Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 220234

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1034 PM EDT Fri Oct 21 2016

Cool high pressure will continue to be in control of our weather
through the middle of next week. After having below normal
temperatures this weekend, temperatures will warm a bit going into
next week.


As of 1015 pm Friday: Trends are looking good for the late evening
update, and for now see no reason to make any adjustments to
overnight lows. Winds have been inched up just a tad based on
observations, and there have been some whoppers out there with a
gust to 89mph at Grandfather Mountain. Saw some webcam footage of
light snow showers at Mt. Mitchell and an mping report of some light
snow up in Avery County...lapse rates are pretty steep and with the
low-level CAA this isn`t totally out of the question, but really
only limited to the higher elevations. So with all that, will
refresh the wind advisory wording but no changes.

Otherwise, gusty northwest winds will continue across the southern
Appalachians through tonight. Mesoscale models indicate a nicely
formed band of downward omega in the lee of the mtns, remaining into
Sat morning. I will extend the current Wind Advisory until noon Sat.

Mixing and remaining pressure gradient will support marginal gusts
developing by mid morning, remaining through the rest of the day.
Temperatures will fall into the 30s and 40s across the mtns with 40s
to the east. Highs are forecast to range from the mid 50s within the
mtn valleys to mid 60s. RH values will fall into the 20s and 30s
east of the mtns.


As of 220 PM Friday, Heights will be on the rise throughout the
first half or so of the short term period, as anomalously deep
trough progresses off the East Coast. Sunday morning should
generally see decent radiational cooling conditions across most of
the mtn valleys and east of the mtns. A frosty morning still appears
to be a good bet in some mtn valley locations, particularly the
Little Tenn Valley, portions of the lower French Broad Valley, and
the high valleys of the northern mtns. Localized freezing temps will
also be possible in some of the notoriously cold spots within these
areas. The frost/freeze potential will continue to be mentioned in
the HWO.

After a typically warm/pleasant late October Sunday, rising
heights/warm advection flow will result in a considerable warm up to
the southeast of a short wave trough advancing across the northeast
quadrant of the country Sunday night into Monday. Temperatures are
expected to be a few degrees above climo during this time, with 80s
expected to return to portions of the Upstate and GA Piedmont Monday


As of 220 PM EDT Friday...starting with Monday evening with an upper
trough over New England and a ridge axis from Texas cross the
Dakotas. Surface high pressure centered over Chicago at that time.
A cold front will be crossing our region from north to south ahead
of this high pressure transiting to across the lower Great Lakes
and Ohio Valley. This front crossing early in the week should
certainly be dry. A trough arriving on Thursday will have some
amount of moisture and if the ECMWF model is correct then all rain
would pass us to the north.  The latest GFS has a 500mb closed low
forming over Wisconsin at 18Z Wed and moving SE toward our area on
Thursday. With this GFS solution, first moisture arrives in the NC
Mtns Thursday AM with at least some rain over the entire forecast
area late Thursday and Thursday night. This closed low opens up over
VA on Friday as all precip moves out to the east. At this point we
will slightly increase POPs and certainly increase some cloud cover
for Thursday into Friday.  Temperatures will be very close to normal
through this medium range period.


At KCLT and elsewhere: Only change to the KCLT TAF for the 03z AMD
is to bring the winds down a couple of kts. Otherwise, NW winds
should subside somewhat overnight, remaining close to 10kt though,
picking up again Saturday morning with sunrise and increased mixing.
Expect SKC for the most part on Saturday, with the only exception
being KAVL where some of the moisture in the NW flow may
occasionally make it up valley.

Outlook: Dry high pressure will then spread across the region on
Sunday and linger into early next week.

Confidence Table...

            02-08Z        08-14Z        14-20Z        20-00Z
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:


NC...Wind Advisory until noon EDT Saturday for NCZ033-049-050-053-


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