188 
fxus61 krlx 212002 
afdrlx 


Area forecast discussion 
National Weather Service Charleston WV 
258 PM EST Sat Nov 21 2009 


Synopsis... 
high pressure remains in control into Sunday with dry weather. 
Upper level low impacts region Sunday night through Monday. Cold 
front moves east Tuesday night into Wednesday with limited moisture. 


&& 


Near term /through Sunday/... 
models not handing patchy stratocu decks around the area but it 
appears this cloud will have little impact on forecast...other than 
their exodus from the forecast for tonight. This results in lower low 
temperatures...will adjust at least to the low side of guidance. 
This raises the possibility for fog by dawn sun...especially mountain 
river valleys like the tygart but also along the Ohio again. 


Model differences show up beginning sun west/r upper level southern 
stream system. Believe short wave currently crossing the area will keep 
the southern stream system at Bay at least through 00z sun. With 
this...together with slower overall evolution of this event...most 
models including most sref members keep forecast area dry through 00z 
Monday. Opted to significantly knock back...but altogether eliminate 
probability of precipitation...for southeast portion of forecast area sun...as east component of low level 
flow starts to set up. 


With the more optimistic forecast for sun...it appears prudent to raise 
high temperatures to or toward the latest guidance values. 


&& 


Short term /Sunday night through Tuesday/... 
NAM dampens out the upper level system as it moves southwest to 
northeast a bit more than the latest run of the GFS. NAM also drags 
it further to the east and leaves the County Warning Area only affected by the well 
depicted southeast upslope along the eastern Highlands. Not sold on 
the NAM at this point taking the system completely east of the 
County Warning Area...although it looks like the GFS does over do the cloud forecast 
in north central West Virginia and southeast Ohio Sunday night into 
Monday. A careful eye is needed for the next model runs to see which 
of these actually prevails with consistency. Probability of precipitation remain highest in 
the aforementioned upslope areas for the short term forecast...and 
have reduced considerably the probability of precipitation for The Lowlands...especially 
along the Ohio River...with an absence of significant forcing other 
than a weak shortwave trough. 


Continue to keep high temperatures much cooler than The Lowlands on 
Monday under southeast flow and extensive low level clouds expected. 
May end up with a situation where the maximum T forecasts lowers even 
more with a small diurnal. 


&& 


Long term /Tuesday night through Saturday/... 
models in slightly better agreement in the long term. Unsettled 
weather returns to the forecast area as an upper level low pressure 
system...and associated cold front...moves out of the northern 
plains and into the region early Wednesday. This will bring a return 
of precipitation and gusty winds to the forecast area. Much of the 
precipitation will taper off later in the day on Wednesday as this 
initial low pressure system moves off to the northeast...although a 
few light upslope showers will continue to linger over the northern 
mountain zones. Model soundings and thicknesses suggest much of the 
precipitation will be in the form of rain...although snow or a rain 
snow mix is expected over the northern mountain zones above 2500 
feet elev late Wednesday night/early Thursday. The real cool down will 
begin on Thanksgiving...as a secondary low pressure center digs 
south out of the northern plains...and moves east through the Ohio 
Valley. This will deepen the upper level trough across the 
region...and usher in much cooler temperatures. By Friday morning 
much of southeast Ohio...and the higher terrain of WV will see light snow 
showers...with much of the WV lowlands experiencing a rain snow mix. 
Models indicating high pressure building in for the weekend. 


&& 


Aviation /20z Saturday through Thursday/... 
18z Saturday through 18z Sunday... 
high pressure still in control. Latest satellite and surface 
observations indicate scattered-broken clouds about 4500-5500 feet above ground level continue 
across portions of northern WV. These clouds should by and large 
dissipate by sunset of not earlier this afternoon. 


Local valley locations will have MVFR mist with isolated IFR fog in 
favored River Valley locations. For the taf sites...ekn will likely 
be the lone site to go IFR before dawn Sunday. The fog/mist should 
dissipate by 14z sun leaving VFR conditions for the balance of the 
day sun throughout the region. 


A system along the Gulf Coast will result in increasing middle and hi 
level clouds Sunday...with at most a small chance for showers across 
southwest Virginia by 18z sun. 


After 18z Sunday... 
IFR conditions possible across portions of Virginia as well as the WV 
mountains...mainly the east to southeast facing slopes...Sunday night and 
Monday in rain showers...primarily on ceilings. 


&& 


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


&& 


$$ 
Synopsis...26/trm/sl 
near term...trm 
short term...26 
long term...sl 
aviation...trm