Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 192317

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
517 PM MDT Wed Jul 19 2017

.DISCUSSION...(This Evening Through Wednesday)
Issued at 137 PM MDT Wed Jul 19 2017

Surface low is located over south central SD early this afternoon.
Outflow from earlier thunderstorms over north central SD has
pushed the surface low and associated cold front southward across
the cwfa a bit quicker today, so temps not nearly as hot across
northwest SD, but are quite hot south of the front across south
central SD. Have taken Haakon county out of the heat advisory as
winds have shifted to the north in Philip.

Thunderstorm chances the rest of the afternoon should be more
confined to south central SD along/ahead of the boundary.
CAPE/Shear values sufficient for a few severe storms that area.
Additional upper level energy embedded in the southwesterly
monsoonal flow will then bring increasing chances for storms this
evening and overnight from northeast WY and across areas
generally near/south of I-90.

A bit cooler on Thursday with some gusty southeast winds in
between surface high over the Upper Midwest and trof moving off
the Rockies. Not much instability early on in the day, but this
will change later into the afternoon and evening as a substantial
upper wave approaches. Convective parameters will be sufficient
for some severe storms across much of the cwfa well into the
evening hours.

Area will remain under flat upper ridge through Friday. Strong
wave topping the ridge on Saturday will allow for some cooling as
cold front moves through. Ridge builds back early next week with
above average temperatures and small chances for thunderstorms.


.AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening)
Issued At 503 PM MDT Wed Jul 19 2017

Gusty winds behind the cold front will begin to subside this
evening. Thunderstorms will continue along the South
Dakota/Nebraska border overnight. Outside of storms, VFR
conditions are expected. Another round of storms are expected to
develop late Thursday afternoon across the Black Hills and
northeastern Wyoming.


SD...Heat Advisory until 7 PM MDT /8 PM CDT/ this evening for SDZ043-



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