Scientific Forecaster Discussion
fxus62 kgsp 170236
Area forecast discussion
National Weather Service Greenville-Spartanburg SC
1036 PM EDT sun Jun 16 2019
seasonal temperatures and humid conditions will persist over the
next few days while unsettled weather returns ahead of a front
drifting down from the Great Lakes. Drier weather is expected by the
end of the week.
Near term /through Monday/...
as of 1030 pm: other than a a couple of small cells in the vicinity
of the smokies and balsams, deep convection has dissipated, and
little in the way of additional activity is anticipated overnight.
Elevated dewpoints will likely lead to more in the way of valley fog
and low stratus Monday morning, esp in the valleys draining into
Otherwise, the main player for the near term is the progress of an
upper wave currently over Oklahoma. This wave progresses eastward,
reaching the Mississippi Valley area by Monday evening. As this
wave approaches our area, chances for and coverage of thunderstorms
increase Monday afternoon as upper wave approaches the region (and
are even higher on tuesday). Heaviest showers, though, are still
expected over the higher terrain where initiation will be more
widespread. Thunder will be largely diurnal, with activity
declining after sunset.
Surface features change little over the next 36 hours, with a broad
high over the Atlantic, and light to moderate southerly to
southwesterly surface winds that will serve to keep dewpoints
seasonally elevated. Temperatures will also be fairly monotonous,
with highs and lows just above climo.
Short term /Monday night through Wednesday/...
as of 215 PM EDT sunday: the short-term forecast picks up at 00z
on Tuesday with flat upper ridging still in place over the region
as a fairly well-defined upper shortwave gradually approaches the
western Carolinas from the west. The latest model guidance has the
shortwave moving over the County warning forecast area late tues into early Wed and moving
off the coast by the end of the period late Wed. At the sfc, the
Bermuda high will still be in control of the large scale pattern
with warm, southerly flow in place as the period begins. On tues, the
models appear to be coming into better agreement with regards to
the development of another sfc low to northwest. They have the low lifting
NE towards the Ohio River valley late tues/early Wed and then over
New England later on Wed. The weak cold front associated with this
low will push thru the fcst area Wednesday morning/afternoon and
move offshore by the end of the period late Wed. The profiles
behind the front appear somewhat drier but the change is not that
significant. With a lingering Lee trof over the area on Wednesday,
sfc winds may become more westerly behind the front briefly, but they
will revert back to a more southwesterly direction by late Wednesday. The
approaching upper shortwave should provide some upper support for
convection on tues with Wed seeing less convective activity. Severe
wx parameters suggest that some of the convection on Tuesday could
become severe with the NC mountains and foothills the more favored
area. At this time it appears that damaging straight-line winds,
and to a lesser extent, large hail will be the main threats. Temps
will remain a few degrees above normal for mid-June.
Long term /Wednesday night through Sunday/...
as of 2 PM EDT sunday: starting at 00z Thursday. After a series of
smaller disturbances moving fairly quickly from west to east from
the Mississippi Valley to the East Coast, a strong shortwave will
cross Missouri Wednesday evening headed our way. On Thursday
morning, both the GFS and European model (ecmwf) have convection from Arkansas to
Ohio and moving toward our forecast area. The atmosphere is forecast
to be a bit more stable late Thursday over our area as cape values
are lower than yesterday's projections. The current ec is a bit
faster with this shortwave than the GFS. Ec has axis at 00z Fri from
cle to tys and atl and GFS has axis from Crossville Tennessee to bmh.
Convection should continue well into Thursday night then move east
of our forecast area Friday morning. The models agree on Friday
being drier as a 500mb ridge builds over the east. It is uncertain
at this point as to how much a fast moving system will affect US
late Saturday. The ec has it passing by to our north giving US a
glancing shot of rain while the GFS has US more impacted. Will
adjust pops accordingly. The ec has US drier Sunday while the GFS
has rain. If storms develop late Saturday or Sunday over the far
west...near Tennessee and Georgia...CAPES 2000 to 3000 could fuel a
Temperatures near normal Thursday and Friday warming by Sunday to 2
to 5 degrees above normal.
Aviation /03z Monday through Friday/...
at kclt and elsewhere: convection remains possible near kavl for the
next 1-2 hours, but chances are far too remote to include any taf
mention at this time. VFR/calm weather is generally forecast at the
terminals until at least Monday afternoon, when isolated to
scattered convection will redevelop. Cannot completely rule out some
brief fog at kavl Monday morning, but the greater chances for valley
fog/stratus will exist in areas along the Tennessee border. Winds
will generally remain SW at 5-10 kts through the period.
Outlook: continued afternoon convection with possible flight
restrictions, mainly across the higher terrain, along with
increasing chances for morning valley fog/low stratus are expected
thru the week.
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: