Temperatures averaged 4 to 5 degrees above normal during September, with precipitation just 25 to 50 percent of normal.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FSD wrote it up.
Temperatures averaged 4 to 5 degrees above normal during September, with precipitation just 25 to 50 percent of normal.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at Aug 31, 9:44 PM CST, 2 hours 16 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 1044 PM CDT Thu Aug 31 2023 .SHORT TERM...(This Evening through Friday) Issued at 212 PM CDT Thu Aug 31 2023 1. Smoke continues to improve, and will generally clear the area by Friday morning as gusty southwest winds will remain in place through Friday. 2. Near record temperatures are expected to return for the holiday weekend. Confidence is lower on the impact of dew points and resultant heat index readings, reducing the potential for excessive heat warnings. 3. Heat will produce impacts this weekend, and all those spending time outdoors over the holiday will need to take precautions to avoid heat related illness. 4. Thunderstorm risks increase by Tuesday and Wednesday, but at this time, the risks for severe storms is possible but still remains low. ------------------------------------------------------------------------------------------ THIS AFTERNOON: Scattered high based showers continue over far eastern South Dakota and western Minnesota. As lift moves north and east of the area, this cloud cover should dissipate as the evening arrives. Winds continue to increase this afternoon as a more southerly direction prevails. Gusts to 30 mph will continue this evening. TONIGHT: Strong warm advection moves through the area tonight, setting the stage for the beginning of a near record stretch of temperatures through Monday. A thin layer of mid-lvl moisture does remain near the Highway 14 corridor, so it's not impossible to see some mid-clouds develop by daybreak. Otherwise temperatures barely fall into the upper 60s and lower 70s (well above normal) due to the mixy boundary layer conditions. FRIDAY: Temperatures begin to surge into the 90s on Friday. Afternoon dew points today are mostly in the upper 50s to lower 60s, indicative of the much drier airmass in place (as opposed to a couple weeks ago). Have followed the ECMWF for dew points which suggest low to middle 60s in the afternoon as some moisture pools along a stalled warm front just north of the CWA. The resultant apparent temperatures should remain out of advisory levels in most areas, but a few spots near the Missouri River could float with 100 degree levels. .LONG TERM...(Friday Night through Thursday) Issued at 212 PM CDT Thu Aug 31 2023 SATURDAY-MONDAY: Near to record breaking temperatures are expected throughout the holiday weekend as low-lvl temperatures residing outside the standard 30 year climatology move into the region. Unlike the past events this Summer, there seems to be a much higher amount of dry air within the upper ridge. Additionally, we're past the prime of peak evapotranspiration, and under another semi-dry spell in the region. So cautiously feel that dew points may mix a bit lower each afternoon likely into the upper 50s to lower 60s. Ensemble high temperature ranges have really tightened up over the past days, with 25/75th percentile spreads of just a few degrees all three days. Temperatures that will be in the area this weekend may be some of the warmest highs we've experienced in September. Sioux Falls hasn't reached 100 degrees in September since 1976, Sioux City since 2000, and Huron since 2001. The end result will be heat index values between 97 and 105 degrees on average, and potential for afternoon RH values dropping below 25 percent along and southwest of the James River valley. At this point, an extended heat advisory may be possible through the holiday weekend. TUESDAY-THURSDAY: The mid-lvl ridge will flatten slightly as troughing moves into the western half of the CONUS. Most of the convection will be focused across the western Dakotas into Tuesday morning, with the front edging southeast by Tuesday evening. Scattered convection may form along this boundary Tuesday evening in an area of increased MLCAPE, but with rather weak mid-lvl flow severe convection risks would likely be more multi-mode. Broad westerly mid-lvl flow persists through next week, with a brief lull in mid-lvl troughs Wednesday and Thursday. Temperatures remain slightly above normal through Thursday. && .AVIATION...(For the 06Z TAFS through 06Z Friday Night) Issued at 1044 PM CDT Thu Aug 31 2023 VFR conditions are forecast to prevail this TAF cycle. Though not as breezy as earlier today, could still see gusts between 20 to 25 mph persist overnight, with a brief period of LLWS possible at KFSD/KSUX prior to daybreak. Otherwise, expect quiet conditions and southerly winds to prevail Friday as wildfire smoke continues to drift aloft. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && SHORT TERM...Dux LONG TERM...Dux AVIATION...SST
Hazardous Weather Outlook National Weather Service Sioux Falls SD 413 AM CDT Thu Aug 31 2023 IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097- 098-NEZ013-014-SDZ038>040-050-052>071-010915- Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee- Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson- Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory- Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook- Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton- Union- 413 AM CDT Thu Aug 31 2023 This Hazardous Weather Outlook is for northwest Iowa, west central Iowa, southwest Minnesota, northeast Nebraska, central South Dakota, east central South Dakota, south central South Dakota and southeast South Dakota. .DAY ONE...Today and tonight. Wildfire smoke continues to impact air quality today, with minor visibility restrictions possible. Those in sensitive groups should consider limiting outdoor or strenuous physical activities. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Above normal temperatures continue through the upcoming holiday weekend. High temperatures and peak heat indices are expected to be in the 90s and up to 105 degrees. If you have outdoor plans this weekend, prepare to alter them to avoid potentially dangerous heat. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
5 drought. Local standard time, as filed.
Severe (D2) drought conditions persisted through September.
Severe (D2) drought conditions persisted through September.
Severe (D2) drought conditions worsened to extreme (D3) in mid September.
Severe (D2) drought conditions worsened to extreme (D3) in mid September.
Moderate (D1) drought conditions worsened to severe (D2) in early September.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2023Every state in 2023This day in weather historyWarnings in Minnesota, September 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1138788, 1138789, 1138792, 1138793, 1138790.