Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 181932

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
132 PM MDT MON JUL 18 2016

.SHORT TERM...(This Evening Through Tuesday Night)
Issued at 132 PM MDT Mon Jul 18 2016

fast flow on the se periphery of the pac ne upper low continues
to support weak impulses in sw flow. The next impulse will arrive
this evening and support ts development over ne wy and far western
sd. Hires models still indicate a linear convection system which
makes sense given cape/flow progs. appreciable moisture in place
with mid to upper 60s dewpoints supporting 2-3 kj/kg over the
region and given the shear in place, a few severe storms will be
possible this aft/eve, esp from the black hills east. Convection
will wane tonight, save for the far south with activity possible
through tonight given a llj.

massive conus ridge will build into the plains tue. This will
support very warm conds over the area, esp eastern areas. Deep
mixing with ongoing dry conds will support temps into the 100s for
much of the sd plains. Will issue an excessive heat watch given
the potential for 4 consecutive days of heat indices at 100 or
higher. Convection will also be possible over the bh tue
afternoon, although cape will be limited (supporting very low
sever risk), and on portions of the plains given diurnal heating
and deep mixing an weak impulses in sw flow. Best chance for
convection looks to be over sw into scentral sd where a mid level
impulse will track.

.LONG TERM...(Wednesday Through Monday)
Issued at 132 PM MDT Mon Jul 18 2016

Upper level ridge over the Central CONUS will remain
nearly stagnant for most of the week. Medium range guidance showing
850mb temps in the 30-35C range from Tuesday through Friday, which
will result in surface temps in the 90s across NE Wyoming to 100-
105F across the South Dakota plains. Both GFS/ECMWF begin to break
down the ridge by the weekend as a shortwave over the Pacific NW
moves into the Northern Plains. This will result in near zonal flow
and temperatures being close to seasonable normals by the weekend,
with increasing chances of showers and thunderstorms.


.AVIATION...(For the 18Z TAFS Through 18Z Tuesday)
Issued At 132 PM MDT Mon Jul 18 2016

Isolated to scattered showers and thunderstorms will be
possible this afternoon and evening. Some of the heavier
showers/storms could produce localized MVFR cigs/vis. Otherwise,
expect VFR conditions through the period.


.UNR Watches/Warnings/Advisories...
SD...Excessive Heat Watch from Tuesday afternoon through Friday
     evening for SDZ014-032-043-046-047-049.



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