Weather

780 
fxus61 krnk 280729 
afdrnk 


Area forecast discussion 
National Weather Service Blacksburg Virginia 
329 am EDT Thursday Aug 28 2008 


Synopsis... 
the remnants of Fay will continue to slowly move northward up the 
western edge of the Appalachians today. However the deepest 
moisture and heaviest rain will shift east by tonight. A weak 
frontal boundary will approach from the west on Friday 
night...then high pressure builds in over the weekend. 


&& 


Near term /until noon today/... 
axis of heavy rain gradually shifting east. Should be just far 
enough east to allow Flash Flood Watch to expire at 4:00 
am...depending on last minute radar trends. Will also be adding 
areas of fog in at higher elevations of northwest North Carolina 
based on current observations. 


&& 


Short term /noon today through Friday night/... 
through the end of the day there is an easterly component to the low 
level winds...then tonight winds weaken. Appears The Wedge does 
not completely erode until Friday afternoon. It may mix out in the 
south and west this afternoon but models strengthen...or at least 
hold the stable air in place overnight with a lot of low level 
moisture. Will keep areas of drizzle and fog in tonight along the 
Blue Ridge...with patchy fog and stratus everywhere else. Will go on 
the cool side of guidance in the typical cad areas for highs 
today. 


Winds come around to the west on Friday which will help erode The 
Wedge and will bring warmer temperatures into the western County 
Warning Area as 500mb heights and 850 mb temperatures start to rise. 
High temperatures Friday for the mountain Empire area and Southside 
will be in the middle to upper 80s but will lower highs in the 
northeast into the upper 70s to lower 80s. The GFS is a little 
slower with the front approaching on Friday night from the 
northwest. Will slow down timing of showers and thunderstorms in the 
mountains on Friday afternoon. 


&& 


Long term /Saturday through Wednesday/... 
weak boundary/upper level disturbances meanders across the Ohio 
Valley on Saturday. This...combined with surface convergence...due 
to departing wedge farther east...should produce elevated 
convection mainly across southeast West Virginia on Saturday. Although the op 
GFS looks too wet...it does have fair support among its ensembles. 
Considering a rather dry layer aloft...from a couple days of 
wedge...would rather go towards NAM/sref...although enough 
instability will be present for at least slt chance/chance probability of precipitation County Warning Area 
wide. Reinforcing high pressure across the upper Great Lakes and 
New England should keep enough easterly component to keep the heat 
to our west through early next week. 


&& 


Aviation /08z Thursday through Monday/... 
eventually all terminals should experience ceilings near or below 
1kft. Kroa may only have temperature IFR ceilings. Expecting klyh/kdan to 
remain at IFR ceiling through Thursday. Kblf may go above by late 
morning...with klwb a little later in the day. IFR ceilings should 
may last through much of Thursday night too at klyh and kdan. 


Wedge persists into Friday as an upper trough moves east of the 
area and high pressure builds in at the surface...but a frontal 
boundary may bring another chance of precipitation by late Friday 
into Saturday 


&& 


Climate... 
Blacksburg may reach another record today for coolest maximum 
temperature. The current record is 69 in 1995. 


&& 


Rnk watches/warnings/advisories... 
Virginia...Flash Flood Watch until 4 am EDT early this morning for 
vaz015>017-022>024-032>035-043>046-058-059. 
NC...Flash Flood Watch until 4 am EDT early this morning for 
ncz001>006-018>020. 
WV...none. 


&& 


$$ 
Synopsis...ams/PM 
near term...air mass 
short term...air mass 
long term...km 
aviation...km/wp 
climate...air mass