textproduct: Sioux Falls

KEY MESSAGES

- Critical fire weather expected today; Red Flag Warning east of US Highway 281 from 10 AM to 7 PM CDT. Use extreme caution to prevent fire start.

- Isolated showers and thunderstorms are possible today, mainly east of I-29. Severe storms are not expected.

- Winds today gust 35-45 mph, with a few stronger gusts possible between the James River Valley and I-29. Strong winds lead to periods of blowing dust in rural areas. Use caution if traveling as visibility may be impacted.

- Temperatures warm though the weekend, with high temperatures 10 to 20 degrees above normal.

- Regional rain chances increase late Saturday and especially Sunday. Uncertainty lingers, but signals remain for strong storms Saturday and continuing risks Sunday and Monday.

UPDATE

Issued at 343 AM CDT Thu May 14 2026

Mid/high clouds are increasing across central SD, moving east with the mid/upper level wave this morning. Winds and gusts are already on the increase as well with the tightening SPG ahead of the surface low ejecting into western SD/NE. Although seeing some returns on radar out west, have not seen any reports of precip reaching the ground, likely due to the very dry sub cloud layer.

No significant changes to the forecast from the previous shift as the trough continues to move east through the day. Refined pops slightly based on some of the latest CAM guidance, but still think any showers/storms remain isolated in nature.

Strong winds today will gust 35-45 mph. Guidance still shows isolated stronger gusts around 50 mph, mainly between the James River Valley and I-29, as well as across the higher elevations of the Buffalo Ridge and Coteau. Although not anticipating any wind headlines, will continue to monitor. Strong winds likely lead to blowing dust and possible visibility restrictions, especially in rural areas. Red Flag Warning in effect from 10 AM to 7 PM CDT east of US Hwy 281; more details in the Fire Weather Section below. Use extreme caution to prevent a spark and report fires to local authorities.

DISCUSSION

Issued at 155 PM CDT Wed May 13 2026

THIS AFTERNOON: An absolutely beautiful afternoon across the region as winds remain light and variable, temperatures have risen into the 70s and plenty of sunshine is around. Expect these conditions to persist into the evening.

TONIGHT: Shortwave ridging moves east of I-29 by daybreak Thursday, with modest low-lvl moisture convergence on the nose of a 50 knot LLJ trying to focus along I-29 by mid-morning. The overnight hours are expected to remain dry but with a mixy wind, temperatures may fail to fall below 50 degrees.

THURSDAY: Multiple hazards likely on Thursday. Early in the morning, guidance shows a narrow tongue of low-mid lvl moisture streaming up I-29. CAMS are a bit split in further development of this moisture into a few showers/sprinkles but feel potential is high enough to warrant slight chc PoPs into NW Iowa and SW MN for a brief period of time. Meanwhile a surface front will approach central SD by daybreak, gradually moving east through the day. A channel of 50+ knots of low-lvl flow ahead of this boundary will begin to mix downward quickly in the morning. Have trended wind gusts towards the 90th percentile of the NBM which aligned well with winds on Tuesday. Peak gusts may break the 45 mph mark at times into the afternoon. Surface based moisture will be extremely limited ahead of this boundary, but another wedge of elevated moisture may be enough to produce high based sprinkles to showers as this front passes east into the afternoon. Slight inhibition at 850 mb will likely prevent any surface based convection from forming. The combination of strong winds Thursday will also produce some patchy blowing dust and minor air quality issues in the afternoon. For fire weather concerns, please see separate discussion below.

THURSDAY NIGHT-FRIDAY NIGHT: The aforementioned boundary will be east of the CWA by daybreak Friday, with winds switching to the west northwest behind the boundary Thursday night. VERY dry air will advect southeast behind this boundary, setting the stage for RH values near 15% in the afternoon of Friday. Latest trends have pushed the strongest wind potential along or north of Highway 14 in the afternoon as high temperatures rise into the 80s. One thing to monitor for Friday evening will be the on/off potential in guidance of some weak low-lvl convergence across northern Nebraska and western Iowa in the evening. This area will be on the edge of some slightly deeper moisture and MUCAPE AOA 800-1000 J/KG. While its an intermittent signal in CAMs, can't discount a thunderstorm or two trying to form south of I-90 or towards Highway 20 if we somehow reach convective temps in the low 90s.

SATURDAY: A brief rise in mid-lvl heights and influence of drier Canadian airmass will prevent moisture and meaningful instability from racing northward Saturday. For most of us, expect a dry and rather nice Saturday as highs rise into the 80s.

SATURDAY NIGHT-MONDAY: Guidance is still quite uncertain, but trends continue to shove a trough into the Plains Saturday night. The speed at which low-lvl flow turns more meridional remains in question, however both the GFS/ECMWF lift an elevated warm front northward by Sunday morning. Convergence and upper dynamics would support growing shower and thunderstorm risks moving northward through the Tri-State area into Sunday morning. While the severe weather risks overnight may be low, elevated parcels might have upwards of 500-1000 J/KG supporting some hail growth through mid-morning Sunday.

Even more uncertainty builds through the day on Sunday, focused on the northward push of the warm sector into the Plains. GFS/EC/CMC ensemble guidance all remains split 50/50 with the warm sector or deeper instability either staying south of I-90, or on the flipside spreading well north and bringing even moderate to strong instability towards the Tri-State area by Sunday afternoon. AI based models and CIPS analog guidance support the potential that does exist for this event, further supporting early SPC day 4 outlooks. Continue to monitor Sunday's forecast if you have outdoor events planned, as this remains a very conditional severe weather forecast.

The upper trough deepens and pivots eastward into Monday, pushing a surface front into the CWA overnight. Several waves of convection could be possible into the morning hours of Monday, with stronger convection potential focused east of I-29. A great deal of uncertainty remains into Monday and it's certainly possible the greatest potential of redevelopment along the front could be pushed east of the CWA.

This entire system should bring meaningful rain to the CWA by time it exits the region. NBM 10/90 percentile QPF over the 72 hour period does range from a quarter inch to nearly 2", with a mean around 0.75" in most locations. Of course convection can influence these locations significantly, which is why the NBM probability of >0.50" is only around 50% in any given location.

TUESDAY-WEDNESDAY: Drier weather and cooler conditions are expected as we move into the middle of next week. High temperatures Tuesday could struggle to climb through the 60s.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1210 PM CDT Thu May 14 2026

VFR skies continue through the region as southwest winds continue to increase over the 40 mph mark. High based showers and isolated thunderstorms will head east through Minnesota, with trailing showers over NW Iowa and northern Nebraska this afternoon.

Further west, we're seeing slight reductions in visibility and even a low cloud deck of blowing dust west of I-29. This dust will spread east into the afternoon.

Overnight, skies will clear and winds will weaken substantially.

FIRE WEATHER

Issued at 343 AM CDT Thu May 14 2026

Red Flag Warning remains in effect today for areas east of US Highway 281 from 10 AM to 7 PM CDT, where strong winds and very low humidity will be coincident today. This combination will lead to critical fire conditions. West of the James River Valley and into the Missouri River Valley, strongest winds (this morning) continue to be offset from the lowest humidity values (this afternoon), so have kept that area out of the RFW. However, elevated to near critical conditions are expected due to the low humidity and dry fuels. Winds today will gust from 35-45 mph for most of the area, with isolated stronger gusts around 50 mph. These higher gusts are most likely between the James River Valley and I-29, as well as across the higher elevations of the Buffalo Ridge and Coteau. RH values improve through the evening, with winds tapering down from west to east more quickly this evening and tonight.

Winds have trended downward slightly in the latest guidance compared to 12 hours ago. Probability of gusts exceeding 35 mph have dropped to less than 10% from the 20-40% along US Highway 14 for Friday afternoon and evening. Given this, have left the Fire Weather Watch as is. However, near critical to critical conditions are still possible due to relative humidity values at or below 20% for the entire area.

Elevated to near critical conditions continue Saturday due to the very low humidity values. Again, relatively lighter winds may temper widespread critical concerns, but near critical conditions are once again possible.

Shower and thunderstorm chances return overnight Saturday into Sunday and continue through early next week. Rainfall and higher humidity should begin to reduce widespread fire concerns.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 7 PM CDT this evening for SDZ039-040- 054>056-060>062-065>071. Fire Weather Watch from Friday morning through Friday evening for SDZ038>040-052>056. MN...Red Flag Warning until 7 PM CDT this evening for MNZ071-072- 080-081-089-090-097-098. Fire Weather Watch from Friday morning through Friday evening for MNZ071-072-080-097. IA...Red Flag Warning until 7 PM CDT this evening for IAZ001>003- 012>014-020>022-031-032. NE...Red Flag Warning until 7 PM CDT this evening for NEZ013-014.