Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston WV
1243 PM EST Sat Dec 27 2014
high pressure exits as a cold front crosses late tonight into
Sunday. A wave of low pressure moves along the front Sunday.
Drier...colder air slowly builds in to close out 2014.
Near term /through Sunday/...
most of West Virginia is basking in the sun at the moment...but
that should change as a cold front moves through tonight and turns
into a stationary front ushering waves of moisture into the state.
Luckily...most model signals indicate that total precipitation
between now and Sunday should remain less than an inch.
With increased model confidence boosted the probability of precipitation over much of the
forecast area. Also notched up the winds in southeast Ohio per hrrr
guidance for this afternoon.
Short term /Sunday night through Tuesday/...
overall...models locked into the short term pattern pretty well
which equates to minimal changes across the short term. Biggest
changes are bumping up the probability of precipitation with added confidence to the
forecast this morning. Otherwise...the story is the same with a cold
front pushing in...going stationary with a wave forming along
it...and ultimately having difficulty exiting the area with the middle
and upper level steering flows nearly parallel to the surface
boundary. As noted last night...no upper level trough axis keeps
this system on the weaker side with quantitative precipitation forecast totals less than half an
inch for the most part. Still have some questions about possible
snow totals in the highest ridges of the mountains Sunday night and
Temperatures fall behind the front eventually to more normal
December values...but still not tapping into any really cold Arctic
air just yet. Few changes to the temperatures in the short term as
well with the most noticeable changes being to the southeast Ohio
counties on Sunday night and taking them below freezing.
Long term /Tuesday night through Saturday/...
overall a fairly quiet long term period. Have probability of precipitation tapering off
Monday night as moisture departs. Bring back in some slight chance
probability of precipitation in the mountains for late Tuesday and Tuesday night with 850mb
temperature trough and weak 500mb shortwave trough sliding through.
High pressure noses in for Wednesday and Thursday. Both GFS and
European model (ecmwf) showing a system moving out of the lower Mississippi Valley at
the end of the week...so do start increasing probability of precipitation right at the end
of the period. Blended new wpc guidance into previous forecast for
temperatures...and then went just a touch cooler on lows.
Aviation /18z Saturday through Thursday/...
VFR transitioning to MVFR and ultimately IFR by early Sunday
morning. Biggest question is how low will the cloud deck get. Went
with IFR over much of area in a stationary front anchored over the
area type of pattern.
Forecast confidence and alternate scenarios through 18z Sunday...
Forecast confidence: high becoming moderate.
Alternate scenarios: timing of IFR onset and offset may vary from
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 h h h h h h h
heights consistency h h h h h h h h h M M l
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 M M
ckb consistency h h h h h h h h h h h h
After 18z Sunday...
IFR possible in rain Sunday into Monday.