Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 290900

Area Forecast Discussion
National Weather Service Aberdeen SD
400 AM CDT Mon May 29 2017

.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 359 AM CDT Mon May 29 2017

The next upper level disturbance rotating around the large upper low
over Ontario will move south across the region today. Cooler air and
clouds also spreading southward currently, and wonder if this may
limit instability a bit today. So, although we are expecting another
round of widely scattered showers and isolated storms, they likely
will not pack the punch as yesterday`s activity. Interesting to note
though that we do see inverted V soundings once again, but sub cloud
dry layer is shallower than yesterday. Breezy northwest winds will
be blowing once again, and these winds will continue right into

Large, cool Canadian high pressure system settles in right on top of
the area by 12Z Wednesday morning. Soundings show rather dry air
throughout the column, so expecting clear skies and light winds. If
there is any cloud cover, it`s probably just thin cirrus. Kept the
trend of going colder than SuperBlend for Tuesday night lows. Stuck
close to the straight MET/MAV guidance which has lows in the upper
30s to around 40 degrees.

Surface high moves away on Wednesday, making way for southerly winds
and warming temperatures. This will start a trend of warming which
will last through the end of the week.

.LONG TERM...(Wednesday Evening through Sunday)
Issued at 359 AM CDT Mon May 29 2017

There are a couple of time periods in the out periods still showing
up with low end precipitation chances. Strangely enough, they hover
around a dirty ridge aloft (higher/warmer heights). Wednesday night,
when the upper level ridge slowly working east is still back over
the northern high plains/Rockies Front Range, lee-side troffing and
a low level jet are in play across western/central South Dakota. If
adequate low level moisture advection and forcing/lift can come
together Wednesday night into Thursday, there could be some
convective activity around. GFS/EC/Canadian models point to a
developing surface warm front somewhere in the region Friday into
Saturday when the upper level ridge and warmest low/mid level temps
will be around. Although models generate precipitation along the
warm front by Friday evening, most of the region will probably be
capped and precip-free. When upper level jet energy barrels into the
western side of the upper level ridge heading into Saturday/Saturday
night, heights are falling/temps are beginning to cool a bit, and
precipitation chances seem a bit more realize-able, especially along
the frontal boundary forecast to sweep through the Dakotas mid-
weekend. 00Z deterministic thermal progs and supporting low level
temperature ensemble output supports warmer than normal high
temperatures during the first half of the period, with readings
falling back down to closer to normal Saturday and Sunday.


.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1242 AM CDT Mon May 29 2017

Expect low clouds (generally 2500ft agl to 4500ft agl) to move
down from the north tonight/early Monday affecting mainly ABR,
MBG, and ATY. Some scattered showers are also expected to develop
on Monday as another upper level trough comes down from the north
and could affect ABR and ATY.




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