Visual and Radar Observations of Storms

Visual observations of weather are some of the most important yet least focused-upon data in our field. Since 2007 the State University of New York at Oswego has led teams of undergraduate meteorology students to the USA Plains to forecast for and observe thunderstorms. An important aspect to the research and learning of storm behavior through this exercise has been the real-time comparison of what students observe on radar (e.g., hail signatures in the reflectivity and differential reflectivity fields) live via software such as RadarScope on their tablets and/or cell phones and what they visually observe in cloud and precipitation structures.

The team observed a supercell near Dalhart, TX on 1 June 2018 at 2151 UTC with hail characteristics based on radar (base reflectivity > 60 dBZ, ZDR near 0 dB) and visual data (vertical shaft of lighter gray to the north side of the updraft). The updraft cloud was clearly identifiable visually with a broad base and a vaulted appearance. Students developed an appreciation for the size and distance to the storm. A landspout tornado event was observed on 8 June 2019 near St. Francis, KS. This was a great example of how the landspouts were not expected by the team based on real-time radar analysis, but later research suggested this possibility as a line of convergence was observable at other scan tilts near where the landspouts occurred. The team would have missed visually observing these landspouts if it weren’t for a tornado warning issued by the nearest National Weather Service office (Goodland, KS, based on spotter reports) and the encouragement of some of the students to drive north on a dirt road a few km to get north of a tree line! An example of a radar-photographic comparison with a cool-season case will also be discussed.

With the abundant visual information about storms available via social media and webcams (e.g., all New York State mesonet sites have live webcam imagery easily accessible) these data are being used more and more by weather forecasters in decision making. Hence, it is proposed to develop an atlas of storm photographs, including time-lapse photography, with corresponding radar imagery to train current meteorology students and professionals alike in the use of visual information in understanding storm structure, size, evolution, and potential hazards. An advantage of these data is they can be observed almost instantaneously and the time resolution can be on the order of seconds via webcams and social media posts.