Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 290521
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1121 PM MDT THU JUL 28 2016

.SHORT TERM...(This Evening Through Friday Night)
Issued at 231 PM MDT Thu Jul 28 2016

20z surface analysis had old frontal boundary from western WY
into northeast CO with trough into southeast MT where a weak low
was located. This weak low was associated with a shortwave over
northeast WY, which is assisting round of convection over the CWA
this afternoon. Next wave upstream appears to be over south
central MT, which should push through the CWA late this afternoon
and early this evening supporting continued SHRA/TSRA. MLCAPE
averaging 500-750J/kg over CWA with weak 0-6km bulk shear.
Activity will wane some with sunset, but given energy upstream
some precipitation expected overnight. Temperatures will be
pleasantly cool.

Friday, upper ridge over the southwest US will slowly push toward
the northern plains, but northwest flow aloft will support a couple
of weak waves moving through with modest MLCAPE values by afternoon.
Leftover boundaries from tonight combined with diurnal insolation
will result in continue TSRA chances by afternoon, but activity
should be less widespread than today. Temperatures will be near
guidance.

Friday night, precipitation will be on the wane as ridging increases
and drier air begins to work into the area.

.LONG TERM...(Saturday Through Thursday)
Issued at 231 PM MDT Thu Jul 28 2016

Weak upper level ridge slides across the northern plains this
weekend as upper low moves into southwestern Canada. With marginal
instability, there is a small threat for isolated thunderstorms.
Temperatures will warm back into the 90s for the weekend. Upper
low continues to move eastward across southern Canada early next
week, with increasing west-southwest mid level flow across the
northern plains. Series of weak impulses will bring a daily chance
of isolated thunderstorms. Temperatures will be cooler, but still
above average by the middle of the week.

&&

.AVIATION...For the 06Z TAFS Through 06Z Friday Night
Issued At 1115 PM MDT Thu Jul 28 2016

Areas of IFR conditions with low status and fog will be located
over parts of far northeastern Wyoming and over parts of western
and south central South Dakota generally from 09Z-15Z. Scattered
showers and thunderstorms will occur on Friday afternoon and
evening.

&&

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

$$

SHORT TERM...Helgeson
LONG TERM...15
AVIATION...10


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