Weather

776 
fxus63 kunr 061019 
afdunr 


Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota 
320 am MST Tuesday Jan 6 2009 


Discussion...10z surface map shows low pressure over North Dakota with 
a trough extending from the eastern Dakotas into south central 
Nebraska. Area radar mosaic showing weak returns across the area but 
surface observations indicate returns are mostly vigra due to the 
dry air in the lower levels. 


For today...another weak shortwave will cross the region this 
afternoon. Not much moisture to work with so will continue the low 
chance probability of precipitation in northestern Wyoming/northern blk hls and northwestern South Dakota. Upslope flow will 
bring best chance of snow to the northern Black Hills. Temperatures will 
be near seasonal norms...mainly in the 30s. 


Tonight through Wednesday...a series of weak shortwaves will cross the area 
in the northwest upper flow...bringing a continued chance of snow. 
Moisture will increase late tonight into Wednesday 
afternoon...creating a good chance of accumulating snow over northestern Wyoming 
the northern blk hls and northwestern South Dakota. Several inches of snow may fall in the 
northern Black Hills...mostly likely from Terry Peak to O'Neil Pass and 
over Butte and Harding counties in northwestern South Dakota. Warmer air will move in 
from the west on Wednesday afternoon...and there may be a short 
period of light freezing rain over parts of northeastern 
Wyoming...the Black Hills and northwestern South Dakota on Wednesday 
night as the warm air overrides the colder air at the surface. An 
upper level ridge building over the area on Thursday will lead to 
warmer than normal temperatures and only a slight chance of rain or 
snow over northwestern South Dakota. 




Extended...northwesterly flow aloft will dominate the weather late 
this week into the weekend. An upper trough and cold front will exit 
the region on Friday. Will keep slight chance for snow showers on 
Friday for the entire area. Gusty northwest winds can be expected 
during the day as well. Mainly dry weather is then expected over the 
weekend with warmer than average temperatures for most locations...except 
possibly the far northeast County Warning Area. There could be another chance for 
precipitation late in the weekend and early next week...but will keep dry for 
now. 


&& 


Aviation...VFR conditions expected across most of the area today. 
The exception will be some MVFR and IFR conditions across portions 
of northeast Wyoming and the hills as snow showers develop. MVFR ceilings 
will likely develop at kgcc by this evening. 


&& 


Unr watches/warnings/advisories... 
South Dakota...none. 
Wyoming...none. 


&& 
$$