Shamrock Colony, SD 57322 Weather

This Hazardous Weather Outlook is for northwest Iowa, west central Iowa, southwest Minnesota, central South Dakota, east central South Dakota, south central South Dakota and southeast South Dakota.

Day one

Today and tonight.

Hazardous weather is not expected at this time.

Days two through seven

Friday through Wednesday.

Hazardous weather is not expected at this time.

Spotter information statement

Spotter activation is not expected at this time.

NWS Sioux Falls will discontinue the Hazardous Weather Outlook product (HWO) on November 8, 2026. Weather hazards and outlooks will continue to be provided through other standard NWS products, including weather briefing packets, forecast discussions, weather story graphics, the graphical hazardous weather outlook, and updated hazard messaging. All local products and visual tools are accessible directly at: weather.gov/siouxfalls.

Key messages

- Areas of fog have developed this morning, with some dense fog mainly near and along river valleys. Watch out for quickly changing visibilities on your morning commute. The last of the fog should lift between 10 and 11 am.

- Rain chances with some isolated thunderstorms return early Friday morning and continue through Saturday and again early next week.

Update

Issued at 402 AM CDT Thu Oct 29 2026

Patchy fog has developed once again early this morning, especially in areas surrounding river valleys, with several spots along/near rivers dropping to a half mile or less. Would want to see any dense fog to spread out into areas away from rivers and become a bit more widespread before issuing a dense fog advisory, but trends will be monitored closely. Either way, be prepared for some areas of fog on your morning commute! The fog has also been quite shallow in places as well, so visibilities may quickly change when going up and down hills. Any fog erodes entirely by about 10 am or slightly afterwards.

Heading into the daytime hours, mid-level clouds associated with a weak wave will move across the far western part of the forecast area this morning and then scrape the Highway-14 corridor in the afternoon. Soundings show some shallow instability within this cloud layer, but dry air below should limit any of this precipitation from reaching the ground. However, can't rule out a few sprinkles in these areas (<20% chance). Otherwise, more appreciable rain chances return to the area on Friday but especially Friday night into Saturday. Friday morning the focus for rain chances will be along the Highway 20 corridor and into northwest Iowa as scattered showers develop with increasing warm air advection. Showers then look to expand in coverage and spread northward later Friday and continuing into Saturday morning. Most of this activity will be on the lighter side (<0.15" totals), though some higher amounts look to be centered around the Highway 20 corridor into northwest Iowa where chances of a quarter of an inch or more of rain have gone up a bit (around a 40-60% chance).

Discussion

Issued at 131 PM CDT Wed Oct 28 2026

Over the next couple of hours, showers and storms are expected to develop over parts of eastern South Dakota and western Minnesota ahead of a cold front. Cannot entirely rule out the possibility of strong to severe thunderstorms, although the best environment will be to the northeast further into Minnesota. Still, a Marginal Risk clips the northeastern-most part of the forecast area, and hail is the main potential severe threat. Strong storms that do develop in that area are expected to exit the forecast area fairly quickly this afternoon. Further south, expectations are that showers will remain fairly light, and just a few hundredths of rain will fall.

Behind the cold frontal passage, a high pressure center will move into the area overnight tonight. After an initial shift to the northwest, winds will become light and variable overnight tonight as the high pressure center moves overhead. There is some signal in high-resolution guidance for some fog development once again tonight due to the light winds and clear skies promoting strong radiative cooling. The main area of concern for fog development is over southeastern South Dakota, particularly the James River Valley. Confidence in the areal coverage is still somewhat low at the moment, but pockets of dense fog may reduce visibility below a mile at times.

The next chances for rain come on Friday into Saturday. Rainfall will move in from the south beginning Friday before expanding to cover the entire forecast area Friday night into Saturday. Generally light rain rates are expected, but perhaps a quarter of an inch or more (20-40%) could fall over parts of northwestern Iowa, northeastern Nebraska, and southeastern South Dakota.

Another low pressure system is set to move into the region early next week, bringing renewed chances for rain into the region. Monday through early Wednesday, chances are fairly high (50-70%, increasing moving from north to south across the forecast area) to see an inch of rainfall accumulation or more. However, there is still significant uncertainty with this system in timing, location, and amounts. 25th/75th spread is generally around two inches for that same time period, so still a lot to resolve as the system comes into focus over the next couple of days.

Aviation

Issued at 637 AM CDT Thu Oct 29 2026

Areas of fog will continue to impact the area through about 15- 16Z, with some dense fog mainly confined to areas near and along river valleys, especially the Missouri River Valley and southern James River Valley. Fog has also been notably quite shallow and so it has dissipated and reformed in a sometimes quickly repeating cycle, and that trend looks to continue.

After fog clears, VFR conditions are expected for the rest of today and this evening. Heading into tonight, lower MVFR cigs will begin to creep into the Highway 20 corridor along with a few showers. Winds will be fairly light through the period out of the east-southeast.

Watches, warnings and advisories

SD: None. MN: None. IA: None. NE: None.