Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
545 am EST sun Nov 23 2014
low pressure approaches from the southwest today...and passes
west of the area tonight. A strong cold front whips through on
Monday. Chilly high pressure Tuesday night.
Near term /through tonight/...
530 am update... no changes previous discussion follows...
Generally fair weather across the area. A few light echoes on
radar over far western WV counties to County Warning Area border otherwise all clear.
Increased probability of precipitation for this afternoon to categorical and similarly
increased wind speeds and gusts. Raised a Wind Advisory for the
mountains. A strong front moves over the area this afternoon and
wind speeds just off the deck peak out near 60 kts. Strongest
gusts should be with the frontal passage around 7 PM tonight. The lower
elevations should generally be spared by this first wave though it
will be a tad windy with gusts to 20 to 25 miles per hour.
Temperatures will be quite warm today nearly 10 degrees above normal.
Short term /Monday through Tuesday night/...
models continue to show a low pressure system strengthening as it
moves from the Mississippi Valley...north into the Ohio Valley and
WV Monday. This system will first bring a warm front under deep
strong south southwest flow into late Sunday night. Then...a cold
front will quickly follow...accompanied by rain showers and strong
gusty winds especially behind the front.
The cold front will cross west to east early Monday. With h850
temperatures around 10c...expect all precipitation to fall as liquid.
Therefore...expect rounds of scattered to numerous rain showers.
Precipitable water around 1.25 inches and strong deep layered shear could produce
a low chance for thunder...but will keep mention out of forecast.
Colder air rushes in behind the cold front dropping to minus 6c by
Weather conditions will improve Monday night into Tuesday as a
brief high pressure builds from the west...with colder
Previous temperatures looking good...perhaps a little warmer Monday
due to strong deep south southwesterly flow.
Long term /Wednesday through Saturday/...
we have low confidence in the details for the long term as fast flow
aloft dominates. This includes several elements not just
probability of precipitation...including clouds and temperature. Generally went a bit
colder than wpc medium range guidance and a bit more Liberal on
chance probability of precipitation for snow showers.
At the start of extended...thinking leftover stratocumulus low
level moisture from the day on Tuesday...especially across the
north...should be drying up/thinning Tuesday evening.
With the mean middle/upper level trough still to our west...European model (ecmwf) most
aggressive kinking the middle level moisture back west for Wednesday.
Can not go that far west...will trend more toward the GFS and CMC
and have just chance probability of precipitation for Wednesday for mostly light snow mainly
12z to 16z Wednesday some eastern mountain counties.
In the wake of that East Coast system...disturbances in the fast
west and northwest flow aloft dominate around Thanksgiving into
Friday night. GFS solution has 850 mb temperatures warming up
Thursday...ahead of one of those systems. Meanwhile...European model (ecmwf) much
colder. Did not go as cold as the European model (ecmwf).
Think coldest 850 mb air should be over US Friday. Will include
some 20 to 30 probability of precipitation for snow showers across northern counties Friday
and Friday night.
Deeper moisture may start returning by end of extended...overnight
Overall...no major storms...but the finer details still hard to time.
Aviation /12z Sunday through Thursday/...
VFR until a strong front arrives late Sunday giving a few hours of
IFR. Gusty winds will accompany the front particularly in the
Forecast confidence and alternate scenarios through 12z Monday...
Forecast confidence: high...decreasing late.
Alternate scenarios: timing of rain and associated MVFR visibility late
Sunday could vary. Low ceilings and strong winds at bkw Sunday
afternoon 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 11 12 13 14 15 16 17 18 19 20 21 22
EST 1hrly 06 07 08 09 10 11 12 13 14 15 16 17
crw consistency h h h h h h h h h h h h
heights consistency h h h h h h h h h h M l
bkw consistency h h h h h h h M M M h h
ekn consistency M M h h h h h h h h h h
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 12z Monday...
IFR possible on eastern mountain slopes and across the middle Ohio
Valley in rain and stratus Sunday nt into Monday morning.
WV...Wind Advisory from 4 PM this afternoon to midnight EST tonight
Wind Advisory from 6 PM to 11 PM EST this evening for