019 
fxus61 krlx 030559 
afdrlx 


Area forecast discussion 
National Weather Service Charleston WV 
1244 am EST Wednesday Dec 3 2008 


Synopsis... 
high pressure building tonight. A strong cold front comes with 
mainly rain Wednesday night and early Thursday...followed by Arctic 
air. 


&& 


Near term /through today/... 
high pressure over the southeast is building into the area and as the 
warm advection is kicking...the lingering clouds are going away. 
They have cleared most of the area...except the extreme northern part 
of WV. But by 5z or 6z the clouds should be all gone. After 
that...the sky will remain clear through the day tomorrow when 
some high clouds return ahead of the next cold front. So have 
adjusted the sky cover to clear things out a touch quicker and 
have also lowered the lows down some more as the winds are light 
and the lower dew points are allowing for more radiational cooling. 


&& 


Short term /tonight through Thursday night/... 
cold front to move through the region Wednesday night and early 
Thursday. NAM is much slower than the GFS with this front. Faster 
GFS has support of the Gem global and UKMET. Current forecast is in 
line with the faster timing so will stay with that scenario for now. 


Behind the front...models showing only very shallow moisture. Will 
reduce probability of precipitation even further...restricting to the mountains...and just 
use snow flurries elsewhere in the cold air. 


&& 


Long term /Friday through Tuesday/... 
decent cold air advection takes place early Friday on the heels of 
frontal passage and build-up of surface high. Maximum temperatures will running 
about 10 degrees cooler from Thursday. Models still hint at keeping 
low level moisture near the mountains with light to moderate 
westerly flow. 12z NAM was a little more pronounced in this line of 
thinking while the GFS was a little on the dry side. Stayed a little 
closer to the NAM solution for this forecast package. This should 
allow for a continuation of light snow shower development through 
the day on Friday...especially over the eastern mountains. 


Alberta clipper system drops southeast along the Great Lakes with 
trailing cold front swinging through the forecast area Saturday 
evening. European model (ecmwf) and GFS in pretty close agreement regarding timing 
this feature. Latest European model (ecmwf) amplifies trough late Saturday night. 
This is where the models begin to diverge in their solution. The GFS 
shows a slightly more progressive transition for this upper level 
trough. Followed HPC lead in keeping forecast on closer to the GFS 
solution late in the period. 


Next system arrives late Monday night and Tuesday in the form of 
another clipper system. By this time...European model (ecmwf) has well developed 
trough across the southern tier of the United States. Per HPC 
guidance...followed GFS trends for day 7. 


HPC temperatures on track...and made minor adjustments to probability of precipitation to account 
for mountain snow showers. 


&& 


Aviation /06z Wednesday through Sunday/... 
06z Wednesday through 06z Thursday... 
high pressure slides east of our area Wednesday...followed by a 
strong cold late Wednesday night and Thursday morning. VFR mostly 
clear...with increasing middle to high clouds west of Ohio River by 00z 
Thursday. VFR ceilings rapidly increase from the west after 
00z...with some MVFR conditions in rain showers west of the Ohio 
River by 06z. 




Aviation outlook /beyond 06z Thursday/...another front with possible 
IFR comes late Wednesday night into Thursday. 


&& 


Rlx watches/warnings/advisories... 
WV...none. 
Ohio...none. 
Kentucky...none. 
Virginia...none. 


&& 


$$ 
Synopsis...aar/rpy 
near term...ess 
short term...rpy 
long term...kmc 
aviation...jmv