Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
330 PM EDT Friday Mar 14 2014
weak cold front crosses tonight. Dry Saturday. Low pressure moves
across Tennessee Valley late Sunday bringing mixed precipitation Sunday
into Monday. Drier Tuesday. Another cold front crosses by middle week.
Near term /through Saturday/...
top of mixing layer tops out around 5000 mean sea level this afternoon. The
stronger forecast gusts of 30 to 35 knots in the Ohio Valley should
diminish toward sunset...but still expected the wind to blow this
evening. 925 mb flow on rap still around 40 knots this evening.
Increased speed a bit in the Ohio Valley for this evening. Special
Weather Statement for enhanced fire threat continues until 23z.
Was about an hour or two faster pushing the prefrontal light shower
across County Warning Area overnight. Overall lowered probability of precipitation about 10 to 20 percent
with that band. Only organization near 18z was actually between pah
and mem not further north. Still think a few hundredths could occur
Have clearing fairly rapidly during predawn hours in the western
lowlands...with some stratocumulus still holding over mountains
around 12z before evaporating.
No major changes in our minimum and maximum temperatures for tonight
Short term /Saturday night through Monday/...
active weather...as usual...in the short term period. High pressure
will be overtaken by a low pressure system that will move out of the
south central U.S. Towards the region. Still continues to be some
model differences concerning this storm...but models are starting
to come into better agreement...trending colder. NAM continues to be
the warmer solun...and brings a closed upper low across the deep
south...and a stronger southerly flow aloft. GFS and European model (ecmwf) are more
in agreement...and are colder soluns...and the European model (ecmwf) as the
preferred solun for this system according to wpc...was used to
configure precipitation types.
Not especially impressive moisture associated with the system...precipitable water
values generally rising to around 0.6 to 0.8 inches...but good
dynamics middle levels and aloft...along with good dendrite growth will
allow for accumulating snows...particularly across the north where
colder air will exist. With using the colder solun...this has wiped
out most of the mixed precipitation...I.E. Sleet and freezing rain
across the County Warning Area. The low will push off to the east Sunday
night...allowing for colder air to filter into the region...and for
precipitation to gradually change to snow or at least a mix...pretty
much County Warning Area wide.
At this point...am holding off on a watch for 1 more
period...allowing the midnight shift to take another look at
things...particularly with the model variability. But it is looking
like several inches of snowfall accumulations possible across
northern zones including southeast Ohio...northern WV...and the
northern mountain zones. At this point...generally have 2 to 5
inches forecast across parts of southeast Ohio and northern WV
zones...with 4 to 6 across northern mountain zones...with higher
amounts possible across higher terrain. Across the crw-heights metropolitan
area and south...generally around an inch or so. Have highlighted
southeast Ohio...northern WV...and northern mountain zones in the
severe weather potential statement for potential headlines.
Long term /Monday 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 /20z Friday through Wednesday/...
strong low level flow continues into tonight...but gradually
weakening 06z to 12z. Front passing ckb-crw line by 09z. Have a few
light showers possible along it for a hour or two...with some
ceilings 2 to 4 thousand feet broken and visibility only dropping to near 5 or 6
miles over the central WV mountain counties.
Leftover stratocumulus at 2 to 4 thousand feet at 12z over mountain
counties should evaporate by 15z...with ceiling unlimited and visibility
Forecast confidence and alternate scenarios through 18z Saturday...
Alternate scenarios: none.
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 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1hrly 16 17 18 19 20 21 22 23 00 01 02 03
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 h 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 18z Saturday...
IFR possible in rain...wet snow...sleet and low ceilings Sunday
afternoon into Monday.