Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 221429

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
929 AM EST Wed Nov 22 2017

In general, dry high pressure will persist over the area through
early next week. A couple of cold fronts will pass the area
without enough moisture for precipitation. Temperatures will
remain seasonable.


As of 930am EST Wednesday: GOES-R Fog imagery shows a little fog still
hanging-on in Chester, York, and Abbeville counties, but this
should clear as well over the next hour. Skies are otherwise
clear. Clear skies today will give good surface mixing
conditions and we expect to see a decent surface reflection of
the 850mb 10 to 25kt north-northwesterly winds with some

Highs will be around 5 degrees below normal across the mountains and
near normal elsewhere.  Winds taper off quickly this evening with
mostly clear skies remaining in place as high pressure builds into
the area. Lows will be around 5 degrees below normal.


As of 245 AM Wed: The base of an upper trough will cross the
Appalachians during Thanksgiving Day, though it is associated
with very little moisture of its own. A shortwave will begin to
separate from this trough over the eastern Gulf of Mexico at that
time. This will be reflected as a sfc low, which will approach
the Florida Peninsula gradually thru Friday. You may recall that
we had been following the models` various depictions of moisture
advection preceding this low Thursday or early Friday, spreading
precip from the Atlantic up into portions of the CWFA. As of this
morning`s 00z cycle, none of the major models indicate this is
likely enough to warrant PoPs. However, a wrinkle: the operational
NAM deviates from GFS/EC/CMC and most SREF members, suggesting
the low will take a more westerly track over the GA/SC coast. As
a result it shows precip spreading into our area early Saturday
morning. This is being discounted with this package. NAM temp
profiles would support freezing rain given subfreezing sfc temps
(which blended min temps do not indicate). But no PoP is being
included in this package for this part of the fcst.

Aside from the sfc low possibility, it is looking likely
Thanksgiving Day and "Black Friday" will be marked by rather
uneventful weather. Weak mid to upper level flow will persist as we
are caught in the weak deformation zone between the aforementioned
features, and little forcing overall. Max temps Thu will be several
degrees cooler than today, with Friday early morning temperatures
ranging from around 30 over much of WNC to the mid to upper 30s
over the western Upstate and NE GA. Near-normal temps return Fri
aftn and Sat mrng.


As of 315 AM Wed: Another northern-stream upper trough moves
into the northeastern CONUS Saturday. The accompanying cold front
initiates NW flow, which will linger into Monday. The global models
indicate the front will lack enough moisture for a mentionable PoP
even along the Tenn border. However, min temps will dip several
degrees below normal Monday morning. The expansive high behind the
front will drift eastward and offshore by Tuesday, suggesting the
cold snap will be brief. Eventually this should set up return flow
and precip chances toward the middle of the week, though after
the end of Day 7.


At KCLT and Elsewhere: Morning fog should burn off relatively
quickly this morning, but low cigs could linger a little longer
before the weak cold front moves through. The mountain clouds should
dissipate through the morning as well leaving cirrus for the bulk of
the day. N to NW winds become N to NE and gusty with mixing behind
the front. Winds taper off this evening. VFR clouds will redevelop
just to the west of the area and could move in late tonight. NE
winds continue overnight.

Outlook: Expect VFR through the forecast period as dry/cool
conditions prevail.

Confidence Table...

            14-20Z        20-02Z        02-08Z        08-12Z
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%     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:




SHORT TERM...Wimberley
LONG TERM...Wimberley
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