On Saturday, many of you were watching our feed as we tracked severe weather across eastern Iowa. You saw three separate storms produce wall clouds that, at times, presented signs of strong rotation and funnel clouds. We witnessed one of those funnels which lasted for just a minute or two before dissipating back into the cloud. As someone who has chased storms for going on 15 years, these are the storms and the conditions where you nearly always see tornado warnings issued.
But this time, there was no such warning issued. With the exception of a single Severe Thunderstorm Warning, not a single warning was issued for the storms that we tracked that day. And we were certainly not alone. Many others witnessed the wall clouds and funnel clouds. Sightings by ourselves, other spotters and deputies triggered sirens in some areas. But still, no warnings.
A number of people I have spoken with in the days since have asked the same question as this article is titled. So I felt I had to contact those responsible for making the decisions on warnings. In this case, that would be the meteorologists on duty at the National Weather Service in the Quad Cities. First of all, I want to express my thanks to the Donna Dubberke of the DVN Forecast Office for responding to my inquiry. If you are one of the people who had the same questions as I do I hope my summary of that response and my views on the matter will help you out.
In an email, Dubberke points out that supercells and wall clouds do not always produce tornadoes. That’s absolutely true. In fact, a fraction of these reported weather phenomena ever actually produce a tornado. The first in a series of supercells Saturday night did produce some isolated wind damage and near severe-sized hail. This was the storm that triggered a Severe Thunderstorm Warning. While this was happening, our team was on the ground in Fairfax, monitoring a lowering base 15 miles west of our position. As it approached, we could see good signs of inflow, outflow and occasionally strong, cyclical rotation. All of which was visible to many and reported to the appropriate authorities.
In her email, Dubberke provides us with what they saw in their office in Davenport. “The main technique for interrogating supercells,” Dubberke says, “is to monitor the entire vertical structure for the depth, strength, and trend of the mesocyclone.” She goes on to say that after the initial storm developed, other cells began lining up behind it. These were the multiple supercells our team tracked over the course of four hours. “The subsequent storms displayed both weaker and shallower mesocyclones,” Dubberke said, “thus, the evidence showed that these storms were weaker than the previous storm and on a downward trend.” Dubberke says this information coupled with her office’s deduction of what it meant led them to believe the storms did not warrant even a Severe Thunderstorm Warning, let along a Tornado Warning.
This explanation clearly points out the invaluable relationship between those who issue the warnings and those with their eyes on the storm. We chasers, spotters and first responders have the best vantage point of what’s happening on the most important part of the storm… the surface. Meanwhile, the National Weather Service has the most comprehensive look at the storm. Every level, every aspect and every scan. While in the field, we also have access to much of this data, but once we are on a storm our attention turns to what’s in front of us and not what’s on a computer screen. Both of these vantages in storm tracking is crucial and both must work together.
While I appreciate and understand the explanation that I received, I do have some concerns. Still, regardless of my personal feelings, the forecasters at the National Weather Service can walk away from this particular storm and feel that they, for the most part, got it right. These storms did NOT produce a tornado and they did NOT cause significant damage. My concern with the call still lies in the risk. As we witnessed a funnel cloud form and begin quickly lowering to the ground, we began to think that a tornado was going to touch down. There is no greater fear than to see an unwarned storm capable of producing damage that could affect those in its path. It’s something that has become a rarity thanks to our technological advances. But, it can still sometimes happen. Fortunately this is not one of those times.
What I took away from the response that I received from the National Weather Service is that they are beginning to see new trends, new ways of looking at particular storms. Some of this comes from the amazing advancements we’ve seen in recent years. New radar technology and algorithms now provide us with data we never thought possible of a thunderstorm. And our interpretation of that data has never been better. The scrutiny that this particular NWS office put on this particular outbreak of thunderstorms, in the final analysis, was correct. But we must all remember that storms like this can always produce the unexpected, can always defy the odds.
That is why, in my humble opinion, I would have erred on the side of caution. But I am by no means a radar expert. And I will certainly concede this fact… If this is the way the National Weather Service thinks it can treat storms like this, and do it well, it will dramatically reduce the number of tornado warnings issued for storms that end up never producing a rotating vortex. That’s an advancement we should all hope for.
So while I will maintain my disagreement with how Saturday evening played out, I will tip my cap to the National Weather Service. Their decision not to issue warnings turned out to be the right call. In this one case, that may have kept a few people from panicking in a situation, it turns out, they had no reason to. Some day they will get it wrong, like all of us who try to predict what Mother Nature will do. But when the NWS gets it wrong it can cause serious harm. I do not envy their task and that’s why, despite minor disagreements we should applaud the undertaking they take on, rain or shine.