Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
157 PM EST Wednesday Nov 26 2014
low pressure exits to the northeast. A weaker clipper system
crosses the southern Appalachians later tonight. High pressure
Near term /through tonight/...
precipitation is fizzling out over the central lowlands as the
main energy of the coastal system continues to the northeast. Dry
slot is holding on over the tri state area...and figure it will
remain there without any further eastward progress thanks to low
level cold air advection. Snow has ended in bkw and will lift out
of Rand/Poca in the next 4 to 6 hours after a decrease in
Meanwhile...over the middle Mississippi Valley...a clipper type
system dives into the Tennessee Valley as the upper level low
carves a path into the deep south. With that said...the next round
of precipitation is not far behind for the southern zones tonight.
However...system is frontolytic in nature...and figure that will
go against the quantitative precipitation forecast and subsequent snowfall amount projections.
Through 00z Friday...not expecting more than an inch or two from
McDowell into Rand/Poca counties.
Further to the west...while the aforementioned low pressure system
will slow the cold air advection tonight...850mb temperatures drop
towards the -10c mark across southeast Ohio. Northwest flow brings
the potential for upsloping conditions...and in the colder air
aloft...the chance for snow showers exists all the way back into
portions of southeast Ohio. This will begin after 18z Thursday as
the low level moisture depth begins to increase.
Using a blend of the guidance...manually adjusted the min
temperatures downward tonight over the southern mountains...and
likewise for the afternoon maximum temperatures Thursday. All in
all...not much to the diurnal temperature curve from late this
afternoon until this time tomorrow.
Short term /Thursday through Saturday/...
air mass cools significantly as a clipper system streams through
the area bringing snow to most locations. Best chance for
accumulating snow is southern WV where they may get an inch.
Light upslope snow continues in the mountains for a few days
afterwards with little to no accumulation.
Below normal temperatures.
Long term /Saturday night through Wednesday/...
used a blend of the European model (ecmwf) and European model (ecmwf) ensemble mean for the forecast.
High pressure slides eastward Friday night and Saturday...providing
warm air advection. Next frontal boundary pushes into the region on
Sunday or Sunday night. The front then hangs near the area on Monday
as a wave moves along the front...pushing it southward Monday night.
The front will return back northward Tuesday as a warm front.
Aviation /19z Wednesday through Monday/...
low pressure system continues to push to the northeast...and will
take the snow with it exiting the area by 03z tonight. Have some
clearing towards the tri state area...but for the most part...IFR
to MVFR ceilings tonight will prevail...with visibilities
improving one the snow ends at each terminal.
Guidance was too pessimistic on the visibilities overnight...so
trended MVFR or better.
Another low pressure system brings snow back into the southern
mountains and eventually into ekn as it tracks through the
southern Appalachians and into the Piedmont. This will occur after
Forecast confidence and alternate scenarios through 18z Thursday...
Forecast confidence: medium.
Alternate scenarios: timing of snow lifting out and improving
ceilings and visibilities could vary. May need an amendment here
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 M h M l l l l l l l
heights consistency h h h h h M h h h M M M
bkw consistency h M M M l l l l l M M M
ekn consistency h h h h h h M M h M M M
pkb consistency M M h h h h h h h h h h
ckb consistency h h h M h h h h l l l l
After 18z Thursday...
IFR conditions in snow showers and stratus over the mountains at
times into Thursday night.
WV...Winter Weather Advisory until 4 PM EST this afternoon for
Winter Storm Warning until 4 PM EST this afternoon for wvz046-