textproduct: Sioux Falls

KEY MESSAGES

- Near-Record Heat and Strong Winds: High temperatures may approach records alongside strong southwest winds of 35-45 mph Saturday. Highest winds along the Buffalo Ridge.

- Elevated Fire Danger and Blowing Dust: Saturday's hot, dry, and windy conditions will lead to elevated fire danger and blowing dust potential. Farmers and travelers should be aware of localized visibility reductions and increased fire risks.

- Sharp Temperature Drop: A cold front arriving late Sunday will push temperatures downwards into early next week, closer to seasonal normals.

- Late Week Rain and Turning Colder: Expect dry seasonable weather through mid-week before a stronger storm arrives Wednesday. A 60% probability of rain is already in the forecast by Thursday with a potential shift to much colder temperatures next weekend.

UPDATE

Issued at 921 PM CDT Fri Oct 9 2026

No major changes to the forecast for tonight into tomorrow. We're still hanging on to a lot of temperatures in the 70s at this hour of the mid evening especially near and west of a Huron to Sioux Falls to Storm Lake line. With that, forecast lows remain largely on track, so still expecting mostly to drop into the low to mid 60s by sunrise Saturday with a few spots in the upper 50s. Breezy conditions are expected to continue overnight as the surface pressure gradient tightens in between a 992 mb low pressure system over the southern Canadian Rockies and a 1026 mb surface high over the eastern Great Lakes region.

A very warm October day is still in store for tomorrow, with highs climbing into the mid 80s to low 90s. These potentially record breaking high temperatures combined with windy conditions and low relative humidity will lead to elevated fire danger, so use caution to prevent any sparks!

DISCUSSION

Issued at 1211 PM CDT Fri Oct 9 2026

THIS AFTERNOON: A rather pleasant day across the region as a weak stationary boundary is beginning to drift northward. Weak convergence along this boundary will keep a narrow corridor of mid and upper 50 dewpoints drifting northward. Elsewhere, as afternoon mixing and heating take over, we should see dew points mix downwards slightly.

TONIGHT: A beautiful evening can be expected through the region as high level cirrus pushes southeast. Winds will stay light and mixy through the night as the aforementioned front lifts northeast. While some valley areas may cool into the 50s, the prevailing overnight low temperatures will stay in the lower 60s in many areas, only a few degrees off typical seasonal high temperatures.

SATURDAY: Near to record high temperatures will arrive for Saturday, accompanied by gusty southwesterly winds and plenty of dry air. The strong surface pressure gradient already pushing 15 to 20 mph sustained winds by mid-morning will continue to tighten through the afternoon, but the deepening mixing will promote mix down of the 40+ knot LLJ that will persist into the mid- late afternoon hours. In these situations historically, deeper mixing models will verify better for dew points and winds, so have mixed both the HRRR/RAP into the forecast through the afternoon hours. This will promote occasional wind gusts of 35 to 45 mph (highest along the Buffalo Ridge), and dew points dropping into the lower 50s. While the NBM has started to catch- up to recent warm temperature bias, making the mean population a bit more reasonable, have again bumped up temperatures slightly towards the 90th percentile given synoptic potential. This will place high temperatures near daily records. One thing to watch for Saturday will be the potential for harvest related blowing dust, which could produce some very localized visibility and AQI reductions. The combination of heat, wind, and drying fuels will lead to elevated fire danger. Please see separate discussion for further details.

SUNDAY: Winds will weaken Saturday night as a frontal boundary begins to approach from the west. However continued mixing after a very warm afternoon will keep overnight low temperatures in the 60s. This front will bisect the CWA by the middle of the afternoon, promoting another day of highs in the 80s along and southeast of the boundary, but a quick drop towards the 60s towards central South Dakota. There will be a sharp increase in mid-lvl clouds along the boundary which may impact heating slightly. The front slowly settles southeast into Monday morning, pulling cooler air into the James River Valley. That said, there's high potential that we'll set new record warm minimum temperatures Saturday and potentially again Sunday.

MONDAY-WEDNESDAY: Broad ridging over the Central CONUS and the remnants of Hurricane Isaias will prevent any meaningful moisture to be able to advect into the Tri-State area behind the passage of the surface trough Monday morning. The end result may be an increase in mid-lvl clouds and occasional virga/sprinkles in the afternoon. Canadian high pressure slides southeast through the middle of the week, keeping a dry forecast going, and dropping high temperatures closer to their seasonal normals for a few days.

THURSDAY-FRIDAY: A bit of uncertainty develops in the extended portions of the forecast as medium range models develop a deep upper trough over the western CONUS. By Wednesday, there seems to be consensus in both ensemble and AI based guidance that the energy at the base of the trough begins to eject in to the Plains. The increasing northward moisture return combined with lift from the opening wave supports high PoPs from the NBM at this time. EC/GEFS probabilities for >0.10" of QPF over 24 hours is already over 60% through the region. While it's still a bit out there, the passage of this trough and eventual deepening of a larger longwave trough through central North America could signal at least a temporary shift towards colder than normal temperatures into next weekend.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1102 PM CDT Fri Oct 9 2026

The low level jet will continue to impact the TAF sites through the mid morning Saturday. VFR conditions to prevail through the period. Will have to watch for any impacts from blowing dust especially over southwest Minnesota where the strongest wind gusts are expected, as this could cause some localized visibility reductions at times. Not enough confidence in this potential at the TAF sites, so opted to leave out any mention in those.

Winds will generally be out of the south through the period, gusting to 30-35 kts for most areas near and east of the James River during the daytime Saturday. The strongest winds will be over the Buffalo Ridge where a few gusts could push 40 kts. Surface gusts will diminish Saturday evening, but it will remain breezy with sustained winds around 13-18 kts. LLWS concerns will also return to areas mainly near and east of I-29 by the end of the period.

FIRE WEATHER

Issued at 1211 PM CDT Fri Oct 9 2026

Concerns for fire weather grow on Saturday and continue Saturday night. Latest guidance continue to support falling afternoon RH into the lower 30% range, with near record high temperatures and seasonally strong winds near 40 mph. The primary aspect of the GFDI that is keeping levels in the "High" category in most areas is the relative percent greenness of fine fuels. Recent rainfall and warm temperatures have led to a slight increase in percent greenness and continues to hold back higher end fire danger. However, we're also now in the heart of harvest season with crops significantly dry in many areas. This is likely where the greater concern is for Saturday, as field activities may be a driving force behind any wildfire potential. The AgGFDI would suggest considerable concern through the Tri- State area, so extreme caution should be used when working outside Saturday.

CLIMATE

Issued at 1211 PM CDT Fri Oct 9 2026

Record High Temperatures:

October 9: KFSD: 89/1980 KSUX: 87/1980 KHON: 90/1980 KMHE: 91/1928 October 10: KFSD: 88/1928 KSUX: 92/1928 KHON: 92/1928 KMHE: 93/1928 October 11: KFSD: 90/2015 KSUX: 91/2015 KHON: 91/1910 KMHE: 95/1910

Record High Minimum Temperatures:

October 10: KFSD: 64/1928 KSUX: 66/1930 KHON: 60/1947 October 11: KFSD: 67/1997 KSUX: 66/1997 KHON: 68/1997

FSD WATCHES/WARNINGS/ADVISORIES

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