Weather

460 
fxus61 krlx 071016 
afdrlx 


Area forecast discussion 
National Weather Service Charleston WV 
615 am EDT sun Sep 7 2008 


Synopsis... 
a weak surface trough crosses this afternoon while the associated 
upper level support tracks over the Great Lakes. A stronger cold 
front is expected to move through Tuesday...then a weaker one Friday. 


&& 


Near term /through tonight/... 
middle clouds continue to trek east with the leading edge close to the ind/Ohio 
border as of 630z. This will be the main challenge in the near term 
and their affect on maxt. 700 mb moisture forecasts keep the bulk of the 
clouds along and north of I-64...so tailored sky grids as such. A brief 
period of mcldy-overcast through midday before they break up allowing the sun to 
appear. As a result...trimmed a few degrees off maxt acr northwestern zones. 
Upper level energy rides acr the Great Lakes and bufr soundings illustrate 
minimal bl relative humidity negating any chance of quantitative precipitation forecast. Diurnal driven clouds fade 
with sunset allowing bcfg to form during the predawn hours. Some of 
the NCEP suite members depict stratocu in wake of the surface trough the 
crosses today...but confidence is too low for any inclusion of high 
sky grids att. 


&& 


Short term /Monday through Wednesday/... 
weak high pressure eases east of the area Monday...providing for a dry and 
warm start day to the work week...once the morning fog is gone. A 
cold front approaches Monday nt and early Tuesday...and moves through Tuesday 
afternoon and evening. Moisture initially increases from the southeast Monday 
nt as the high exits...introducing clouds and even spotty light 
precipitation. 


Dew points increase Tuesday in the strong SW feed ahead of the cold 
front which feature good low level convergence. Even GFS brings surface 
dew points to around 70f...forecast values in gfe were raised into the 
middle 60s for now. Operational members of both the GFS and the NAM 
show up to 2.5kjkg-1 cape Tuesday...though sref probability has only small 
pockets of 20% for cape values above 2kjkg-1. Sref probability for at 
least 1kjkg-1 do exceed 60%. So thunderstorms can become rather 
strong per Storm Prediction Center slight risk across WV/Virginia as front pushes east. One 
thing lacking is upper level dynamics and cooling...as the short 
wave passes northwest of the area. 


Front and its precipitation push on through Tuesday evening although 
stratocu deck could linger behind for awhile behind the front. 
Delayed clearing a few hours for now. High pressure brings dry and 
cooler weather for Wednesday...though may eventually need to add cloud S 
depending upon southward progress of front. 


Went close to the mav on highs Monday...except a little below north. Lows 
Monday nt were raised to a blend of the new numbers...especially west in 
the increasing S flow ahead of the cold front. Highs Tuesday looked 
reasonable for now. Cooled the northwest a tad Tuesday nt. Highs Wednesday were 
lowered toward the 00z mex with cool...Canadian high pressure moving 
in. The aforementioned clouds may also play a role S Wednesday. 


&& 


Long term /Wednesday night through Saturday/... 
made minor topographical adjustments to highs Thu-Sat. Rest same. 


Models now agreeing more on letting cold front clear the entire County Warning Area 
Tuesday night...and leaving area in brief high pressure /most if not 
entire area dry/ Wednesday. However...boundary still looks to drift 
back northward as a warm front into Thursday night followed by 
another cold front Friday. Went lower than HPC probability of precipitation Wednesday 
through Thursday morning...given fair model agreement on boundary 
staying to our south. Accepted HPC probability of precipitation in the 40s range by 
Friday...and expect chances to get higher in coming shifts as models 
settle more on timing. At end of the long term period...eyes will be 
on Hurricane Ike to see when and if its remains could impact our 
area. At this time...landfall could be just about anywhere along the 
Gulf Coast...so it is not incorporated at all into our forecast for 
now. 


&& 


Aviation /11z Sunday through Thursday/... 
widespread LIFR fog rapidly lifts with the appch of broken-overcast middle deck 
arriving from Ohio between 12-13z. Fog channel already indicating at high 
based cumulus developing out ahead in central WV. VFR for today with scattered-broken 
clouds between 5-10kft. The sky clears after sunset setting the stage for 
another fog night at most sites. Despite a weak trough of low pressure 
passing this afternoon...no precipitation is predicted. 


Aviation outlook /beyond 12z Monday/...IFR weather possible in rain shower/thunderstorm Tuesday. 


&& 


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


&& 


$$ 
Synopsis...trm/29 
near term...29 
short term...trm 
long term...mdp 
aviation...29