textproduct: Sioux Falls

KEY MESSAGES

- Breezy to gusty northwesterly winds will continue through this evening with gusts between 30-40 mph expected. Isolated pockets of up to 50 mph will be possible briefly. The breezier conditions will be main catalyst for today's locally enhanced fire weather concerns.

- Scattered showers are expected this morning mainly along and east of I-29. While an occasional rumble of thunder can't be ruled out, severe weather is not expected.

- Continued dry and breezy conditions will lead to additional elevated fire weather concerns by Saturday and again by Monday.

UPDATE

Issued at 234 AM CDT Fri Apr 17 2026

Taking a look across the area, we're continuing to see surface winds increase directly behind an approaching cold front roughly stretching from Platte to Mitchell to De Smet as of 2 am. As this near-surface feature progresses southeastwards through the morning, northwesterly surface winds between 30-40 mph are expected for most areas. However, a stronger push of cold air advection (CAA) and a tight SPG could lead to slightly stronger gusts up to 50 mph directly behind the front for a brief time (1-2 hours). While this could temporarily push some areas into wind advisory criteria, decided to forgo an advisory at this time since winds speeds quickly decreased back to the expected ranges the further they got away from the front according to downstream observations across the Black Hills.

Otherwise, we're still on track for scattered "popcorn" showers along and east of I-29 as bits of isentropic lift interact with a strengthening LLJ (35-45 kts). While we can't rule out an occasional rumble of thunder especially with 800-1200 J/kg of instability present, a small cap aloft will likely keep a lid on our severe weather chances this go-around. With this in mind, expect any developing activity to continue from daybreak (6am) through about midday (12pm) before things clear behind the front. From here, expect a cooler and breezier day with a non-diurnal temperature curve due to the frontal passage. As a result, temperatures will likely trend cooler throughout the day instead of warmer. Combine this with northwesterly winds in the 30-40 mph range, and its gonna likely feel chilly at times. Lastly, the breezier conditions will be the main driver of any locally enhanced fire weather concerns as relative humidity values will be well above critical thresholds (35%- 45%).

DISCUSSION

Issued at 157 PM CDT Thu Apr 16 2026

A strong LLJ will be in place tonight with some elevated instability, but a capping inversion will likely preclude any thunderstorm development. Strong southerly flow at the surface will keep temperatures very mild through the night, but a strong cold front will move into central SD later tonight will bring a quick drop in temperatures. This front will be near I-29 by sunrise and east of northwest IA and southwest MN by noon. There will likely be a small window in the morning near and east of I-29 that may allow for scattered showers and isolated thunderstorms to develop. With 1000 J/kg CAPE available a very isolated storm could produce hail to the size of quarters. For now the capping inversion will likely not allow for this stronger development.

Overall, temperatures should be falling through the day for most locations, likely stabilizing with a small rise near and west of I- 29. With wind gusts of 30 to 40 mph, elevated fire danger is expected. Some spotty very light showers will be possible but impacts will be minor.

A period of quiet weather will settle into the area Saturday through about Wednesday next week as a stronger northern stream jet keeps drier air in place. What will initially start as a cool day in the 50s on Saturday with breezy conditions will transition to a period of highs generally in the 70s Monday through Friday next week. Thursday into Friday upper level troughing moves into the Rockies with varying degrees of agreement on placement and strength of the potential system. Regardless this should bring the chance for showers and thunderstorms back into the forecast during this time as deeper southerly flow develops ahead of this system.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1233 AM CDT Fri Apr 17 2026

VFR conditions begin the TAF period. A cold front continues to push through the area. This front will turn winds to out of the northwest in its wake. Winds will also strengthen up 30-40 knots. Low level wind shear (LLWS) begins the TAF period as the low level jet (LLJ) remains strong aloft. The LLJ will weaken as the cold front pushes through. MVFR ceilings will develop late tonight and persist through the morning hours. Showers look to develop along with the lower ceilings mainly along and east of I-29 by around daybreak tomorrow morning. There could be a few rumbles of thunder with these showers but confidence is not high enough to include in a TAF at this time. Any chance for rain will come to an end during the afternoon hours, leaving the breezy northwest winds to finish out the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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