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fxus63 kunr 130902 
afdunr 


Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota 
300 am MDT Monday Oct 13 2008 


Discussion...current surface analysis has low pressure over 
southeast mb...with trailing cold front well east of the area. Upper 
level analysis shows large trough over The Rockies region and the 
Western Plains. The trough is splitting...with main northern low 
moving northeastward into ND and southern Canada...while southern 
branch is beginning to break off across the southern Great Basin. 
Skies remain mostly cloudy at most locations with temperatures primarily in 
the 20s and 30s...some teens noted across snow covered areas of 
northeast Wyoming. 


A chilly start to the week is on tap...with a warming trend back to 
near average temperatures by the middle of the week. Warming will be much 
more gradual across snowcovered areas...especially northeast Wyoming. Dry 
weather should be the rule for the most part as flow aloft becomes zonal 
in nature after exiting system today. Changes to the going forecast 
through Wednesday will be rather subtle. 


For today...skies will be variably cloudy...with the most sunshine 
across southern and western areas. Some patchy fog is possible 
across far northeast Wyoming and possibly far northwest South Dakota 
early this morning. Have kept some isolated snow showers in the 
forecast for far northwest South Dakota this morning...but it looks like the 
bulk of leftover activity will be north of the area. Highs today 
will range from the middle to upper 30s across much of northeast Wyoming to 
the lower 50s well south and east of the hills. Brisk northwest 
winds can be expected across northwest South Dakota during the peak heating of 
the day as low pressure continue to move away from the region. 


Skies will generally clear out tonight as temperatures drop into the 20s 
and 30s. Will see highs mostly in the 50s on Tuesday...40s 
over northeast Wyoming. Weak shortwave energy will move east across the 
region later Tuesday through Wednesday...bringing some cloudiness... 
but lack of low level moisture and significant lift should keep area 
dry. Will keep a low chance pop for far northwest South Dakota Wednesday night 
as potential daytime showers over Montana may hang on into the western 
Dakotas overnight. 


Extended...on Thursday short wave will move through zonal flow across ND/ 
central South Dakota and bring low chance probability of precipitation of a few showers to central South Dakota. 
Weak upper ridge will then dominate weather for Friday and Saturday. 
Another short wave forecast to move across northern portions of northern plains on 
Sunday and may bring a few showers to northwestern South Dakota and portions of northestern 
Wyoming. Temperatures through the period will be near seasonal normals. 


&& 


Aviation...some MVFR ceilings are expected through 14z as large storm 
system pulls away...VFR conds are expected after 14z. Leftover 
low level moisture and decreasing dew point depressions will allow 
some IFR conds due to low clouds/br to develop through 12z. 


&& 


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


$$