Weather

081 
fxus61 kctp 280602 
afdctp 


Area forecast discussion 
National Weather Service State College PA 
202 am EDT Thursday Aug 28 2008 


Synopsis... 
moisture from the remnants of old Tropical Storm Fay will bring a 
chance of rain through Thursday. Moderating temperatures will 
follow for the weekend as high pressure returns. 


&& 


Near term /until 6 am this morning/... 
rainfall thus far over southwestern PA has been rather paltry. IFLOWS 
indicates only up to one quarter inch over southern Somerset Colorado. 
This area of the Laurel Highlands will continue to see the 
steadiest rain overnight...as moist sserly ll jet funnels moisture 
from ts Fay remnants into the southern alleghenies. 
However...unimpressive upstream radar trends lends confidence to 
the latest /21z/ sref data...which indicates only modest 
additional rainfall overnight of 0.5 inch or less across the 
alleghenies. Eastward progress of rain will be slow tonight...as 
cut off low east of new eng is keeping system at Bay. 


&& 


Short term /6 am this morning through 6 PM Friday/... 
the anomalous southeast low level jet gradually turns more southerly in 
time Thursday which suggests the upslope component to the flow 
will relax and the chances for rain diminish in time. With the 
high in the position forecast by the models...it also suggests a cool 
air damming component to the flow so a rather cloudy-cool day is 
likely with the best chance of rains early in the day tapering to 
scattered showers which will likely linger into the evening. 


&& 


Long term /Friday night through Wednesday/... 
the remnants of Fay will continue to move away Thursday night 
while a sharp but shearing upper trough approaches from the central 
Great Lakes. This should nudge a slow moving cold front eastward 
across the area Friday night into Saturday bringing the welcome 
chance for showers and a few thunderstorms...even to eastern 
sections. The front may stall across eastern sections Saturday 
afternoon prolonging shower chances there...but doubt many will 
mind given the parchedness of that area. 


For the remainder of the extended period...upper ridging building 
into the central Great Lakes...through Ontario and western Quebec 
will promote the upstream development of a middle-upper level cutoff 
low from over the Canadian Maritimes Sunday into Monday...which 
will keep a dry northerly flow across the area through early next 
week. The upper low is prognosticated to meander southward well off of 
the middle Atlantic coast...while the upper level ridge axis remains 
over or slightly west of PA...which is typically a dry scenario 
for US. Thus...will go along with the return to persistent dryness 
Sunday and beyond with near to slightly above normal temperatures 
and below normal humidity for this time of year as Canadian surface 
anticyclone maintains tranquil conditions across the region. 


&& 


Aviation /06z Thursday through Monday/... 
tropical remnants struggle to saturate boundary layer this 
morning...despite radar returns indicating numerous rain showers 
across the alleghenies. Most airfields remain at VFR 
conds...however expect that between 06-10z many sites will finally 
saturate the llvls and lower ceilings to around broken/overcast at or above 1-3kft 
above ground level...with guidance hinting at this criteria persisting through 00z 
Friday. Vcsh will give way to steadier rain showers...with periods of vsbsy 
be reduced to around MVFR tempo IFR mainly during nocturnal hours. 


Airfields will continue to see reduced ceilings/visibilities through Friday early 
Sat as an area of high pressure allows cooler moist boundary layer 
airmass to filter in from the east...before broad area of high 
pressure acros the Ohio River valley moves in for the middle weekend 
period brining VFR back for the remainder of the weekend. Sat night 
early sun will feature best chance for fog to dev...possibly bringing 
IFR/LIFR to numerous airfields before mixing out after sunrise. 


&& 


Ctp watches/warnings/advisories... 
none. 


&& 


$$ 
Synopsis...lacorte 
near term...Fitzgerald 
short term...lacorte 
long term...devoir 
aviation...beachler