textproduct: Aberdeen

KEY MESSAGES

- 20-40% chance for moisture east of the James valley today. Maybe a few hundredths overall. Another round of isolated showers (20%) overnight/early Sunday

- Well above normal temperatures Sunday, with highs in the 70s to low 80s (15 to 25 above normal). A west wind with gusts 25 to 35 mph. Grassland Fire Danger increases to High/Very High category Sunday.

DISCUSSION

Issued at 1227 AM CDT Sat Apr 11 2026

Return flow on the back side of high pressure, with warm advection ceilings around 10kft. 1/2km winds out of the south are also on the increase, around 40kts which will continue to spread east overnight.

NAM BUFKIT profiles indicate more stratus coming up from Nebraska, and we can see that ceilings in southern Nebraska are falling down to 2kft. This should end up across far eastern South Dakota later today. There isn't much of a wave aloft, with ridging overall through the day. With the moisture profile, this is primarily a drizzle type event, with little indication of moisture ever above 9kft, when saturation is at its thickets. This last from a little after 12Z through about 21Z with drying aloft forcing the stratus to shrink down to 3-5kft thickness, which is probably not high enough to generate moisture. Adjusted the jumpy NBM POPs to something more consistent across the east.

The stronger southwest flow shortwave comes up through northwest South Dakota early Sunday, a little slower progression in comparison to 24 hours ago. Not a lot of mid-level moisture with this feature, and mid level lapse rates only support skinny elevated CAPE. As such, not a lot of evidence for widespread moisture with this wave. Still seeing an isolated GEFS plume or two with 0.1" to 0.2" of moisture. Most CAMS have an isolated blip or two moving out of western South Dakota, so cant totally discount the NBM 20% chances. This lasts through about 12-13Z in the CAMS, and 15Z in the NAM after which the surface low lifts into northern Minnesota. NBM has us dry after 12Z, totally fine.

A really good mixing day expected for Sunday. 1/2km winds are westerlies starting around 40kts at 12Z. The surface gradient is about 5-6mb north to south. Mixed winds are around mid 20kts. As for temperatures, the core of the warmest 850mb temperatures associated with the southwest flow shortwave is also overnight, departing to the east by 15/18Z. Very subtle cold advection follows, which will only aid in mixing. Plus we have the departing wave leading to cloud free conditions. So the main question is how warm and dry as we look to potential enhanced fire weather conditions. We're still at the NBM 10th percentile for highs Sunday. 00Z HRRR is latching onto slightly drier dewpoints as well. That said, HREF probability of lower than 20% humidity is only about 20% down along the White River. Additionally, area webcams are showing a rapid greenup in the wake of last weeks 1/2 to 1 inch of moisture. Will bump up high temperatures closer to the 50th percentile given such favorable mixing conditions, trend dewpoints just a tad lower. Again, winds are low end for Red Flag, and without additional info to improve confidence, no headlines for now.

Ridging for the start of Monday, with a north south temperature gradient off a surface high to our north. Weak low pressure develops in advance of a southwest flow wave late in the day. NBM POPs are around 20-30%, but represent mainly mid level moisture/instability. GEFS plumes again showing a blip here and there of precipitation, but nothing overwhelming. Another wave is set for later Tuesday as the trough out west opens up and migrates east. There is a brief period Wednesday/Thursday with zonal flow aloft before the next upper trough comes in from the west. Behind that system, deterministic models bring in a colder airmass, with GEFS 850 temperatures down to about a standard deviation below climo.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1227 AM CDT Sat Apr 11 2026

Terminals KABR,KATY,KPIR,KMBG

We're starting out with VFR conditions at all of the TAF sites. Increasing winds and MVFR ceilings are expected at ABR/ATY by 14Z. IFR ceilings will move in by 18Z and continue through the TAF period. At PIR/MBG mainly VFR conditions will continue. Low level wind shear will develop around 03Z Sunday with winds around 55kts just above the surface.

ABR WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None.