Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 171731
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
131 PM EDT Tue Apr 17 2018

.SYNOPSIS...
Temperatures will warm once again through midweek, but then 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.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1:30pm EDT Tuesday:  Temperatures are warming rapidly
following this morning`s cold low.  Today will warm to just shy of
normal, with above normal temps on Wednesday. As 850mb flow remains
strong, wind advisory for the highest elevations will continue until
this evening.  Radar and satellite are clear this morning as well,
with snow showers having ended along the TN border.  Next upstream
system approaches from the west late on Wednesday with some showers
possible in the mountains.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 230 AM EDT Tuesday: Shortwave ridging will be in place just to
our west with the departing upper low over New England continuing to
lift out, and another developing upper low working its way down the
MO Valley. With strengthening surface low over the Lower MO Valley
at the beginning of the period, surface pressure gradient will
remain strong and expect breezy conditions with yet again on
Wednesday, with strong winds out of the SW a good 15-20mph.
Temperatures temperatures will rise again a good 5 or so degrees
above seasonal normals in the low-level WAA regime and with
increasing thicknesses. The surface low will work its way east
across the Midwest Wednesday into Wednesday night, dragging a cold
front with it, and though the system will be mainly dry, still looks
like slight to low chance pops Wednesday night are warranted. Behind
the front on Thursday temps will be knocked down almost 10 degrees
from those on Wednesday, still breezy but with winds WNW (with
typical gap wind gusts were applicable). Well below normal Thursday
night and will likely have to consider some freeze products for the
NC mountain zones that are turned on; likely at this point too
breezy for frost concerns but will continue to reevaluate.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 300 AM EDT Tuesday: Very quiet to start the extended, with a
really lovely weekend in store across the area. High pressure over
the Northern Plains will work east as the omega-looking wavetrain
pattern progresses. Strong upper ridge over the Plains will slowly
damp during the weekend but mean troughing will remain in place over
our area through the period. Desert Southwest closed low will fill
somewhat as it moves east toward the Southern Plains early Sunday,
taking a bit of a southerly track underneath the ridge. Temperatures
will be 4-5 degrees below seasonal normal, but very pleasant and
dry conditions expected through the weekend.

The Southern Plains upper low and associated surface low will lift
moisture northward from the Gulf into the Lower MS Valley on Sunday,
as the New England upper trough continues to dominate. The upper
ridge forced north over Canada will set up a nicely confluent flow
over Ontario and Quebec. The Northern Plains surface high will
translate east over the Great Lakes Sunday and begin ridging down
the Eastern Seaboard Monday in a fairly strong Classical damming
pattern, with diabatic enhancement as moisture lifts into the Deep
South from the approaching surface low. Global models are trending
more south with the track of the surface low, more over the Gulf
Coast. Also, while 00z GFS and 12z ECMWF still bring/brought precip
up into our area, but new 00z ECMWF is now completely dry for us
Monday into Tuesday, and so to reflect that uncertainty have delayed
onset of pops and then reduced them accordingly. Temperatures on
Monday will definitely feel like we`re in a wedge, with current
guidance 10 degrees below normal.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
At KCLT and elsewhere:  Generally good VFR conditions with gusty
winds this afternoon and Wednesday afternoon. Westerly winds most
areas will decline after dark due to boundary layer decoupling,
except at higher elevations like KAVL.  Winds will pick-up again
during the day on Wednesday, backing to be more southwesterly as
upstream system approaches from the west. Wind gusts today and
tomorrow are expected to peak at aerodromes at around 25kts. Skies
will remain mostly clear with very few cumulus this afternoon, and
some high clouds entering from the west on Wednesday.

Outlook: Mostly dry conditions will continue for the rest of the
week. A dry cold front will arrive from the west on Thursday, with
some scattered restrictions possible and some showers in the
mountains.  Winds will be gusty at times in the afternoon through
Thursday.

Confidence Table...

            17-23Z        23-05Z        05-11Z        11-12Z
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:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory until 8 PM EDT this evening for NCZ033-048>052-
     058-059-062>064.
SC...None.

&&

$$
SYNOPSIS...TDP
NEAR TERM...WJM
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...WJM



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