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Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
204 am MDT Tuesday Jul 26 2016

Short term...(today through Wednesday night)
issued at 203 am MDT Tue Jul 26 2016

Active zonal flow will persist in the period. A slow moving
impulse will force a Lee side trough east today across the region.
Moist southerly flow east of this feature will allow appreciable
moisture into the area, with pos Theta-E adv ongoing this morning.
Isold shra/ts will be possible this morning, trending east across
the fa associated with waa under steep mid level lapse rates.
Diurnal heating with a sfc trough in place across western South Dakota will
support shra/ts over much of the fa this afternoon, esp invof the
Black Hills. Appreciable cape (2000 j/kg +) with around 40 knots
of deep layer bulk shear will certainly support a severe threat
with any cells, esp across western South Dakota this afternoon and central
South Dakota this evening. Cells should gradually merge into a forward
propagating MCS given a llj and wind profiles this evening as
activity pushes into central SD, thus better coverage expected
there. Retained at least an isold mention most places through
tonight given jet streak lift and residual moisture under steep
mid level lapse rates. Weak cool front will settle across the
western fa and stall Wed. Weak impulses in westerly flow coupled
with moist easterly upslope flow and weak inhibition should
support sct-isold ts activity in the afternoon, esp invof the
Black Hills. Isold severe cells will be possible, esp in the Black
Hills. Lingering activity will be possible in the evening with
coverage waning overnight. Kept a slight chance mention overnight
Wed given jet streak forcing which will be present once again.

Hot conds expected most places today with highs in the 90s, with
cooler conds Wed given easterly flow.

Long term...(thursday through monday)
issued at 203 am MDT Tue Jul 26 2016

As high pressure slowly slides southeastward
over the northern plains, a boundary will set up over the County Warning Area on
Thursday. Models are showing around 2000 j/kg MLCAPE developing over
northeastern Wyoming and western South Dakota 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 Wyoming and far western South Dakota. 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 12z tafs through 12z Tuesday night) issued
at 203 am MDT Tue Jul 26 2016

Isolated thunderstorms with MVFR visibilities are
possible this morning, mainly across northwestern South Dakota. More
widespread thunderstorm activity is expected this afternoon and
evening, especially over the Black Hills and western South Dakota. IFR
conditions are possible in stronger storms.

&&

Unr watches/warnings/advisories...
South Dakota...none.
Wyoming...none.
&&

$$

Short term...jc
long term...pojorlie
aviation...pojorlie

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