Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
636 am EDT Sat Mar 15 2014
dry today and tonight. Low pressure brings a winter storm late
Sunday and Sunday night. Another cold front crosses by middle week.
Near term /through tonight/...
630 am update...
no changes at this time.
Previous discusion below...
had some Stout wind gusts around 04z across WV ASOS sites on the
order of 40 kts. Some precipitation associated with middle level jet
dynamics fell through a very dry airmass near the
surface...helping to bring down some of the 50 knots low level jet around 850 mb.
Did not last long as low level jet shifts east...still some decent gusts though
in advance of cold front. This cold front will race through and exit
mountains around dawn. Have some high probability of precipitation with broken line of rain showers but
very low quantitative precipitation forecast. Winds will slacken next few hours as gradient relaxes
and weak surface high noses in from SW.
Today will feature sunshine...amid some flat stratocu...mainly
across southeast Ohio/north WV. With bl drying out once again...should be
another efficient mixing day...albeit with not quite the gusts of
recent days as winds atop the mixing layer not strong at all. As
such...looking at 20 to 25 miles per hour gusts today. This combined with
another day of low dewpoints and 10 hour fuels drying...will
probably lead to another enhanced fire danger afternoon. Will pass
along to day shift to contact forestry partners to coordinate
possible fire Special Weather Statement again today...especially for S half of County Warning Area. For
temperatures...used a blend of mav and local MOS...yielding 60 to 63f S
areas to middle to upper 50s southeast Ohio/north WV non mountain locations. Have
40s in the highest elevations.
Attention then turns to next storm system. Trend in models is to
slow everything down enough to keep area dry through 12z Sunday.
Still bring in thick cirrus canopy overnight which should keep
temperatures from bottoming out as some guidance is trying to show.
Short term /Sunday through Tuesday/...
for storm system Sunday and Sunday night...models are showing a
significantly colder solution today versus last nights runs...with
fairly decent agreement among models. This would push the mixed
precipitation band into southern WV with snow north and west of this
region. Southwest Virginia still looks to be mostly rain on the
current models. With models changing so much for the previous
night...will hold off on headlines until models stabilize a bit.
Models then disagree on whether a second wave pushes precipitation
back into the region. NAM and GFS are most aggressive with this and
in fairly good agreement. Canadian and European model (ecmwf) are keeping this system
south and east of the area. With two models showing some
precipitation...will include small probability of precipitation in the south and east...but
confidence is low.
Long term /Tuesday night through Friday/...
with a cold front probably to our east and south...a Canadian high
pressure builds across the Great Lakes region into the northern
portions of WV late Monday. This feature will provide dry weather
A surface low pressure system develops over the Central
Plains...strengthening as it track east northeast into the Great
Lakes region by Wednesday. The local area should remain in the warm
sector...with warm front lifting north on Wednesday...followed by a
cold front Wednesday night...exiting early Thursday.
The latest European model (ecmwf) is consistent with its previous run...bringing a
cold front late Wednesday night...decaying early Thursday. The GFS
is about 18 hours faster with this feature. There are large
differences in European model (ecmwf) ensembles temperatures. Although some spread is
noticed on the GFS ensembles with the upper trough...some consensus
in noticed among its members. Preferred the slower solution and went
with the European model (ecmwf) with the timing of the cold front.
Therefore...increase chance probability of precipitation on Wednesday...with higher probability of precipitation
Generally used HPC guidance. Temperatures should gradually warm
at or above seasonal levels by middle week. Tweaked down temperatures Friday
day 7 to compromise with neighboring offices.
Aviation /12z Saturday through Wednesday/...
some leftover stratocu between 3 to 4 thousand feet around 12z over
mountain counties should evaporate by 15z...with VFR conditions
area wide remainder of taf period with just some daytime flat 4 to
6 thousand feet stratocu across southeast Ohio/north WV. Despite weaker winds
aloft...another day of efficient mixing will allow for gusty winds
today. Not to the level of recent days though...generally on the
order of 15 to 20 kts out of the west.
Surface winds turn more NE tonight as a warm front develops across
the Tennessee Valley ahead of the next low pressure system. Thick canopy
of cirrus will overspread the area from SW to NE overnight.
Forecast confidence and alternate scenarios through 12z Sunday...
Alternate scenarios: timing of wind and wind gusts diminishing may
vary through dawn.
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
EDT 1hrly 07 08 09 10 11 12 13 14 15 16 17 18
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 h h h h h h h h h h h h
ekn consistency l h 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 Sunday...
IFR possible in rain...wet snow...sleet and low ceilings Sunday
afternoon into Monday.