Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 171744

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1144 AM MDT Sat Jun 17 2017

Issued at 922 AM MDT Sat Jun 17 2017

Upper shortwave continues to move into the northern plains this
morning, with a 110 kt jet streak approaching the CWA. Skies are
mostly cloudy, and scattered rain showers continue across the
area. Northwesterly winds are starting to increase across
northwestern SD. MET and MAV guidance have toned down wind speeds
slightly, but still expecting gusty winds across the advisory
area this afternoon.


.DISCUSSION...(Today Through Friday)
Issued at 308 AM MDT Sat Jun 17 2017

Upper level analysis has near zonal flow from the Pacific
Northwest through the northern Plains. Upper shortwave in this
flow is moving into the forecast area early this morning,
producing widespread light rain showers. At the surface, weak low
pressure was located across eastern ND with high pressure over the
northern Rockies. Temperatures at 3am are in the 50s and 60s.

Today...Upper shortwave will cross the forecast area and shift
into eastern SD by this afternoon. Precipitation will continue,
but gradually diminish through the day. Hi-res convective models
are indicating a few afternoon thunderstorms possible across
northwestern SD, which is supported by increasing instability
through the day. Cold air advection will enhance gusty winds
across the SD plains late morning to early evening, although
pressure rises are not too impressive. Models are in good
agreement of 25-35 mph winds across northwestern into west central
SD. Strongest winds are expected across northwestern SD, but low-
end advisory criteria will probably be reached in the Rapid City
area. A Wind Advisory will be in effect from late morning through
early evening for the northwest and west central SD plains. Highs
will be in the mid 60s to mid 70s.

Tonight...As upper shortwave shifts east and atmosphere begins to
decouple, winds and precipitation will diminish. Surface high
pressure slowly builds into the area with mostly clear skies
expected. Lows will be in the 40s.

Sunday into next week, strong upper ridging will build back into the
region with generally dry weather expected. Sunday will be mainly
in the 70s, with temperatures warming into the 80s and 90s by
Monday and Tuesday. The warm temperatures will stick around
through Thursday, with slightly cooler temperatures by Friday. Low
temperatures will warm back to the 50s and 60s for much of next


.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1137 AM MDT Sat Jun 17 2017

Rain showers will persist across the KRAP terminal location
through 1930z before tapering off. vfr cigs will remain. while
vsbys may briefly drop into the mvfr category...not expected to
become prevaling. ISOLD TS is also psble however not likely. NW
winds from 25-35kts are also expected on the SD plains. Further
west...pcpn is over at the KGCC terminal with improving conds
already taking place. SCT vfr clouds will remain through 00z
before going SKC. By 02z SKC conds are expected for both terminal
locations with winds 10kts or less. Good VFR conds expected to
remain for remainder of valid terminal fcst period.


SD...Wind Advisory until 7 PM MDT this evening for SDZ001-002-012>014-



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