Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
114 PM EST sun Feb 1 2015
low pressure entering Ohio River valley...with cold front passing
overnight/early Monday. High pressure builds in Monday night into
Near term /through Monday/...
light precipitation still hanging on in NE County Warning Area...but should be moving out
soon. Have cancelled the Winter Weather Advisory that was in
effect for Perry and Morgan County. With rain expected through
most of the night...and moisture quickly moving out once snow
starts again...do not have enough additional snow forecast to need
Looking into tonight...precipitation still a couple hours away from the
SW. Will arrive through the afternoon as rain. With low level
temperatures well above freezing...even 850mb temperatures 3c-6c through
midnight...so anticipate rain through much of the night. Cold air
arrives in the west during the pre-dawn hours. So rain will change
to snow from west to east through the morning. Snow may not reach
Ohio River until around 12z...I-79 corridor around 14z...and into
the mountains shortly there after. As middle level temperatures continue to
plummet...with 850mb temperatures -12c to -15c by 18z. This will lead to
light fluffy snow that could accumulate well by late morning into
the afternoon. Currently have everything below advisory
criteria...but does not take a large stretch to see things getting
into the 2 inch range for The Lowlands of West Virginia so will
include in severe weather potential statement. Will also have rather gusty winds as the cold air
plows in. This will cause reduced visibilities as the light fluffy
snow blows around. This will be hitting during morning commute
time for much of The Lowlands.
Have non-diurnal temperatures both tonight and Monday. Tonight...not
falling as quickly through 1-2 am...and then beginning to
accelerate downward. Temperatures will continue to fall through Monday.
Short term /Monday night through Tuesday night/...
strong low pressure system exits northeast Monday.
However...models indicate very cold air behind its associated cold
front changing any precipitation to all snow. The flow will shift from the
northwest to produce ideal set up for upslope snow over the
northeast mountains while moisture remains available through
Monday night. The rest of The Lowlands and central mountains will
see snow after dawn on Monday.
As the moisture starts to decrease after all precipitation transitions into
snow...only light accumulations are expected...generally 2 to 4
inches possible across Perry County....with 1 to 3 in Morgan
County...and around an inch for the remainder of southeast Ohio.
Expect much of the West Virginia lowlands to receive around an
inch or less...except northern West Virginia lowland counties such
as Clarksburg area...where a good inch or two will be possible.
Northeast mountains could easily get 2 to 4 inches...with higher
amounts possible on northwest facing slopes. The snow will transition
to a lighter fluffier snow as the day progresses on Monday as
850mb -16c air rushes into the region.
A Winter Weather Advisory remains for Perry and Morgan counties
through Monday morning. Will keep monitoring the potential for
additional advisories over mountainous counties.
High pressure will build in late Monday night into Tuesday...with
dry conditions...and moderating temperatures.
Long term /Wednesday through Saturday/...
broad eastern middle/upper level trough with fast flow...and few
opportunities to access the Gulf of Mexico moisture.
Weak warm air advection ongoing Tuesday night...will try to bring
some 20/30 probability of precipitation a bit faster south by dawn Wednesday into our
12z GFS a bit more aggressive with the moisture moving up the Ohio
Valley Wednesday along that frontal boundary. European model (ecmwf) certainly not as
moist. For now...will keep probability of precipitation in chance category with front
Wednesday into Wednesday night.
Have colder air blowing south again overnight Wednesday night into
Thursday. Went colder than our previous forecast.
Drying again Thursday night through Friday night.
In the fast flow...next system could arrive by late day 7.
Aviation /18z Sunday through Friday/...
VFR conditions in place across County Warning Area currently...except maybe some
MVFR ceilings at highest elevations of the northern mountains.
Precipitation will arrive from west to east late today in the form
of rain. Ceiling/visible will be dropping into MVFR this evening through
tonight. Could even get some IFR in the heavier pockets of rain.
Cold air arrives early Monday morning...changing the rain to
snow...with IFR expected at most locations. Gradual improvements
from the west towards the end of the taf period. Winds gradually
increase out of the south through the night...and shift west then northwest
behind the cold front...also becoming quite gusty.
Forecast confidence and alternate scenarios through 18z Monday...
Forecast confidence: medium.
Alternate scenario: timing of drops into MVFR and IFR may vary.
IFR also possible in rain overnight.
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 18 19 20 21 22 23 00 01 02 03 04 05
EST 1hrly 13 14 15 16 17 18 19 20 21 22 23 00
crw consistency h h h h h M M M M M h h
heights consistency h h h h M M h h h h h M
bkw consistency h h h h h h M M M M M h
ekn consistency M h h h h h M M h h h h
pkb consistency M h h h h M M h h l l l
ckb consistency M M h h h h h M M h h h
After 18z Monday...
IFR conditions may linger into Monday night in the eastern
lowlands and mountains of WV.