Scientific Forecaster Discussion
fxus61 krlx 201738
Area forecast discussion
National Weather Service Charleston WV
1238 PM EST Wed Nov 20 2019
high pressure builds in today, remaining into Thursday. Next
storm system Friday and Saturday with rain and possibly some
brief snow. Cooler over the weekend.
Near term /through tonight/...
as of 910 am Wednesday...
Sky grids updated to reflect stubborn low stratus and linger it
longer into the early afternoon.
As of 145 am Wednesday...
Models showing lower levels of the soundings in the mountains saturating
with moisture early this morning, then slowly cooling. There is a
slight chance that this could create some drizzle or freezing drizzle.
As daytime heating takes over, this threat should end.
A high pressure system will then build in for today and tonight,
with clouds gradually scattering then clearing.
Short term /Thursday through Friday night/...
as of 230 am Wednesday...
Upper level ridging/surface high pressure shifts east through
the day Thursday as a surface low tracks northeast from Iowa
into the central Great Lakes. This will leave our forecast area
in the warm sector of the aforementioned surface low much of the
day with increasing southwesterly flow yielding quite mild
temperatures for the end of November. Despite warm frontal
passage a significantly dry sub-cloud layer will yield little,
if any, precipitation reaching the ground during the daylight
hours, mainly confined to the Ohio River valley. As the cold
front with the low edges closer Thursday night into Friday
morning will see a plume of locally higher precipitable water
values being advected into the region just head of the front in
southwesterly flow. This, combined with synoptic ascent from the
back end of an h250 jet core moving into the eastern Great
Lakes along with ripples embedded in westerly flow aloft will
yield increasing precipitation chances late Thursday night into
Friday morning with a lull in precipitation Friday evening into
early Saturday morning as the front briefly stalls along our
Long term /Saturday through Wednesday/...
as of 145 PM Tuesday...
Boundary mentioned in the short term discussion starts to drift
back to the north Saturday morning as a southern stream 100kt
h250 jet Max approaches the Ohio Valley. Wouldn't be out of the
question to see a few flakes mixing in along the northern
fringe of very light precipitation across our northern zones
Saturday morning as it starts to move north, but no
accumulations expected. Should be a rather wet Saturday during
the daylight hours with another chance for some light snow or
rain snow mix on the tail end of precipitation Saturday night,
mainly across our mountain and Ohio River valley zones while
eastern downslope off the mountains keeps areas in-between
above freezing. Again, no significant snow accumulations are
expected with this activity. High pressure builds in for Sunday
and Monday with the next chance of precipitation Tuesday night
into Wednesday as a upper level wave/closed low develops out of
the central rockies.
Aviation /18z Wednesday through Monday/...
as of 1235 PM Wednesday...
MVFR ceilings gradually scatter out/lift to VFR 18-00z
Thursday. VFR through the remainder of the period.
Winds strongest at ckb/ekn/bkw westerly/northwesterly 8-12kts,
otherwise vrb less than 5kts.
Low stratus gives way to upper level moisture ahead of a cold
front that lies beyond the scope of this forecast, and ceilings
in the 20-25kft range.
Forecast confidence and alternate scenarios through 18z Thursday...
Forecast confidence: high.
Alternate scenarios: timing of ceilings lifting could vary.
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.
UTC 1hrly 17 18 19 20 21 22 23 00 01 02 03 04
EST 1hrly 12 13 14 15 16 17 18 19 20 21 22 23
crw consistency h h h h h h h h h h h h
heights consistency M M M h h h h h h h h h
bkw consistency h h h l h M h h h h h h
ekn consistency M M M M M M h h h h h h
pkb consistency h h h h h h h h h h h h
ckb consistency h M M M M M h h h h h h
After 18z Thursday...
IFR possible Friday and Friday night in rain.