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fxus63 kunr 220336 
afdunr 


Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota 
836 PM MST Friday Nov 21 2008 


Discussion...the surface low is centered over western South 
Dakota this evening with the main area of precipitation pushing into 
central South Dakota. Rain is currently falling in php with snow 
falling to the north of that. 


With snow pushing eastward this evening...have cancelled the 
advisory for Harding and Perkins counties early and will update 
again in a bit when the remainder of the advisory expires. With 
the moist atmosphere over areas that snow fell today...have added 
patchy fog for the rest of tonight into the morning. Also 
increased lows for tonight with cloud cover and high dew points 
expected to hang around for much of the night. 


&& 


Aviation...areas of snow will continue to push east across the 
area this evening. IFR/MVFR conditions within the precipitation will 
increase to VFR conditions tonight as the precipitation departs. Some 
areas of MVFR ceilings may be possible across far northwestern 
South Dakota for the remainder of tonight. 


&& 


Previous discussion... /issued 152 PM MST Friday Nov 21 2008/ 


Discussion...current surface map shows low pressure across 
southwest North Dakota...with trough/warm front moving east across 
western South Dakota. Area of snow continues across northwest South 
Dakota with 1-3 inches of snow so far. A few rain/snow showers 
across southwest South Dakota. For tonight...upper low over 
northwest South Dakota will move southeast...with snow diminishing 
late this evening. Will keep headlines in place. 


For Saturday...weak upper level ridge across the area. 850-700mb 
temperatures support highs in the 40s to lower 50s...coolest 
across the northwest. Weak shortwave moves across the northern 
plains Sunday...with slight chance of snow showers northeast 
Wyoming/far western South Dakota. 


Extended...an upper level ridge will build over the area for the 
beginning into the middle of the upcoming work week. This will bring 
dry conditions along with above average temperatures. 


Aviation...areas of snow will continue to push east across the area 
this afternoon into the evening. IFR/MVFR conditions will increase 
to VFR conditions tonight as the precipitation departs the area. VFR 
conditions will continue through Saturday. 


&& 


Unr watches/warnings/advisories... 
South Dakota...Winter Weather Advisory until 11 PM MST this evening for 
northern Meade Colorado plains-Ziebach. 


Wyoming...none. 
&& 


$$