844 
FXUS63 KUNR 111115
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
415 AM MST Tue Dec 11 2018

.DISCUSSION...(Today Through Monday)
Issued at 207 AM MST Tue Dec 11 2018

Clouds are moving into the northern plains ahead of an 
upper-level trough. Regional radar and obs show some light snow over 
southeastern MT and parts of WY. At the surface, a trough stretches 
across the northern plains, and a cold front is making its way 
across the CWA. Winds are light, and temperatures range from the 
teens to the 30s. 

Light precip (mainly snow) and cooler temps are expected today 
behind the front, with little to no snow accumulation. Highs will be 
in the 30s. 

Brief upper ridging and warm air advection Wednesday will allow for 
temperatures to warm slightly (upper 30s to mid 40s). However, 
another trough will push into the region late Wednesday into 
Thursday. Another round of light precip is expected, with warmer 
temps keeping precip as rain or a mix across the western SD plains. 
Across northeastern WY and the Black Hills, though, cooler temps 
will result in snow, with some minor accumulations. Raised snow 
amounts slightly, as models are consistent with accumulating 
snowfall across these areas. Expecting around an inch across 
northeastern WY, with a couple inches possible over the northern 
Black Hills. Behind the surface trough, 3-4 mb/3 hr pressure rises 
will contribute to gusty northwesterly winds Wednesday night, so 
raised winds a little. Currently expecting winds to remain below 
advisory criteria. 

Another upper ridge builds for the end of the week into Saturday, 
resulting in mild and dry weather. Highs in the 40s and even some 
50s will be possible Friday and Saturday. Both the GFS and ECMWF 
show another trough this weekend, with the GFS a bit faster, 
stronger, colder, and wetter. However, in general, weather looks 
fairly benign through early next week. 

&&

.AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning)
Issued At 413 AM MST Tue Dec 11 2018

MVFR/Local IFR conditions expected this morning across portions 
of northeastern Wyoming and northwestern South Dakota with
scattered snow showers. Otherwise, VFR conditions are expected 
through tonight.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION...Pojorlie
AVIATION...7