textproduct: Sioux Falls

KEY MESSAGES

- Dry and warm conditions continue to start the new work week, leading to persistent fire weather concerns. Those concerns grow towards elevated levels this afternoon and continue into Tuesday.

- A strong cold front arriving early Tuesday morning may bring a brief window of 40 to 50 mph gusts as it moves through.

- Precipitation chances begin to rise by the middle of the week with a growing potential for accumulating snow from Wednesday into Thursday.

- Additional chances for meaningful precipitation are expected from Friday through Saturday with 20-40% probabilities of 0.50" or greater of QPF with the highest confidence east of I-29.

UPDATE

Issued at 320 AM CDT Mon Mar 30 2026

Not too many changes in the overall forecast. The main focus continues to be on the elevated fire weather concerns through Tuesday. For today, unseasonable warmth will continue with highs mainly in the 70s to mid 80s with the warmest conditions along and south of I-90. With another round of dry conditions expected this afternoon, decided to blend in some of the 00z HRRR into our dew points to decrease RHs a bit further with values in the 15-30 percent range expected. However, surface winds will be much lower compared to recent days with gusts peaking in the 15-25 mph range. With all this in mind, the more prominent concerns will be tied to northwestern IA and far southeastern SD where the better collocation will occur this afternoon. Lastly, north-northwesterly surface winds will increase overnight into Tuesday as a cold frontal progresses southeastwards leading to gusts in the 30-40 mph range at times.

By Tuesday, cloud cover will continue to increase with the previously mentioned cold front. Could see a few "popcorn" showers develop ahead of the front to start the day as some lift with a weak wave interacts with the LLJ. With about 400-600 J/kg of instability available with this developing activity, pockets of moderate rain along with a few rumbles of thunder can't be ruled out. Otherwise, the breezier conditions will slightly decrease throughout the day with gusts between 25-35 mph persisting through the evening. This combined with drier conditions behind the previously mentioned front will drive additional elevated fire weather concerns for most areas. With this in mind, make sure to limit burning as much as possible especially by Tuesday.

DISCUSSION

Issued at 1215 PM CDT Sun Mar 29 2026

THIS AFTERNOON: A weak front continues to settle southward early this afternoon spreading an area of light and variable winds across the CWA. Some stronger 15 to 20 mph winds will linger over NW Iowa into late afternoon, and with RH values near 30% fire danger will remain elevated. Elsewhere, temperatures will rise into the middle to upper 70s.

TONIGHT: Mid-lvl vorticity increases overnight, likely leading to an expansion of upr cloud cover by daybreak. This cloud cover may prevent a sharp drop in overnight low temperatures despite light winds.

MONDAY: Low-lvl troughing increases early on Monday, as warmer temperatures begin to surge into the I-90 corridor. Greatest concerns through the day remain focused on fire weather. While a slightly bump in Tds can be expected into Monday, the return of a southwesterly to westerly wind by mid-day may usher in lower dew points and drop RH towards the 20 to 30% range. Winds remain very questionable through the day, with some hints that a frontal boundary will approach the James River Valley areas by early afternoon. The greatest fire weather concerns would develop in the afternoon across NW Iowa into southern Minnesota ahead of this boundary. This area would have the best alignment with the 925:850 SW winds ahead of the trough, and greatest potential to mix the 20 to 30 mph wind down to the surface. While RH is higher in these areas, expected elevated to near critical fire weather conditions to develop as highs rise into the lower 80s. Confidence is not high enough for headlines ATTM, but conditions will need to be monitored closely given recent fire behavior.

Soundings show some elevated moisture streaming northward Monday afternoon and evening, but soundings show surface based activity would be capped off. That said, an elevated shower/thunderstorm could not be ruled out along or south of Highway 20 after 3pm.

TUESDAY: A deeper upper trough crossing the Canadian border will push a cold front southwards through the Dakotas Monday night into Tuesday. This front, arriving in the northwestern CWA after midnight, will surge southeast by daybreak bringing strong low-lvl cold advection with it. In addition to a low PoP for potential elevated showers behind the front, have boosted wind gusts significantly over NBM guidance. Latest CAMs suggest potential for 40 to 50 mph gusts immediately behind the boundary, with winds settling down into the 25 to 35 mph range through most of the daytime hours. Tuesday will be another day where the combination of falling afternoon RH and persistent 20 to 30 mph afternoon gusts may lead to widespread elevated fire weather conditions.

WEDNESDAY-THURSDAY: We'll preface this section by saying that it's not an April fools joke. We're beginning to see a shift in model guidance as we approach the middle of the week. Latest runs of the NAM/CMC/EC both bring a stronger upper trough out of the Four Corners region and into the Central Plains by Wednesday. The 12Z GFS has also shifted towards a further north track of this wave, but not nearly as much as other guidance. Ensembles are also becoming more bullish on QPF chances late Wednesday into Thursday, shifting probabilities of >0.10" of QPF 20 to 40% higher than on Saturday. What this means is that depending on low-lvl temperatures, the increasing dPVA combined with persistent low-lvl warm advection ahead of this wave could lead to drastically increased risks for snow/rain mix Wednesday afternoon into Thursday and even accumulating snow. Latest ensemble and AI ensemble guidance from the EC suggests a >60% probability of more than 1" of snow along and north of I-90 with >3" probabilities in this area near 40%. The northward shifts in the GFS and it's ensembles would also support increasing rain/snow chances but it still remains slightly further south than other global ensembles. Given the shifts in recent ensemble and deterministic guidance, the latest NBM runs may generally be biased and optimistically warm both Wednesday and Thursday, with a noted 10+ degree spread in high temperatures Wednesday and nearly 15 degree spread on Thursday. Should colder and further north solutions verify, highs may instead remain in the 30s. Just another reminder that we can go from 80 degrees to snow anytime in Spring in the Tri-State area.

FRIDAY-SATURDAY: This initial wave moves east of the area late Thursday, but as we've been talking the past days about, a secondary and much deeper trough moves into the Rockies by Friday. This second system still will provide the best chance for widespread meaningful precipitation through most of the Central and Northern United States, but exact locations remain a bit uncertain. Ensembles are however pointing to IVT approaching the 90th percentile of climatology for early April through the Plains ahead of an advancing cold front. It's the placement of this front, likely driven by the depth and orientation of the Rockies trough, that will determine where the heaviest precipitation will occur. Ensembles continue to show high probabilities of measurable rain >0.25" through the Plains and Upper Midwest, but are now starting to narrow down the corridor of higher totals >1.0 along but especially east of I-29. PLENTY of time for things to shift over the upcoming days, but this would at least be a system to monitor for meaningful rainfall potential.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 635 AM CDT Mon Mar 30 2026

Mainly VFR conditions will persist this TAF period. Besides variable winds for most of the day today, we could also see some scattered showers develop this afternoon and tonight. However, a dry-sub cloud layer according to soundings will likely shift things over to virga instead in both cases. Otherwise, surface winds will become more north-northwesterly tonight and increase on the heels of an approaching cold front leading to gusts in the 30-45 mph range briefly.

FSD WATCHES/WARNINGS/ADVISORIES

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