Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 211757 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1257 PM CDT Fri Jul 21 2017

.UPDATE...
Issued at 1253 PM CDT Fri Jul 21 2017

See below for an aviation forecast discussion for the 18Z TAFs.

UPDATE Issued at 1119 AM CDT Fri Jul 21 2017

Only minor adjustments needed to the wx/pops/qpf forecast for the
rest of today into this evening. The only tidbit to note is a Fire
Weather Watch has been issued for Saturday for central and north
central South Dakota for the combination of dry fine fuels
(drought area), breezy northwest winds and dangerously low
relative humidity values.

&&

.SHORT TERM...(Today through Sunday Afternoon)
Issued at 422 AM CDT Fri Jul 21 2017

Continue to see scattered showers and storms across the region but
much of the activity over the CWA has diminished over the past few
hours. Recent development over FSD CWA seems to be related to the
low level jet.

Much like a couple days ago, the main stories today will be the high
heat and the threat for severe storms for eastern areas. Concerning
the heat, it appears the heat advisory is still in good shape so no
changes were made to that as heat indices are still expected to
exceed 100 degrees in the advised area. For this afternoon, strong
instability will develop over eastern portions of the area ahead of
the approaching frontal boundary. Deep layer shear will also be
sufficient to support strong to severe storms for the eastern CWA.
There is low confidence in areal coverage of storms, as well as
initiation within our CWA as it appears a large area from the
eastern Dakotas into western MN are all game. Could even have a few
storms back into central SD due to very strong surface heating ahead
of the front.

On Saturday, drier and more stable air will enter the region as
northwest winds begin to increase. Concern will switch to fire
weather as RH values drop into the upper teens and lower 20s over
central SD. The trend over the past couple days has been to increase
winds above SuperBlend for Saturday afternoon, which may put at
least north central SD into critical fire danger worthy of a
headline. Further south things appear more marginal. Will let day
shift consider the need for a fire weather watch as neighbors to the
north have already done so. Although, winds may be a bit stronger
further north in the region.

.LONG TERM...(Sunday Evening through Thursday)
Issued at 422 AM CDT Fri Jul 21 2017

Latest models are in fair agreement with the overall flow pattern.
That mid level flow pattern should feature a continuation of a
southern/southwestern ridge, with various s/ws tracking across the
Northern Plains/southern Canada. The period should start off dry
with sfc high having just moved across the region. However, by early
to mid week, another boundary will slide south into the region, with
a renewed chance of convection, especially the Tuesday through
Wednesday time frame. Temperatures will probably average out right
around normal for the time period as mid level heights and temps
remain fairly stout.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1253 PM CDT Fri Jul 21 2017

It`s possible that later this evening and for several hours
overnight (until a frontal passage switches winds around to the
northwest and starts drying out the boundary layer), some sub-vfr
stratus clouds could develop across northeast South Dakota into
west central MN (including the KATY terminal, and maybe even the
KABR terminal). Otherwise, flying weather is expected to be good
VFR except in/near any thunderstorms that get going later today
into tonight. Large hail, damaging winds and torrential rainfall
may accompany convective activity over the next 12 hours or so.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from Saturday afternoon through Saturday
     evening for SDZ267>270.

     Heat Advisory until 8 PM CDT /7 PM MDT/ this evening for
     SDZ016>018-033>037-045-048-051.

MN...None.
&&

$$

UPDATE...Dorn
SHORT TERM...TMT
LONG TERM...TDK
AVIATION...Dorn



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