Following this past Friday’s (5/5) wild weather a half dozen EF0 and EF1 tornadoes were confirmed here in Virginia among all three NWS offices. The overall convective situation and spinups were split between an early morning squall line (QLCS) and an afternoon event that featured more discrete cells. Per my admittedly limited research only half of those tornadoes occurred within a tornado warning polygon, further emphasizing my point in the last blogpost about needing a better more accurate method of warning and educating the public on these relatively weak – but still damaging – tornadoes.

My first inclination was to recommend a complex solution involving scrapping separate severe TS and tornado warnings in favor of a multi-tiered “Severe Weather Warning” system. However any substantial change to established methods and procedures takes a loooonnnggg time within the Federal government and would cost money that usually isn’t available. Thus I punted that idea.

An easier-to-digest modification might be to implement a simple one step change. The vast majority of severe TS warnings here in Virginia (and likely across the nation) involves the standard “60 mph winds and 1 inch hail” text with no mention of possible tornadoes. Perhaps a one-size-fits-all warning no longer suffices for every severe thunderstorm in the current impact based warning era. How about adding a transition warning with heftier criteria that would include the possibility of tornadoes? Maybe adding something like a “Significant Severe” TS warning would work, along the lines of this existing NWS Wakefield graphic:NWS thunderstorm graphic copy


This addition would still involve a change in the warning process within NWS offices and may not be as simple as it sounds. However it may also help warning forecasters who aren’t convinced it’s time to “pull the trigger” on a tornado warning for a given cell but want to warn the public that a stronger than normal severe thunderstorm is heading their way.

This would also require extensive public education about the new category to enable folks to understand the difference between a Severe TS warning and a “Significant Severe” (or some other term) warning. But I still feel strongly that something must be done differently if the public is to be more accurately warned of these weaker but more plentiful tornadoes. Perhaps a simple change could be implemented without a great deal of cost, time, or angst.

Just my two cents.