textproduct: Sioux Falls

KEY MESSAGES

- Widespread frost and freeze continue this morning with temperatures in the upper 20s to upper 30s. A Frost Advisory remains continues for central and south central South Dakota, with a Freeze Warning elsewhere. Both remain in effect until 9 AM.

- Breezy southerly winds Saturday with gusts of 25-35 mph, and as high as 45 mph over the Buffalo Ridge. These winds coupled with drier air could lead to marginally elevated fire weather concerns in the afternoon.

- Dry conditions and warmer temperatures continue into mid next week with highs back above normal.

UPDATE

Issued at 241 AM CDT Sat Oct 17 2026

Temperatures early this morning remain generally on track, in the upper 20s to upper 30s - warmest across central and south central SD. Temperatures are already beginning to warm for locations where southerly winds have increased. If winds briefly lighten again through the morning, temperatures may fall a couple of degrees. Regardless, no changes to headlines at this time.

Breezy southerly winds expected today thanks to the compressed SPG and mixing. Gusts through the day on track for 25-35 mph. Guidance still shows wind gusts around 40-45 mph along the higher elevation of the Buffalo Ridge later this morning, but think that duration and coverage precludes any brief headlines. Dry weather and plenty of sunshine expected which again could lead to very locally elevated fire concerns for drier areas later today. Dry and breezy again Sunday.

Minor changes to high temperatures for the next couple of days, with southerly flow. Further adjustments may be needed for Sunday, with guidance pulling in even warmer 925 mb temperatures than what is expected today so will keep an eye on trends. Main impact would be to any fire weather concerns for areas that have missed out on the higher rainfall totals recently (like portions of south central SD). Highs in the mid 50s to near 70 today, warmest west of the James thanks to more prolonged southerly flow and WAA. Highs in the 60s to possibly around 70 again Sunday.

DISCUSSION

Issued at 225 PM CDT Fri Oct 16 2026

The last of the clouds will continue to diminish over northwest Iowa and southwest Minnesota over the hour or two, leading to plenty of sunshine across the area! This sunshine should allow most areas to reach the lower 50s for highs, and decreasingly breezy winds will make for a cool, but fairly pleasant fall evening.

Winds will be decreasing due to a surface high pressure system moving across the region. These lighter winds coupled with clear skies will mean temperatures will drop rather quickly after the sun sets. By the late night hours though, the high pressure system will quickly slide eastward and allow for the return of southeasterly winds to the area. This should halt the faster cooling and allow for areas especially over south- central South Dakota to remain above freezing, though still remain cold enough for frost. Thus, a frost advisory will be in effect for these areas tonight. Farther east, do think the slight uptick in southeasterly winds will not make it in time to prevent these areas from dropping to 32 degrees or lower. Generally speaking, the farther east you go across the area tonight, the longer it will take for the slightly elevated winds to arrive and thus the colder you'll get. Though there is still some lingering uncertainty on the westward extent of the freezing temperatures, current thoughts are that clear skies, light winds, and dry air during the early overnight will lead to these areas dropping to freezing by daybreak. All that said, frost is expected across the entire area overnight.

Southeasterly winds will continue to increase heading into the day tomorrow as the high pressure system slides east and a low pressure system develops off the northern Rockies. Winds won't be as strong as what we've seen this morning and this past night, but expect most areas to see gusts in the 25-35 mph range during the day on Saturday. A few gusts to 45 mph will be possible over the higher elevations of the Buffalo Ridge, but this is not expected to be widespread enough to warrant wind headlines at this time, though trends will be monitor. Another thing to monitor will be locally elevated fire weather conditions Saturday afternoon. Warmer temperatures are expected especially over south-central South Dakota, with highs in the 60s and possibly near 70. This combined with dew points well down into the 30s will lead to relative humidity values just below 30% in south-central South Dakota. Elsewhere, relative humidity values will be around 30-50% Saturday afternoon. This could all result in locally elevated fire weather concerns mainly in cured grasses and cropland.

Ridging aloft builds in through the weekend, allowing for a seasonal weather pattern to return that will also continue into early next week. Sunday looks to be the better weekend day for outdoor activities with diminishing winds, sunny skies, and highs in the middle 60s. A weak upper wave will ride into the central Plains into the upper Midwest Tuesday into Tuesday night, though probabilities of measurable rainfall with this system is low (<20%) and focused near and east of I-29 according to latest LREF probabilities. After this weak system passes through, ridging builds back in aloft, and this combined with continued southerly flow will lead to even warmer temperatures by the middle of the week. Highs by Wednesday and Thursday will potentially climb into the 70s across parts of the area. The NBM is a bit more aggressive than other ensembles, though is only warmer by a few degrees comparatively speaking. Either way, forecast temperatures will likely get refined as mid week approaches as more smaller scale details come into better focus. Looking out to the end of next week, the weather pattern may turn a bit more active as guidance indicates a western trough potentially ejecting into the area, though the timing of this is where models really diverge. The broad 20-40% PoPs as highlighted by the NBM next Friday is largely in line with 16.12Z LREF, though details with this system will once again become more clear as we approach the end of next week.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 629 AM CDT Sat Oct 17 2026

VFR conditions expected through the period with clear skies.

Southerly winds increase this morning, with gusts 20 to 30 knots into the evening hours. A few stronger gusts around 35 knots or higher are expected in the higher elevations near the Buffalo Ridge. Winds taper down late this evening, but expect gusts around 20 knots to continue into the overnight and early Sunday. There could be some marginal directional LLWS overnight, with speed shear over 30 knots possible if gusts drop off completely. Greatest chances for LLWS would be from KYKN to KMML and southeast with a LLJ around 45 kts. Omitted at this time given more marginal conditions with gusts.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Freeze Warning until 9 AM CDT this morning for SDZ039-040- 054>056-060>062-065>071. Frost Advisory until 9 AM CDT this morning for SDZ038-050-052- 053-057>059-063-064. MN...Freeze Warning until 9 AM CDT this morning for MNZ071-072-080- 081-089-090-097-098. IA...Freeze Warning until 9 AM CDT this morning for IAZ001>003- 012>014-020>022-031-032. NE...Freeze Warning until 9 AM CDT this morning for NEZ013-014.