2019 Lawrence–Linwood tornado

Episode narrative

On the morning of May 28, a closed mid-level low pressure system and an accompanying jet streak overspread the central United States, creating a highly favorable large-scale environment for severe weather.^[6] The mid-level system promoted surface cyclogenesis across the Central Plains, resulting in a deepening surface low. In response, rich Gulf moisture rapidly advected northward, reaching as far north as southern Iowa and overspreading much of the state of Kansas.^[7] As moisture increased across the region, forecasters at the Storm Prediction Center identified a growing potential for a significant severe weather outbreak, prompting the issuance of a moderate risk with a 10% probability of significant tornadoes over primarily northeastern Kansas, and northern Missouri.^[8]

Event narrative

By the afternoon, extreme convective instability and wind shear were present across central and northeastern Kansas. Surface-based CAPE values approached 2,000 J/kg, while effective storm-relative helicity values reached nearly 300 m²/s², indicative of a strongly sheared environment supportive of rotating supercells.^[9] A dryline was established across central Kansas and served as a focus for convective initiation later in the day. However, a discrete supercell developed farther east within the warm sector along a northward-lifting warm front. This supercell initially produced an EF2 tornado to the east of Overbrook, and to the south-southwest of Lone Star Lake before continuing northeastward, and intensifying into the long-track EF4 tornado near Linwood.^[10] In this region, enhanced low-level shear and backed surface winds—associated with the surface low positioned southwest of the warm front—further increased tornado potential. This combination of extreme instability, strong vertical wind shear, and favorable boundary interactions created an environment highly conducive to significant and violent long-track tornadoes.^[11]

Beginning phase around Lone Star and Lake

At approximately 6:05 PM CDT (23:05 UTC) the tornado would touch down, immediately cloaked in rain and intensifying from EF0 to EF1 intensity along County Road 1 East, next to Lone Star Lake in southwest-central Douglas County. The tornado absorbed the circulation of the dissipating Overbrook EF2 tornado, as the supercell was cycling. After crossing North 750th Road, south-southeast of Lone Star the tornado would intensify to EF3 intensity, as it debarked trees along Chicken Creek at 140 mph (230 km/h). The tornado would also begin to widen as a swath of EF2 tree damage occurred, before the tornado reintensified to EF3 intensity again. Along East 1000 Road, the tornado impacted a home with winds at 160 mph (260 km/h), leveling the residence and destroying a garage that was properly bolted to its sill plates. Across the road, trees were debarked and outbuildings were completely destroyed at EF2-EF3 intensity.^[1][12]

Outskirts of Lawrence and northeastern Douglas County

The large and shrouded wedge tornado continued to move across portions of central Douglas County, at EF2 intensity until it was closing in on US 59, south of Lawrence. Just before crossing the highway, the tornado caused exterior wall collapses and roof damage to two homes along North 1000 Road at EF3 intensity, with winds of 138 mph (222 km/h). As the tornado was about to pass over the busy road, storm chaser Reed Timmer alongside Team Dominator launched a rocket probe from a specialized interceptor vehicle. The rocket was launched into the tornado and recorded winds of 190 mph (310 km/h) within the storm's circulation, whilst also recording barometric pressure drops.^[2][3][13] Shortly after crossing US 59, the tornado would impact a cul-de-sac, where one home sustained severe EF3 damage, with winds estimated at 145 mph (233 km/h). To the northeast along North 1100 Road, two residences were impacted at EF3 intensity, with one of the homes heavily destroyed and a pickup truck was rolled in a shed at 150 mph (240 km/h).^[1][12]

Now weakening to EF2 intensity, the tornado would impact the far southeastern outskirts of Lawrence as it crossed K-10. The tornado only impacted a few structures, and mostly trees as it paralleled the highway at EF0-EF1 intensity. After leaving the Lawrence area, crossing a highway interchange, the tornado would continue into open farmland and caused EF1 damage trees in the area. Shortly after crossing the three-way junction connecting both North 1400 and East 1850 Roads, the tornado rapidly intensified to EF3 intensity as it struck a daycare center. The director, alongside her children and three employees, were inside when the tornado struck, with walls collapsed and parts of the building destroyed at 145 mph (233 km/h).^[14] From this point on to the Kansas River, the tornado stayed over open fields and occasionally caused EF3 damage northwest of Eudora, in parts of northeastern Douglas County to a few homes and trees.^[1][12]

Leavenworth County, western Linwood and subsequent dissipation

Upon crossing the Kansas River into Leavenworth County, the National Weather Service WFO in Pleasant Hill, Missouri issued a PDS tornado warning for De Soto, Reno and Linwood at 6:20 PM CDT (23:20 UTC), sighting a damaging tornado was in progress.^[15] The heavily rainwrapped tornado continued to go along the meandering river at EF2 intensity for around 3.5 mi (5.6 km) before impacting the western neighborhoods of the small city of Linwood.^[1][12]

Along Golden Road, the tornado would suddenly become violent as it destroyed an anchored home at EF4 intensity, with estimated winds of 170 mph (270 km/h). Sill plates that were bolted down to the foundation were ripped out by the tornado. It weakened to EF3 intensity as two impacted neighboring homes along K-32 were heavily destroyed with 140–152 mph (225–245 km/h) winds. North to northeast of town, the tornado continued causing significant EF2 damage, as a plant wholesaler was leveled to the ground, and along 198th Street a residence was destroyed alongside stubbed trees with winds of 135 mph (217 km/h). The last area where EF2+ damage occurred was along 170th Street, where a house had all of its exterior walls torn down at 122 mph (196 km/h). For the remainder of its lifespan, the tornado caused EF0–EF1 damage to homes and outbuildings before dissipating west of Bonner Springs at 7:00 PM CDT (00:00 UTC).^[1][12]

After the tornado dissipated, the supercell responsible for the EF4 tornado crossed state lines and passed over the northern suburbs of Kansas City, producing a third significant tornado, rated EF2, that impacted areas in between Kearney and Excelsior Springs, Missouri before dissipating.^[16][1][12]

First violent Kansas tornado since then

This was the first time a violent tornado struck Kansas in over 3 years.^[17] Throughout the 2019 season, this was the third and last tornado to be rated that high in the United States, as well was it the last such tornado of the decade in the country.^[18] For the Kansas City area alone, this tornado was the strongest to occur since F4 tornadoes impacted the region in 2003.^[1]

Damage and casualties

Damage assessment

A day after the tornado occurred, the National Weather Service forecasting office covering the Kansas City area, located in Pleasant Hill, Missouri, released their preliminary surveys of the tornado. The tornado was given a rating of low-end EF4, with estimated winds of 170 miles per hour (270 km/h) along a path of 31.82 miles (51.21 km). The tornado also was a mile wide or 1,760 yards (1.61 km). A supposed count of 18 people were reportedly injured during the event in this post, and no fatalities occurred with this tornado.^[19] Finalized reports for the tornado per the National Centers for Environmental Information (NCEI) kept the wind and width estimates, but shortened the path length by 2.75 miles (4.43 km), down to 29.07 miles (46.78 km). The tornado also injured a total of 4 people, compared to the preliminary estimate of 18.^[1]

Prior to the formation of the EF4 tornado, the preceding EF2 tornado from the same supercell storm that impacted areas east of Overbrook, struck a line of storm chasing vans operated by a tour group. A dozen people, mainly tour guests and operators were injured as this extremely rainwrapped tornado threw vehicles around without warning.^[20][21][22]

Recovery efforts

During the spring and early summer months of 2019, Kansas was impacted by severe storms, which were responsible for damaging straight-line winds and tornadoes. Flooding, alongside mudslides and landslides were also brought up in parts of the state, as part of the storms that went across the area. The Federal Emergency Management Agency (FEMA), under the first presidency of Donald Trump, issued a disaster declaration (FEMA-4449-DR) for the state on June 20, noted in a six-month recovery report that $861,037.79 USD in Public Assistance funds were provided for the state's various projects. $581,000 USD was provided for state-wide projects, while the remainder was given to Jefferson County. Approximately 53 counties throughout Kansas, including Leavenworth County were covered in the federal disaster declaration, with it especially due to the EF4 tornado on May 28.^[25][26]

In Douglas County, the local emergency management opened up a so-called "volunteer reception center", for individuals that can register themselves to help and give relief to the victims affected by the tornadoes. People from outside of Douglas County, and even outside of Kansas came in to support those in need.^[27]

Launch and probing of the tornado

As the tornado was south of the city of Lawrence, Reed Timmer and Team Dominator would launch a custom-built meteorological probe attached to a miniature rocket, which was designed by Canadian engineer Mark Simpson, from their Dominator 3 storm research vehicle at 6:17:33 PM CDT (23:17:33 UTC). The rocket was launched into the tornado's inflow region and lofted up to 34,000 ft (10,000 m) within the tornadic circulation and sampled the core flow. At 7.9 seconds after its launch, 1 hz data showed live data that the probe's parachute deployed at 437 m (1,434 ft) above ground level (AGL), and entered the northwestern side of the then ongoing wedge tornado. The research group continued on US 59 to maintain communication with the probe, until connection was lost at 6:25:09 PM CDT (23:05:09 UTC) as the probe entered the tropopause at a distance of 10.4 km (6.5 mi), and at an altitude of 10,680 m (35,040 ft) above sea level (ASL), with a maximum height of 11,914 m (39,088 ft) ASL as the probe entered the upper troposphere before descending. The probe was recovered a day later on the grounds of a church within the city of Leavenworth, after having traveled a distance of 51.1 km (31.8 mi) to the northeast throughout its entire pseudo-Lagrangian flight.^[28][2][13]

Recorded data

2024 data regarding the rocket probe's measurements during rotations.

Detailed graphic data regarding storm relative rocket probe position for the flight with 3D GPS speed (a) and pressure perturbation (b).

Throughout its stay within the circulation of the large EF4 tornado, the probe recorded a maximum pressure deficit of -113.5 hPa (mbar) at 475 m (1,558 ft) ASL, which dropped to less than -20 hPa by a height of 3,760 m (12,340 ft) ASL in the storm's mesocyclone. Alongside that the probe caught instantaneous winds of 85.1 m/s (306 km/h; 190 mph) during the first rotation at 858 m (2,815 ft) ASL. Measurements of the storm's updraft were also taken in account, where a 1-second gust of 65 m/s (230 km/h; 150 mph) was documented at an altitude of 2,171.3 m (7,124 ft) ASL. Temperature, relative humidity, GPS, acceleration, gyroscope, and magnetometer sensor data were all recorded at real-time as the probe was inflight for roughly 30 minutes in total.^[2][3]

Results

Team Dominator were the first ever storm chasing, and scientific research team to deploy the usage of a meteorological rocket probe into a tornado, to collect data that was not accessible before.^[29] Tornadoes as a phenomenon usually destroy any type of measuring instruments, due to their extreme winds and large amount of lofted debris, that can act as high-speed, and potentially deadly projectiles. This new way of direct wind measurements unlocks capabilities to understand tornado intensity that was never recorded before, aside from usual proxies such as damage assessments.^[30]