898 FXUS63 KABR 160923 AFDABRArea Forecast Discussion National Weather Service Aberdeen SD 423 AM CDT Tue Sep 16 2025
.KEY MESSAGES...
- There is a marginal risk, or threat level 1 out of 5, of severe weather late this afternoon into this evening near and east of a line from Kadoka to Highmore, Redfield, and Sisseton. The main concerns with the strongest storms will be winds to around 60 mph or hail around the size of quarters.
- A prolonged period of wet weather is expected Wednesday and Thursday, with most of the rain slowly coming to an end Friday into Friday night. Moderate rain over the same area could create flooding issues.
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.DISCUSSION... Issued at 423 AM CDT Tue Sep 16 2025
The early morning surface weather map showed a 1014mb low centered over our forecast area with a deeper 1010mb low over eastern CO . Northwesterly winds were set up on the back side of the low (over central SD), with winds still out of the south to southeast across eastern SD and western MN. The showers and thunderstorms that moved near the MO River around 06Z have since diminished in intensity and coverage, with only a few showers lingering from Eureka through Gettysburg and Lyman County as of 840Z. As the showers continue east they will get into less favorable air. However, there are additional showers and storms over northern NE and south central SD that will result in at least a 20% chance of precipitation in the forecast for our far southwestern counties through 12Z.
The eastern CO low will track east, with a trough set up from eastern SD through western KS by 00Z Wednesday, allowing for a conveyor belt of moisture to surge north. There is a marginal risk of severe weather ahead of the low, for portions of south central to northeastern SD and west central MN. This will be for late afternoon, mainly after 22Z with precipitation over south central SD that will be shifting northeast across the rest of the area. The NCAR medium-range real-time convective hazard forecasts have highlighted this area as a concern for the past several days. Still, there is some significant uncertainty on how far northeast the stronger storms will be able to make it this evening. Even one of the most robust CAMs, the NAM Nest keeps convection south of US Highway 212 and mostly south of US Highway 14. A few strong to severe storms will be possible late this afternoon through this evening.
More steady rain, and a few embedded thunderstorms, can be expected by late Wednesday morning. This is when our chance of precipitation increases to 60-80%. While there will be breaks from the rain, the off and on precipitation may result in localized flooding issues. There is a 40-70 percent chance of getting an inch of rain by Friday, and around a 20-40 percent of getting over 2 inches of rain. At this time, the highest amounts/highest chances of over 1 or 2" is expected over northeastern SD and western MN. We remain in a WPC marginal risk area of at least 5% risk of rainfall exceeding flash flood guidance within 25 miles of a point over much of our area Wednesday through Friday.
The surface low will shift from over the forecast area Thursday to our north late Friday into Saturday. Friday will be our transition day, with the more steady rain coming to an end as drier air takes hold. Expect dry weather over central SD Friday night through at least Tuesday. The forecast is a little trickier for northeastern SD and western MN as the low lingers nearby, and a 15-30 chance of rain during the day Saturday.
Temperatures today will top out in the low to mid 80s, and in the 60s to low 70s Wednesday through Friday. Low temperatures will remain in the 50s to low 60s through Friday, lowest over central South Dakota.
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.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1204 AM CDT Tue Sep 16 2025
Terminals KABR,KATY,KPIR,KMBG
A line of showers and thunderstorms will may impact the KPIR/KMBG TAF sites during the first hour or two of the TAF forecast. The biggest concern with any thunderstorms near a TAF site will be erratic and gusty winds.
Otherwise, a weak cold front will very slowly slide from west to east across the region. Winds will respond by becoming light and then switching to a more northerly direction. Winds have already switched at KMBG. KPIR/KABR will follow suite closer to 12-15Z and KATY will be later Tuesday afternoon.&&
.ABR WATCHES/WARNINGS/ADVISORIES... SD...None.
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.ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. &&
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DISCUSSION...06 AVIATION...Serr
NWS ABR Office Area Forecast Discussion