Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 161733
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
133 PM EDT Sun Oct 16 2016
Moisture will diminish over the region today as an upper level
disturbance passes to the south. A low level ridge of high pressure
will remain over the area, with drier ridging building in aloft
through at least the middle of the week.
.NEAR TERM /THROUGH TONIGHT/...
As of 1045 am EDT Sunday: Pretty quiet out there for the late
morning update, with temperatures picking up fairly quickly as
expected. Have made some minor updates, namely to increase afternoon
highs just a tad across the Upper Savannah Valley, and decreased sky
cover a little this afternoon. No changes to PoPs at this time as
CAMs still developing some isolated convection across the mountains.
Otherwise, spotty slight shower chances will continue over the
higher ridge tops through the day as the low level flow veers around
more southwesterly and the parent surface high pressure center
migrates farther offshore. Maximum temperatures will likely run a
category or better above climo this afternoon as heating improves a
bit through the day.
500 mb ridging will return behind the wave from the lower MS river
valley through tonight. Clouds may be a bit less tonight under the
building ridge but moderating thicknesses will allow minimum
temperatures to recover another degree or two in most areas. Light
winds will make patchy fog a bit more likely.
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
At 200 AM Sunday: On Monday morning and upper ridge will extend from
TX to Hudson Bay, while an upper trough will be over the Western
USA. The pattern progresses such that by Wednesday morning the upper
ridge is centered over the Carolinas, and the trough upstream is
crossing the Rockies.
At the surface, on Monday morning a surface ridge will extend from
the Southern Appalachians to the the vicinity of Bermuda. Limited
moisture from the Atlantic and Gulf will stream north over this
ridge, but isentropic upglide and upslope flow will be rather week,
and not very supportive of precipitation. The surface ridge moves off
the coast on Tuesday, with limited Gulf moisture into the mountains
persisting. Temperatures will run above normal under the upper ridge.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
At 200 AM Sunday: On Wednesday morning an upper ridge will be extend
from LA to the Western Atlantic off the NC coast, while a trough
will be over the Rockies. By Friday the ridge moves offshore and the
trough reaches the Great Lakes and lower MS River Valley. By
Saturday the base of the trough crosses the Gulf States, with the
ECMWF closing off a deep upper low over near the border of AL/GA and
FL, and the the ECMWF closing one off over SC.
At the surface, on Wednesday a cold front will approach the lower MS
River Valley from the Northwest, crossing the river on Thursday.
Moist Gulf inflow ahead of the front appears to be limited with only
a modest pressure gradient in place, but precipitation chances should
ramp up as the front advances. The front reaches the Southern
Appalachians on Friday, where it slows due to the upper low forming.
Coastal areas appear more likely to get the heaviest rainfall based
on the latest model data, especially in the stronger ECMWF surface
low forms near the coast. Temperatures will start our above normal
under the upper ridge, followed by a decreasing diurnal range as
moisture increases with the arrival of the front.
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: VFR this afternoon and evening with FEW-
SCT VFR Cu and light S/SSW winds (5kt or below). With little in the
way of cloudiness overnight, expect patchy MVFR fog to form at most
sites, though chances are too low to include at KCLT at this time.
For KAVL, most guidance is pointing to 1/4SM or less, but have kept
current trend of 1SM given trend of poor overnight vsby guidance.
Any fog/br should lift quickly Monday morning with continued lgt/vrb
or light S/SSW winds.
Outlook: Surface high pressure, drier profiles, and ridging aloft
will set up across the region through the middle of the week. The
potential for mountain valley fog and low stratus will continue each
17-23Z 23-05Z 05-11Z 11-12Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% High 100% High 100% Med 75%
KHKY High 100% High 100% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 83%
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: