252 
fxus61 krlx 211805 
afdrlx 


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


Synopsis... 
high pressure remains in control into Sunday...with dry weather. 
Upper level low impacts region Sunday afternoon 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 night/... 
models are struggling big time on what to do with system moving out 
of the Gulf of Mexico. Models have backed off considerably from 
last nights runs...and serious timing questions remain. Will 
therefore lower probability of precipitation outside of the southeast upslope region...and 
linger probability of precipitation longer. Confidence in this system is very low. 


Models still showing a cold front for Tuesday night...so will 
continue chance probability of precipitation with this system. 


&& 


Long term /Wednesday through Saturday/... 
same basic trends as yesterday with the operational GFS the fastest 
in the cool down...with the Gem and European model (ecmwf) slower. 


Main theme in our forecast continues to be the gradual cool 
down...with no sudden or sharp change. Also no major precipitation 
event during this period...good news for travelers. 


Leftover low level moisture Monday night...but with warming in low 
levels thought we could keep pop at or below 14 percent 00z Tuesday to 12z 
Tuesday. 


Left our medium range HPC low chance probability of precipitation late Tuesday into Tuesday 
night for possible shower with initial cold front. Lull in probability of precipitation 
Wednesday before increasing again to our chance pop range with 
middle/upper air trough Wednesday night into Friday. Did have a small 
likely pop area around Elkins late Thursday and Thursday night 
figuring on low level upslope. 


Maximum temperature on Wednesday is difficult...with low level flow 
remaining southwest. I am a bit warmer than my neighboring 
offices...still have the axis of the low level thermal trough 
not until Thursday night or Friday. 


Thinking some of the western lowlands...at least have a chance of 
light rain or snow showers by Friday. If so...would be their first 
flakes. This is unusually late for the first flakes of the season. 
Temperatures so far this month have been averaging 3 to 4 degrees 
warmer than normal. 


&& 


Aviation /18z 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...trm/rpy 
near term...trm 
short term...rpy 
long term...ktb 
aviation...trm