Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 271723

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1123 AM MDT WED JUL 27 2016

.SHORT TERM...(Today Through Thursday Night)
Issued at 153 AM MDT Wed Jul 27 2016

Impulse laden nw flow will persist in the period, bringing rounds
of shra/ts to much of the fa. Weak cool front has settled across
the region, stalling across the far western fa. Weak shortwave
trough now traversing the northern plains supporting sct shra/ts
activity over western areas. This wave should support sct showers
over much of the western third through morning...possible edging
into the eastern fa by late morning. Otherwise...diurnal heating
will support shra/ts over the fa this afternoon, mainly the
western third, and esp over the black hills. Mean ml cape around
1500 j/kg with 40 knots of deep layer shear will support the
chance for a couple supercells over the western third. Otherwise,
mostly isold activity expected on the sd plains given weak
subsidence and associated cin. Strong impulse will begin to push
into the region tonight, supporting precip chances in a pos
theta-e adv regime. This system will slowly traverse the region
Thursday, supporting a good chance of diurnal convection thurs
over much of the area, esp invof the Black Hills. Lack of
applicable cape and marginal shear thur, will highly limit severe
threat. Overall slow flow aloft will allow some areas to see
appreciable rains where cells develop, given pw/s in excess of
1.25 inches. Carried precip chances through thur night, although a
drying trend is likely overnight.

Seasonal temps expected today, with even cooler conds thurs given
clouds, moisture, and rain. Mainly places will see highs in the
70s thurs.

.LONG TERM...(Friday Through Tuesday)
Issued at 153 AM MDT Wed Jul 27 2016

Chances for showers and thunderstorms will continue
Friday, mainly over the eastern CWA where upper energy will be
focused. Highs will be in the 80s.

With weak upper ridging briefly over the region this weekend, warmer
and drier conditions are expected. Towards the end of the weekend,
the ECMWF and GFS agree that a Canadian low pressure system will
push the ridge eastward, placing the northern plains back in more
active zonal to southwest flow. Above average temperatures will
continue into early next week.


.AVIATION...(For the 18Z TAFS Through 18Z Thursday)
Issued At 1116 AM MDT Wed Jul 27 2016

A band of showers/storms continues to move across the Bear Lodge
Mountains in WY and across northwestern SD. These showers are
expected to persist and move eastward through northwest SD and the
Black Hills this afternoon, with IFR to MVFR conditions around
heavier showers and storms. Mainly VFR conditions expected by
early evening as showers and storms move east and south of the
area. Additional rain showers with MVFR conditions expected across
northeast Wyoming and western SD by early Thursday morning.


.UNR Watches/Warnings/Advisories...


LONG TERM...Pojorlie
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