Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 162132

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
532 PM EDT Mon Apr 16 2018

After cold conditions tonight, temperatures will warm once again
through midweek. Another cold front will move through the area on
Wednesday night, bringing a chance of rain to the mountains. Dry and
seasonal conditions are expected for the end of the week.


As of 530 PM Monday: Minor adjustments made to
temperatures/dewpoints to coincide with latest trends, as the rest
of the near term forecast remains on track.

As seen from latest radar imagery, light snow continues to fall
across the mountains, mainly along the TN border and in the higher
elevations. Elsewhere across the Upstate and NW Piedmont, conditions
remain quiet and will continue to do so through tonight, as will the
breezy northwest winds. As skies gradually clear, temperatures
currently in the 40s to 50s (30s to 40s across the mountains), will
drop quickly under ideal radiational cooling, bringing the coldest
temperatures expected for the rest of the week to the FA. A Frost
Advisory remains in affect for portions of the NW Piedmont and
Upstate, as well as a Freeze Warning for the southern mountains.

Otherwise, clear skies and dry surface air will create conditions
possibly favorable for a cold Tuesday morning, though this will be
mitigated to some extent by continued winds.  Winds in the piedmont
area look to decline to 4 to 6 kts, and some areas of frost look
reasonable.  Frost Advisory is in effect for areas with minimum
temperatures 34 or less that were not already in a freeze warning.
Frost may not be visible due to dry air limiting condensation, but
surface skin temperatures below 32 will have the same effect on
plants. Tuesday will rapidly warm and frost/freeze conditions will
be short lived. Highs Tuesday will be close to seasonal normal.

With northwesterly upslope flow along the TN/NC border, some snow
showers that we`ve seen most of today at higher elevations with up
to an inch of accumulation, will continue until midnight or so this
evening, after which continued drying will eliminate any precip
chances.  850mb northwesterly winds of 40 kts will also continue
this evening, as will the wind advisory for some high elevations.
Anticyclone over the Gulf of Mexico will maintain 850mb flow over
the area through Tuesday, and some strong wind gusts at high
elevations in the mountains will continue to be possible Tuesday.


As of 200 PM EDT Monday: Westerly flow will develop across the
region Tuesday night and Wednesday ahead of a system crossing the
Ohio Valley. This will lead to a rapid warm up to above normal
temperatures on Wednesday. Expect highs to reach around 80 in the
Piedmont and into the middle 70s in the mountain valleys.

A cold front associated with the Ohio Valley system will move across
the region Wednesday night. This will be a dry front for most of the
forecast area. However, a few light showers can be expected in the
mountains near the Tennessee border. Highs will cool to at or just
below normal on Thursday with readings in the lower 70s in the
Piedmont to lower 60s in the mountain valleys.


As of 230 PM EDT Monday: The medium range period will begin quiet,
with a very interesting flow pattern evolving by early next week. An
upper trough axis will be on its way out of our area in the wake of
a dry front Thursday night and Friday, with benign and slightly
cooler than normal conditions expected through Saturday as surface
high pressure moves through the OH River Valley and slowly migrates
towards the Mid-Atlantic coast by early Sunday. Aloft, a split flow
pattern will take shape as an upper low cuts off over the southern
plains and swings down towards the southeastern states.

As this upper low and its surface reflection drop towards the Gulf
coast Sunday, the sprawling surface high (over parts of New England
and extending off the coast) appears that it will set up a wedge-
like surface pattern down the spine of the Appalachians. Global
models are in surprisingly good agreement on this point, though the
evolution of this type of pattern is generally quite uncertain. The
upper/surface cutoff low will spread precipitation into our area
beginning Sunday night, aided by the potential wedge of surface high
pressure over the Carolinas. The pattern isn`t particularly
progressive, so without getting into finer details, it appears that
the start of next week will be wet, with a reduced diurnal range and
max temperatures well below average.


At KCLT and elsewhere:  Strong surface low centered east of the
Great Lakes will keep 850mb flow strong through Tuesday and maintain
northwesterly to southwesterly surface winds of 10 to 20 kts with
gusts to 25kt.  No restrictions due to CIGs or Visibility, as air is
drying with only some afternoon cumulus around FL030 to FL050, which
will be broken this afternoon, with clearing after dark.  Some
isolated showers will persist through this evening along the TN
state line.

Outlook: Other than perhaps some lingering mountain showers, dry and
cooler conditions will continue into mid week. A dry cold front will
arrive from the west on Thursday, with some scattered restrictions

Confidence Table...

            21-03z        03-09Z        09-15Z        15-18Z
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:


GA...Freeze Warning from midnight tonight to 9 AM EDT Tuesday for
NC...Frost Advisory from 3 AM to 9 AM EDT Tuesday for NCZ035>037-
     Freeze Warning until 9 AM EDT Tuesday for NCZ051-052-058-059-
     Freeze Warning from midnight tonight to 9 AM EDT Tuesday for
     Wind Advisory until 8 PM EDT this evening for NCZ033-049-050.
SC...Frost Advisory from 3 AM to 9 AM EDT Tuesday for SCZ001>003-


LONG TERM...Carroll
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