Weather

122 
fxus61 krnk 292326 
afdrnk 


Area forecast discussion 
National Weather Service Blacksburg Virginia 
726 PM EDT Friday Aug 29 2008 


Synopsis... 
a weak front will approach from the west tonight...slowly 
passing through the region through Saturday night. By Sunday and 
into next week...strong high pressure will build down from the 
Great Lakes into the southern Appalachians. 


&& 


Near term /through Saturday/... 
weak surface ridge over the County Warning Area today sandwiched between coastal trough 
and weak cold front pushing into the Ohio Valley. Morning soundings 
show abundant low level moisture under strong subsidence inversion at 
600mb with very dry air aloft. Some weak energy aloft riding north 
through the Carolinas may trigger some convection late today and this 
evening...assuming the cap weakens as model soundings indicate. 
However...chances are very low. Mostly clear skies late along 
with light winds and high soil moisture levels will result in 
considerable amounts of fog tonight...especially in the west. 


Cold front approaching the western counties Saturday should be able 
to trigger scattered to widely scattered showers and thunderstorms across the County Warning Area with 
heating tmrw although low level convergence and dynamic forcing is 
weak. 


&& 


Short term /Saturday night through Sunday/... 
cold front slowly travels trough the region Saturday into Sunday. 
As the front pushes south...high pressure will build in. Drier air 
will move into our area. Played temperatures close to mav gud 
for Saturday night and Sunday. Kept light probability of precipitation across southern 
portions with best chance early Saturday with instability. Allowed 
for isolated convection on Sunday...but do not expect much coverage. 


&& 


Long term /Sunday night through Friday/... 
upper ridge will build over the Great Lakes and spill southeast. 
The strong upper high over the Great Lakes will allow heat to build 
over parts of the Ohio Valley. Slightly cooler air will be 
reinforced over our region as an easterly component to the wind 
persists thanks to a strong surface high over the northeast and 
middle Atlantic region. Temperatures will moderate around midweek 
and cool back down during the weekend. Through Thursday...Hannah 
will likely be still east of southern Florida due to the blocking 
ridge to the north. Check the latest advisories from NHC on 
tropical systems during the period. 


&& 


Aviation /23z Friday through Wednesday/... 
strato cumulus layer between 050-070 will gradually fade this evening. 
Light winds...clear skies...and a moist boundary layer will 
promote development of fog after midnight...thickest in the 
mountain valleys. 


Fog will dissipate by middle Saturday morning with formation of 
cumulus...then building cumulus ahead of approaching front Saturday 
afternoon. Showers and thunderstorms will develop over the 
mountains Saturday afternoon. Steering winds are light...so 
movement of storms will be slow...mean wind 10 kts or less. 


After Saturday...with the exception of Mountain Valley fog during 
the overnights...VFR conditions will prevail Sunday and into the 
middle of next week...high pressure building across the middle 
Atlantic region. 


&& 


Rnk watches/warnings/advisories... 
Virginia...none. 
NC...none. 
WV...none. 


&& 


$$ 
Synopsis...air mass 
near term...ams/js 
short term...ams/js/kk 
long term...kk 
aviation...PM