Scientific Forecaster Discussion
fxus62 kgsp 140250
Area forecast discussion
National Weather Service Greenville-Spartanburg SC
1050 PM EDT sun Oct 13 2019
a progressive jet stream will support unsettled weather through this
evening with active weather returning late Tuesday into Wednesday.
Much cooler and breezy conditions are expected behind a cold front
Wednesday night into Thursday with a gradual warming of temperatures
heading into next weekend.
Near term /through Monday night/...
as of 1050 PM edt: minor adjustments made to
temperatures/pops to coincide with latest trends, as the rest of the
near term forecast remains on track. Showers continue to linger
across the area this evening, as the recently passed cold front
remains just outside the eastern fringes of the forecast area. Elsewhere,
conditions remain fairly quiet with some patchy areas of fog across
the northern foothills.
Previous discussion: pops will continue to diminish rapidly from
west to east through the late evening hours as the boundary and
associated deeper moisture move off into the central Piedmont of the
Carolinas. The main concern for the overnight will be mid/upper
drying over lingering moisture on the ground and in the boundary
layer. This could lead to areas of fog and low stratus, and the fog
could become dense in some locations if the winds remain light
The morning fog will burn off fairly quickly Monday morning to
provide good insolation for the bulk of the day. Thus, maximum
temperatures should rebound to 5 to 10 degrees above climo once
again, with dry conditions throughout the day.
Short term /Tuesday through Wednesday night/...
as of 2:45 PM sunday: the short-term forecast picks up at 00z on
Tuesday with flat upper ridging over the region. By late Tuesday
into early Wednesday, another upper trof will dig down across the
northern plains and move towards the Ohio River valley. The trof
will amplify as it approaches our area, with the trof axis expected
to pass just to our north by the end of the period late Wednesday.
At the sfc, dry high pressure will briefly spread over the region
late Monday into early Tuesday. The drying will be short-lived as
the next round of deep, pre-frontal moisture spreads over the fcst
area from the southwest on Tuesday. The models have been trending
a bit slower wrt the spread of the deep moisture into the cwfa,
and pops have been lowered a bit in the 12 to 18z range over the
SW zones. The actual cold front won't reach the County warning forecast area until early
Wed, however the bulk of the quantitative precipitation forecast is still expected to fall late
tues into early Wed. Anticipated storm total quantitative precipitation forecast is still in the
1 to 2 inch range for most of the non-mtn zones with less expected
over the higher terrain. Flood concerns remain minimal.
Long term /Thursday through Sunday/...
as of 2:35 PM sunday: the extended forecast picks up at 00z on
Thursday with a broad upper trof axis passing just to our north.
The trof is expected to rapidly lift NE and away from the fcst
area on Thursday with a weaker, secondary trof axis trailing the
main axis late Thursday into Friday. This feature should move off
the Atlantic coast by Friday afternoon with heights recovering
in its wake. Upper ridging will then spread back over the region
for the remainder of the period. At the sfc, cool and dry high
pressure will be spreading back over the region by early Thursday
as a cold front moves offshore. The high will linger over the
region into next weekend. By the later part of the weekend, the
high will move off the Atlantic coast allowing more moist southerly
flow to gradually spread back over the County warning forecast area. The period should
remain dry with the main concern being low temps cold enough to
possibly produce frost over the higher terrain early thurs and
Fri. In addition, the higher terrain will also see wind gusts
in the 25 to 40 mph range thurs morning with speeds diminishing
later in the day.
Aviation /03z Monday through Friday/...
at kclt and elsewhere: expect a mixture of VFR/MVFR/IFR due to low
cigs, areas of fog, and precipitation through tonight, with any
lingering showers tapering off prior to the overnight hours.
Conditions are progged to improve by late Sunday morning.
With a cold front just to the south and east of the fa, another
batch of showers continues to stream into portions of the area,
currently affecting kgmu, kgsp, and kand. With the better
instability along the front, expect lingering activity through
tonight to remain -shra/-dz. Latest fcst soundings continue to
depict drier air infiltrating in behind the recently passed front,
especially at the mid to upper levels. However, with available low
level moisture and light winds, continue to anticipate MVFR cigs
along with patchy areas of fog, potentially IFR at kavl overnight
Expect conditions to improve on Monday after daybreak, with VFR
prevailing through the remainder of the valid taf period. Northwest winds
at or below 5 kts will prevail, with nearly clear skies.
Outlook: flight restrictions possible mid-week with another
approaching cold front.
03-09z 09-15z 15-21z 21-00z
kclt high 80% Med 64% high 100% high 100%
kgsp high 100% high 97% high 100% high 100%
kavl high 100% Med 62% high 100% high 100%
khky Med 73% high 84% high 100% high 100%
kgmu high 100% high 97% high 100% high 100%
kand high 100% high 94% 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: