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fxus61 krnk 131738 
afdrnk 


Area forecast discussion 
National Weather Service Blacksburg Virginia 
1238 PM EST Sat Mar 13 2010 


Synopsis... 
low pressure will continue to track slowly north along the middle 
Atlantic coast through Sunday. 


&& 


Near term /through tonight/... 
steady rains have ended...and currently transitioning to a showery 
regime. With this in mind...and not expecting widespread 
rains...will drop the Flood Watch for entire County Warning Area. 


See Hydro section below for current flooding issues. 


For this afternoon...the thunder chances will remain over the 
southeast as they are currenty in the sun...but cumulus/SC is filling 
back in pretty fast. The upper low over the Tennessee Valley shifts east 
into the southern Apps this afternoon and the forcing will be 
sufficient for showers to redevelop over the County Warning Area. MUCAPES and Li/S 
this afternoon are marginal...but with steep lapse rates could see 
some gusty winds and hail in the far southeastern County Warning Area this afternoon...but 
main focus could be further southeast...so kept isolated thunder 
in for now. 


As upper low approaches temperatures at 850 mb start to drop. 
Took a blend of met/mav guidance for highs today. Lows tonight 
will be into the 30s in the mountains so kept the mix of snow in 
at higher elevations late tonight. Still slightly too warm for 
anything but minimal accumulation. 


&& 


Short term /Sunday through Tuesday night/... 
Sunday into Monday...the area remains in northwest flow behind the 
exiting upper low. Precipitation will be confined to primarily the 
mountains...especially those of southeast West Virginia. The 
precipitation type will be mainly rain showers. However...with 
colder air building behind the departing low...we cannot rule out 
some isolated snow showers for a few hours late Sunday night...and 
Monday night at the higher elevations of southeast West Virginia and 
in the northern mountains of North Carolina. Any accumulations would 
be under one half inch each night. Winds will increase on Monday as 
the pressure gradient tightens between the departing low and an 
approaching area of high pressure. This high pressure will begin to 
build into the region on Tuesday bringing decreasing cloud cover and 
a dry forecast. 


&& 


Long term /Wednesday through Saturday/... 
the extended period is characterized by dry weather and near to 
slightly above normal temperatures. We will remain in a mean trough 
through the period...with 850mb temperatures starting out around 1c 
on Tuesday and increasing to 4-5c by Friday. This will mean we will 
see increasing temperatures each day through Friday...used 850mb 
temperatures as a starting point for highs and blended with mosguide. 


With the trough overhead we will have rather steep low level lapse 
rates Tuesday through Thursday...which could allow isolated 
afternoon showers to develop. The best chance for this appears to be 
across the west...but any showers will be isolated and therefore 
currently just going with a dry forecast. The next chance for more 
widespread rain does not appear to be until Sunday...when models 
show a cold front moving through. 


&& 


Aviation /18z Saturday through Thursday/... 
there will be scattered to numerous showers around this afternoon 
with best coverage from blf to lwb. Ceilings here stay in the MVFR to 
IFR range...but could see some scattered breaks in them early. Further 
east...ceilings will stay VFR this afternoon with less shower 
covergage...but potential is there for each terminal to get a 
shower...with thunderstorms possible near Dan. Added cumulonimbus to account 
for this. 


Tonight...ceilings will drop in blf/lwb area to below 1kft...with 
patchy showers and drizzle around through Sunday morning. 


Looks like low clouds and spotty -ra may keep at least MVFR 
conditions going mainly in the mountains into Monday with some slow 
improvement to VFR Tuesday into Wednesday. 


&& 


Hydrology... 
currently flash flood warnings until 115 PM for southeast WV into portions 
of the New River valley...will transition to just an areal and 
river flooding this afternoon. Will monitor any heavier showers 
that could develop for additional flood warnings. 


&& 


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


&& 


$$ 
Synopsis...ams/wp 
near term...ams/wp 
short term...ds 
long term...mc 
aviation...ams/wp 
hydrology...