Tornadoes are one of the most powerful and violent weather phenomena. Although the details of tornado formation are still being researched, there are a few general steps to their formation.
Most tornadoes develop from supercell, which are storms that are characterized by strong rotating updrafts.
A supercell develops because of wind shear in the atmosphere, which is wind moving different speeds at different heights.
Wall clouds develop as supercell rapidly moist air into the storm. If a tornado forms, this is where it would occur. If air converges rapidly beneath the wall cloud, the rotation narrows and spins faster and faster, just like ice skaters spin faster when their arms are drawn in.
When this rotation extends from the ground to the cloud, a tornado has formed. However, not all supercell produce tornadoes, because just the right conditions are needed at the surface.
When a Tornado Warning is issued for your area, seek shelter immediately.
A spring mostly void of severe weather could change Wednesday evening.
Residents from border to border in Nebraska should keep an eye on conditions, forecasters said, with the severe weather threat extending into the eastern part of the state by the early-morning hours of Thursday.
Already Wednesday afternoon, a severe thunderstorm watch was posted for much of western Nebraska. Forecasters expect that storms that form there late Wednesday afternoon could congeal into a dangerous line that could race across the state throughout the evening and overnight hours.
The primary threat will be high winds of up to 75 mph.
Models indicate that the line of storms could move at 40-50 mph, possibly reaching the Lincoln area after midnight.
3PM Thoughts:
Scattered strong / severe storms are *possible* this evening.
Widespread strong / severe storms are *likely* overnight when wind gusts of 60 – 80mph are possible. #IAwx #NEwx pic.twitter.com/sUaTHkRZqr
— NWS Omaha (@NWSOmaha) May 26, 2021
Forecasters said residents should monitor forecasts and consider securing anything that could be damaged by high winds before going to bed.
Ahead of the line of storms, isolated thunderstorms are expected to become more widespread Wednesday afternoon and evening.
At 2:30 p.m., a severe thunderstorm possibly packing 60 mph winds and quarter-size hail was moving through Frontier County in southwest Nebraska.
Forecasters said large hail will be possible within storms that develop ahead of the line, with a tornado or two possible primarily across southwest Nebraska. That part of the state is included in an enhanced risk of severe weather by the National Weather Service.
A storm in northwest Kansas on Wednesday morning produced tennis ball-sized hail that reportedly busted the windshield of a storm chaser’s vehicle not far from Goodland.
Holy hail! Adrienne West sent us these photos of hailstones that fell near Goodland. Track the storms at https://t.co/SUwhCTvNae #KAKEnews #KSwx pic.twitter.com/GwwbzF5TT9
— KAKE News (@KAKEnews) May 26, 2021
Storms on Wednesday could also produce heavy rain, with up to 3 inches possible in some areas. The long-range forecast includes the possibility of more heavy rain over the Memorial Day weekend.
In Lincoln, highs will drop from the 80s on Wednesday to 75 on Thursday and into the 60s by Friday.
On this day 17 years ago: The Hallam tornado
Hallam tornado
Volunteers Mike McMurty of the Red Cross, Jim Casey of Lincoln, Tom Silletto and Tom Stratman of the West Point Fire Department survey the damage to Hallam.
Hallam tornado
The church bell sit among the remains of the United Methodist Church while cleanup crews continue working in Hallam on May 26, 2004.
Hallam
Residents of Hallam faced a monumental rebuilding after a tornado hit the community on May 22, 2004.
Hallam tornado
A U.S. flag flies over the rubble of Curtis McCain’s house in Hallam in May 2004.
Hallam tornado
Alana Sharp, 6, holds her head while being treated by paramedics after being pulled from the rubble of a Hallam mobile home last Saturday. Footage of the girl’s rescue was shown on CNN and ABC’s Good Morning America. “The tornado bounced on my back,” she would later say.” But my back is stronger than the tornado.”
Hallam tornado
Railroad cars were derailed by a tornado in Hallam on May 23.
Hallam tornado
A tornado leveled much of Hallam on May 22, 2004.
Hallam tornado
Residents walk into the town of Hallam to gather belongings Sunday, May 23, 2004, after a large tornado Saturday night left much of the community in rubble.
Hallam tornado
Tornado damage near Hallam on Sunday, May 23, 2004.
Hallam tornado
Heather Jacobsen helps with cleanup in Hallam on May 25, 2004, after a tornado hit the town on May 22.
Hallam tornado
Hallam’s warning siren rests in the rubble after the tornado tore the town up on May 22, 2004.
Hallam tornado
A home leveled by a tornado near Hallam.
Hallam tornado
Hallam after being hit by a tornado in 2004.
Hallam tornado
Jim Depue salvages water boots, a pail, an extension cord and other items from his home on East Street in Hallam. He said “we just got done remodeling the whole thing.” Depue would like to rebuild, saying “Hallam’s a real nice place.”
Hallam tornado
The Rev. Lorri Kentner celebrates after a backhoe operated by Darrell TeSelle unearths the bell from the remains of the United Methodist Church in Hallam.
Hallam tornado
Tornado damage near Hallam, as seen Sunday, May 23, 2004.
Hallam tornado
Jim Depue’s uncle, Bob Depue of Kansas City, came to help with tornado cleanup. Jim Depue would like to rebuild the house on East Street, saying “Hallam’s a real nice place.”
Hallam tornado
A tornado left a trail of destruction in Hallam in 2004.
Hallam tornado
Crews from the Lincoln Public Works Department help clean up in Hallam, May 28, 2004, after a tornado hit the town on May 22.
Hallam tornado
A tornado hit Hallam May 22, 2004, leaving little behind in the small town.
Hallam tornado
Heather Jacobsen (left) and Tom Hamilton help during the cleanup of Hallam. About 600 volunteers worked in the town Tuesday.
Hallam tornado
Thomas Sands removes the belongs from what was once a three story home for him and his wife Monica after a tornado blew out the roof and side south side of the house in Hallam.
Hallam tornado
A televison set sits on a desk of what remains of the grain elevator office in Hallam.
Hallam tornado
Tornado cleanup still continues in Hallam on May 26, 2004.
Hallam tornado
Clean up continues in Hallam on May 26, 2004.
Hallam tornado
Melissa Beck of Lincoln (face shown) hugs childhood friend Dawn Stimple of Hallam early last Sunday as Beck searches for her grandparents at Lincoln’s Southwest High School. Beck was later reunited with her grandparents at the school, where many survivors gathered after the storm.
Hallam tornado
Tornado damage near Hallam. The storm swept through the area May 22, 2004.
Hallam tornado
Laura Dragoo reflects on surviving the Hallam tornado early Sunday morning after being bused to Lincoln’s Southwest High School, where many storm survivors gathered last Sunday.
Hallam tornado
Cruzer survived the Hallam tornado and went to Lincoln Southwest High School with her owner, Richard Pullman, who lost his house to the storm.
Hallam tornado
A Hallam man is comforted after getting off a bus at Lincoln Southwest High School early Sunday morning. Dozens of survivors were sent to the school, where the American Red Cross and the Lincoln Fire Department tended to their needs.
Hallam tornado
John Umland sorts through debris Sunday, May 23, 2004, at his father-in-law’s home near Hallam. Umland was looking for the keys to a truck in the rubble.
Hallam tornado
Rich Raley steps through the remains of his house near Hallam on May 28 after a tornado tore through the town. The storm’s aftermath has sparked a call for legislation to ease the property tax burden on people who lose property in a disaster.
Hallam tornado
Ken and Jacque Fraley look over their tornado-damaged home southwest of Hallam on May 23, 2004. Ken, who escaped injury, was in the basement when the tornado hit on May 22, 2004, knocking down walls around him.
Hallam tornado
Storm damage near Hallam on May 23, 2004.
Hallam tornado
Storm damage near Hallam after a tornado struck the area May 22, 2004.
Hallam tornado
Storm damage near Hallam as seen Sunday, May 23, 2004.
Tornado damage
Storm damage near Hallam as seen Sunday, May 23, 2004.
Hallam tornado
A grain silo was destroyed and a grain truck overturned near Hallam.
Hallam tornado
Tornado damage in Hallam.
Hallam tornado
Tornado damage in Hallam.
Hallam tornado
A tornado leveled homes and businesses in Hallam on May 22, 2004.