Scientific Forecaster Discussion
fxus61 krlx 200234
Area forecast discussion
National Weather Service Charleston WV
1034 PM EDT Sat Oct 19 2019
remnants of Post tropical cyclone Nestor pass to the southeast
overnight. Cold front crosses late Monday into early Tuesday.
Near term /through Sunday/...
as of 1030 PM Saturday...
Other than slightly faster timing on rain spreading south to
north across the eastern half of the area, the forecast is on
As of 805 PM Saturday...
Tightened the pop gradient a bit between the middle Ohio Valley
and central Appalachians overnight into Sunday morning. The
forecast was otherwise generally on track. With rain just
starting to reach the ground near the southern tip of the
forecast area, in southwest Virginia.
As of 130 PM Saturday...
Upper level cloudiness continues to stream into the region this
afternoon ahead of Post tropical cyclone Nestor. These will continue
to thicken and lower through the evening with rain eventually
spreading into southern and eastern portions of the area overnight.
Total accumulations of a quarter to half an inch are expected across
these areas with the heaviest precipitation well to the east of US
in central Virginia. Given substantial cloud cover overnight, there
is little risk of waking up to a frosty windshield Sunday
morning with lows in the mid to upper 40s.
Precipitation tapers off in the mountains Sunday morning with skies
clearing from west to east through the day and daytime highs for The
Lowlands in the lower 70s.
Short term /Sunday night through Tuesday night/...
as of 230 PM Saturday...
Longwave trof amplifies over the upper Midwest amid strong
surface cyclogenesis Monday. This system will become occluded
over the western Great Lakes with the surface front slated to
arrive late Monday night. I continue to delay onset of pops
from nbm solution given increasing southeast low level flow.
This should keep the daylight hours Monday dry, with showers
arriving holding off until the evening hours. There may be a
rumble of thunder given the strong dynamics and jet, however,
instability is expected to be meager at best. Despite the
baroclinic zone being fairly progressive, quantitative precipitation forecast amounts could
approach an inch in spots given strong jet dynamics and some
deep moisture advection from the Gulf of Mexico. It will be
rather warm ahead of this system for the Monday with afternoon
highs reaching well into the 70s, with perhaps an lower 80s
across portions of The Lowlands.
Upper trof moves in Tuesday as the surface front pushes east of
the area. The atmospheric column dries out nicely save for some
cold air advection enhanced cumulus across the north. Good boundary layer
mixing will allow for some 20 to 25 kt gusts in the afternoon as
temperatures peak to more seasonable levels. Enough gradient
wind will exist to mitigate frost Tuesday night.
Long term /Wednesday through Saturday/...
as of 240 PM Saturday...
Surface high passes to our south and east Wednesday and
Wednesday night as the upper trof axis passes east. This will
result in tranquil and seasonable weather to continue for
Wednesday. There may be more of a frost threat Wednesday night
with the high just to our south.
Upper level flow turns more southwesterly thurday as yet
another amplifying system organizes in the plains. This will
result in temperatures climbing back above normal to end the
work week while generally remaining dry into at least the first
part of Friday. Thereafter, deep moisture advection ahead of
low pressure across the Red River valley will make for an
increasingly wet beginning to the weekend.
Aviation /03z Sunday through Thursday/...
as of 805 PM Saturday...
Clouds will lower and thicken overnight, as low pressure
representing the remnants of once tropical storm Nestor,
approaches. The system will pass east of the area overnight, so
ceilings will get lowest in the central Appalachians, likely
dropping to MVFR overnight, and then IFR toward dawn Sunday.
Visibility will drop to MVFR in rain in the mountains, and
perhaps as far west as crw, late overnight.
IFR ceilings will improve to MVFR at crw after daybreak Sunday
morning and toward noon Sunday in the mountains, and then the
stratocu should break up early Sunday afternoon crw, and late
Sunday afternoon in the mountains.
Across the middle Ohio Valley and in northern WV over to ckb,
conditions will remain VFR, although ceilings are likely to
lower to around 4 kft for a time early Sunday morning.
Gusty southeast surface flow in the mountains will gradually
diminish overnight, and surface flow will otherwise generally be
light and variable. Light south flow aloft overnight will
switch to light north Sunday morning.
Forecast confidence and alternate scenarios through 00z Monday...
Forecast confidence: medium to high.
Alternate scenarios: in the mountains, and in the southern and
central WV lowlands, conditions in rain overnight, and stratocu
and stratus overnight and Sunday morning, may vary. There may be
Post-Rain Valley fog where rain exits southern WV before dawn
Experimental table of flight category objectively shows consistency
of weather forecast office forecast to available model information:
h = high: taf consistent with all models or all but one model.
M = medium: taf has varying level of consistency with models.
L = low: taf inconsistent with all models or all but one model.
Date sun 10/20/19
UTC 1hrly 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1hrly 20 21 22 23 00 01 02 03 04 05 06 07
crw consistency h h h h h h h M M M M h
heights consistency h h h h h h h h M l l l
bkw consistency h h h h l h h h M h h h
ekn consistency h h h h h h M M M l l l
pkb consistency h h h h h h h h h h h h
ckb consistency h h h h h h h h h h h h
After 00z Monday...
IFR valley fog possible Monday morning. Cold front arrives
Monday night into Tuesday, with IFR conditions possible.