Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 260218

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1018 PM EDT Tue Oct 25 2016

Seasonal and dry high pressure remains over the region Wednesday...
before a weak cold front crosses the area Thursday. Warm high
pressure returns Friday before another weak frontal passage occurs
late Sunday. Warm and dry high pressure moves in early next week.


As of 1000 PM EDT...Areas of cirrus continue to stream across the
area within northwesterly flow aloft. The clouds are not having much
impact on temps, with readings running 8-12 deg cooler than this
time last night. I blended in a little more coop mos into the min
temps, which knocks them down a few degrees in some of the normal
cool spots. This results in greater coverage of frost, but still
with temps in the upper 30s to lower 40s, expecting frost to remain
patchy. I will opt not to issue any frost advisory this evening.

Otherwise, a 1032 mb high pressure continues to build eastward from
the southern shores of the Great Lakes. Shallow ridging continues
aloft with little moisture in profiles except for thin cirrus
arriving from the northwest. The ridge will settle overhead tonight
through Wednesday with any additional mid/high level moisture
passing over the ridge axis to the north of our area.

Southwesterly low level flow will then get slowly reestablished
through Wednesday as the surface high pressure center drifts toward
the eastern seaboard. Maximum temperatures will be comparable to
today as thicknesses should be slow to recover in the light veering


At 2 PM Tuesday: On Wednesday evening a low amplitude upper ridge
will be along the East Coast, while an upper trough will be crossing
the MS River Valley, and a high amplitude upper ridge will be over
the Rockies. The pattern progresses such that by Friday the upper
trough reaches the East Coast, and the upper ridge moves over the
Great Plains.

At the surface, on Wednesday evening a surface ridge will be along
the Eastern Seaboard, while a cold front will be crossing the MS
River Valley. Moisture ahead of the front will increase over our
area through the night, but will not be especially robust, as inflow
from the Gulf of Mexico diminishes with a wakening pressure
gradient. Instability appears to be marginal for convective. Frontal
passage appears to take place on Thursday night and Friday, with
drier air working into the area behind the boundary. Temperatures
will warm from near normal to slightly above normal.


At 2 PM Tuesday: On Friday evening the upper pattern deamplifies
over the Southeast, leading to nearly zonal flow. By Monday an upper
ridge amplifies from the Gulf of Mexico to the Great Lakes, and this
feature progresses to the Easter Seaboard by Tuesday.

At the surface, on Friday evening high pressure will extend down the
Eastern Seaboard, and will linger over the Carolinas and Georgia
into Saturday. A mainly dry cold front is expected to cross the area
from the northeast on Saturday night, with little or no
precipitation resulting, followed by more high pressure building
over our area into Tuesday. Temperatures will cool slightly, but
will remain above normal.


At KCLT and elsewhere: VFR conditions will continue through the
period at all the TAF sites. The only area with much threat of MVFR
fog overnight will be the southwest NC mountain valleys as the
airmass modifies. Winds will calm or very light overnight, favoring
a SE direction until around 9z, then briefly going back to ENE
across the foothills/piedmont. Winds will switch back to SE for good
by late Wednesday morning. Expect little more than a few cirrus

Outlook: High pressure will migrate offshore Wednesday night. A
fast-moving cold front will cross the area Thursday into Thursday
night, but with very limited moisture. Dry high pressure will return
Friday through the weekend.

Confidence Table...

            02-08Z        08-14Z        14-20Z        20-00Z
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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