textproduct: Sioux Falls

KEY MESSAGES

- A Red Flag Warning remains in effect from late morning through early evening for the entire forecast area. The combination of warm temperatures, very dry conditions, and strong winds could lead to rapid, explosive fire growth. This is a potentially dangerous situation.

- Additional elevated to near-critical fire weather risks will continue daily into next week.

- While drier conditions will persist to finish out the month, a pattern shift by early April could lead to renewed chances for rain and/or snow.

UPDATE

Issued at 324 AM CDT Sat Mar 28 2026

Taking a look across the area, quiet conditions persist on the backside of the surface ridging. We're starting to see a slight uptick in wind speeds across central and western SoDAK this morning as the nocturnal LLJ strengthens. As we approach daybreak, this low- level feature along with increasing mixing will be responsible for the sharp increase in our surface winds by mid-morning. As a result, south-southwest winds will likely produce gusts in the 35-50 mph range through early evening. This combined with the drier fuels and conditions will fuel our Extreme fire weather risk this afternoon (more in the fire weather section).

While some considerations were given to adding a wind advisory to our Red Flag Warning, decided to keep our current headlines the same since the Red Flag Warning also encapsulates the threat of stronger winds. Nonetheless, we'll have to keep an eye on observations near the Buffalo Ridge as some high-resolution guidance continues to show the potential for some isolated High Wind Warning (55-60 mph) level speeds at times during the mid to late morning hours. Otherwise, we'll continue to see the potential for blowing dust mainly across southeastern SD from the late afternoon into the overnight hours. While air quality guidance continues to show the higher concentrations overnight, anyone in a sensitive group should start to monitor their local air quality heading into Sunday.

DISCUSSION

Issued at 216 PM CDT Fri Mar 27 2026

Looking aloft we see an upper ridge continuing to settle over the central United States. At the surface high pressure is pushing into the region, resulting in subsiding air. At the surface this means significant drying is taking place causing dew points fall into the single digits to teens. The resultant relative humidity this afternoon will be near critical to critical falling to less than 25% south of a rough line from Huron to Ida Grove. North of there humidity will range from 25-35%. Northwest winds will be decreasing through the afternoon, therefore the highest gusts and lowest relative humidity should be offset from one another by a couple hours. However, Fire Danger remains High to Very High today. Critical to near critical fire conditions continue through the weekend and into next week. Please see the Fire Weather Discussion below for further details. As far as highs for this afternoon are concerned they will be close to average for this time of year, in the 40s for most of the CWA with a few 50s possible along and south of Highway 20. Overnight lows will be cold thanks to clear skies and light winds, in the 20s.

Overnight the center of the surface high will move to the southeast, turning winds to the south. Strong WAA ahead of a low pressure moving southeast out of Alberta will work to tighten the pressure gradient from the surface through the mid-levels. Surface winds and the LLJ increase in response. Sustained winds of 25-35 mph are expected Saturday morning through the late afternoon. Good afternoon mixing will tap into the 45-55 kts jet, mixing down gusts of 40-45 mph with a few gusts between the James River Valley and I-29 potentially reaching 50 mph. Winds are very near Wind Advisory criteria, but with a little uncertainty in peak gusts remaining, and after collaboration with neighbors, have decided to wait on issuing a headline at this time. Highs for Saturday will climb to the upper 50s to low 60s east of I-29. To the west low to upper 60s are expected. Overnight lows will be in the 30s. The combination of strong winds, dry conditions, and warm temperatures have resulted in the issuance of a Red Flag Warning Saturday morning through Saturday evening.

Another warm and dry day is in store Sunday, but thankfully with lighter winds. The previously mentioned low will traverse from Montana through Wyoming and into Nebraska, passing by just to our south. As it does so winds will gradually become northeast to east. Highs will climb into the upper 60s to low 70s north of I-90, with temperatures increasing to the upper 70s as you move south. Even warmer for Monday with highs in the upper 70s to the mid 80s. A more organized wave takes shape and moves toward the region Monday. Winds increase again turning from east to south to southwest and gusting 20-25 mph. Overnight Monday into Tuesday the wave and associated low pressure system drag a cold front through the region. Winds become north to northwest and once again gusty. Overall guidance is in fairly good agreement for a system that is still four days out. But there remains a few deviations in exact track of the low and where the heaviest precipitation will fall. For now will carry the NBM low PoPs of 15-30%. Precipitation will most likely begin as rain and may transition to a wintry mix to snow through the day Tuesday. A more active pattern for the latter half of the week may bring additional rain and snow chances Wednesday, Thursday and Friday.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 632 AM CDT Sat Mar 28 2026

VFR conditions will persist this TAF period. While mostly clear conditions are expected, a strengthening LLJ will lead to a few hours of LLWS at KHON and KFSD. As we tap into the jet more, south-southwest surface winds will sharply increase with gusts between 35-50 mph expected through this evening. Otherwise, winds will gradually taper down by late evening becoming light southeasterly overnight.

FIRE WEATHER

Issued at 324 AM CDT Sat Mar 28 2026

A favorable fire weather set up is expected today. Looking across the area, the forecast remains on track for south- southeast winds to sharply increase from mid-morning onwards with gusts between 35-50 mph expected. As mixing increases along with our surface temperatures, expect drier air to be funneled to the surface leading to relative humidity (RH) values in the 13-20 percent range area-wide. The stronger winds combined with the drier conditions and crispy fuels will lead to extreme fire danger for all areas. With this in mind, our Red Flag Warning looks to be in great shape which will be in effect from 10 am to 9 pm.

Looking ahead, Sunday continues to look like a drier day as warmer temperatures and low dew points lead to RH values in the 20-30 percent range. However, unlike the past few days; southeasterly winds will be on the lighter side with wind gusts up to 15 mph possible. As a result, while high fire danger will be possible; this threat would be mostly driven by the warmer and drier condition. By Monday, near-critical concerns will be in play as warmer temperatures and lower dew points lead to RH values in the 15-30 percent range. However, this will also be accompanied by increasing southwesterly winds with gusts between 20-30 mph which will result in very high fire danger for most areas. Until we get an appreciable return in precipitation, expect the intermittent fire weather risk to continue over the next several days.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning from 10 AM this morning to 9 PM CDT this evening for SDZ038>040-050-052>071. MN...Red Flag Warning from 10 AM this morning to 9 PM CDT this evening for MNZ071-072-080-081-089-090-097-098. IA...Red Flag Warning from 10 AM this morning to 9 PM CDT this evening for IAZ001>003-012>014-020>022-031-032. NE...Red Flag Warning from 10 AM this morning to 9 PM CDT this evening for NEZ013-014.