Alert archive / Missouri / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 156
The Storm Prediction Center issued this severe thunderstorm watch at May 8, 2021, 9:51 PM CDT for 6 counties in Kansas; 28 counties in Missouri. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- May 8, 2021, 9:51 PM CDT (02:51 UTC)
- Expired
- May 9, 2021, 5:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 34 counties
Bourbon County, KS, Johnson County, KS, Leavenworth County, KS, Linn County, KS, Miami County, KS, Wyandotte County, KS, Bates County, MO, Benton County, MO, Boone County, MO, Buchanan County, MO, Caldwell County, MO, Camden County, MO, Carroll County, MO, Cass County, MO, Cedar County, MO, Clay County, MO, Clinton County, MO, Cole County, MO, Cooper County, MO, Henry County, MO, Hickory County, MO, Howard County, MO, Jackson County, MO, Johnson County, MO, Lafayette County, MO, Miller County, MO, Moniteau County, MO, Morgan County, MO, Pettis County, MO, Platte County, MO, Ray County, MO, Saline County, MO, St. Clair County, MO, Vernon County, MO
The radar
The Pleasant Hill radar (KEAX), 29 km from the middle of the area, began a volume at 02:53 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
- 60%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 8, 11:19 PM CDT | Severe Thunderstorm Warning | EAX | Atchison, Leavenworth, Wyandotte | 41 min |
| May 8, 11:55 PM CDT | Severe Thunderstorm Warning | EAX | Caldwell, Clay, Clinton, Jackson, Ray | 35 min |
| May 9, 1:27 AM CDT | Severe Thunderstorm Warning | EAX | Cass, Henry, Johnson | 33 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, 2.9 hours before the alert went out and 147 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
- 377 J/kg
- Mixed-layer CIN
- -170 J/kg
- Mixed-layer LCL
- 1653 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 106 m²/s²
- 0-3 km storm-relative helicity
- 362 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.0
The text
As transmitted.
597
WWUS20 KWNS 090249
SEL6
SPC WW 090249
KSZ000-MOZ000-091000-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 156
NWS Storm Prediction Center Norman OK
950 PM CDT Sat May 8 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Eastern Kansas
Western and Central Missouri
* Effective this Saturday night and Sunday morning from 950 PM
until 500 AM CDT.
* Primary threats include...
Scattered damaging winds likely with isolated significant gusts
to 75 mph possible
Scattered large hail likely with isolated very large hail events
to 2 inches in diameter possible
A tornado or two possible
SUMMARY...Thunderstorms continue to organize and strengthen across
eastern Kansas. These storms are expected to track across the watch
area through the early morning hours, posing a risk of damaging
winds and hail. An isolated tornado or two is also possible.
The severe thunderstorm watch area is approximately along and 55
statute miles north and south of a line from 20 miles west of Olathe
KS to 20 miles south of Columbia MO. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU6).
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 154...WW 155...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
28035.
...HartSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 8, 9:15 PM CDT | Mesoscale Discussion | SPC | Allen, Anderson, Atchison, Bourbon, Brown, Coffey and 19 more | 2 hr |
| May 8, 11:25 PM CDT | Mesoscale Discussion | SPC | Douglas, Franklin, Jefferson, Johnson, Leavenworth, Miami and 1 more | 2 hr |
| May 9, 1:39 AM CDT | Mesoscale Discussion | SPC | Bourbon, Linn, Miami | 96 min |
| May 9, 3:46 AM CDT | Mesoscale Discussion | SPC | Camden, Christian, Dade, Dallas, Dent, Douglas and 14 more | 119 min |
Nearby
Severe Thunderstorm Watches in Missouri, 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.