769
FXUS63 KUNR 252130
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
330 PM MDT Sun Sep 25 2016

.UPDATE...
Issued at 327 PM MDT Sun Sep 25 2016

Cancelled the wind advisory. Northwest winds will continue to
diminish as high pressure moves in from the west.

&&

.SHORT TERM...(This Evening Through Monday Night)
Issued at 327 PM MDT Sun Sep 25 2016

Latest analysis shows the upper trough has moved eastward over
Manitoba and the eastern Dakotas/western Minnesota with an upper
ridge building over the western CONUS. A tight surface pressuregradient
combined with low level cold advection is producing gusty winds
over parts of western and central South Dakota. The winds will
diminish by late aftn/early eve as a cool sfc high slides
southward across the forecast area. Clear skies and light winds
will create good conditions for radiational cooling tonight,
however warm air advection will increase above the boundary layer
before midnight so expect the potential for frost to be localized.
Have issued a frost advisory for Oglala Lakota and Bennett
counties in southwestern South Dakota overnight where the winds
are expected to be lightest the longest, and the temperatures
coldest overnight. The upper ridge will begin to build over the
area on Monday, producing clear skies and warm temperatures.

.LONG TERM...(Tuesday Through Sunday)
Issued at 327 PM MDT Sun Sep 25 2016

Strong upper ridging combined with a slowdown in the
upper pattern will bring mainly dry weather to the region through
much of the work week. A weak upper trof will cross the Northern
Plains Thursday night...with some isolated thunderstorms possible.
Southwest flow is progged to develop across the region very late in
the week as a strong trof pushes into the Pac NW. This will bring
some showers and thunderstorms to the area for the weekend. With the
strong ridging and mainly dry conditions...temperatures will be well
above average through the extended period.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 327 PM MDT Sun Sep 25 2016

VFR conditions are expected through Monday morning. Very
gusty NW winds across the western SD plains will diminish quickly
this evening.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Frost Advisory from 3 AM to 7 AM MDT Monday for SDZ042-044.

WY...None.
&&

$$

Update...10
SHORT TERM...10
LONG TERM...15
AVIATION...15