Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 131949

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
249 PM EST Mon Nov 13 2017

High pressure will provide dry weather into mid week then a front
lingers near our area Thursday. A strong cold front crosses our
region on Saturday with much cooler temperatures to start next week.
 Expect another strong cold front to arrive in the middle of next
week just in time for Thanksgiving.


As of 205 PM EST Monday: A few small patches of low clouds remain,
but should be gone shortly, leaving a mostly sunny sky for the
rest of the afternoon. The exception will be the upslope areas
near the TN border, where the NW wind will continue to produce
clouds through sunset.

The next 24 hours should be dry as surface high pressure builds in
from the NW. Breezy conditions over the mtns will diminish this
evening. Min temps tonight are expected to be on the order of a
category below normal in most spots. Temps should get cool enough
for some fog to form in the mtn valleys. A short wave trof will
move overhead midday Tuesday, but with little to no moisture to
work with, its passage may be marked only by a deck of high-based
stratocu. High temps on Tuesday afternoon will also run about a
category below normal.


As of 2:30 PM Monday: A shortwave will continue to push off the
Carolina coast Tuesday evening as weak ridging aloft builds in
across the area on Wednesday, with high temperatures climbing into
the low to upper 50`s. A bit of a timing disagreement remains
between the GFS & ECMWF in regards to an approaching cold front, but
have kept with the general consensus of late overnight Wednesday
into Thursday morning. Do not expect much in the way of accumulation
with this system as the latest fcst soundings continue to illustrate
a fairly dry atmospheric column with the exception of limited low-
level moisture, but even then, forcing remains weak. Any chance of
rainfall will be along the TN/NC border Wednesday evening/Thursday
morning across the higher elevations. Cloud cover will gradually
decrease Thursday afternoon with high temperatures warming into the
mid 60`s across the piedmont and upstate, upper 40`s to upper 50`s
across the mountains.


As of 245 PM Monday: Guidance still showing significant
discrepancies regarding timing of the main weather maker during the
medium range. Before then, Friday looks to be a dry and mild day
with high pressure sliding east across the area. Lows will be near
normal and highs around 5 degrees below normal.

A strong short wave then crosses the area pushing a relatively
strong cold front through the area. The guidance agrees on this.
However, the GFS is fast pushing the front across the area on
Saturday. The ECMWF is significantly slower with the front crossing
the area Saturday night. The Canadian and GEFS mean is somewhere in
between the two. Likely PoP will be needed for some period,
especially across the mountains and northern tier where moisture and
forcing are best. However, given the continued timing differences,
have capped PoP at high chance across the mountains for now and
slightly below that elsewhere. Still keep the highest PoP on
Saturday this seems to be in the middle of the timing extremes but
slowed precip onset Friday night and linger chance PoP through the
evening Saturday night. None of the guidance looks especially
unstable or produces more than moderate QPF with this front. Winds
will become quite gusty just ahead and behind the front. Lows Friday
night will be a little above normal while highs Saturday will be a
little below normal. Lows Saturday night drop to around 5 degrees
below normal putting the potential for some high elevation NW flow
snow in place. Right now, no significant accumulations are expected.

Cool and dry high pressure builds in behind the front. Winds will
remain gusty on Sunday then taper off Monday. Highs around 10
degrees below normal fall to 10 to 15 degrees below normal Monday.
Lows will be around 10 degrees below normal.


At KCLT and Elsewhere: VFR through the period. Any remaining low
IFR stratus on the eastern fringe of the fcst area should be gone
by 1830Z and has already departed the TAF sites, as indicated
by satellite trends. The afternoon should have a N wind at 5-10,
with few/sct high based stratocu forming, particularly over the NC
Piedmont. Wind will be gusty from the NNW at KAVL through the end
of daylight. Sky will start clear after sunset, but models show
some moisture drifting in from the NE in the pre-dawn hours. Have
elected to keep this SCT for now, but a BKN ceiling is possible
mainly at KHKY/KCLT, around 080-100 if it materializes. Wind should
stay light NE overnight and Tuesday morning.

Outlook: Drying conditions will keep the area generally free of
restrictions through Wednesday, with the exception of typical
mountain valley restrictions around daybreak each morning. Another
front will move into the region from the northwest Wednesday night
into Thursday, but moisture will be limited.

Confidence Table...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       High  87%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High  94%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     Low   58%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High  94%     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:




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