textproduct: Sioux Falls

KEY MESSAGES

- Strong winds are expected late Thursday afternoon into Thursday night with gusts 55 to 75 mph expected, the highest gusts most likely north of I-90. A High Wind Warning is now in effect for the entire area late Thursday afternoon into Thursday night.

- A Red Flag Warning is in effect for Thursday afternoon and early evening. Windy and dry with generally fully cured fuels and dry conditions.

- The potential for major travel impacts due to snow and wind will arrive Saturday and continue into Sunday. Stay tuned for updates and be prepared for possible changes to plans on those days, especially Saturday night into Sunday.

UPDATE

Issued at 957 PM CDT Wed Mar 11 2026

Model soundings continue to indicate strong west southwest winds on Thursday which will lead to critical to near critical fire danger for many locations. Some indications that the stronger winds could start to mix down by mid to late morning with a strong core of winds not too far off the surface. The locations most at risk will be near and south of a Huron to Spencer IA line. Afternoon RH levels drop to 25 to 35 percent with expected wind gusts approaching 40 mph at times, likely averaging about 25-35 mph. The only question mark may be some extensive cloud cover which could limit heating a bit, but strong mixing as low pressure deepens to the north should allow for deeper mixing.

As this low pressure deepens and drops southeast into MN, strong CAA will move through the area with wind gusts of 50 to 75 mph likely. Confidence continues to grow that gusts will not only reach 60 mph, but could approach or exceed 75 mph given very high winds near the top of the mixed layer in the RAP and HRRR. Have expanded the high wind warning across the entire area for Thursday night.

Attention then turns to the weekend, particularly Saturday night into Sunday. Most of the major models are suggesting strong winds and a band of heavy snow within the four state region with the EC Ens, Canadian Ens and GEFS indicating a 40-70% chance for a half an inch of liquid with a 10-20% chance for an inch or more of liquid content. That would likely equate to a band of 5-10 inches of snow. Some potential that the southern side of the band could be fairly tight, so any movement north or south could equate to some large local differences. The main message here is that if traveling, there is a good chance hazardous to potentially dangerous conditions are expected. Currently looks like the heaviest snow would be Saturday night into Sunday morning with very strong winds, possibly at or above 50 mph, on Sunday.

DISCUSSION

Issued at 310 PM CDT Wed Mar 11 2026

CURRENTS & TONIGHT: Another cool day continues! Taking a look across the area, mostly clear conditions persist this afternoon as temperatures approach the mid 30s to low 40s across the area. While this has succeeded in melting most of the snow, still have a light snow pack across portions of far southeastern SD and northwestern IA. With this in mind, have slightly decreased temperatures for the day with most areas topping out in the upper 30s to upper 40s with the mildest conditions across southcentral SD. Shifting gears to precipitation, we're starting to see a few sprinkles to light showers develop mostly along the Highway-14 corridor mainly in response to the arrival of a shortwave. However, much of this won't reach the ground due to a dry sub-cloud layer according to soundings. Lastly, another cool night is ahead with lows mainly in the low to mid 20s.

THURSDAY: Looking into Thursday, things will get pretty interesting aloft as a decently strong clipper wave crosses into the Northern Plains and Great Lakes regions bringing strong winds, light rain, and lower humidity values at times. Starting with the precipitation, a strong surface warm front will progress through the area on the nose of jet streak. This combined with a little bit of isentropic lift should lead to scattered showers developing across areas mainly north of I-90 between the afternoon and evening. While accumulations of 0.10" of an inch or less are expected, can't completely rule out a few hundredths across northwestern IA as well. Next, a well-mixed environment along with increasing mid-level warm air advection (WAA) will lead to temperatures in the 50s to mid 60s for the day with the warmest conditions across the Missouri River Valley. This combined with lower RH values will likely lead to some elevated fire weather concerns on by Thursday afternoon (more details in the fire weather section).

Finally, we'll shift over to the main concern which are the stronger winds. A tightening SPG along with an approaching cold front will lead to increasing southwesterly to westerly winds between Thursday afternoon and Friday morning. Given the mixy environment and strong LLJ (85-95 mph at 700 mb), wind gusts between 45-55 mph with pockets of 60+ mph are expected across most of the area. With this in mind, decided to upgrade part of our High Wind Watch to a High Wind Warning mainly north of a Tyndall to Canton to Spirit Lake, IA line. Anything south of the line was kept in a High Wind Watch. The current thinking was to upgrade the parts of the watch that we have the highest confidence of higher wind speeds. While we can't rule out additional upgrades to the watch, decided this would be a good starting point to emphasis the stronger winds.

FRIDAY ONWARDS: Heading into the extended period, an active pattern will continue aloft through at least Saturday. Persistent northwest flow will help usher in multiple system into the weekend potentially leading to accumulating snowfall on both Friday and Saturday. While some of the 11.12z guidance has started to come into better agreement with features, there is still some uncertainty as far as amounts. Nonetheless, with the potential for moderate to heavy and/or mixed precipitation make sure to monitor your local forecast heading into St Patrick Day weekend and be prepared to alter any travel plans. Otherwise, we'll get another taste of winter temperature-wise over the weekend with highs decreasing into the 20s to low 30s on Sunday and Monday.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 639 PM CDT Wed Mar 11 2026

Once the convective snow showers dissipate in northwest IA and northeast NE by about 1z, VFR conditions are expected through the remainder of the period. Concerns turn towards winds with gusty southerly winds Thursday morning turning to the west southwest with gusts of 30 to 40 mph possible. By late afternoon in central SD and in the evening over the remainder of the area winds will turn northwesterly with gusts of 45 to 65 mph possible. The strongest winds winds will likely be near and north of I-90 in the evening and early overnight hours.

FIRE WEATHER

Issued at 1122 PM CDT Wed Mar 11 2026

Southerly flow will quickly increase Thursday mid-morning and turn a bit more west southwest through the afternoon. Wind gusts of 25 to 40 mph are expected through the afternoon. Along with the strong winds will be dry conditions with the relative humidity falling to 25 to 35 percent generally near and south of a Huron to Spencer IA line. A Red Flag Warning is in effect near and south of this line.

Near and north of this line the relative humidity will remain higher along with what looks to be a bit more extensive cloud cover. There will also be the potential for a few rain showers in this area.

While the relative humidity will improve Thursday evening, a very strong cold front will bring northwest winds with gusts of 55 to 75 mph likely. Burning is highly discouraged Thursday.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning from noon to 9 PM CDT Thursday for SDZ038-050- 052>055-057>071. High Wind Warning from 9 PM Thursday to 7 AM CDT Friday for SDZ066>071. High Wind Warning from 7 PM Thursday to 7 AM CDT Friday for SDZ038>040-050-052>065. MN...High Wind Warning from 7 PM Thursday to 7 AM CDT Friday for MNZ071-072-080-081-089-090-097-098. IA...Red Flag Warning from noon to 9 PM CDT Thursday for IAZ001>003- 012>014-020>022-031-032. High Wind Warning from 9 PM Thursday to 7 AM CDT Friday for IAZ001>003-012>014-020>022-031-032. NE...Red Flag Warning from noon to 9 PM CDT Thursday for NEZ013-014. High Wind Warning from 9 PM Thursday to 7 AM CDT Friday for NEZ013-014.