Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 152023
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
323 PM EST Wed Nov 15 2017

.SYNOPSIS...
A weak cold front crosses our region early Thursday. A strong cold
front crosses the area over the weekend with much cooler
temperatures to start next week.  Cool high pressure will be the
dominant weather feature for the first half of next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 2:30 PM Wednesday...Latest observations depict temperatures
overall ranging from the low to upper 50`s across the forecast area
this afternoon, as lower values are generally noted along the Blue
Ridge escarpment where a prolonged stratus deck lingered through the
late morning/early afternoon hours. Through the rest of this
afternoon, do expect temperatures to climb by another degree or two
before capping off for the day as cloud cover gradually increases
from west to east ahead of an approaching cold front, as seen in
latest visible satellite. Moisture and forcing remain limited with
this feature, thus have kept any mentionable rainfall confined to
the mountains and portions of the foothills this evening through the
early overnight hours. Would not entirely rule out areas of patchy
fog early Thursday morning, but confidence is low attm. Though any
fog that develops will be short-lived. After daybreak, high pressure
will quickly build in behind the recently passed front. Expect
slightly warmer temperatures on Thursday with high`s in the low to
mid 60`s, slightly cooler across the mountains.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As of 215 PM EST Wednesday: The rest of the week looks fairly
quiet until we get into the weekend. The upper pattern will remain
progressive with a broad and flat upper ridge supporting high
pressure moving across the region through Friday, and then off
the coast of the Carolinas by Saturday morning. The passage of
the ridge should allow temps to return close to normal on Friday,
and then a category or so above normal on Saturday in advance of
the approaching upper trof. The western Gulf opens up ahead of this
system, giving it far better access to moisture than the previous
front. A strong short wave is expected to move quickly in from the
WNW on Saturday and then overhead Saturday night. Developing sw flow
upslope and warm advection may bring the arrival of showery precip
during the day, so precip chance slowly ramps up from the SW and W
through the day while the main frontal band of precip remains to
the west through sunset. The model guidance is fairly consistent
with blasting the front across the western Carolinas mainly
Saturday evening with a quick shot of deep moisture and forcing
that warrants a likely probability of precip. The front is moving
so quickly that the back edge of precip should be long gone to the
east by sunrise on Sunday. Temps will be tricky as they will depend
on the timing of the front, which remains uncertain this far out.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 205 PM EST Wednesday: Starting at 12Z Sunday, the strong cold
front moving toward the Carolina coast on the GFS.  The ECMWF lags
the front a bit as the EC has it over the mountains early Sunday.
All precip ends quite quickly as the large dome of high pressure
ridges in from the west. The center of the surface high will be near
the Red River Sunday afternoon while the axis of the 500mb trough
crosses the Appalachian chain. Expect the wind to be breezy on
Sunday, especially at higher elevations, then diminish as the
pressure gradient relaxes Sunday night into Monday. The high will be
over Alabama to Tennessee vicinity by Monday afternoon with our wind
becoming light. As the high moves off the Carolina coast Tuesday
night into Wednesday, low pressure should be forming over Texas with
return moisture behind the departing high pressure off the Gulf
lifting over areas west of the Mississippi River. The latest GFS
takes bands of generally light precip toward our region Wednesday
afternoon and Wednesday night.  The EC keeps us dry with high
pressure from the northern plains and pushing the low into the
western Gulf and Mexico. Considering the difference in the models
comes at the end of the current forecast, best plan is to keep it
dry for now until better model agreement creates higher confidence
in terms of POPs.

Temperatures will be coolest on Monday as they will be 10 degrees
below normal then milder Tuesday and Wednesday just 3 or 4 degrees
below normal.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
At KCLT and Elsewhere: Expect VFR to prevail through the 18Z TAF
period. Lingering stratus deck affecting KAVL/KHKY/KAND earlier
today has since dissipated, giving way to FEW/SCT cirrus across the
entire area with light SW winds this afternoon. Expect this trend to
continue over the next few hours as cloud cover will gradually begin
to increase west to east this evening ahead of an approaching weak
cold front. Limited moisture will accompany this system, but would
not entirely rule out a few light showers at KAVL/KHKY between 02-
05Z. However, do not anticipate any restrictions as a result. After
daybreak, VFR will persist behind the front as cloud cover gradually
decreases and light and variable winds become southwesterly around
13-15Z, increasing to 5 to 8 kts.

Outlook: Potential for MVFR/IFR with a cold front on Saturday as
increased cloud cover and widespread SHRA may allow for reduced
vsbys/cigs. Otherwise expect VFR.

Confidence Table...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       High  87%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High  94%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     Low   58%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High  94%     High 100%     High 100%     High  83%

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...None.
SC...None.

&&

$$
SYNOPSIS...DEO
NEAR TERM...ARK/SGL
SHORT TERM...PM
LONG TERM...DEO
AVIATION...ARK/SGL



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