Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 270708

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
308 AM EDT Thu Oct 27 2016

A weak and mostly dry cold front will cross the area today...with
warm high pressure building back in on Friday. Another weak frontal
passage occurs late Sunday...before strong and dry high pressure
returns early next week.


As of 245 AM...not much happening across the western Carolinas apart
from thickening mid/high clouds streaming overhead. Upstream radars
show some light returns, but it seems unlikely that any precip will
reach the ground over the western zones before sunrise. Min temps
should be a few degrees warmer than normal.

Over the next 24 hours, our hopes for some much-needed rain are
pinned on a short wave approaching from the west, driving a
weakening surface front down across the fcst area this evening. I
suspect the overwhelming majority of us will end up disappointed.
The models show the short wave dampening and weakening as it moves
in from the west late in the day. The models never showed much in
the way of upper forcing either. There isn`t much hope of making up
the lack of mid/upper forcing at low levels, either, as the cold
front will tend to lay down across the region this evening. The NAM
appears to be doing its usual misrepresentation of sfc dewpoint east
of the mtns this afternoon and evening, with lower 60s values
driving the sfc based CAPE up to a respectible 1500 J/kg. Don`t bet
on it. The GFS at half that is probably still overdone given the
lack of moisture flux from the Gulf and the very dry land surface. A
slight chance of showers/storms will be included east of the mtns,
but that still feels almost like a wish-cast at this point. The best
chance will be across the NC mtns this afternoon as convection may
fire in ern TN and move in before we lose daytime heating. The small
precip chances will gradually diminish from the west in the evening
hours. High temps today will be on the order of a few degrees warmer
than yesterday. Low temps tonight will be a bit warmer with the
front laying down across the region.


As of 205 AM EDT Thursday: Lingering llvl cloud cover will wane
rather quickly Fri as a small scale hipres center traverses
southeast across the mid-Atl region and the Carolinas. This high
will merge with Atl ridging into Sun all while a strong and dominant
sub-trop high builds over the srn CONUS. Model soundings show a very
deep dry layer with little chance of Cu development and a strong subs
inversion setting up arnd H7. Thus...a dry fcst will continue over
the period with max temps reaching about 10 degrees above normal Fri
and Sat. Mins will be persistent as well with readings in the m50s
non/mtns and arnd 50 mtn valleys. Afternoon mixed dewpoints will
remain high enuf and winds weak enuf to preclude any meteor fire wx
concerns...however fuel moisture levels will remain low and become
even lower thru Sun.


As of 220 AM EDT Thursday: Not much change was needed or made over
the ext range. The op models continue to show very good agreement
with a high confidence synoptic pattern. Sun will begin with
nearly zonal low aloft as a weak s/w pushes east across the mid-Atl
by the evening. An associated cold front will reach the NC mtns by
00z...but with little dynamics and nil available llvl moisture...the
greatest effect will be increased cloud across the nrn zones. The
front will stall or wash out just to the north of the CWFA early
Mon...while the srn sub-trop high strengthens and centers east
across the deep south with long wave ridging extending into New Eng.

This deep ridging will help bring down a Canadian high into ME and
ridging will advance a fairly dry backdoor cold front into the area
Mon night. The GFS has a few -shra assoc with the leading edge of this
front overnight...however will keep the fcst dry given the extent of
the deep layered dry air and subs inversion. The sub-trop ridge
continues to advance east and will center/strengthen over FL by Wed.
This will continue the dry fcst through the period. Max temps shud
have no problem reaching arnd 10 degrees above normal each
afternoon. The NC fhills and Piedmont may be a little cooler Tue
with the ne/ly sfc high building in. Mins will remain a couple cats
above normal.


At KCLT...VFR conditions are expected to persist for at least the
next 12 hours or so. There is some indication that a visibility
restriction could develop to the S and E of CLT, but the chances of
that developing at the airfield appear to low to mention. Expect a
light SE wind with thickening high and mid clouds through the early
morning hours. At some point around daybreak, the wind should come
around to SW and stay there for the rest of the period. Some lower
clouds will eventually arrive but the base should be above 050. The
operational models suggest a shower chance in the late afternoon,
but prefer to keep only a hint of this with a VCSH after 17Z. Even
if this does develop, in all likelihood it would not produce a
flight restriction. The actual cold front will be moving through
right around the end of the TAF period.

Elsewhere...will be watching for fog development in the mtn valleys,
which has limited potential because of high cloudiness and high
dewpt depressions at the current time. Included a TEMPO for some
MVFR visibility at KAVL but confidence is kind of low. The other
problem might be an MVFR-level cloud deck encroaching on the Upstate
of SC around daybreak. Some of the model guidance has this, so a
TEMPO or prevailing condition was included at KAND/KGMU/KGSP through
the late morning. Once that lifts, there could be an isolated shower
or patches of light rain, so a VCSH was thrown in. The best
chance...around 30 pct...will be at KAVL thru the afternoon hours.
The front will cross the mtns this evening, bringing the wind around
to NW by the end of the period at KAVL.

Outlook: Dry high pressure will build in behind the front Friday
through the weekend. The influence of the high will continue into
early next week with VFR conditions.

Confidence Table...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High  91%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High  86%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High  92%     High 100%     High 100%
KAND       High 100%     High  87%     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:




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