Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
309 PM EST Thursday Feb 11 2016
high pressure shifts east tonight. Snow showers pick up again
Friday into Saturday as another Arctic front plows through the
area giving even colder weather.
Near term /through Friday/...
brief high pressure tonight will allow mainly diurnal clouds to
dissipate this evening. Went on lower side of temperature guidance
but did not hit that too hard due to some uncertainty later on
tonight about the timing of the increasing clouds from the next
system. Models have this high pressure rapidly shifting east by
Friday...which allows the next upper disturbance heralding an
Arctic front to sweep across the area Friday. The disturbance and
best forcing looks to track just south of the area...but warm
advection ahead of the Arctic front will bring some snow to most
of the area Friday. With the speed of the system and its limited
moisture...snow totals from this disturbance through the day Friday
look to be on the light side...with the heaviest over the southern
mountains. Later Friday afternoon...as the front passes and
northwest flow with strong cold advection develops...we look for
this to transition into mainly an upslope mountain event...but
with the best upslope snow showers in the mountains occurring
mainly after this period. Thus...outside the southern Coal fields
and southwest Virginia where 1 to 2 inches of snow may fall
Friday...we look for generally around an inch in most of the
remaining low lands. In the mountains...we have some higher
amounts due to upslope. Given all this...snow totals will be just
below advisory criteria...so no headlines. Look for frigid temperatures
tonight...and temperatures Friday reaching closer to the 30 degree
mark ahead of the front.
Short term /Friday night through Sunday night/...
high pressure to start with...but a slug of moisture gets ushered
in on zonal flow increasing probability of precipitation by Friday afternoon. Still plenty
cold for snow with generally 1 to 3 inches for The Lowlands and
2-5 in the mountains upper level trough whisks off to the east
bringing Arctic front through Friday night with more upslope snow.
Then cold high pressure hunkers down for Saturday night into
Sunday for some very cold temperatures with 850 temperatures down to -22
c. Probably will need advisory headlines for wind chills for the
highest mountain counties and maybe for snow too.
Long term /Monday through Thursday/...
still lots of uncertainty in the extended period...although
models are gradually trying to come together. Series of potent waves
to affect the area early next week. First Sunday night into
Monday...as wave moves into Great Lakes region...spreading mainly
light snowfall into the region. The second more powerful wave and
associated low will move northeast out of the southern U.S. Towards
the region by Monday night into Tuesday. Depending on the track of
the low...will determine whether area is looking at an all snow
event...or a wintry mix at times. At this point...looks like a
wintry mix can be expected at times...particularly across The
Lowlands...which of course will limit snowfall potential. With the
overall uncertainty in the models at this time...will keep a mention
out of the severe weather potential statement for one more day...and allow focus to remain on
systems and impacts expected this weekend.
Aviation /20z Thursday through Tuesday/...
18z Thursday through 18z Friday...
generally MVFR ceilings with scattered snow showers and flurries
in higher elevations of the mountains...becoming VFR ceilings
19-22z...then scattered-broken VFR clouds at or above 7000 feet above ground level after 00z.
Elsewhere...sct-bkn VFR clouds at or above 4000 feet above ground level...except VFR
flurries this afternoon over portions of extreme southeast Ohio.
West winds will diminish later this afternoon and be light and
variable tonight. Middle level clouds ahead of an upper level
disturbance will spread eastward across the area after 04z...with
MVFR conditions in light snow possibly arriving in mainly
southwest Virginia by 12z Friday.
After 12z Friday...rapidly becoming MVFR in general light snow as
the aforementioned upper disturbance races eastward...with heavier
snow showers in the mountains by 18z.
Forecast confidence and alternate scenarios through 18z Friday...
Forecast confidence...medium to high.
Alternate scenarios: snow showers in the mountains may end quicker
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 15 16 17 18 19 20 21 22 23 00 01 02
EST 1hrly 10 11 12 13 14 15 16 17 18 19 20 21
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 h h
bkw consistency M h h h h h h h h h h h
ekn consistency M M M M M M M M M h h h
pkb consistency h h h h h h h h h h h h
ckb consistency M h h h h h h h h h h h
After 18z Friday...
IFR conditions in snow showers will be possible again Friday
night through Saturday night...especially in the mountains.