Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 151821
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
221 PM EDT Sat Oct 15 2016
Moisture will increase from the west tonight ahead of an approaching
upper level disturbance. Cool high pressure atop the region will
weaken on Sunday. A dry and increasingly warm southerly flow of air
will then be seen Monday through Wednesday.
.NEAR TERM /THROUGH SUNDAY/...
As of 215 PM EDT Saturday: Weak upslope flow around the base
of the surface high pressure in place over New England has led to
increasing cloud cover especially across the Piedmont this
afternoon. Temperatures are being held a little cooler than forecast
in these areas, though they have risen to near normal where the sun
has managed to peek through. Weak ridging aloft up the Eastern
Seaboard continues with weakness over the Tennessee River Valley
continuing to separate from the main shortwave flow which is working
its way up over the Great Lakes.
The weakness will slowly slide east across the Deep South through
the period as the northern shortwave and associated front push the
surface high to the south, which will bring winds around from more
E/ESE to SE/S through the period. Low-level moisture will continue
to advect into the region (not much in the way of deep-layer
moisture), though with the trajectory shift in low level flow the
upslope component will be more confined to the southwest mountains
than the entire Piedmont to Blue Ridge areas. Expect another round
of patchy fog and low clouds in the morning, and cannot rule out a
few sprinkles or brief showers in those southwest mountain areas.
This will again hold overnight lows several degrees above normal,
not too dissimilar from what we saw this morning. For Sunday, the
southerly flow and WAA will allow temperatures to warm up, several
degrees warmer than those today, and a good 5 degrees above seasonal
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
At 215 PM Saturday: Mid level heights will increase through the
period across the region with the center of a 500 mb high expected
to be over South Carolina at 00z Wednesday. At the surface, high
pressure will be centered along the coast for the entire period.
Expect a warming trend through the period with highs outside the
mountains climbing into the lower 80s on Monday and the into
the middle 80s in spots on Tuesday. No rain is expected.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 215 PM Saturday: A robust but flat upper ridge will be in
place over the Southeast Tuesday night and Wednesday, becoming
centered more offshore Thursday as an amplifying trough moves
through the middle of the CONUS. This trough reactivates a stalled
frontal boundary over the Ohio Valley, which subsequently pushes
thru the Southeast as a cold front. Some model depictions thereof
would suggest this will be our first really good blast of cold air
It still looks likely the CWFA won`t see any precip until this
frontal system enters the region. The GFS is a bit more interesting
than the EC, as it depicts a cutoff low developing within the trough
and moving across the Upper South Friday and Friday night. As the
trough begins to take on a negative tilt, shear parameters ramp up
invof the southern Appalachians, implying some possibility of a
high-shear low-CAPE event. The EC is faster in its progression of the
pattern and puts said threat over the southeast coast, and slightly
earlier at that.
Max temps will remain very warm, 10 to 15 degrees above normal, on
Wednesday. As heights fall and clouds build ahead of the fropa,
slightly cooler temps arrive Thu before more remarkable temps return
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: MVFR cigs continue to dominate the Upstate
as well as NC Piedmont with upslope flow continuing. Except for
KAVL, expect that MVFR cigs will continue through 20z or so. Lgt/vrb
to light SE winds will continue this afternoon. With little change
to the pattern, expect to see another round of MVFR restrictions
overnight and toward daybreak, though expect we will see see IFR at
KHKY and KAVL. As surface high slides south tomorrow, at some point
winds will veer around to the SW, but likely not until beyond the
end of the period.
Outlook: Surface high pressure will persist across the region
through late weekend, with upper ridging becoming more dominant
through the middle of next week. The potential for mountain valley
fog and low stratus will continue each morning.
18-24Z 00-06Z 06-12Z 12-18Z
KCLT Med 67% High 100% High 97% High 100%
KGSP High 100% High 85% High 94% High 100%
KAVL High 100% Med 60% Med 66% High 95%
KHKY Med 69% Low 58% Med 79% High 94%
KGMU High 100% High 92% Med 77% High 100%
KAND High 100% High 97% High 88% High 97%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link: