Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 132319
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
519 PM MDT Fri Jul 13 2018

.DISCUSSION...(This Evening Through Friday)
Issued at 212 PM MDT Fri Jul 13 2018

Weak shortwave ridge over the area with low level SE upslope
flow. Theta-e ridge over eastern WY will support isolated TS this
afternoon/evening there in addition to the northern BH. Low
CAPE/weak shear should keep storms on the tame side with small
hail and gusty winds possible with a few cells. Warmer conds
expected Sat as the thermal ridge builds into the region. Capping
will hold off convection until late afternoon and evening when the
upper trough and associated cold front pushes into the region.
Sufficient CAPE of 1-2 KJ/kg with increasing shear will support
support a few strong to perhaps isolated severe storms Sat
evening. Frontal boundary will push into the region Sat evening
and provide the focus for shra/ts chances, esp post frontal Sat
night into Sunday morning when a secondary upper impulse pushes
into the region. CAA/clouds/and precip will hold temps down
Sunday, with highs struggling out of the 60s in some locations
around the Black Hills. Flow will then turn more NW early next
week as the western CONUS ridge rebuilds, with enough lingering
moisture in place to support shra/ts with any weak impulse. Most
activity in this pattern will be widely scattered to isolated,
with the best chances around and SE of the Black Hills. The upper
ridge looks to shift east by mid week, with warmer/drier weather
expected after. Look for seasonal temps in the period, with the
coolest day on Sunday.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 518 PM MDT Fri Jul 13 2018

Isolated to scattered thunderstorms with local MVFR conditions
will end by 03z over northeast WY/Black Hills. Additional storms
with local MVFR conditions are possible over northeast WY/far
western SD late Saturday afternoon. Otherwise, expect VFR
conditions through the period.

&&

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

$$

DISCUSSION...JC
AVIATION...Helgeson



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