textproduct: Sioux Falls

KEY MESSAGES

- Lingering Fire Danger Risk: Near record warmth and wind gusts approaching 25 mph will create an elevated agricultural fire danger risk in NW Iowa this afternoon.

- Extreme Temperature Ranges Monday: A stalled cold front will create a sharp contract in temperatures Monday. 50s are possible near Huron, while the 80s will be likely near Sioux City/Storm Lake.

- Dry Mid-Week With Rain Returning Thursday: Near normal temperatures and dry conditions likely through Wednesday. Scattered rain by Thursday with a 60% probability of greater than 0.10" of rain by Friday.

- Turning Colder: Temperatures into next weekend fall below normal into the 50s.

DISCUSSION

Issued at 1242 PM CDT Sun Oct 11 2026

THIS AFTERNOON: Another very warm day across the Tri-State area as temperatures continue to rise into the 80s. Further west however, a frontal boundary has stalled from Gregory to near Huron and north of Watertown. Northwesterly drainage winds are doing what they like to do and keeping temperatures cooler with considerable stratus through central and northern South Dakota. This front will stay nearly stationary into late afternoon, perhaps sliding a bit further southeast into the MO River valley. Temperatures will likely fall short of records in most locations, however gusty winds greater than 25 mph in NW Iowa could promote elevated agricultural related fire risks to sunset.

TONIGHT: My confidence is rising that the cold front will continue slipping southeast through the overnight hours, though just how far southeast is still in question. Should the front reach into NW Iowa and NE Nebraska, then a significant amount of cooler air may drain southeast knocking temperatures further into the upper 40s to lower 50s. Anticipating stratus to reform late tonight, especially in areas from Gregory to Brookings and Marshall where cool air will continue to drain.

MONDAY: We're likely to start the day with quite a bit of stratus in the CWA, potentially as far SE as Sioux Falls. A mid-lvl shortwave tracking through the Dakotas mid-morning to mid-day will accomplish two tasks, lifting the cold front very slightly back northwest, but also pinning in cooler and moist air in the drainage flow on the backside of the front. The end result may be an extreme temperature gradient of the 80s in Sioux City and Storm Lake/Spencer, to the 50s in Huron. Latest NBM will not catch these mesoscale temperature gradients, so have adjusted and blended in higher resolution guidance. However the gradient may still be more defined than the current forecast suggests. While moisture is lacking aloft, a few sprinkles to light rain showers could develop through central and northeastern SODAK in the day. Have also manually pushed up stratus through mid-day west of I-29.

MONDAY NIGHT: Northwest winds continue through the overnight hours into Tuesday as quite a bit of cooler Canadian air filters southeast This will push overnight lows into the 40s in several areas with some questions on cloud cover potential lingering.

TUESDAY-WEDNESDAY: Latest forecast guidance continues to trend drier with precipitation chances during the middle of the week. The amplitude of mid-lvl ridging through the Central and Southern Plains may be strong enough to prevent any cut off energy in the Four Corners from moving eastward as quick as guidance hinted yesterday. The end result will be dry conditions Tuesday and Wednesday with highs near or even slightly above seasonal normals.

THURSDAY-SATURDAY: The cutoff energy in the Four Corners may eventually phase with a secondary northern stream trough crossing the Canadian Rockies by Thursday. Increasing warm advection and moisture return ahead of this trough combined with mid-lvl dPVA may result in the development of scattered rain by Thursday. Latest ensemble probabilities continue to suggest light rain amounts with 60-70% probabilities of >0.10", but only 30% probabilities of more than 0.50". High pressure will quickly swing southeast into the Plains for Friday and the upcoming weekend. Temperatures for at least a couple days may cool below seasonal normals, but only slightly.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1242 PM CDT Sun Oct 11 2026

VFR conditions continue early in the TAF period. A cold front drifting in from the northwest will allow stratus to develop and drop ceilings to MVFR level from Wagner through Mitchell and up to Brookings around 7z. Western areas of the CWA including KHON may drop further to IFR levels around 11z. Low stratus may continue across these regions through the end of the TAF period. Confidence in exact frontal timing is low but will change prevailing winds from southerly to northerly, anticipating variable winds along the boundary through the transition.

FSD WATCHES/WARNINGS/ADVISORIES

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