textproduct: Aberdeen

KEY MESSAGES

- There is a Marginal Risk, level 1/5, for isolated severe storms this afternoon and evening over northeastern Roberts County in SD through west central Minnesota. Main threats will be hail of 1" in diameter and wind gusts of 60 mph. Weak cold air funnels or a landspout is also a possibility.

- Widespread rainfall is expected Saturday evening through Sunday evening focused across central South Dakota. Probability of rainfall of 1" or more through Monday is 65-90% along and south of a line from Eagle Butte to Fort Thompson, highest over south central SD.

- Temperatures remain near to slightly below normal through next week. Coolest day being Sunday at 10 to 20 degrees below normal.

DISCUSSION

Issued at 203 PM CDT Fri Jun 19 2026

As of 1pm, the center of the positive tilted shortwave is hovering over the ND/MN border with the center of its low over northern MN/ND/Canadian border and cold front extending along the Dakotas and MN border. Satellite indicates cumulus clouds moving in from the northwest over north central and northeastern SD/western MN with showers and thunderstorms ongoing near the low/front over ND/MN border. Cams indicate ongoing heating (ML Cape is currently 200-500 j/kg) could lead to vertical growth resulting in spotty thunderstorms developing (or moving in from ND) over our far northeastern CWA later this afternoon through the early evening. There is a Marginal Risk, level 1/5, for isolated severe storms over northeastern Roberts County through west central MN during this time. Main threats will be hail, up to 1" in diameter, and 60 mph wind gusts. Low and mid level lapse rates are steep with Hail Cape between 300-500 j/kg and inverted V soundings which lead to these threats. Of note, SPC meso parameters also indicate surface vorticity overlapping with 0-3km ML Cape of 100-200j/kg suggesting cold air funnels or landspout could possible through this evening. As of 1830Z the best overlap and NST parameter of 1-2 is near the low/boundary along the ND/MN border. The positive tilted shortwave will continue to track southeast through this evening, with the axis over MN/WI at 00Z. The surface high pressure system will move in over the region keeping the area dry tonight and keeping conditions dry over north central SD through the morning and northeastern SD/western MN through Saturday evening as the high tracks eastward over ND/Canada and into MN.

Our attention then turns to this weekend where widespread rainfall is forecast with the focus across central SD, especially south central SD. Another shortwave and its embedded pulses will track west to east across the Central Plains and northward through SD early Sunday through early Monday. At the surface, an elongated area of low pressure will extend from the Northern Rockies through the central Rockies Saturday with several lows lying along a the boundary. Within this, a Colorado Low develops Saturday evening, with a secondary low developing and tracking across the Central Plains Sunday into Sunday evening. As what the previous shift mentioned, the rain will be more elevated and stratiform per this shortwave and less surface based/convective as the region will be north of this Co low/surface boundary and east of the lows/boundary over the Rockies.

Ensemble models overall agree on precip tracking northward from the Central Plains and moving in over south central SD Saturday midday/afternoon. The rain continues to track northward over central/north central SD through Saturday evening and becoming widespread and covering much of central SD and portions of northeastern SD by Sunday morning. Far northeastern SD/western MN will either see very light rain or nothing as the high will keep conditions dry. If the high drifts further south, then the cutoff will be more southwest of here and vice versa. The last of the rain is forecast to exit the southeastern CWA by Sunday night/early Monday. The bulk of the precip will be 00Z Sunday-00Z Monday with NBM pops of 40-95%, highest over south central with pops diminishing the further northeast you go in the CWA. PWAT values (with the exception of far NESD/MN) are on the order of 1-1.4" highest over south central SD. This is above the 90th percentile here, per ensemble mean, and around 2 standard deviations above climo per NAEFS. NBM probability of 48hr rainfall>1", ending 12Z Monday is 65- 90% along and south of a line from Eagle Butte to Fort Thompson, highest over south central SD. Probability of 2" is 40-55% over south central SD. Due to this, the WPC has put central SD in a Slight Risk, which is a 15% chance exceeding flash flood guidance. The 25-75th spread ranges from 0.3 to 1.3" along and west of a line from Aberdeen to Redfield. The high spread is due to the exact track of low and how much this high pressure system influences rainfall north and northeast of south central SD. Any track north or south of the system will impact where the heaviest rainfall will occur. As for convection, it will be low cape/"high" shear as MUCAPE<500j/kg (skinny cape) and shear of 30-40kts (mainly over Jones/Lyman) with the better forcing to our south and southwest. While no severe is anticipated, some afternoon heating could result in general thunderstorms.

Another shortwave over Canada/Northern Rockies will track east/southeast and over the Northern Plains Monday/Tuesday, along with its surface low, bringing the return of precipitation across the CWA. NBM pops range from 40-70% as precip will track west to east across the CWA Monday afternoon through Tuesday evening. This is a quicker moving system and more convective/surface based with low confidence in exact amounts as any stronger rain shower or storm could produce locally higher rainfall. Overall, probability of rain>0.25" per NBM is 55-70% along and north of a line from Aberdeen to Ortonville and highest over far NESD/MN. Daytime heating and mixing will lead to the chance of thunderstorms in the afternoon and evening. As of now, no severe weather is anticipated. Behind this low/shortwave, a ridge builds over the western CONUS and its high over the Southwest as the CWA remains in northwest flow. This will push eastward and over the region by the end of the week. Exact amplitude of this wave is unknown at the time given this is several days out as NAEFs indicates it becoming lower in amplitude as it tracks east. Moisture chances return for the end of the week with general pops of 20-40%.

Highs for Saturday, per east/southeast flow and ridge aloft, will range in the mid to upper 70s. Cooler on Sunday due to rain and low clouds with highs in the 60s and 70s, coldest over central SD. Monday-Wednesday will remain in the lower to mid 70s and mid to upper 70s for the end of the week, with the possibility of some 80 degree readings on Friday.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1222 PM CDT Fri Jun 19 2026

Terminals KABR,KATY,KPIR,KMBG

VFR cigs are forecast through the end of the TAF period at all terminals. Winds will continue out of the northwest, with gusts of 20-30kts this afternoon through the evening and diminishing as a high pressure system moves into the region and becoming light and variable overnight. Winds will prevail out of the east and southeast for Saturday with gusts of 20kts over KPIR by the afternoon

ABR WATCHES/WARNINGS/ADVISORIES

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