774 
fxus61 krlx 210950 
afdrlx 


Area forecast discussion 
National Weather Service Charleston WV 
450 am EST Sat Nov 21 2009 


Synopsis... 
high pressure remains in control into tonight...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/... 
still some clouds around some clouds between 3500 and 4500 feet above ground level 
moving southeast into northern West Virginia at this time. These clouds 
should continue moving southeast today. Across the remainder of the 
state...only some high clouds are anticipated. These clouds should 
generally be rather thin...so sunshine is expected. 


Upper level low over Texas at 2 am is expected to move east and then 
northeast with time...impacting the region. Latest models as well 
as the ensembles are slower than previous runs with the onset of any 
precipitation from this feature on Sunday. In fact...the nam12 
suggests region will generally be dry into Monday. 


Nam12 is much slower than GFS and ensembles...so will generally 
tweak previous probability of precipitation toward the GFS timing to reflect slower 
trend. 


End result of this new timing will be cloud thickening 
tonight...specially across southern portions of the region. 
However...area should remain precipitation-free. 


On Sunday...expect precipitation chances will spread into our Virginia 
counties shortly after sunrise...and then spread northeast...mainly 
along the mountain counties during the day. 


Made few changes to high today as latest guidance was very similar 
to previous forecast and looks believable. Lows tonight were 
tweaked downward...especially across the north...where cloud cover 
should be less. On Sunday...generally tweaked highs up a degree or 
two closer to the cooler mav. 


&& 


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 Friday/... 
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 /12z Saturday through Wednesday/... 
12z Saturday through 12z Sunday... 
high pressure still in control. Latest satellite and surface 
observations indicate scattered-broken clouds about 3500-4500 feet above ground level 
continue across portions of northern West Virginia. Models 
indicate these clouds should continue into the early afternoon 
hours. In addition...expect scattered-broken high level clouds into the 
afternoon. 


Some local valley locations have MVFR conditions in fog/mist with 
isolated IFR conditions in favored locations. The fog/mist should 
dissipate by 14z leaving VFR conditions for the entire region. 


A system along the Gulf Coast will result in increasing middle and hi 
level clouds tonight...with a small chance of showers across 
southwest Virginia by 12z sun 


After 12z Sunday... 
IFR conditions possible across portions of Virginia as well as the WV 
mountains on Sunday in rain showers. 


&& 


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


&& 


$$ 
Synopsis...jsh/rpy 
near term...jsh 
short term...rpy 
long term...ktb 
aviation...jsh