Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 221742
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
142 PM EDT Sat Oct 22 2016
High pressure will build across the region over the weekend. A dry
cold front will move through on Monday...with strong high pressure
building back in through the middle of next week.
.NEAR TERM /THROUGH TONIGHT/...
As of 140 PM: The forecast remains in good shape. I will further
decrease sky cover and lower afternoon RH values east of the mtns.
As of Noon: I will issue a update to remove Wind Advisory headlines
from the forecast and HWO. The current forecast appears on track. I
will align near term grids to align with recent sky and temperature
As of 1030 AM: The latest visible satellite loops shows a striking
houndstooth appearance in the standing wave clouds from NC north
across the VA Appalachians. Regional observations and power outage
maps indicate that the gusty winds are still having an impact across
the eastern slopes of the central and northern NC mtns and adjacent
foothills. I will leave the Wind Advisory in place. I will update
the forecast to make minor tweaks to the morning temperatures and
sky, Pops will be lower to zero east of the mtns.
635 am update: temps appear to have bottomed out a bit warmer than
expected this morning with lows in the upper 40s for most of the
lower elevations. NWLY flow continues to generate sct to bkn cloud
cover along the NC/TENN border. Cloud cover should gradually dissipate
as the drier air associated with the sfc high spreads over the region.
As of 255 am Saturday: temps have been cooling steadily over the
past few hours under mostly clear skies and min values still appear
on track later this morning. We should see values below freezing
over the higher NC peaks, however any widespread frost potential
should be minimal when considering the brisk winds. Over the past
few hours we`ve seen wind gusts around 40kts over our northern NC mts
and just north of there, so the current wind advisory looks good
thru 16z today. Daytime mixing should support continued gusty winds
this afternoon and into the early evening with values dropping off
after the sun sets and the synoptic scale pressure gradient weakens.
High temps will be the coolest we`ve seen them for some time, with
values in the low to mid 60s over the lower elevations and upper 40s
to low 50s over the mts. Values will fall again early Sunday into the
30s across the mtns with upper 30s to lower 40s over most of the lower
elevations. With winds decoupling overnight, there appears to be good
potential for widespread frost over much of the higher terrain Sunday
morning. There could also be some spotty frost over the foothills and
piedmont if temps get cold enough. Otherwise, we can expect mostly
clear skies and dry conditions.
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 220 AM Saturday...the weather looks exceedingly quiet for the
first part of next week as we remain under a NW flow aloft. Sunday
looks like an awesome October day with near normal temps, light
wind, and bright sunshine. The only feature of interest will be the
passage of a reinforcing cold front on Monday. The front should move
through dry, but will allow for a brief warmup on Monday that should
see highs climbing back above normal in the afternoon. Temps will
fall off again Monday night but not to the point where frost/freeze
would be a concern.
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 250 AM EDT Saturday...the middle part of the week looks like a
continuation of dry and fair weather courtesy of upper ridging and a
surface high moving past to the north. Things change toward the end
of the week as the models show the next system moving across the
Plains on Wednesday and then over the Gt Lakes/Midwest on Thursday.
The model trend is toward a more amplified solution with the upper
trof on Thursday, which allows for some tap of Gulf moisture ahead
of the cold front. The GFS wants to close off an upper low over the
Midwest on Thursday and then drop it southward through the end of
the period. This looks overdone similar to what that model was doing
for our current weather earlier this week. Think the ECMWF has the
better handle on keeping the upper trof progressive. Either way, the
trend is toward a better chance of precip Thursday and lingering
into Thursday evening, so precip chances were nudged upward a bit,
perhaps optimistically. Friday was kept dry. Temps were unchanged
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Building dry high pressure will provide VFR
conditions through the 18z TAF period across the western Carolinas.
Gusty northwest winds should continue through the rest of the
daylight hours. Winds are forecast into a steady light NW wind
overnight. Winds could become occasionally calm near KCLT, KHKY,
KAND, possibly allowing thin patchy frost to develop during the pre
dawn hours. Near term guidance indicates that a shallow lee trough
will form during the mid morning hours, resulting in light SW winds
across the foothills and Piedmont by 15z.
Outlook: Dry high pressure will continue to spread across the
southeast CONUS on Sunday with another reinforcing Canadian High
moving over the region on Tuesday.
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:
GA...Frost Advisory from midnight tonight to 9 AM EDT Sunday for
NC...Frost Advisory from midnight tonight to 9 AM EDT Sunday for