textproduct: Sioux Falls

KEY MESSAGES

- Locally elevated fire danger concerns continue through the early evening hours. Low humidity and breezy winds will persist through Tuesday, continuing elevated fire danger each day. Tuesday has the highest chances for fire danger.

- Frost is expected to develop tonight, mainly along and northeast of a Huron, South Dakota to Sioux Falls, South Dakota, to Orange City, Iowa line. A Frost Advisory has been issued for this area and is in effect from 3 am to 9 am Monday.

- Temperatures begin to warm through the upcoming work week, and by the end of the work week and weekend may further warm to the 80s

- The upper level pattern remains uncertain for the end of the week and weekend. Chances for rain will depend on how the pattern evolves.

UPDATE

Issued at 858 PM CDT Sun May 10 2026

A quiet but chilly night is ahead for the area. Winds have come down as the sun has set and skies are mostly clear with the exception of some high clouds streaming into areas west of I-29. For tonight, did blend in some of the NBM 10th percentile to areas which will see the lightest winds through the night (mainly east of I-29) because last night, under fairly similar conditions, parts of the area dropped as low as the 10th percentile with how dry the air has been. Winds should be slightly higher than last night overall, so did not go full NBM10th, but temperatures are trending cold enough to warrant an expansion of the Frost Advisory to include Cherokee and Buena Vista Counties in northwest Iowa. Otherwise it goes unchanged and runs from 3 am to 9 am Monday.

Only other thing to note about tonight is that southeasterly winds will begin to increase towards daybreak over south- central South Dakota and that's where we will generally see the warmest lows tonight, in the lower 40s. The coldest air tonight will reside over southwest Minnesota and adjacent areas of northwest Iowa and eastern South Dakota where temperatures drop to around 33-34 degrees. Could see a few spots briefly drop to 32, but the expected duration and patchy nature of this precludes the need for freeze headlines at this time.

DISCUSSION

Issued at 153 PM CDT Sun May 10 2026

Partly clear skies persist this afternoon, allowing high temperatures to warm to the 60s and 70s. Low humidity and marginally breezy winds will keep elevated fire danger conditions going through the rest of the afternoon hours. Temperatures tonight remain on track to be on the cold side once again, falling to the low to mid 30s to low 40s. Thus, have issued another Frost Advisory for locations along and northeast of a Huron, South Dakota to Sioux Falls, South Dakota, to Orange City, Iowa line. The Frost Advisory is in effect from 3 am to 9 am Monday.

An upper level trough will begin to push into the Northern Plains from Canada on Monday. Warm air advection (WAA) will strengthen ahead of this wave throughout the day. The WAA will push high temperatures above average across the area with highs into the 70s and 80s expected. Dew points will remain low though, resulting in humidity values down to near critical to critical levels. The low humidity along with breezy southerly winds with gusts up to 20-35 mph, strongest along and west of I-29, will result in another day of elevated fire danger across the area. While conditions will be near critical to critical, greening fuels continue to lessen the overall fire danger. A cold front tied to this upper wave will push through the area during the overnight hours. The low level jet (LLJ) will strengthen ahead of the front, keeping breezy winds going through the night. A few showers to perhaps a thunderstorm or two could develop along the front as well. Severe weather is not expected as instability will be quite weak, but perhaps some gusty winds could be possible. Low temperatures will be much warmer, only falling to the 50s overnight.

Tuesday and Wednesday look to remain warm across the area as upper level ridging builds over the central CONUS. Tuesday will be the cooler of the two days with high temperatures warming to the 70s. However, winds will be quite breezy out of the northwest within the post frontal cold advective airmass with gusts up to 30-40 mph. Humidity values will be low across the vast majority of the area and will hit critical thresholds. Despite recent greening of fuels, Tuesday continues to have the highest fire danger potential with a high GFDI. Wednesday will be a little bit warmer with highs in the 70s to low 80s. The low humidity will persist but winds will be much lighter, keeping fire danger at bay.

There remains uncertainty regarding how the upper level pattern will evolve for the rest of the work week and weekend. Medium range guidance, including the machine learning guidance, continue to vary on how the shortwave trough over the west coast progresses. The main two camps that the models are split over is whether the upper low slows down and potentially cuts off over the west coast or continues eastwards as a more progressive shortwave. If the wave stays progressive, then rain chances could increase beyond what they currently are (20-30%). If the waves cuts off, then chances for rain could diminish. Tough to say which solution is most likely at this time but something that will be monitored over the coming days. Aside from rain chances, Thursday and Friday continue to look very warm with high temperatures warming into the 80s across the area.

The models are in slightly better agreement for next weekend with zonal flow taking over. This could still change depending on how the previously mentioned upper level low evolves but for now, it does seem most likely that rain chances will increase across the Northern Plains. This is supported by the ensembles as they show increasing chances for rain, up to a 30-50% chance for exceeding a tenth of an inch of rain. Sunday has the highest probabilities at this time. High temperatures look to remain warm but a little bit cooler than Thursday and Friday with highs only warming to the 70s and 80s.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 636 PM CDT Sun May 10 2026

VFR conditions expected through the period. Winds become lighter through the evening and start to veer to the east-southeast with time. Winds will become light enough near and east of I-29 late tonight where a variable wind direction can be expected. West of I- 29, southeasterly winds will start increasing heading towards daybreak as a low pressure systems deepens off to our west. Southeasterly gusts of 20-30 kts will gradually spread east across the area through the daytime hours Monday.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Frost Advisory from 3 AM to 9 AM CDT Monday for SDZ038>040- 053>056-061-062-067. MN...Frost Advisory from 3 AM to 9 AM CDT Monday for MNZ071-072-080- 081-089-090-097-098. IA...Frost Advisory from 3 AM to 9 AM CDT Monday for IAZ001>003- 012>014-021-022. NE...None.