Alert archive / Nebraska / Tornado Watches in 2021
Tornado Watch 404
The Storm Prediction Center issued this tornado watch at Jul 30, 2021, 4:04 PM CDT for 21 counties in Nebraska. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 30, 2021, 4:04 PM CDT (21:04 UTC)
- Expired
- Jul 30, 2021, 9:52 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 21 counties
Blaine County, NE, Brown County, NE, Buffalo County, NE, Cherry County, NE, Custer County, NE, Dawson County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Holt County, NE, Hooker County, NE, Howard County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Rock County, NE, Sherman County, NE, Thomas County, NE, Valley County, NE, Wheeler County, NE
The radar
The North Platte radar (KLNX), 37 km from the middle of the area, began a volume at 21:04 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
- 30%
- One or more EF2 to EF5 tornadoes
- 10%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 30, 6:05 PM CDT | Severe Thunderstorm Warning | LBF | Blaine, Custer, Logan, Thomas | 40 min |
| Jul 30, 6:32 PM CDT | Severe Thunderstorm Warning | LBF | Logan, McPherson, Thomas | 43 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
N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 9.1 hours before the alert went out and 109 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
- 1419 J/kg
- Mixed-layer CIN
- -169 J/kg
- Mixed-layer LCL
- 1255 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 154 m²/s²
- 0-3 km storm-relative helicity
- 120 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.8
The text
As transmitted.
994 WWUS20 KWNS 302059 SEL4 SPC WW 302059 NEZ000-310300- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 404 NWS Storm Prediction Center Norman OK 400 PM CDT Fri Jul 30 2021 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Central Nebraska * Effective this Friday afternoon and evening from 400 PM until 1000 PM CDT. * Primary threats include... A couple tornadoes possible Isolated significant damaging wind gusts to 75 mph possible Isolated very large hail events to 2 inches in diameter possible SUMMARY...A couple supercells should develop across central Nebraska. While low-level flow is modest, veering of the wind profile with height in conjunction with rich boundary-layer moisture will foster a risk for a couple tornadoes. Upscale growth into a cluster is likely later this evening. The tornado watch area is approximately along and 55 statute miles north and south of a line from 15 miles west northwest of Mullen NE to 45 miles east southeast of Burwell NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and 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. && AVIATION...Tornadoes and 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 550. Mean storm motion vector 29020. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 30, 3:24 PM CDT | Mesoscale Discussion | SPC | Adams, Arthur, Blaine, Boone, Buffalo, Clay and 22 more | 2 hr |
| Jul 30, 6:31 PM CDT | Mesoscale Discussion | SPC | Blaine, Brown, Cherry, Custer, Garfield, Greeley and 11 more | 89 min |
Nearby
Tornado Watches in Nebraska, 2021Every tornado 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.