Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 231048

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
448 AM MDT Mon Jul 23 2018

.DISCUSSION...(Today Through Sunday)
Issued at 239 AM MDT Mon Jul 23 2018

Perturbed westerly flow in place with a ll baroclinic zone spread
across the High Plains. BL has sig dried out across the NW 2/3 of
the fa. However return flow will ensue today with gusty SE winds
expected across eastern WY later. Recycled moisture will stream
north across eastern WY with a weak impulse expected to time this
afternoon there. Diurnal heating in an upslope positive theta-e
adv regime may support an isolated storm or two this afternoon
/evening over NE WY, possibly carrying into the Black Hills this
evening. Ample deep layer shear will be place with sufficient CAPE
to support an isolated svr cell or two of LP nature. Convection
should wane this evening although some hires models suggest pos
theta-e adv may support a few elevated shra/ts across NW SD early
Tue morning. Theta-e ridge will be over western SD Tues supporting
decent CAPE in a high deep layer shear env. Advancing jet
streak/impulse will only further enhance convective potentials by
afternoon with a supercell or two expected over the Black Hills
and to the SE. Better chances for more widespread convection in
the evening and overnight as the bulk of the impulse and
associated forcing moves thorough the region. Definitely a decent
svr threat with stronger cells, given good dynamics in place
(1500-2000 J/kg CAPE with around 50 knots of bulk deep layer

Unsettled NW flow will continue through the remainder of the
week, with models still trending toward deep troughing over
interior Canada by late week. This would support cooler conds with
continued chances for shra (esp over the SW third) given wavering
stalled baroclinic zone over the region.


.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 447 AM MDT Mon Jul 23 2018

Other than some MVFR visibilities with any isolated storms that
develop over northeastern WY and the Black Hills this
afternoon/evening, VFR conditions are expected through Tuesday




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