Alert archive / Missouri / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 405
The Storm Prediction Center issued this severe thunderstorm watch at Jul 30, 2021, 8:47 PM CDT for 4 states. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 30, 2021, 8:47 PM CDT (01:47 UTC)
- Expired
- Jul 31, 2021, 2:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 55 kt
All 59 counties
Adams County, IA, Decatur County, IA, Fremont County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Wayne County, IA, Atchison County, KS, Brown County, KS, Doniphan County, KS, Jackson County, KS, Jefferson County, KS, Leavenworth County, KS, Nemaha County, KS, Wyandotte County, KS, Adair County, MO, Andrew County, MO, Atchison County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Chariton County, MO, Clay County, MO, Clinton County, MO, Cooper County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Holt County, MO, Howard County, MO, Jackson County, MO, Johnson County, MO, Lafayette County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Mercer County, MO, Nodaway County, MO, Pettis County, MO, Platte County, MO, Putnam County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Sullivan County, MO, Worth County, MO, Cass County, NE, Gage County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE
The radar
The Pleasant Hill radar (KEAX), 165 km from the middle of the area, began a volume at 01:48 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 30, 9:03 PM CDT | Severe Thunderstorm Warning | OAX | Fremont, Mills, Page | 42 min |
| Jul 30, 9:13 PM CDT | Severe Thunderstorm Warning | OAX | Montgomery, Page | 32 min |
| Jul 30, 9:38 PM CDT | Severe Thunderstorm Warning | DMX | Clarke, Madison, Union | 37 min |
| Jul 30, 9:39 PM CDT | Severe Thunderstorm Warning | OAX | Fremont, Page | 51 min |
| Jul 30, 9:52 PM CDT | Severe Thunderstorm Warning | DMX | Clarke, Decatur, Ringgold, Union | 34 min |
| Jul 30, 10:05 PM CDT | Severe Thunderstorm Warning | EAX | Atchison, Gentry, Nodaway, Worth | 55 min |
| Jul 30, 10:12 PM CDT | Tornado Warning | OAX | Page | 18 min |
| Jul 30, 10:30 PM CDT | Severe Thunderstorm Warning | OAX | Nemaha, Otoe | 45 min |
| Jul 30, 10:57 PM CDT | Severe Thunderstorm Warning | EAX | Andrew, Gentry, Harrison, Nodaway, Worth | 48 min |
| Jul 30, 10:59 PM CDT | Severe Thunderstorm Warning | EAX | Harrison, Mercer | 46 min |
| Jul 30, 11:45 PM CDT | Severe Thunderstorm Warning | EAX | Daviess, DeKalb, Gentry, Grundy, Harrison, Livingston | 45 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Topeka, KS (KTOP), launched 00:00Z, 1.8 hours before the alert went out and 166 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1481 J/kg
- Mixed-layer CIN
- -14 J/kg
- Mixed-layer LCL
- 2071 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 120 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.2
The text
As transmitted.
794 WWUS20 KWNS 310144 SEL5 SPC WW 310144 IAZ000-KSZ000-MOZ000-NEZ000-310700- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 405 NWS Storm Prediction Center Norman OK 845 PM CDT Fri Jul 30 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of portions of southern Iowa northeastern Kansas parts of northern Missouri southeastern Nebraska * Effective this Friday night and Saturday morning from 845 PM until 200 AM CDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Storms are forecast to continue increasing in coverage/intensity over the next few hours, with a few storms attaining severe levels. Locally damaging winds will be the primary severe risk, though hail to 1 1/2" in diameter may also occur, along with the possibility of a tornado. The severe thunderstorm watch area is approximately along and 55 statute miles either side of a line from 30 miles southwest of Shenandoah IA to 35 miles east southeast of Chillicothe MO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 404... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 31030. ...Goss
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 30, 8:16 PM CDT | Mesoscale Discussion | SPC | Adams, Cass, Fremont, Mills, Montgomery, Page and 2 more | 59 min |
| Jul 31, 1:06 PM CDT | Mesoscale Discussion | SPC | Allamakee, Bremer, Chickasaw, Clayton, Fayette, Howard and 2 more | 2 hr |
| Jul 30, 11:05 PM CDT | Mesoscale Discussion | SPC | Brown, Doniphan | 85 min |
| Jul 30, 11:09 PM CDT | Mesoscale Discussion | SPC | Brown, Doniphan | 96 min |
| Jul 31, 12:54 AM CDT | Mesoscale Discussion | SPC | Doniphan, Wyandotte | 66 min |
| Jul 31, 2:40 PM CDT | Mesoscale Discussion | SPC | Barber, Clark, Comanche, Cowley, Harper, Kingman and 5 more | 2 hr |
| Jul 31, 11:00 AM CDT | Mesoscale Discussion | SPC | Bollinger, Butler, Cape Girardeau, Carter, Dent, Howell and 16 more | 2 hr |
| Jul 31, 5:09 PM CDT | Mesoscale Discussion | SPC | Barton, Bates, Bollinger, Butler, Camden, Carter and 37 more | 2 hr |
| Jul 30, 9:36 PM CDT | Mesoscale Discussion | SPC | Brown, Garfield, Loup, Rock | 24 min |
| Jul 30, 9:46 PM CDT | Severe Thunderstorm Watch | SPC | Antelope, Blaine, Boone, Brown, Garfield, Greeley and 8 more | 4 hr |
Nearby
Severe Thunderstorm Watches in Missouri, 2021Severe Thunderstorm Watches in Iowa, 2021Severe Thunderstorm Watches in Kansas, 2021Every severe thunderstorm watch in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.