FXUS63 KUNR 181015

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
315 AM MST Fri Jan 18 2019

.DISCUSSION...(Today Through Thursday)
Issued at 245 AM MST Fri Jan 18 2019

Latest upper analysis shows a shortwave currently crossing the
area in northwesterly flow aloft. At the surface, low pressure is
centered over the Oklahoma panhandle with cold high pressure
dropping into the Dakotas from Saskatchewan and Manitoba.
Relatively moist mid-level warm advection crossing the cold air at
the surface is contributing to the lift and associated
precipitation currently crossing western South Dakota. The western
edge of the main band of snow is currently located from near
Lemmon to Rapid City and then into the southwestern corner of
South Dakota, moving eastward. There may be a period of dry
weather behind that line early this morning, then expect to see
another round of snow move into the area later this morning as an
upper circulation drops southeastward out of Montana. Snow totals
in the previously issued Winter Weather Advisory area toward
central South Dakota still look to be reasonable, with a broad
area of 2-4 inch total snow accumulations, and 4-6 inches
possible in south central South Dakota by the time the snow
completely ends this afternoon. Chances for light snow exist into
this evening over parts of northeastern Wyoming and the northern
Black Hills, with little or no additional snow accumulation
expected in those areas this evening.

Much colder than average temperatures will arrive on Saturday,
particularly across the SD plains, but forecast 850 mb temps show
a quick rebound late in the weekend. More substantial troughing
will develops over the Northern Plains and Upper Midwest next
week. For now, appears coldest air will remain to our east, but
northwest flow aloft could contribute to brief bouts with below
average temps, light snow, and windy conditions.


.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 1010 PM MST Thu Jan 17 2019

Widespread IFR conditions expected through Friday due to
fog/snow/stratus. Local LIFR conditions will be see over western
SD overnight due to FZFG/stratus. The snow will end from west to
east Friday morning through Friday evening.


SD...Winter Weather Advisory until 5 PM MST /6 PM CST/ this afternoon
for SDZ014-032-043-044-046-047-049.



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