textproduct: Aberdeen

KEY MESSAGES

- Much of the region is forecast to drop to 32 degrees or below overnight, with mid/upper 20s possible in and around the James River valley.

- Warming trend forecast by this weekend, with highs back into the 60s.

UPDATE

Issued at 618 PM CDT Tue Oct 21 2025

Updated for the 00Z Aviation Discussion.

Overall, the forecast looks to be on track. Watching an area of clouds dropping southeast out of western/central ND and the latest RAP seems to have a decent handle on the areal coverage of the moisture in the 800-700mb region. Have made minor tweaks to the Sky grids for now, but may need to bump up to more of a partly-mostly cloudy sky for a time tonight along the MO River and eastward towards the James River. The latest RAP does indicate that moisture lingering into tomorrow morning in the James River area, which would lead to some concerns on lows for tonight, if the clouds move in and stay here. No changes to the lows for now.

SHORT TERM /THIS EVENING THROUGH WEDNESDAY NIGHT/

Issued at 208 PM CDT Tue Oct 21 2025

Low pressure center will continue to shift off to the east today, weakening the pressure gradient over the forecast area and subsequently allowing the strong wind gusts to move out of the area. Minimal impacts are expected after the strong winds today. Afternoon humidity remains fairly high (40-50%) and does not coincide with the strongest winds, so fire weather is also not a large concern today either. A weak surface ridge builds in behind, and light winds gusting to a maximum of around 15 miles per hour are expected. Mostly clear skies are also expected with the departure of the low, but a scattered low to mid cloud deck is expected to move in this evening.

High pressure and minimal cloud cover overnight tonight will be conducive to strong radiational cooling, as are light northwesterly winds. The wind direction also continues, albeit at a lower rate, the cold air advection near the surface. All of these factors combined indicate that the forecast area is set to see the coldest night of the season thus far, down into the mid to upper 20s. Temperatures are forecast to reach below freezing for nearly the entire area, and ensemble probabilities show a 75-95% chance for areas east of the Missouri River. There is still a bit of uncertainty as to exactly how low temperatures will get, and if cloud cover is persistent overnight and limits radiational cooling, the James River may "only" reach around freezing overnight. Conversely, if cloud cover is fairly scattered as the latest HREF would seem to suggest, the James River Valley could see the first hard freeze (below 28 degrees) of the season. High temperatures Wednesday will return closer to normal (mid-50s) with height rises from the incoming upper-level ridge and the continuation of little cloud cover both contributing to the slight warmup.

LONG TERM /THURSDAY THROUGH TUESDAY/

Issued at 208 PM CDT Tue Oct 21 2025

Upper level setup Thursday consists of a large mid level low over eastern Canada and its trough extending southward over the eastern half of the CONUS. West of here, a high amplitude ridge will be over the Intermountain west extending well northward through Canada. This is a split flow pattern as a trough/low will also be positioned over the Southwestern US. Clusters agree on this ridge (with embedded shortwaves within it over Canada) will move over the Northern Plains Friday, and the southern trough/low also moving eastward over ~Colorado. Through the weekend, this ridge will continue to shift east as a broad negative tilted trough will move in over the western CONUS Sunday, with the axis shifting eastward from the central Plains and northwestward through the Northern Rockies into western Canada by Monday. Further into the extended this trough will push east with a ridge moving in behind it. Surprisingly, the Clusters agree really well on this overall pattern with differences between the ensembles on the intensity of this trough moving in early next week.

With this setup aloft, high pressure will be to our southeast Thursday with a surface lee trough setting up to our west Friday- Sunday. Through Sunday, the pattern is forecasted to remain dry with our next chance of precipitation moving in early next week as a low will move across the region, associated with shortwaves in this overall broad trough. As mentioned, with differences between the ensembles aloft lead to differences on intensity of its surface low and timing that will sweep across the region ~Monday-Wednesday. Models do agree on precipitation with this with the highest NBM pops of 40 to 60% Monday across the entire CWA, highest east of the James River for now. PWAT's are forecasted to run between 75-85th percentile ranging from 0.6-0.8" highest over far eastern SD Monday. Probability of 24hr QPF>0.25 is 40-60%, highest east of the Coteau Monday and 25-45% of QPF>0.50" as of now.

With the steepening lee trough this weekend and incoming low early next week, winds will increase with the gustiest day being Tuesday on the backside of this system per CAA/pressure rises/steeper pressure gradient. Probability of wind gusts>40 mph is 35-55% west of the James River, highest over central SD. Under this ridge, southwest to southerly flow at 850mb will bring in warmer air with forecasted highs in the 50s to around 60 on Thursday and temps ranging in the 60s Friday-Sunday, with our warmest day of the week forecasted to be Saturday with highs potentially ranging the mid to upper 60s west of the James River as 850mm temps are forecasted to range between 9 to 15C! However, the spread between the 25-75th percentile does increase Saturday with a spread of 5-8 degrees and a spread of up to 10 degrees Sunday. As CAA (850mb temps ~0 to 1C) moves in behind the system early next week temps will gradually cool back in the 40s/50s.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1228 AM CDT Wed Oct 22 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will continue through the TAF period. Do have some mid clouds moving through KABR and eventually KATY during the overnight hours, otherwise winds will be light tonight and then be northwest of 10-18kts during the afternoon on Wednesday.

ABR WATCHES/WARNINGS/ADVISORIES

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