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fxus61 krnk 132321 
afdrnk 


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


Synopsis... 
low pressure will continue to track slowly east along the middle 
Atlantic coast through Sunday. High pressure will build in by 
Tuesday. 


&& 


Near term /until 6 am Sunday morning/... 
numerous showers ongoing over the foothills and into the lower New 
River valley. Had reports of small hail from convection in NC as 
colder air aloft from the upper low slides in. Decided to add small 
hail to the forecast into early evening as sunshine has helped 
enhance lapse rates with temperatures in the 60s. 


Forecast for thunder seems reasonable as well down east. Speed of 
movement has concerns for excessive rain. Since the cells are 
fluctuating in strength and not as widespread will not issue any 
Flash Flood Watch...but will monitor progression. Not out of the 
question a Flash Flood Warning could be issued. 


Should see some diminishing in coverage overnight with loss of 
heating...but strong dynamics will keep chances around...with best 
lift moving across NC....with winds becoming more west to northwest aloft. 
Should also see some colder temperatures into overnight with snowfall over 
the higher mountains in NC/SW Virginia and southeast WV. Snow amounts should be less 
than inch due to wet ground. 


Kept lows tonight up due to slowness of colder air in the low levels 
and cloudiness/precipitation lingering. 


&& 


Short term /6 am Sunday morning through Tuesday night/... 
the upper low pressure system will exit the region Sunday into 
Monday with a northwest flow following in its wake. The upslope flow 
will enhance the precipitation mainly in the western mountains of 
southeast West Virginia. 


Cooler air will advect into the area behind the departing low with 
850 mb temperatures ranging from -1c south to -3c north. 
Therefore...some snow will mix in with the rain overnight Sunday and 
Monday. Low temperatures will be around freezing but expect little 
to no snow accumulation. If any accumulation occurred it would be 
confined to the higher elevations and do not expect more than a 
dusting. 


A more northerly flow will dominate the area Tuesday morning which 
will allow the upslope precipitation to be cut off. Have reduced 
temperatures for Tuesday a couple of degrees as the 1000-850 
thicknesses are slightly below normal. 


&& 


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. 


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 /23z Saturday through Thursday/... 
light to moderate showers along with isolated thunderstorms and rain will continue 
to meander across the southern and eastern areas this evening 
before slowly diminishing. Within these showers...a period of MVFR 
conditions likely with gusty winds to 30 kts and a brief reduction 
in visibility. Otherwise expecting mainly VFR outside of rain showers over the east 
while the west lingers in MVFR/occasional IFR in lower ceilings and spotty 
-ra. Ceilings will likely start to lower even more at kblf as deeper 
westerly flow develops with ceilings going below 1kft...under patchy 
showers and drizzle which should stick 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 by middle week. 


&& 


Hydrology... 
areal flooding continues over portions of southeast West Virginia 
and southwest Virginia. Will monitor any heavier showers that 
could cause additional flooding. As far as rivers go...the Flood 
Warning is cancelled for Buchanan along the James River. The New 
River at Radford is forecast to rise just under flood stage late 
tonight. 


&& 


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


&& 


$$ 
Synopsis...reb 
near term...wp 
short term...reb 
long term...mc/reb 
aviation...jh/reb 
hydrology...