonable magnitude
will continue. Mixing will be a little deeper than usual, and
winds at the top of the mixed layer suggest low advisory-level
gusts remain possible beyond the original expiration of the wind
advisory. By mid-afternoon, say 18z, the stronger gusts probably
will be confined to high elevations. Given the difficulty in
messaging a switch from a full-zone to high-elevation wind product,
we have opted just to extend the advisory until 6 PM for the same
zones, given that an occasional 45 mph gust can`t be ruled out in
high elevations until mixing completely ceases diurnally. It is
possible some zones could be let go earlier in the afternoon. On
another note, as temps return to about normal but dewpoints mix
down, RH ends up below 30 percent in many areas. See Fire Wx
section below for info on possible Increased Fire Danger Statements
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
As of 2:35 PM EDT Friday: The short-term fcst picks up at 00z on
Sunday with broad upper trofing moving further off the Atlantic
Coast, as broad relatively flat upper ridging builds over our
region. A fairly weak, embedded upper shortwave will translate
over our area late Sunday as broad upper trofing persists well
to our north over eastern Canada. Upper ridging will linger over
our area for the rest of the period as another upper trof cuts
off a closed low over the SW CONUS towards the end of the period
late Monday. At the sfc, broad high pressure will be centered to
our south over the Gulf Coast as the period begins. Over the next
24 to 36 hrs, a weak cold front associated with the above-mentioned
upper shortwave will move thru our area. The front should not have
much impact on our sensible wx other than some brief low-end PoPs
over our northernmost zones late Sun into early Mon. Otherwise,
temperatures will warm thru the period with values well-above
climatology.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 2:25 PM EDT Friday: The extended fcst picks up at 00z on Tuesday
with broad upper trofing will to our north and upper ridging over the
Southeast. Over the next couple of days, a southern-stream upper trof
will lift out of the Southwest CONUS and move up and over the upper
ridge causing it to flatten. The trof axis is expected to pass over
our area late Wed into early Thurs just as another broad upper trof/
closed low moves SE from central Canada. This system will continue to
translate SE thru the end of the period, and likely be centered some-
where over the Great Lakes by the end of the period next Fri. At the
sfc, our area will be under weak SLY low-level flow and the western
fringe of the Bermuda High as the period begins. Over the next 24 to
36 hrs, a robust low pressure system will eject from the Central Plains
and bring a fairly dry cold front to our doorstep by early Wed. The
front is progged to move thru our fcst area on Wed and then offshore
by early Thurs. In its wake, the sfc pattern remains progressive with
another low spinning up just behind the first low and moving another,
potentially stronger cold front to our doorstep as the period is ending
on Fri. As for sensible fcst, the first part of the period should be
mostly dry with chances for showers and tstorms ramping up towards the
end of next week as the stronger frontal system approaches our CWA.
Temperatures will remain well-above climatology thru the period.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: VFR thru Sunday morning. A few sprinkles
are possible at KAVL and KHKY early in the period but likely with
minimal impact aside from possibly enhancing gusts; FEW-SCT clouds
in the 050-080 level may be seen there and at KCLT. Breezy winds
will be the story again this period, although not nearly as robust
as they were Friday. Gusts will return by mid-morning at all sites,
with 15-20 kt gusts at times until nearly sunset. KAVL`s gusts will
ramp up after daybreak, frequently reaching 30 kt from late morning
through mid-afternoon. Except at KAVL, winds generally will remain
W to WSW this morning, going N of W with onset of diurnal mixing,
and probably backing slightly S of W when the gradient relaxes
more significantly tonight. KAVL will remain solidly NW to NNW.
Outlook: VFR conditions will persist through early next week as
high pressure builds across the region.
&&
.FIRE WEATHER...
Minimum RH values today are forecast to drop below 30 percent over
much of the western Carolinas, but winds will not be as gusty
as today. Nonetheless, low-end gusts of 15 to 25 mph over the
lower terrain and gusts of 20 to 40 mph over the mountains are
expected. Thus, Fire danger statements will be considered and if
issued will be out by 4 AM.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory until 6 PM EDT this evening for NCZ033-048>050-
052-053-059-063>065-501-503-505-507-509.
SC...None.
&&
$$
SYNOPSIS...Wimberley
NEAR TERM...Wimberley
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...Wimberley
FIRE WEATHER...GSP