Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 212350 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
650 PM CDT Wed Jun 21 2017

Issued at 649 PM CDT Wed Jun 21 2017

00z aviation discussion updated below.


.SHORT TERM...(This Evening through Thursday Afternoon)
Issued at 349 PM CDT Wed Jun 21 2017

Short term forecast concern will be possibility of evening
convection across the northeast corner of the cwa followed by
another wave moving through on Thursday bringing another chance of
precip to portions of the area.

Warm frontal boundary parallels the James valley this afternoon
followed by a cold front entering the northwest corner of South
Dakota. Warm front has seemed to be a bit slower in progression
eastward this aftn than previously forecast. Vsbl Satl showing CU
field forming across northcentral SD/southern ND ahead of the cold
front. Instability starting to increase ahead of the cold front with
mlcapes 1000-1500 j/kg and decent deep layer sheer of around 50 kts.
The only bit of a caveat is fcst soundings do show a bit a cap in
place thru early eve across northeast South Dakota.

So, confidence not the highest in a widespread convective situation
happening this evening. However, a few of the CAM solutions do paint
a picture of a few strong to possibly severe storms popping ahead of
the cold front across northeastern South Dakota and west central
Minnesota. Locally strong winds and large hail would be the primary
threats from any storms that do get going to build to strong enough

This front will clear the cwa later this evening and most areas
should be left with a quiet overnight. Another quick moving upper
level wave will traverse the region on Thursday. This will bring in
another round of precip to portions of the area. This system looks
to mainly affect areas along and south of a Highway 12 corridor. Not
expecting any severe weather with this system as most instability
remains well south.

.LONG TERM...(Thursday Evening through Wednesday)
Issued at 349 PM CDT Wed Jun 21 2017

The long term period begins with a broad upper level trough over the
region with much cooler temperatures filtering into the CWA. The GFS
is showing a 500 mb shortwave crossing the region Friday
night/Saturday morning with showers possible, mainly in far NE SD
and western MN. 925 mb temps behind this system are only in the
single digits by 12Z Saturday. High temperatures on Saturday should
range in the mid to upper 60s, or some 15 degrees below normal.

Upper level ridging will slowly built into the region Sunday and
Monday before breaking down by Tuesday. Summer temperatures will
return to the region by Tuesday with highs reaching the 80s.
Humidity will also increase by Tuesday.


.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 649 PM CDT Wed Jun 21 2017

Scattered showers and thunderstorms will move across northeast SD
through the evening affecting ABR and maybe ATY. Otherwise, more
numerous showers and storms will move in from the west later tonight
and Thursday affecting mainly PIR and ATY at or in the vicinity.
Conditions are expected to be VFR through the period.




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