559 FXUS63 KABR 092045 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 345 PM CDT Tue Oct 9 2018 .SHORT TERM...(This Evening through Wednesday Afternoon) Issued at 345 PM CDT Tue Oct 9 2018 A strong upper level low pressure trough and its associated surface low pressure area to our south late this afternoon will be making their way northeast through the night and Wednesday. Intense deep layer lift with this system will result in rain overspreading the entire cwa through the evening. The issue will be with the temperature profiles along with the location of the dry slot surging north into the eastern part of the region tonight. As a result, the models vary on the change over to snowfall tonight into Wednesday. The GFS was the warmest with the NAM the coolest with the thermal profile through Wednesday. The EC and Canadian were in between these two models. Believe the cooler models and the change over to snow should occur by midnight west of the James Valley and to the east of the James Valley after midnight into Wednesday morning. The dry slot will lift into our far east and will affect snowfall amounts. Otherwise, there are good indications of a good deformation zone setting up northwest of the upper low along with some mid level frontogenesis combined with some negative epv. Therefore, there could be some banded snowfall with heavier amounts. The trowal feature will be also be wrapping around the upper low pressure area. Snowfall should be heavy enough during the nighttime to be able to accumulate decently on the grassy surfaces. Roads will also see slushy accumulations. At this time, 2 to 5 inches look good with lesser amounts in the far east and southeast in the Wheaton/Watertown areas. The winds will also be strong in the 20 to 35 mph range with blowing snow not expected to be an issue. Lowered highs on Wednesday with the expected caa and snowfall occurring. Expanded Winter Weather Advisory east from the James Valley to the Sisseton Hills earlier today. .LONG TERM...(Wednesday Evening through Tuesday) Issued at 345 PM CDT Tue Oct 9 2018 Gusty winds and snow will continue into Wednesday evening across the northeastern half of the forecast area. While the main 500mb low exits our northeastern counties Wednesday night, the large trough remains in place across the Northern Plains through Friday morning. The sun looks to return Thursday, at least glimpses of it as high pressure moves in at the surface. Looking back at the MODIS imagery, this may be the first time of significant sunshine since September 28th. It will still be cool through, with temperatures topping out in the 30s and 40s. Even with the warmup later Friday and Saturday (40s and 50s), temperatures will remain well below normal. While a brief 500mb ridge slides overhead Friday, it will quickly be replaced by zonal flow on Saturday as the next 500mb low (and surface low) shifts across south central Canada. Gusty winds look to return for Friday night (not quick mixing to the 35kt wind around 900mb) and Saturday where 15-20kt winds should be common over the western half of the forecast area. Light snow may clip the ND/SD border Sunday morning. Reinforcing cold air will move in for Sunday, with highs in the mid 30s to near 40 degrees. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon) Issued at 1244 PM CDT Tue Oct 9 2018 Complex weather scenario shaping up in this forecast period as an early season winter storm moves into the region. Anticipate cigs will remain IFR through the period at all TAF sites. A more steady type rain begins to move in late this afternoon and early evening. Colder air drawn in overnight will change the rain to snow at KMBG and provide for a mixture at KPIR and KABR. A more brief period of all snow could be possible at KPIR and KABR early Wednesday morning. Eventually the mix works into KATY Wednesday morning. Visibilities will mostly be IFR but in heavier precip, LIFR vsbys will be possible...especially at KMBG and KABR. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Winter Weather Advisory from midnight CDT /11 PM MDT/ tonight to 1 PM CDT /noon MDT/ Wednesday for SDZ003>005-009-010- 015>017-033>037-045-048-051. Winter Weather Advisory from midnight tonight to 7 PM CDT Wednesday for SDZ006>008-011-018-021. MN...None. && $$ SHORT TERM...Mohr LONG TERM...KF AVIATION...Vipond