Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 300231
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1031 PM EDT Thu Sep 29 2016
A dry southwest flow of air will be setting up across the region on
Friday and linger through the weekend. Progressively warmer
temperatures are on tap through Monday.
.NEAR TERM /THROUGH FRIDAY/...
As of 1025 PM EDT: Latest surface analysis frontal boundary has
occluded and taken on a north-south orientation. Moist and unstable
air remains over the Northern Mountains and I-40 corridor, south
along and east of highway 321. Moisture convergence along this
boundary is leading to a regeneration of convection. While not
strong, showers and isolated thunderstorms will linger through at
least midnight, but could go through daybreak. Although they should
slowly shift north and east with time as the boundary resumes its
slow movement. Brief heavy rainfall cannot be ruled out. Elsewhere,
dry conditions will continue. Still expect fog and low clouds to
form along, north and east of the frontal boundary where low level
moisture remains high. Mountain valley fog, some dense, should
develop as well. Lows will have a tight E to W gradient with
readings in the I-77 corridor around 5 degrees above normal, with
near to a little below normal readings to the west.
Upper low makes little progress on Friday, but surface boundaries
move completely out of the area by Friday afternoon. Chances for
significant precip on Friday are, thus, greatly reduced. Eastward
movement of surface boundaries will also drop temperatures down to
near seasonal normals with highs on Friday 5 degrees cooler than
today. With dryer and cooler air on Friday, it may finally begin to
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
At 200 PM Thursday: On Friday evening a large, deep closed upper low
will centered over the over the OH River Valley, with associated low
pressure extending outward to the Great Lakes, the NC Coast, and the
Gulf Coast. The low drifts slowly northeast to Southern Ontario by
Sunday evening, while upper troughing persists to to the southwest
as far as the Gulf States.
At the surface, on Friday evening a deep surface low will be over
the middle Ohio River Valley, while a weak surface front is expected
to be near the fall line of the Central to Eastern Carolinas and
Georgia. The models show dry air across most of Western Carolinas
and Northeast Georgia, with the possible exception of the Western NC
Mountains. This pattern by and large persists into Sunday, with the
result being little to no precipitation over our area. Temperatures
will exhibit an increased diurnal range due to anomalously dry air,
with minimums below or near normal, and highs above normal.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 130 PM EDT Thursday...It doesn`t look like any changes will
need to be made to the inherited dry and warm fcst to start off the
workweek with the medium range model consensus continuing the deep
and dry wsw flow aloft atop the region. Monday`s max temperatures
are slated to be two to three categories above the early Oct climo.
Even into Tuesday, the effectively dry wx should remain with max
temperatures perhaps a few deg F less warm than persistence within
the tightening easterly flow between TC Matthew and moderately
strong sfc hipres center over New England. For the latter half of
the period, at this stage of the game, any notable affects of
Matthew are progged to be well se/e of the cwfa. So, sensible wx
remains dry and warm for Wed/Thu, with the potential for breezy
easterly and/or northerly winds given the continued strength of
the pressure gradient.
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
At KCLT, surface front still hasn`t moved much. Cannot rule out a
shower the next couple of hours, but chance too low to include in
the TAF. Winds should shift to the S overnight as the front finally
moves north and east. Better chance of fog/low clouds north and
northeast of the airfield, but they could drift south by daybreak.
Have included non-restrictive fog and low clouds to indicate the
potential. SSW winds pick up in speed through the day with any low
Elsewhere: KHKY may still see some convection through midnight or
so. Otherwise, dry fcst. Clearing skies expected through the evening
with MVFR and TEMPO IFR at KAVL and KHKY by daybreak. LIFR possible
at KHKY with VLIFR possible at KAVL. Do not expect any restrictions
for the SC sites with drier air already in place. WSW winds continue
through the period at the SC sites. KHKY will see light and variable
wind becoming SSW. KAVL will see NNW winds through the morning, then
become SSW for the afternoon.
Outlook: VFR conditions expected in most places through the
beginning of next week as dry high pressure settles in over the area.
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 87% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 88% Low 52% High 88% High 100%
KHKY High 95% High 80% High 81% 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: