textproduct: Sioux Falls

KEY MESSAGES

- Widespread frost continues to be expected tonight into early Saturday morning as temperatures fall into the lower to mid 30s. A Frost Advisory remains in place for central and south- central South Dakota, with a Freeze Warning elsewhere. Both headlines remain in effect from midnight to 9 AM.

- Breezy conditions are expected tomorrow with gusts of 25-35 mph expected, locally higher over the Buffalo Ridge. These breezy winds coupled with drier air could lead to marginally elevated fire weather concerns in the afternoon.

- Mainly dry conditions and warmer temperatures return this weekend into early next week with highs back above normal.

UPDATE

Issued at 910 PM CDT Fri Oct 16 2026

A surface ridge continues to push through the area this evening. Its trajectory remains on track as a few locations west of the James River and across south central South Dakota are showing light southerly winds. This is also resulting in well behaved temperatures that continue to fall in line with expectations. Thus, still expecting temperatures to fall to the low to mid 30s, to even upper 20s in a few locations. The coldest temperatures continue to look to occur over parts of northwest Iowa where winds will go southerly the latest. As such, have kept all headlines in place. Still looking at temperatures to warm above freezing by the time the headlines expire at 9 AM.

Winds remain on track to strengthen through the morning hours tomorrow, as low level pressure gradients continue to tighten. Southwest gusts up to 25 to 35 mph remain expected for the afternoon timeframe. Isolated higher gusts up to about 45 mph remain on the table as well along the Buffalo Ridge. Looks like any chance for these stronger wind gusts will come during the morning hours, right as mixing begins to deepen. These isolated stronger gusts will be short lived though as 925mb winds will be weakening a bit for the afternoon hours. Temperatures remain on track to warm to 50s and 60s, warmest along and west of I-29. These temperatures along with dew points remaining in the 30s will result in humidity values down to about 30-50%, lowest across south central South Dakota. The breezy winds, warm temperatures, and lower humidity will result in marginally elevated fire danger. While the highest potential fire danger will come across south central South Dakota, this area looks to be slightly offset from the strongest wind gusts. Will monitor the potential for fire danger in this area but think that locally higher fire danger is not as likely due to continued warm advection aloft, preventing deeper mixing from being achieved. Any fire danger will come to an end by sunset as temperatures cool and humidity increases.

Sunday continues to look to be a pleasant day with highs remaining in the 60s but winds will be weaker, with gusts only reaching up to about 25 mph.

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 /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1029 PM CDT Fri Oct 16 2026

VFR conditions are expected for the TAF period. Starting to see winds turn southerly along and west of the James River late this evening. Locations east of the river are observing light and variable winds. Winds will continue to turn out of the south through the rest of the night and begin to strengthen.

Winds will veer to out of the southwest by Saturday morning and continue to strengthen. Gusts up to 20-35 knots are expected for tomorrow afternoon. The strongest gusts will occur along the Buffalo Ridge in southwest Minnesota and across south central South Dakota. Winds will slowly wane through the rest of the period. At the same time, some low level wind shear is expected to end the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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