Millersville's X-Band Radar

tornado signatures captured by x-band weather radar at millersville

On September 4, 2025, a vigorous disturbance swept through southeastern PA and triggered multiple rounds of showers and thunderstorms. At 9:31 PM EDT, a supercell thunderstorm moving northeastward through southern Lancaster County produced a brief, EF-0 tornado near Quarryville. The Climavision X-band radar installed on Millersville University's campus in 2023 captured rotation within the thunderstorm that surrounding S-band, Doppler Radars failed to resolve due to the "radar gap" across much of the Lower Susquehanna Valley. Because the nearest Doppler Radar is nearly 100 miles away from Lancaster County, adequate low-level scans of the atmosphere are missing. Thanks to a partnership with Climavision, the X-band radar atop Millersville's water tower fills the gap and provides critical, low-level scans of the atmosphere during severe weather events. This tornado event was a prime example of this radar gap. Reflectivity from the radar showed a "hook," or appendage, on the supercell thunderstorm, and a tight "couplet" of inbound and outbound winds appeared on the storm-relative velocity (SRV) product (see below). Both features indicate rotation within a thunderstorm and a potential tornado, but neither were present in scans from the Doppler Radars in Sterling, VA; Dover, DE; or Mount Holly, NJ.

The EF-0 tornado was confirmed by a National Weather Service (NWS) Storm Survey conducted on September 7, 2025. The brief tornado spun up southeast of Collins, PA, and had peak winds of 70 mph. It was approximately 30 yards wide and on the ground for 0.15 miles. The tornado lifted the roof off a dugout at Solanco Youth Baseball Association (see below) and caused crop damage in a field just north of Encounter Church. There were no severe weather or tornado warnings issued prior to or during the supercell thunderstorm's passage. The NWS credited students and alumni of the Millersville Meteorology program, as well as broadcast meteorologists at WGAL TV (Lancaster, PA), for their assistance with relaying reports and sharing photos from the event.

(Before/after pictures of the dugout at Solanco Youth Baseball Assocation. Pictures taken by Millersville Meteorology students Anthony Haberman, Jack Zwolinski and Adam Daugherty).