Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Greenville-Spartanburg SC
204 PM EDT Tue Oct 25 2016
seasonal and dry high pressure remains over the region Wednesday...
before a weak cold front crosses the area Thursday. Warm high
pressure returns Friday before another weak frontal passage occurs
late Sunday. Warm and dry high pressure moves in early next week.
Near term /through Wednesday/...
as of 200 PM edt: 1032 mb high pressure continues to build eastward
from the Southern Shores of the Great Lakes this afternoon. Shallow
ridging continues aloft with little moisture in profiles except for
thin cirrus arriving from the northwest. The ridge will settle
overhead tonight through Wednesday with any additional mid/high
level moisture passing over the ridge axis to the north of our area.
Good radiating conditions will lead to another chilly night of
mostly upper 30s and 40s min temps. Patchy frost will once again be
possible around daybreak in sheltered NC mountain valleys and over
the northwest NC Piedmont, but with coverage too low for any
Southwesterly low level flow will then get slowly reestablished
through Wednesday as the surface high pressure center drifts toward
the eastern Seaboard. Maximum temperatures will be comparable to
today as thicknesses should be slow to recover in the light veering
Short term /Wednesday night through Friday/...
at 2 PM tuesday: on Wednesday evening a low amplitude upper ridge
will be along the East Coast, while an upper trough will be crossing
the MS River Valley, and a high amplitude upper ridge will be over
The Rockies. The pattern progresses such that by Friday the upper
trough reaches the East Coast, and the upper ridge moves over the
At the surface, on Wednesday evening a surface ridge will be along
the eastern Seaboard, while a cold front will be crossing the MS
River Valley. Moisture ahead of the front will increase over our
area through the night, but will not be especially robust, as inflow
from the Gulf of Mexico diminishes with a wakening pressure
gradient. Instability appears to be marginal for convective. Frontal
passage appears to take place on Thursday night and Friday, with
drier air working into the area behind the boundary. Temperatures
will warm from near normal to slightly above normal.
Long term /Friday night through Tuesday/...
at 2 PM tuesday: on Friday evening the upper pattern deamplifies
over the southeast, leading to nearly zonal flow. By Monday an upper
ridge amplifies from the Gulf of Mexico to the Great Lakes, and this
feature progresses to the Easter Seaboard by Tuesday.
At the surface, on Friday evening high pressure will extend down the
eastern Seaboard, and will linger over the Carolinas and Georgia
into Saturday. A mainly dry cold front is expected to cross the area
from the northeast on Saturday night, with little or no
precipitation resulting, followed by more high pressure building
over our area into Tuesday. Temperatures will cool slightly, but
will remain above normal.
Aviation /18z Tuesday through Sunday/...
at kclt and elsewhere: VFR conditions will continue through the
period at the taf sites. The only area with much threat of MVFR fog
overnight will be the southwest NC mountain valleys as the airmass
modifies. Otherwise east-northeast winds early in the period will toggle east-southeast to
southeast late this afternoon throughout. Some adjustment back to east-northeast is
likely overnight across the foothills/Piedmont but winds will be
very light and will quickly toggle back to southeast for good by late
Wednesday morning. Expect little more than a few cirrus throughout.
Outlook: high pressure will migrate offshore Wednesday night. A
fast-moving cold front will cross the area Thursday into Thursday
night, but with very limited moisture. Dry high pressure will return
Friday through the weekend.
18-24z 00-06z 06-12z 12-18z
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 99%
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: