Scientific Forecaster Discussion
fxus62 kgsp 170235
Area forecast discussion
National Weather Service Greenville-Spartanburg SC
1035 PM EDT Mon Sep 16 2019
warm high pressure will linger near the region through Tuesday
before a cold front moves through the area on Wednesday. Dry high
pressure then returns for the latter half of the week.
Near term /through Tuesday/...
as of 1030 PM EDT monday: forecast still on track. There is a
cluster of light showers drifting southeastward across southeast Kentucky into NE Tennessee. This
is within a tongue of some 500-1000 j/kg of MLCAPE, which is
becoming capped. So I don't expect any of this to survive to the
northern NC mountains. But cannot rule out a stray shower or
sprinkle later tonight up that way. Otherwise, quiet weather
expected overnight, as an upper ridge expands over the eastern Continental U.S.
And Humberto spins at a safe distance off the coast of the
Surface high pressure will remain in place into tomorrow, and with
light nwly flow expected to continue across the area, very little in
the way of moisture return or cloud cover is expected overnight. The
only note of interest tomorrow morning should be another instance of
Mountain Valley fog. The pattern has changed very little from the
weekend and we're three for three on valley fog the past few days,
so persistence seems to be the best bet here.
Tomorrow, we'll begin to see a pattern shift as a weak backdoor
front starts to drape towards our area. This will manifest mainly as
an increase in cloudiness in the afternoon, though some showers are
possible later in the evening as a wedge of high pressure sets up
along the eastern Appalachians, especially in the higher terrain.
Despite the increase in cloud cover later tomorrow, temperatures
will be hot once again, generally 5-10 degrees above normal.
Short term /Tuesday night/...
as of 200 PM EDT monday: mid level ridging will remain entrenched
across the lower Mississippi Valley through the period. At the
surface, a cold front will push south to the east of the
Appalachians Tuesday night and Wednesday. Cooler high pressure will
build into the region for Wednesday night and Thursday.
A chance of showers associated with the frontal passage will exist
from Tuesday night through Wednesday night. Thursday is expected to
be dry except for the western mountains where a few showers will be
possible. Much cooler highs are expected both days with highs in the
70s to around 80 in the Piedmont and mountain valleys.
Long term /Wednesday through Monday/...
as of 200 PM EDT monday: dry high pressure will be in place across
the region for Friday into the weekend. A weakening cold front will
approach the mountains for Sunday into next Monday bringing a slight
chance of showers with it. Highs will warm through the period
starting below normal on Friday and then warming above normal over
the weekend as surface high pressure pushes off the coast.
Aviation /03z Tuesday through Saturday/...
at kclt and elsewhere: VFR conditions are expected at all taf sites
through the period, as strong high pressure brings dry air into the
region. Some fog is expected in the mountain valleys again late
tonight through Tuesday morning. However, I don't expect it to
quite make it to kavl. A back door cold front will push in late
aftn, and will increase the coverage of a high-based cu field.
Isolated to scattered showers and garden-variety tstms are
expected to develop across the ridgetops. Coverage still too
isolated to put a prob30 at kavl, but that may be added in later
tafs. Winds will be lgt/vrb or calm overnight, then pick up out of
the north/NE in the morning.
Outlook: a back door cold front will push through late
Tuesday, which may bring a chance of some more widespread stratus
for early Wednesday across the Piedmont, along with scattered
showers near the Escarpment. VFR conditions should return by
Wednesday aftn. Dry high pressure builds in for the end of the week,
with just some Mountain Valley fog each morning for restrictions.
02-08z 08-14z 14-20z 20-00z
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: