Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 221803
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
203 PM EDT Wed Mar 22 2017
Cooler air returns to the region behind a departing cold front and
will linger through the end of the work week. A warm front will lift
north over the region over the weekend bringing increased chances
for widespread precipitation.
.NEAR TERM /THROUGH THURSDAY/...
As of 200 PM: As heights rise over the Southeast, surface high
pressure will move from the Great Lakes to the Mid-Atlantic region by
tomorrow morning. Low level cold advection will continue through that
time, as the high takes on a CAD configuration. However, while
warm advection will ramp up over the high during the day, it
does so without enough moisture for sustained cloud cover, much
less precip. Therefore it looks unlikely CAD will remain locked
in for long.
With skies remaining only partly cloudy overnight, temps are expected
to dip a few degrees below normal. A light breeze is progged to
persist overnight which should minimize any frost. However, the
northwest NC Piedmont is still expected to drop below freezing. The
Freeze Warning issued by the previous shift will be expanded to
include Lincoln and Cabarrus counties with the 3 PM package. Despite
sunshine, max temps will be held down 6-9 degrees below normal
tomorrow as the cold airmass remains in place.
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 220 AM EDT Wednesday: The center of the damming high
slides off shore Friday but the ridging remains in place even as
it takes on more of and east-west orientation through Friday
The guidance is also now in agreement on a dry forecast through
Friday. Lows Thursday night will be a few degrees below normal,
keeping frost concerns going for the NC Foothills and Piedmont
and eastern Upstate. Highs Friday will be near to slightly below
Low level moisture and upslope flow develops on Friday night and may
lead to isolated showers near the Blue Ridge over the NC/SC/GA
borders. Lows will be 5 to 10 degrees above normal.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 340 AM EDT Wednesday: Guidance in good agreement through the
medium range. The first of a series of upper lows moves from the mid
MS valley Saturday, to between the Great Lakes and OH valley Sunday,
then into New England Monday. A second upper low over the southern
plains Monday opens up and crosses the area as a weakening short
wave on Tuesday.
At the sfc, deep moisture increases from west to east Saturday and
Sunday as a cold front associated with the first upper low moves
toward the area. Precip chances slowly increase across the mountains
Saturday then spread across the area Saturday night and maximize on
Sunday. The front then washes out as it moves into the area from the
north on Monday. Precip chances taper of Sunday night and Monday in
response. Deep moisture and weak forcing return Tuesday as a weak
front moves in from the west with the second upper low/short wave.
Precip chances ramp back up in response.
Temps remain nearly steady 5 to 10 degrees above normal Saturday and
Sunday, rising to 10 to 15 degrees above normal Monday, before
dropping a few degrees Tuesday.
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR. Dry high pressure will build in from
the north tonight, in a pattern similar to CAD. However, moisture
will be insufficient to produce precipitation, and low cloud
cover will be confined to SW NC and western Upstate SC. Thus,
only KAVL and KAND are fcst to have a cig, which is still at VFR
level. Winds will reflect the CAD-like regime, mainly staying in
the NE quadrant through tonight in the Piedmont, but eventually
favoring SE at KAVL. The Piedmont sites may see winds veer to near
due E by midday Thu.
Outlook: Low level moisture begins to return from the south
Thursday thru Friday, resulting in a gradual increase in shower
chances and low cigs into the weekend.
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:
NC...Freeze Warning from midnight tonight to 9 AM EDT Thursday for