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fxus63 kunr 161100 

Area forecast discussion for western South Dakota and northeastern Wyoming
National Weather Service Rapid City South Dakota
400 am MST Mon Dec 16 2019

Discussion...(today through sunday)
issued at 151 am MST Mon Dec 16 2019

Western noam ridge will shift east this week, supporting mild
conds by mid week on. Active split flow ongoing with another dry
impulse passing through the flow tonight. Bulk of forcing from
this system will remain well northeast of the region. Main local
impact will be some passing low clouds and patchy fog over far northwest
South Dakota this morning as well as weak cold air advection which will hold thermal fields
steady with high temps similar to yesterday most places. Breezy
winds are expected across northwest South Dakota this afternoon as linked flow
combined with the upper jet will be in place. Frontside of the
ridge will begin to creep east tonight with warm air advection ensuing over the
west. In addition, falling pressures combined with fast flow aloft
and a weak impulse will allow breezy westerly winds to develop
late tonight, with Black Hills downslope areas seeing the best
chances for gusty winds toward dawn. Bulk of fast ll flow will
push through in the late morning and early afternoon, with gusty
winds possible from this. The question that remains is how much
mixing will occur. If decent mixing occurs, near adv winds would
result for much of northwest South Dakota. Mean ridging expected the remainder of
the week with warming temps. Highs in the 40s and 50s can be
expected most places mid week on, with a good chance for more
widespread 50s (local 60s) by Saturday as warm west-southwest flow spreads
over the region. Other than a few breezy days, dry and quiet
weather can be expected through the weekend with no precip


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 359 am MST Mon Dec 16 2019

VFR conditions are expected through the period. Northwesterly
winds will become breezy this afternoon, especially across
northwestern South Dakota. Overnight, southwesterly winds will become
breezy, especially across northeastern Wyoming.


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

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