Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 160850
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
250 AM MDT Sun Apr 16 2017

.SHORT TERM...(Today Through Monday Night)
Issued at 250 AM MDT Sun Apr 16 2017

Current surface analysis shows weak high pressure over the
forecast area. A surface low is present to the north of the
region, across southwest Manitoba, with a cold front trailing
southwestward into far northwest ND and northern MT. Upper level
analysis shows cutoff low over south central Canada finally
starting to move eastward out of the region. Strong westerly jet
is to the south of the low across the Northern Plains, with fast
zonal flow stretching back to the Pacific NW. Skies are mostly
clear with light winds in most areas. This is allowing for cool
temps early this morning, mostly in the upper 20s and 30s right
now.

A nice day is on tap with mostly sunny skies and some high clouds
passing across at times. The dry cold front to the northwest will
slowly slide south across the area today. Brisk west to northwest
winds will develop behind it across northwest SD this afternoon,
with locally breezy conditions behind it elsewhere later today. High
temperatures will range from the upper 50s over northern parts of
northeast WY and far northwest SD to near 70 over south central SD.
Highs will be in the 50s across the Black Hills. Clear to partly
cloudy conditions will continue tonight will lows generally in the
30s.

Clouds will increase from the west toward daybreak Monday and spread
across the area by the afternoon as a shortwave trough moves across
the Rockies. This system will reach the area by late afternoon, with
chances for showers and storms increasing. Front to the south will
lift back north into the area as a warm front during the day as low
pressure develops along it across eastern WY. Highs will be in the
60s and lower 70s, warmest over far southern SD. Strengthening low
to the west will bring increasing south to southeast low level flow
and increasing moisture. MUCAPE values are forecast to approach 1000
j/kg by late afternoon/early evening across southwest SD. Shear
looks adequate enough for at least the potential of short-lived
supercells over this area. Isolated strong to severe storms are
possible during the late afternoon and early evening, mainly from
southwest into south central SD. Hail and gusty winds will be the
main threats from any stronger storms. The best chances for rainfall
late Monday into Monday night will be mostly east of the Black Hills
as low pressure moves quickly across SD during this time. Pcpn will
move quickly east out of the forecast area late evening/around
midnight. Lows will be in the upper 30s and 40s.

.LONG TERM...(Tuesday Through Saturday)
Issued at 250 AM MDT Sun Apr 16 2017

After a mild and partly sunny day on Tuesday, unsettled weather
will return Tuesday night and continue through the middle part of
the week. The next shortwave system will affect the area Tuesday
night through Wednesday evening, with widespread high chances for
rainfall. There is uncertainty as to where the better chances for
more significant rainfall will be, but the more favorable areas at
this point look to be from the Black Hills eastward to central
SD. The next system moving into the plains late in the week looks
to track mostly south of the region. Will keep some low pops
across the far southern CWA for Thursday night and Friday. Cool
temps midweek, with a gradual warming trend toward the end of the
week and next weekend.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Sunday Night)
Issued At 1016 PM MDT Sat Apr 15 2017

VFR conditions expected through the period.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

SHORT TERM...26
LONG TERM...26
AVIATION...JC



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