Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 281053

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
653 AM EDT Tue Mar 28 2017

A cold front will approach from the northwest today and settle
southeast of the area tonight into Wednesday. Drier weather will
develop as high pressure builds southward from eastern Canada along
the east coast. Moisture will gradually return on Thursday, with
abundant moisture setting up by Friday as a strong low pressure
system moves east from the Mississippi River Valley. Drier weather
will return for the weekend.


As of 645 AM EDT: PoPs have been trimmed back to feature mainly
scattered showers across the Charlotte area and lower piedmont for
the next couple of hours as a vigorous wave lifts by to the north.
The latest surface analysis shows a front settling southeast of the
Ohio valley and this boundary is expected to push in the northern
tier through the afternoon hours. Mid level drying will work in from
the west behind the wave, but low levels will remain moist in the
pre-frontal airmass and scattered thunderstorms along and ahead of
the boundary are expected - especially out across I-77 this

Westerly downsloping flow will work against coverage in most other
foothill and lower piedmont locations through late day. Upper
ridging will develop tonight as the surface cold front gradually
settles off to the southeast by daybreak Wednesday.


As of 255 AM EDT Tuesday: Upper ridging will build over the area
through Wednesday east of a strong closed low moving across north
Texas. The passing surface cold front will settle well south of the
region and high pressure will nose down east of the Appalachians
from the Great Lakes/eastern Canada through Wednesday night. Despite
the fropa, good insolation will boost temps back into the upper 70s
to lower 80s east of the mountains Wednesday afternoon.

The upstream low pressure system will lift northeast through the
southern plains on Thursday with persistent ridging downstream
across the southeast. Very weak upglide may get reestablished over
the developing cold air damming as early as late Wed. night, with
PoP increasing gradually through Thursday. Will lean toward the
cooler MOS temps for Thursday afternoon with cold air damming onset
quite possible.


As of 255 AM EDT Tuesday: Heights will fall from the mid Mississippi
river valley and the lower OH valley toward the TN river valley
through the day on Friday. This trough should cross our region
Friday night. Improving upglide moisture will get established well
east of this system by Thursday evening and deeper moisture will
arrive mainly Friday through Friday night. The surface low pattern
should evolve in a Miller B type fashion, with gradual erosion of
the wedge layer and instability steadily uncovered from south to
north during the day Friday. This will make thunderstorms quite
possible, and severe weather not out of the question Friday as the
southerly low level jet ramps up.

Dry ridging will return over the southeast Saturday through Sunday.
Temperatures should run generally 5 to 10 degrees above climatology
in most areas over the weekend. Atlantic moisture return around the
high pressure, and associated with upslope flow, may bring some
clouds back into the picture Monday, and possibly light
rain/showers. Temperatures should thus be a bit cooler Monday
afternoon, with less diurnal range.


At KCLT: All of the better early morning convection has moved east
of the airfield at issuance time, with just lingering VCSH through
mid morning. Mainly VFR cigs are being observed, but abundant low
level moisture remains in place ahead of the approaching surface
front and occasional MVFR cigs look likely. The trailing surface
cold front will approach from the northwest for the afternoon hours.
Will time some TEMPO TSRA along the front to mainly after 19Z.
Surface winds will be southwesterly with possible low end gusts this
afternoon, turning WNW with fropa during the evening hours and
slackening overnight.

Elsewhere: Precipitation will be sparse the rest of the period as
drier air is working in aloft from the west. However, low levels
remain very moist and MVFR tempo IFR cigs are likely through mid
morning before conditions return to VFR. Coverage along the
approaching boundary this afternoon should be less across the
mountain/foothill sites than at KCLT. Southwest winds will be gusty
at times ahead of the front, turning northwest with fropa later this
evening. Winds will remain NW at KAVL throughout.

Outlook: Drier conditions should briefly return Wednesday before
another storm system begins affecting the region Thursday through
Friday. Drier conditions will return again for the weekend.

Confidence Table...

            11-17Z        17-23Z        23-05Z        05-06Z
KCLT       High  94%     High  94%     High 100%     High 100%
KGSP       High  94%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     Med   62%
KHKY       High  87%     High 100%     High 100%     High 100%
KGMU       High  94%     High 100%     High 100%     High 100%
KAND       High  94%     Med   61%     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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