Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 272033

Area Forecast Discussion
National Weather Service Aberdeen SD
333 PM CDT Tue Jun 27 2017

.SHORT TERM...(This Evening through Wednesday Afternoon)
Issued at 328 PM CDT Tue Jun 27 2017

A strong area of low pressure is currently located over eastern MT
with a frontal boundary running southward across western SD.
Instability will continue to increase ahead of the frontal boundary
with surface base CAPE between 1K and 2K J/KG. Still a far amount of
CIN to overcome. It is uncapped in SE Wyoming where convection has
developed. A few CAMS suggest the current convection will grow
upscale into an eastward propagating complex. This would largely
remain south of Highway 14, bypassing central SD. Convection
would then spread into eastern SD after 6Z due to a strong LLJ.
Additional convection will be possible along the ND/SD border
where the surface low will interact with moderate MU-Cape and
cooler 700 mb temps. With the lack of significant DCAPE, large
hail will be the main hazard along and north of ND/SD border.

The convective potential between I-90 and KMBG is a little
more unclear. Half of the CAMS are showing convection developing
along the frontal boundary. As stated early, others bypass most of
central SD. With such a strong system, will keep high pops going
through tonight. Convection should push east into MN by 15Z
Wednesday with dry conditions likely for the rest of the day.

.LONG TERM...(Wednesday Evening through Tuesday)
Issued at 328 PM CDT Tue Jun 27 2017

The forecast models today are fairly consistent with the idea that
the larger scale flow pattern should remain relatively progressive
throughout the period.

Still looks like some precipitation chances will be anchored on
Thursday/Friday under the influence of a cold core low over the
Dakotas (cold air instability showers mainly). Then a couple of days
of upper level ridging set up over the region Saturday and Sunday
before another area of low pressure working east through the region
knocks the ridge back down Sunday night into Monday, bringing some
precipitation potential back to the forecast. After Monday, ridging
starts to build back up.

Temperatures will be near to below normal for most of the period. By
early next week, a warmer airmass begins to return to the region.
The 4th of July is starting to look like a rather toasty warm day.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1237 PM CDT Tue Jun 27 2017

VFR conditions will prevail through this evening. A strong area of
low pressure will cross the region late this afternoon and through
the overnight hours. Winds ahead of the surface low will be gusty
from the south with sustained winds in the 20 mph range. Winds
will shift to the west then northwest behind the surface low.
Strong to severe thunderstorms will be possible as the low crosses
the region. Some storms could produce damaging winds and large
hail. Flying conditions will change drastically for any terminal
that experience a thunderstorm tonight.




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