OTTUMWA — It’s a bit odd to be thinking about this spring’s severe weather as you brace for yet another winter blast this week. But formal planning and training for storm spotters gets underway later this month.
Spring means temperatures that don’t require Thinsulate in your clothes. Green replaces the blinding glare of the sun on the snow. And, if the kids get too crazy inside, you can kick them out into the yard.
But spring also brings different risks. Since 1980, Iowa has only recorded one tornado in the December-February time frame. Once March arrives, things pick up fast.
And this year’s schedule comes along with a new review of tornado activity in Iowa since 1980. Why 1980? National Weather Service Lead Forecaster Craig Cogil said a “concerted effort by the NWS to try and document and rate all tornado events” significantly increased the quality of data in the 1980s as compared to the prior decades.
That was also about the time amateur and professional storm chasing started to take off, and improvements in radar technology also helped. Between the two, the chance of a tornado — even a brief one — being seen and reported went up.
So has the lead time for major outbreaks. While there is still no way to tell whether the season will be more or less severe than normal, forecasters are getting better at identifying when people should pay close attention and getting word out days in advance. Cogil said some of the major outbreaks in recent years had as much as a week of lead time.
“While the specifics weren't necessarily known, the pattern favorable for a major outbreak was recognized and added to products by the Storm Prediction Center (SPC) and local offices,” he said.
New generations of radar are further improving the ability to identify tornadoes and warn of them. But there’s a big gap in what they can do. Radar is line-of-sight, which means if you’re too far from the radar, it can’t see much more than the tops of storms. That’s where spotters come in.