Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 262047
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
247 PM MDT TUE JUL 26 2016

.SHORT TERM...(This Evening Through Wednesday Night)
Issued at 245 PM MDT Tue Jul 26 2016

20z SPC mesoanalysis still reveals a large cap in place for most
of the CWA from this morning`s convection, but should start to see
that erode this afternoon. Already seeing convection developing in
the Black Hills, though at this time it has struggled to move off
the terrain. Several boundaries are also in place across the CWA,
and those could serve as a lifting mechanism for new storms to
develop as cap erodes.

LLJ develops across Western NE this evening with the nose of the jet
reaching S-Central SD ahead of a weak cold front. Wouldn`t be
surprised to see elevated showers and storms develop along the nose
of the jet in S-Central SD. Additional showers and storms from WY
and MT could filter into the CWA as models prog a weak shortwave to
pass through the area overnight.

Convection from Tuesday evening could still be lingering around the
CWA by 12z Wednesday but should taper down by late morning. 0-6km
shear increases to 35-45kts by late afternoon in Northeast WY and
Southwest SD ahead of yet another shortwave progged to move into the
CWA, but instability appears to struggle in recovering from morning
convection and only tops out around 500-1500J/kg. Can`t rule out a
couple of isolated severe storms Wednesday given the aforementioned
parameters, but expect most storms to remain below severe criteria.

.LONG TERM...(Thursday Through Tuesday)
Issued at 245 PM MDT Tue Jul 26 2016

As high pressure slowly slides southeastward over the northern
plains, a boundary will set up over the CWA on Thursday. Models
are showing around 2000 J/kg MLCAPE developing over northeastern
WY and western SD by midday, with 0-6 km bulk shear around 30 kts.
As weak energy moves over the region, the boundary will be the
focus of shower and thunderstorm development...mainly across
northeastern WY and far western SD. Highs will be in the low to
mid 80s.

Chances for showers and thunderstorms continue on Friday, but a
warming and drying trend will begin as an upper ridge builds over
the region. Weekend highs will be in the upper 80s to mid 90s, with
low chances of precip mainly over the Black Hills.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)
Issued At 245 PM MDT Tue Jul 26 2016

Scattered thunderstorms with MVFR ceilings and visibilities are
expected through this evening, especially over the Black Hills and
western SD. IFR conditions are possible in stronger storms.
Another batch of shower and thunderstorms are possible late this
evening and overnight across Northeast Wyoming and the Black Hills
area. Some low clouds/fog may develop after midnight across parts
of the plains, with MVFR conditions possible.

&&

.UNR Watches/Warnings/Advisories...
SD...None.
WY...None.
&&

$$

SHORT TERM...McKemy
LONG TERM...15
AVIATION...15



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