Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 231735

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1035 AM MST Thu Nov 23 2017

.DISCUSSION...(Today Through Wednesday)
Issued at 240 AM MST Thu Nov 23 2017

Latest upper level analysis shows a high amplitude upper ridge
over the western CONUS. A weak surface trough extends from
Alberta/Saskatchewan southward into eastern Montana and the
central Dakotas.

For today, the upper ridge axis will move eastward over the high
plains with even warmer temps expected over the forecast area
today. Some record or near record highs are possible today, highly
dependent on the thickness of the cirrus crossing the area today.

A substantial northern stream trough will affect the Northern
Plains on Friday. 850mb winds will increase to 40-50kts Friday
morning with mixing behind the frontal boundary likely pushing
surface winds into the advisory range on the SD plains. Northwest
winds of 25 to 35 mph with gusts to 50 mph will be likely for much
of Friday morning as the cold front moves through. Winds should
begin to subside a bit during the afternoon hours. Little moisture
to work with so any precipitation should be light.

Upper ridge then rebuilds across the Northern Plains over the
weekend into Monday. Dry conditions expected. An even more
significant trough is expected to move through on Tuesday with
better chances for precipitation for Tuesday morning. Dry weather
is then expected from Tuesday afternoon through Wednesday.


.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1029 AM MST Thu Nov 23 2017

VFR conditions will prevail through the forecast period. A strong
cold front will move through the region early Friday morning, with
northwest winds gusting to 35-45 knots. The front will arrive in
the KGCC area around 4AM, and in the KRAP area around 5AM. Winds
will persist through early afternoon, then slowly diminish through
the remainder of the day.




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