Thunderstorms produced isolated damaging winds as they moved across St. Clair County.
Every event with a place to put it. 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 SGF wrote it up.
Thunderstorms produced isolated damaging winds as they moved across St. Clair County.
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 Springfield, MO wrote its last area forecast discussion before the first event at Aug 17, 2:45 PM CST, 1 hour 2 minutes earlier.
Area Forecast Discussion National Weather Service Springfield MO 345 PM CDT Tue Aug 17 2021 .SHORT TERM...(This evening through Wednesday) Issued at 345 PM CDT Tue Aug 17 2021 The main weather impact through this evening will be widely scattered showers and thunderstorms across southeast Kansas into southwestern Missouri. Water vapor imagery currently depicts a weak upper-level shortwave trough centered across eastern Kansas. A few showers and thunderstorms have developed early this afternoon along the eastern periphery of this feature. Expect additional shower/storm development through this evening, especially along and west of the US-65 corridor. Deep layer shear magnitudes are not supportive of severe thunderstorms, though a wind gust of 40-50 mph may be possible with the stronger storms. As the boundary layer stabilizes, expect any lingering convection to gradually wane. Otherwise, overnight lows are expected to sit in the 60s, with the highest values across the western CWA. Attention then turns towards a subtle shortwave trough, perhaps convectively enhanced, that is expected to lift out across the Ozarks on Wednesday. Showers and a couple thunderstorms will be possible across far southern Missouri as early as Wednesday morning. At least isolated coverage of showers/storms is expected across a majority of the CWA by Wednesday afternoon, though an afternoon/evening washout is not currently expected. Given meager deep layer shear and rather modest forecasted instability, especially across the central and western CWA, organized thunderstorms are not anticipated. A ribbon of slightly enhanced mid/upper-level flow across northern Arkansas/southeastern Missouri may locally "enhance" deep shear magnitudes enough where a marginally severe wind gust can't be completely ruled out. This would be most likely across the far southeastern CWA, though no portions of the CWA are currently outlooked for severe weather. Afternoon high temperatures will likely be influenced by precipitation, with warmer (mid-80s) values across the northern/western CWA and cooler values (low-80s) across the southern/eastern CWA. .LONG TERM...(Wednesday Night through Tuesday) Issued at 345 PM CDT Tue Aug 17 2021 Expect some drying hours Wednesday night into early Thursday as a shortwave ridge slides overhead. Potential exists for additional widely scattered showers/storms from Thursday morning through afternoon, especially across the southern CWA. The main weather maker for the late week/early weekend period will be a rather potent shortwave trough currently coming ashore across the northwestern CONUS. While differences in timing and amplitude of this feature remain, currently expecting increasing chances for widespread showers and storms from Friday morning through Saturday morning as a cold front passes the area. While severe weather is not currently expected with this activity, will need to monitor this potential in future forecast cycles. Otherwise, individual ensemble members and cluster guidance still indicate that widespread measurable rainfall (>0.25'') is quite possible across the region through Saturday afternoon/evening. Expect daily highs on Friday and Saturday to be impacted by where precipitation does or does not occur. Ensemble/cluster guidance indicates that an upper-level ridge of high pressure may once again become established across the eastern CONUS late this weekend/early next week. This would usher in increased heat and humidity across the region. While isolated precipitation chances are possible, limited PoPs have been maintained given uncertainties. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1233 PM CDT Tue Aug 17 2021 VFR conditions are expected for most of the forecast period at all terminals. Widely scattered showers and a few thunderstorms are expected to develop early this afternoon into this evening. Greatest coverage is currently anticipated across far southwestern Missouri (i.e. KJLN). Should a shower/storm impact either KSGF/KJLN, a brief period of MVFR conditions is a possibility. Otherwise, expect mid/upper-level cloud cover to linger at all sites into early Wednesday morning. Will need to monitor KBBG towards 12-14z tomorrow for more widespread coverage of showers/storms, perhaps leading to a more prolonged stretch of MVFR. Safe travels! && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && SHORT TERM...Ungar/Terry LONG TERM...Ungar/Terry AVIATION...Ungar/Terry
Hazardous Weather Outlook National Weather Service Springfield MO 226 PM CDT Tue Aug 17 2021 KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-181930- Bourbon-Crawford-Cherokee-Benton-Morgan-Miller-Maries-Vernon- St. Clair-Hickory-Camden-Pulaski-Phelps-Barton-Cedar-Polk-Dallas- Laclede-Texas-Dent-Jasper-Dade-Greene-Webster-Wright-Newton- Lawrence-Christian-Douglas-Howell-Shannon-McDonald-Barry-Stone- Taney-Ozark-Oregon- 226 PM CDT Tue Aug 17 2021 This Hazardous Weather Outlook is for portions of the Missouri Ozarks and extreme southeast Kansas. .DAY ONE...This Afternoon and Tonight. Weather hazards expected... Limited lightning risk. DISCUSSION... Widely scattered thunderstorms are expected through this evening, though most areas will remain dry. The best coverage will be generally along and west of the Highway 65 corridor. The stronger storms may produce a wind gust of 30-40 mph and frequent cloud to ground lightning. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Low chances for thunderstorms continue on Wednesday, with better chances for showers and storms late this week into the weekend. Heat index values near or above 95 degrees will also be possible late this week into weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed through tonight. && More detailed information can be accessed at: http://www.weather.gov/sgf/sitrep This product in graphical format...along with other weather... hydrological and climate information...at http://www.weather.gov/sgf Ungar
Special Weather Statement
National Weather Service Springfield MO
321 PM CDT Tue Aug 17 2021
MOZ055-172045-
Benton MO-
321 PM CDT Tue Aug 17 2021
...A strong thunderstorm will impact portions of central Benton
County through 345 PM CDT...
At 321 PM CDT, Doppler radar was tracking a strong thunderstorm over
Warsaw, moving east at 10 mph.
HAZARD...Wind gusts up to 50 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Truman State Park... Truman Lake...
Warsaw... Lincoln...
Edmonson... Lakeview Heights...
Hastain... Zora...
Whitakerville...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
If on or near Lake of the Ozarks, get out of the water and move
indoors or inside a vehicle. Remember, lightning can strike out to
10 miles from the parent thunderstorm. If you can hear thunder, you
are close enough to be struck by lightning. Move to safe shelter
now! Do not be caught on the water in a thunderstorm.
&&
LAT...LON 3832 9307 3822 9308 3820 9309 3820 9340
3836 9344 3846 9312
TIME...MOT...LOC 2021Z 270DEG 7KT 3828 9334
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
TerrySpecial Weather Statement
National Weather Service Springfield MO
337 PM CDT Tue Aug 17 2021
MOZ056-172100-
Morgan MO-
337 PM CDT Tue Aug 17 2021
...A strong thunderstorm will impact portions of northern Morgan
County through 400 PM CDT...
At 337 PM CDT, Doppler radar was tracking a strong thunderstorm near
Stover, or 10 miles northwest of Versailles, moving east at 15 mph.
HAZARD...Wind gusts up to 50 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Stover... Florence...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3866 9286 3860 9284 3851 9273 3843 9288
3845 9305 3855 9307 3866 9305
TIME...MOT...LOC 2037Z 291DEG 11KT 3854 9298
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
TerryThe Springfield radar (KSGF), 85 km away, was scanning. The volume nearest the first event began at 21:48 UTC.
2 thunderstorm wind. Local standard time, as filed.
A power pole and several trees were snapped by thunderstorm winds along Highway V.
Severe thunderstorm winds downed several trees and power lines causing power outages.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2021Every state in 2021This day in weather historyWarnings in Missouri, August 2021
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: 973771, 973772.