textproduct: Aberdeen

KEY MESSAGES

- Temperatures will fall into the low 30s over portions of northeastern SD overnight into Monday morning. Patch frost to areas of frost will be possible, with a Frost Advisory in effect.

- On Monday, continued dry conditions with relative humidity falling to 15 to 30% and southerly winds gusting 30-40 mph will bring high Grassland Fire Danger Index values to portions of central to northeastern SD. Red Flag Warnings or Fire Weather Watches are in effect for portions of mainly central SD for Monday afternoon.

- High to very high Grassland Fire Danger is forecast Tuesday and Thursday as winds gust 35 to 45 mph, with a few locations gusting to near 50 mph. Relative humidity over much of the area will fall into the 15 to 30% range.

- High temperatures Monday through Saturday will be in the 70s and 80s, highest Thursday through Saturday when temperatures will be around 20 degrees above normal.

UPDATE

Issued at 634 PM CDT Sun May 10 2026

Aviation discussion updated below for the 00Z TAFs.

DISCUSSION

Issued at 249 PM CDT Sun May 10 2026

The 19Z surface weather map showed 1025mb high pressure over southeastern Manitoba, with a ridge extending across the Dakotas and northern MN. This ridge will exit across MN as the main area of high pressure settles across the Upper Great Lakes Monday. By 18Z Monday our forecast area will be stuck between the exiting high and an elongated trough of low pressure set up from the southern Saskatchewan/Manitoba border down through the Black Hills. Southerly winds will be in force, with temperatures being about 20 degrees higher than today. Temperatures will rise in the 70s east of the James River, and mainly rise into the 80s west of the James River. Increasing winds with winds gusting 30 to near 40 mph, hot, and dry conditions will result in high to very high Grassland Fire Danger Index values Monday afternoon, especially west of the James River. Given coordination with fire management personnel, the short grasses are green across much of the area. Still, taller dry grasses are still being receptive to fire movement. Our ongoing mainly dry weather has dominated now for nearly 2 weeks. A Fire Weather Watch remains for Brown/Spink Counties west. The highest confidence in reaching Red Flag Warning criteria was over south central SD (Jones/Lyman/Stanley Counties), where relative humidity falls to 15 to 25%. This is the driest area Monday. The main concern there is if wind will be strong enough during the driest part of the day to allow for 3 hours of 20% or lower relative humidity and wind gusts of 25 mph or more. As we move through the afternoon, winds will diminish in this area. Later shifts will need to monitor the latest trends to see if the relative humidity will be low enough, as winds will be gusting at or above 25 mph. Even going with some of the lowest guidance, confidence was low in reaching criteria.

Expect a cold front and shifting winds Monday night into Tuesday morning around 02Z over north central SD, 05Z near the James River, and 08Z over far northeastern SD and west central MN. We continue to message not only the hot, dry, and windy conditions, but the wind shift that could impact any ongoing or new fires.

Light showers, and even a rumble of thunder will be possible with the passage of the cold front, mainly over our eastern and southern counties. A wetting rain (0.01" or more) is not expected at this time.

Winds increase out of the northwest Tuesday (cold air advection peaking 00-06Z Tuesday), with gusts of 35-45 mph during the day. Given these winds, lowing dust will be possible Tuesday Aberdeen to Clark and west, so mainly west of the Prairie Coteau of northeastern SD (where less precipitation has fallen over the last couple of weeks and crops are minimal).

High pressure will be overhead Wednesday. After lighter winds Wednesday, winds will be out of the south on Thursday. Minimum relative humidity much of the week will be 15 to 30%, with mainly dry weather continuing. The strongest winds are expected Thursday, with a 40-60% chance of winds gusting over 45 mph east of the Missouri River. A Wind Advisory may be needed for Thursday. Highs Thursday will be in the 80s to low 90s (warmest of the next 7 days).

There are some differences in the track/strength of the next surface low Thursday night into Friday. Temperatures will only fall a few degrees, and still mainly be in the 80s through the upcoming weekend.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 634 PM CDT Sun May 10 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Light winds this evening will gradually increase from the south-southeast late tonight and through the day Monday. Gusts by mid/late morning and afternoon will approach 30 knots.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Frost Advisory from 3 AM to 9 AM CDT Monday for SDZ005>008-010- 011-017>023. Fire Weather Watch from Monday afternoon through Monday evening for SDZ003>006-009-010-015>018-034>037-051. Red Flag Warning from 1 PM CDT /noon MDT/ to 9 PM CDT /8 PM MDT/ Monday for SDZ033-045-048. MN...Frost Advisory from 3 AM to 9 AM CDT Monday for MNZ039-046.