Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 241801

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
201 PM EDT Mon Oct 24 2016

Seasonal and dry high pressure will remain over the region through
Wednesday. A weak cold front will cross the area Thursday. High
pressure briefly returns before another weak frontal passage on


As of 200 PM EDT: Upper level divergence on the south side of a
broad mid Atlantic jetlet may produce a few thin mountain cirrus
clouds into tonight. Meanwhile, A back door cold front at the
surface will move southward through western NC by this evening and
then settle south of the forecast area overnight. Only a few
locations in sheltered northern mountain valleys appear cool enough
for any patchy frost formation, so no advisory is expected.

Otherwise, deep layer NW flow will continue, with heights rising and
the pressure gradient relaxing through Tuesday. Surface high
pressure will build over from the north behind the front and push
lower thicknesses into the region. Weak downsloping will
continue to provide some measure of warming east of the mountains
despite the falling thicknesses - with maximum temperatures fairly
close to climatology.


At 2 PM Monday: On Tuesday evening an upper trough will be off the
East Coast, while an upper ridge will be over the Great Plains. The
ridge retrogresses over the Rockies on Wednesday while the eastern
trough progresses offshore, and another trough amplifies over the MS
River Valley. By Thursday the upper trough reaches the Great Lakes,
and the Central and Southern Appalachians, with an associated
shortwave crossing the mountains, while the upper ridge progresses
to the Eastern Slopes of the Rockies.

At the surface, on Tuesday evening a cold front will be well south
of our area, an high pressure will extend from the Great Lakes to
the Carolinas. High pressure persists over our area into Wednesday
night, finally weakening as a cold front approaches from the west
on Thursday. Meager moisture ahead of and along the front will limit
precipitation amounts, while instability will be limited for
convective development. Temperatures will run near normal.


At 2 PM Monday: On Thursday evening an upper trough will be over the
Eastern USA, while an upper ridge will exist along the East Slopes
of the Rockies. The pattern progresses such that by Saturday the
easter trough moves offshore, while the ridge upstream remains along
the Front Range, resulting in deamplification and more zonal flow.
By monday the upper ridge progresses to the MS River Valley, while
the trough downstream moves little, and as a result, the upper
pattern amplifies.

On Thursday evening a cold front will be dropping south across our
area, with only limited moisture along the boundary. High pressure
settles in over our area on Friday and Saturday. Another cold front
reaches our area from the north on Saturday night, moving slowly
south of the area by Monday. Moisture with the second front will be
limited as well, and instability will be lacking. Temperatures will
run slightly above normal.


At KCLT: Deepening mixing just ahead of an approaching back door
front is toggling winds WNW, with low-end gusts expected through the
afternoon hours. More solidly NW then NE flow is expected overnight
behind the front, with NE to ENE winds less than 10 kt continuing
through the end of period. Any clouds will be limited to thin cirrus
developing off the Blue Ridge.

Elsewhere: Thin cirrus developing in mountain wave cloudiness will
impact mainly KAVL to KHKY this afternoon and evening. NW flow is
expected at the NC TAF sites, with low end gusts, while WSW flow
initially in the Upstate of SC will toggle NW then NE overnight
behind a passing back door front. Anticipate VFR conditions
throughout, with light NE to ENE winds across the foothills through
midday Tuesday, except more northerly flow in the French Broad
Valley around KAVL.

Outlook: Dry high pressure will persist over the Southeast through
Wednesday. Then a fast-moving cold front will cross the area
Thursday or Thursday night, but with limited moisture. Dry
conditions return for next weekend.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
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%     High 100%
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 100%

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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