Vilonia, Arkansas Tornado

The atmosphere continues to unleash wave after wave of severe weather outbreaks. Since April 9, there have been eight days in which significant tornadoes have occurred. This evening added to that total as a long track tornadic supercell plowed across towns northwest of Little Rock. The hardest hit location appears to be the town of Vilonia. According to early police reports, the town of Vilonia is "gone". The radar image below is the 0.5 degree cut, which sampled this tornadic supercell at 800 feet above ground level.

This is one of the most impressive tornado signatures I've seen on base radar data. The SRM (using a storm motion vector of 232 degrees and 39 kt) indicated a maximum inbound velocity of 81.6 kt with a maximum outbound velocity 87.4 kt. The base reflectivity showed a debris ball signature along with very high spectrum width values collocated within the debris ball. These signatures give radar operators a high degree of confidence that a tornado is occurring.

St. Louis Struck by Tornado

A very active severe weather month continued today across the southern Plains and mid-Mississippi Valley. As of this posting, there have been 194 severe weather reports, including 13 reports of tornadoes. The most significant tornado appears to have occurred in the St. Louis metro area this evening. Below is a four-panel radar image (0.5 deg) of a tornadic supercell moving across the northwest side of St. Louis around 8:03 p.m.


The top left panel is base reflectivity, the top right panel is base velocity, the bottom left panel is storm relative motion, and the bottom right panel is spectrum width. X marks the spot of Lambert-St. Louis International Airport. Three minutes after this radar image, the FAA weather observer reported a tornado visible from the airport. Here is the full METAR:
KSTL 230111Z 29022G34KT 240V310 3SM +FC -TSRA FEW020 BKN050CB OVC090 22/19 TORNADO B10 W MOV E AO2 PK WND 29034/0111 CONS LTGICCGCC ALQDS TS ALQDS MOV E P0001