textproduct: Sioux Falls

KEY MESSAGES

- Patchy areas of locally dense fog will continue mainly across portion of northwestern IA and the MN/IA state line through mid-morning before gradually dissipating.

- The return of mild and breezy conditions will lead to elevated fire weather concerns this afternoon with the focus across southcentral SD. More widespread concerns are expected by Friday.

- Confidence continues to increase in periods of light to moderate snow returning from Friday night into Saturday. While overall amounts are still uncertain, the U.S. Highway-14 corridor and portions of southwestern MN look to be the areas of focus.

UPDATE

Issued at 304 AM CST Thu Feb 26 2026

Taking a look across the area, mostly clear conditions have returned this morning with lighter surface winds. With this and lingering low- level moisture in place, patchy areas of locally dense fog have developed along the MN/IA state line and portions of northwestern IA. With many surface observations across northwestern IA now starting to report visibilities of 1/2 mile or less, have decided to issue a dense fog advisory for these areas. With this in mind, make sure to slow down and be prepared for rapid changes in visibility on those morning commutes! Heading into today, more mild and dry conditions are expected as west-northwest surface winds and a weak warm frontal passage help temperatures peak in the low to upper 50s for the day. With breezier conditions (20-30 mph gusts) expected this afternoon, elevated fire weather concerns will return for most areas as RH values gradually decrease into the 25%-35% range with the driest conditions across southcentral SD. However, with these conditions being limited to short window of 3-4 hours; decided to forgo any fire headlines at this time.

Looking ahead, Friday looks to be a better fire weather day with milder temperatures in the 50s to mid 60s and RHs in the 20%-30% range. With this in mind, not only is most of our area outlined in the very high category of the GFDI; but most areas are also outlined in the 95th percentile of the HDWI probabilities. As a result, we'll probably need some type of fire weather headline. However, we'll forgo it at this time until we get more short-range guidance. Otherwise, confidence continues to increase in periods of light to moderate snow returning to the Highway-14 corridor and portions of southwestern MN from Friday night into Saturday. While overall amounts are still questionable at this time, most ensemble guidance shows low to moderate confidence (20%-50%) in at least 1 inch of snow and low confidence (20% or less) in 2 inches or more. Based on what is being depicted in the latest 00z/06z deterministic guidance, expect these probabilities to increase over the coming runs with some models (Canadian and NAM) showing the potential for 3+ inches in some spots. With this in mind, make sure to follow your local forecast as the potential amounts and track of this system are subject to change.

DISCUSSION

Issued at 149 PM CST Wed Feb 25 2026

Light snow is currently moving through the region, and is expected to exit to the southeast this evening. Additional accumulations of a dusting to a a tenth or two for most locations. Slightly higher additional accumulations up to a half an inch is possible for portions of southwestern Minnesota and northwestern Iowa. Clouds will slowly scatter out through the overnight and winds will become light. Early Thursday morning patchy dense fog may develop for areas east of the James River Valley. Visibility may briefly be reduced down to 2 miles or less at times. Fog burns off quickly after day break.

The rest of Thursday will be pleasant with clear skies and warm highs in the upper 40s to 50s. Afternoon winds will be breezy with west-northwesterly gusts 25-30 mph west of the James River. To the east, gusts will be lighter between 15-25 mph. Friday will be even warmer thanks to a strong push of WAA. Good mixing through the 850 mb layer will result in surface highs in the 50s and 60s, with the warmest temperatures expected along the southern Missouri River Counties. Taking a look aloft a large low pressure system will move through central into eastern Canada Thursday through Friday. Friday afternoon it will drag a trough axis through our region. This will turn winds to the northwest by late morning. Winds will then increase in response to a tightening SPG, with afternoon gusts reaching 25-35 mph. Winds decrease after sunset but remain on the breezy side, with gust of 15-20 mph.

The main concern for both these days is the High to Very High Grassland Fire Danger. Though relative humidity values will be well above critical thresholds, the warm temperatures and breezy winds could aid in rapid fire growth through cured fuels. Please use caution, especially in areas of longer grass like ditches or dense field stubble. Should a fire start, report it immediately.

With the change in wind direction comes a strong push of CAA. This will bring our high temperatures Saturday down closer to average in the 20s and 30s. Along with cooler temperatures, a subtle embedded shortwave with in the larger low mentioned earlier may provide just enough lift for light snow showers to form. Snow may linger into Sunday. Many details are uncertain at this time, but a an inch or two of accumulation may be possible. Highs for Sunday will be colder than average in the 20s. But don't fret, we begin a warming trend again Monday that continues through mid week.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 514 AM CST Thu Feb 26 2026

Mostly VFR conditions with occasional MVFR to LIFR vsbys this morning with transition to VFR conditions by this afternoon. Taking a look at satellite imagery, patchy areas of locally dense fog continue to sit over the portions of northwestern IA and southwestern MN this morning promoting MVFR to LIFR vsbys. While these conditions could persist through daybreak, most the fog should gradually erode by mid-morning. Otherwise, light southwesterly winds will become more west-northwesterly throughout the day and breezy with gusts between 20-30 mph expected.

FSD WATCHES/WARNINGS/ADVISORIES

SD...None. MN...Dense Fog Advisory until 9 AM CST this morning for MNZ089-090- 098. IA...Dense Fog Advisory until 9 AM CST this morning for IAZ002-003- 013-014-022. NE...None.