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FXUS63 KUNR 252239
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
439 PM MDT Sun Jun 25 2017

.DISCUSSION...(This Evening Through Sunday)
Issued at 251 PM MDT Sun Jun 25 2017

Northwest flow continues across the northern Plains today as
an upper ridge builds in from the western CONUS. Latest obs show
partly cloudy skies and temps reaching the 70s to low 80s...and
upper 50s into the 60s over the Black Hills. Short range models
showing a quiet night across the CWA with lows in the upper 30s to
upper 40s. The 12z GFS suggests some shower activity developing
across south central SD this evening...however believe it will not
reach the ground if anything develops much like the afternoon
showers over parts of NW SD today.

Return flow will set up tomorrow as the surface high pressure pushes
east of the area. Temps Monday will be slightly warmer than today
with dry conditions continuing. Tuesday will be much warmer as a
thermal ridge crosses the region. Highs will reach into the 90s and
dewpoints reaching into the 50s. A dryline is progged to cross
northeast WY and far western SD into the early afternoon. Ahead of
the boundary...models showing MLCAPE reaching 2500-3000 J/KG with a
weakening cap. 0-6km shear reaches up to 40kt...enough for supercell
development. Think the bulk of severe weather will be across central
SD in the late afternoon into the evening before pushing east of the
CWA. A second round of storms may develop with a cold frontal
passage late in the night across western SD. Upper low develops
across the upper Midwest for much second half of the work week with
active W/NW flow across the region. This will bring continued
chances for precip along with seasonable temps.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 438 PM MDT Sun Jun 25 2017

Generally clear skies and VFR conditions are expected through the
period.

&&

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

$$

DISCUSSION...13
AVIATION...JC