Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 172322

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
522 PM MDT Sun Jun 17 2018

.DISCUSSION...(This Evening Through Sunday)
Issued at 149 PM MDT Sun Jun 17 2018

Upper low persists over the Pacific Northwest, with
continued southwest flow over the northern plains. Upper-level
energy continues to produce widespread rain showers across the
region. At the surface, high pressure sits to the northwest, with a
stationary boundary southeast of the CWA. Winds are northeasterly
around 5-10 kts, and temperatures are only in the 50s and 60s.

Precipitation will diminish a bit this evening, especially across
the north, as high pressure pushes in. Then rain showers will expand
over the region again late tonight into Monday, as another wave
moves in, supported by an upper jet streak. Forecast QPF for the
rest of today through Monday afternoon is around 1 inch across much
of western SD, highest over the Black Hills. Considered a Flood
Watch, but latest 6 hr FFG is 2-3 inches over these areas. Also,
radar estimates show not much rain has fallen recently over the
Black Hills. Will forgo the watch at this time. Lowered highs on
Monday to reflect another rainy day.

Conditions will dry out a little Monday night, before another round
of rain midweek. The upper low will gradually shift into the region,
weakening as it crosses the northern Rockies, but then redeveloping
over the northern plains. The NAM is showing PWs of 1 to 1.5 inches
during this time period, and over a couple of days, some places
could receive over 2 inches of rain. This on top of already
wet soil may result in some flooding.

Some smaller chances for showers will linger through the end of the
week, but the low will gradually move eastward out of the region.
After a cool week, temperatures are expected to warm again, as weak
ridging develops Friday/Saturday. Both the GFS and ECMWF are showing
yet another wave approaching the area during the weekend, increasing
chances for showers/storms again.


.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 521 PM MDT Sun Jun 17 2018

Widespread MVFR/IFR (local LIFR around the Black Hills)
conditions expected tonight into Monday with rain showers and
isolated thunderstorms.




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