Area Forecast Discussion
Issued by NWS Rapid City, SD

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364
FXUS63 KUNR 211111
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
511 AM MDT Sat Oct 21 2017

.DISCUSSION...(Today Through Friday)
Issued at 314 AM MDT Sat Oct 21 2017

Upper trough is crossing the central to northern Rockies into the
High Plains. Shortwave energy is just west of the CWA...crossing
Wyoming with forcing across western SD. Surface analysis shows the
cold front now crossing south central SD approaching KICR. Behind
the front...winds are generally 20-30 mph with gusts up to 45 mph.
KUDX radar showing showers across western SD over the last few
hours. Upper trough will quickly push through the area today with
the line of showers transitioning eastward into central SD by mid to
late morning. Gusty NW winds will continue across the area today.
The strongest winds will be across northwest SD at 25-35mph with
gusts to 50 mph...so will continue the wind advisory across those
locations. The northern foothills through the plains east of
Piedmont into KRAP may briefly get to advisory criteria in the late
morning to early afternoon...but a weakening pressure gradient later
today will result in gradually decreasing winds across the CWA
through the mid afternoon hours...so will not be extending out the
advisory headlines at this point. Showers will move east of the CWA
by early afternoon with skies clearing from the west. Highs today
will be in the 50s to low 60s.

Surface high pressure building into the region will keep quiet
weather over the CWA through Sunday. Warmer temperatures will move
back into the area with highs reaching into the 60s to mid 70s.
Upper ridging over the region will weaken as a series of upper
waves push into the northern Rockies and Plains. A cold front will
cross the CWA Sunday night with a few showers possible. Strong
ridging will then develop over the western half of the CONUS through
the first half of the work week bringing another stretch of dry
weather. Highs Monday will be in the 50s to low 60s...then a warming
trend will culminate to highs in the mid 60s to mid 70s Wednesday.
An upper shortwave trough and strong cold front is then progged to
cross the region Wednesday night into Thursday morning. While some
brief precip will be possible Thursday...very little QPF is
expected. Cool and dry weather is then expected for the second half
of the week.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Sunday Morning)
Issued At 508 AM MDT Sat Oct 21 2017

Gusty northwest winds are expected on the plains today, quickly
diminishing tonight. A band of showers east of the Black Hills
will exit the area by early afternoon. VFR conditions expected
through the period.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 6 PM MDT this evening for SDZ001-002-012-013.

WY...None.
&&

$$

DISCUSSION...13
AVIATION...Helgeson



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