Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 251949

Area Forecast Discussion
National Weather Service Aberdeen SD
249 PM CDT Tue Jul 25 2017

.SHORT TERM...(This Evening through Wednesday Afternoon)
Issued at 248 PM CDT Tue Jul 25 2017

The threat for severe storms this evening will be the main forecast

A surface low pressure system located in south central SD with a
warm front extending into western MN. Decent moisture convergence,
combined with hot temperatures will create an unstably environment
along the front. While 700 mb temps exceed 13C, cin is beginning to
erode, mainly in northern NE and south central SD. Overall upper
level support is lacking, there appears to be the presence of a weak
upper level shortwave which should aide in convective development
within the next few hours in south central SD. There is consensus
among models for a rapid expansion of convective development along
the front. Large hail and damaging wind gusts will be the main
threats. However with high PWATS, a slow storm portions, and surface
front parallel to the upper level flow, heavy rainfall will also be
possible. East central SD, from Watertown to Brookings, will have
the best potential of seeing locally heavy rainfall. Timing of the
severe storms is best between 4 pm to 10 pm.

High pressure building into the area from the north will bring dry
conditions for most locations on Wednesday. Areas along and south of
Highway 14 will have a chance for pcpn Wednesday morning.

.LONG TERM...(Wednesday Evening through Tuesday)
Issued at 248 PM CDT Tue Jul 25 2017

Zonal flow continues Thursday before starting to shift to a more
meridional flow throughout the rest of the forecast period. Models
are fairly consistent in that an upper-level ridge and associated
high pressure build into the region Friday.  This will result in a
few shortwaves and the potential for sporadic convection over the
weekend and into early next week.

Models are inconsistent on temperature output, with the GFS being
much warmer Friday and Sunday, while the Euro is significantly
cooler Saturday. Overall, blended temperature highs appear to be at
or slightly below average across the CWA.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1221 PM CDT Tue Jul 25 2017

VFR conditions are expected over the region through the valid taf
period. By late afternoon and early evening storms are expected
to light up along a front situated from KPIR/KATY. Some of those
storms will be strong to severe. Brief periods of IFR conditions
can be expected with any storms that move over a terminal.




LONG TERM...Telken
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