Scientific Forecaster Discussion
fxus61 krlx 182340
Area forecast discussion
National Weather Service Charleston WV
640 PM EST Mon Nov 18 2019
weak systems early this week give way to high pressure mid
week. Stronger system for the end of the work week.
Near term /through Tuesday/...
as of 600 PM Monday...
Did some fine tuning to the forecast even though it is still on
track for the most part. Added in a little more drizzle this
evening matching up with radar and observations. Also, added
more for Tuesday especially in the mountains and took out
freezing drizzle for most places except for the highest
elevations in the northeast mountains. Tweaked temperatures and
they came in slightly warmer by a degree or so and with Road
temps not below freezing as well, opted for just drizzle in The
Lowlands and with some freezing drizzle in the highest
elevations. With the short wave coming in Tuesday afternoon
switching over all precip chances to rain in The Lowlands and
mostly snow for the highest elevations with a mix in the lower
valleys of the mountains through the evening. Minimal precip
accumulations are expected through tomorrow with the mountains,
particularly around Snowshoe, having the best chances for some
snow accumulations and higher rain amounts elsewhere in that
As of 1230 PM Monday...
Overall, general idea in terms of forecast in the near term
period remains the same. Upper low moving into the mid Ohio
Valley will move across the area later today and tonight, with
increasing low level moisture as it does so. This will set the
stage for the possibility of patchy drizzle tonight, with the
possibility of patchy freezing drizzle across the mountains. Due
to the overall isolated nature, and very light amounts
anticipated, elected not to issue any winter weather headlines
concerning this, but will put a mention in the severe weather potential statement and have
future shifts monitor the potential.
Better chances for precipitation occur on Wednesday as a second
upper shortwave cross the area. Low ceilings, and areas of light
precipitation, are expected. Model soundings would suggest a
continuation of drizzle across the forecast area, but could be
enough lift during the event tomorrow to warrant light rain or
even light snow showers across the higher terrain. General
inclination is to lean towards mainly drizzle on Wednesday, but
in keeping with consistency with surrounding offices went with
slight chance rain/snow showers.
Short term /Tuesday night through Wednesday night/...
as of 245 PM Monday...
Upper trough axis swings across Tuesday night with enough
forcing to generate a few showers, with snow showers in the
mountains. Model soundings show moisture thins sufficiently to
put ice nucleation in question overnight so some patchy light
freezing rain or freezing drizzle will be possible, again
mainly in the mountains.
Upper ridging builds in for the remainder of the short term with
dry conditions Wednesday and Wednesday night.
Long term /Thursday through Monday/...
as of 245 PM Monday...
Forecast uncertainty increases dramatically during the long term
as models have trouble resolving what happens to a series of
closed lows over the southwest U.S. And eastern Pacific. Models
are varying a lot from run to run and model to model in this
difficult pattern so stayed close to the blended model solution
with forecast details. This results in increasing rain chances
Thursday and Thursday night, followed by varying pops Friday
into the weekend as there is a potential for several
disturbances to impact the region. There is some potential for
snow or a rain snow mix at times over the weekend, but that will
hinge on eventual low track and surface temperatures, which are
again very low confidence at this time frame.
Aviation /23z Monday through Saturday/...
as of 640 PM Monday...
MVFR cigs will persist into the night with the possibility of
IFR cigs affecting all sites besides ckb/heights in the early
morning. Cigs will likely erode somewhat in the afternoon from
south to north on Tuesday although they will make a comeback
from the west as another slightly stronger short wave approaches
the area. Soundings indicate plenty of moisture at the boundary
layer and with a trough overhead that low stratus may even
persist longer through the morning at some locations especially
in the mountains. With a weak pressure gradient and high
pressure ridge building in, boundary layer flow will be weak
causing winds to be light and mainly westerly. Possible drizzle
overnight in the mountains becoming more widespread later in
the morning. Increasing moisture and lift through the afternoon
will promote rain chances and IFR/MVFR cigs for all terminals
into the evening. No significant restrictions to visible are
expected at this time.
Forecast confidence and alternate scenarios through 00z Wednesday...
Forecast confidence: medium to high.
Alternate scenarios: not the greatest confidence with IFR cigs
overnight and the stratus may not make it over some sites.
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 22 23 00 01 02 03 04 05 06 07 08 09
EST 1hrly 17 18 19 20 21 22 23 00 01 02 03 04
crw consistency h h h h h h h h M h h h
heights consistency h h h h h h h h h h h h
bkw consistency h h h h h h h h h h h h
ekn consistency h h h h h h h h h M M M
pkb consistency h h h h h h h h h h M M
ckb consistency h h h h h h h h h h h h
After 00z Wednesday...
IFR possible Friday and Friday night in rain.