Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 140538

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
138 AM EDT Wed Mar 14 2018

An upper level disturbance will cross the region overnight, with
cold and otherwise dry high pressure building across the area
through Thursday. Windy conditions will develop from time to time as
well, mainly during the daylight hours. Expect a warming trend later
in the week to near and above normal temperatures. A cold front and
area of low pressure will bring showers early in the weekend.


As of 1030 PM: The forecast remains on track, with water vapor
imagery showing the potent upper vorticity lobe surging southeast
into Kentucky late this evening, and with IR imagery showing plenty
of cold tops along with weak radar returns indicating snow showers
over the mountains. Cold cloud tops of minus 18C are already
impinging on the TN border area of the North Carolina mountains, and
cloud top temps of minus 25C are indicated upstream just ahead of
the vorticity maximum. No changes appear needed to the hazards on
the late evening update. Still expect that snow showers should lay
down some quick accumulations farther east than the traditional
upslope areas given the strong shortwave forcing. Finally, scattered
snow flurries, with some slight chances of measureable snow showers,
will still be featured east of the mountains across western NC after
08Z as the deeper forcing arrives. Cannot rule out some snow reports
anywhere in western NC overnight into Wed. morning, and possibly
across the far northern/eastern Upstate as well. Western mountain
locations should see very slippery roadways with temperatures in the
teens and 20s as well.

The snow showers will wind down through Wed morning, giving way to
another unseasonably cool (maxes about 5 degrees below today`s
readings, or about 15 degrees below climo), windy, and very dry day.
In fact, RH is expected to fall to the 15-25 percent range across
the Piedmont and foothills during the afternoon. (See Fire Wx


As of 215 PM Tue: Heights will rise Wednesday night into Thursday
as the upper trough lifts out of the region. Min temps will remain
below normal Thursday morning, though they will be warmer than those
Wednesday morning. Despite the retreating trough, the gradient flow
will in fact peak during the day Thursday. Advisory level wind
gusts are likely over at least the higher mountain elevations,
although gusts will be a nuisance throughout the area. Max temps
will be about normal.

Thursday night into early Friday, the axis of a low-amplitude
ridge will move east across the lower Mississippi Valley, while
high pressure simultaneously builds south through the western
Great Lakes. A very slow-moving cold front will set up over
KY/TN and be forced southeastward into our area. The flow into
the mountains still will be northwesterly, and the cold front
seems to pool enough moisture that some guidance members develop
a small amount of upslope QPF Friday morning. We will reflect
small precip chances as a result. Temperatures may be near or
slightly below freezing in the high elevations at onset, but the
mention of snow has been minimized due to low confidence and with
thermal profiles potentially being too warm aloft for any real snow
growth. The cold front will shift across the CWFA later Friday,
bringing higher precip chances to the mountains and allowing at
least a slight chance to most other locales. Max temps warm to
about a category above normal across the Piedmont, staying near
normal in the mountains due to cloudier skies.


As of 245 PM EST Tuesday: The medium range forecast begins Friday
night as latest guidance continues to prog an overall unsettled
weather pattern for most of the weekend and through into early next

Sfc low across the central plains Friday night will continue to
propagate eastward towards the southern Appalachians through into
Saturday and move overhead Saturday night, as the once extended warm
front pushes through the FA as a back door cold front. As a result,
expect mentionable PoPs across the NC mountains Friday night to
gradually expand through into the NW Piedmont and Upstate on
Saturday and Saturday evening, with the higher PoPs to remain
confined along the TN border. Given colder temperatures across the
northern NC mountains into early Saturday morning, would not
entirely rule out a transition from rain to wintry precip, with a
brief period of snow showers before daybreak, transitioning back to
all rain as temperatures warm. Elsewhere, expect any precip that
falls to fall as all rain. As this system pushes off the Carolina
coast into Sunday afternoon, sfc high pressure will build in across
the area with upper ridge setting up across the upper Midwest and
southward, allowing for dry conditions to settle in for the rest of
the weekend and a few peaks of sunshine amidst the otherwise cloudy
forecast period.

Into early next week, guidance continues to disagree on the timing
and placement of the next approaching system, with the latest GFS
solution faster than that of the ECMWF, placing the system further
south as well. For now, kept with overall trends of low end
mentionable PoPs for Monday and Monday night across the FA. Guidance
continues to depict some weak instability on Monday, which could
trigger a few isolated thunderstorms, especially across the
southwestern portions of the FA. Temperatures overall will remain
above normal for afternoon highs, to around normal for overnight


At KCLT and elsewhere: MVFR cigs have developed at KAVL with -SHSN
moving across. This will likely bounce up and down early this
morning. Have included TEMPO -SHSN for KCLT and KHKY as well as
moisture moves into the NC Piedmont. Low VFR this morning will give
way to SKC or at worst intermittent cirrus the rest of the period.
NW winds expected through most of the period, continuously gusty to
25-30kt at KAVL and picking up through the morning at the rest of
the TAFs. Winds should begin to subside this evening and back around
to the WSW, with timing at KCLT of 06z.

Outlook: VFR conditions are expected to persist through at least
Thursday. Chances for precipitation and restrictions will gradually
increase from late Friday into the weekend.

Confidence Table...

            05-11Z        11-17Z        17-23Z        23-00Z
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:


Gusty northwest winds developing in the wake of a strong upper air
disturbance will bring drier air to the region on Wednesday.
Sustained mountain winds of 15 to 25 mph, with gusts as high as 40
mph are expected, while winds/gusts will be about 10 mph less than
that in the foothills/Piedmont. Meanwhile, minimum RH in the 15 to
25 percent range is expected across the Piedmont and foothills, with
25 to 30 percent min RH expected in the mtn valleys. Based upon the
latest RAWS fuel moist observations, and per information from NWS
state liaison coordination calls with land management agencies,
fuels aren`t really dry enough to entertain any special Fire Wx
products. However, with fuels having another day to dry out, and
another dry/windy day anticipated for Thursday, coordination may be
needed tomorrow for potential headlines on Thursday.


NC...Winter Weather Advisory until 11 AM EDT this morning for


SHORT TERM...Wimberley
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