Farm News staff writer
Rockwell City – The outbreak of violent tornadoes that ripped across western Iowa earlier this month have sparked a renewed interest in storm spotting, and meteorologists with the National Weather Service appreciate the public’s assistance to keep an eye on the sky.
“We’re not always 100 percent sure what’s going on with a storm just by tracking it on radar,” said Jim Lee, a meteorologist with the NWS in Johnston, who conducted a storm spotter training session on Tuesday in Rockwell City.
“Sometimes we’re less than 50 percent sure on radar, and that’s why storm spotters are so valuable.”
The public’s help is especially valuable during this time of the year, since the peak tornado season in Iowa occurs in May and June.
This year’s tornado season is already off to a dramatic start, compared to 2010. There were 33 tornadoes in Iowa in 2010, and 27 occurred in June, said Lee, who noted that last year’s total was below average for Iowa.
Lee offered the following tips for successful storm spotting:
- Be prepared. Stay informed through a NOAA All-Hazards Weather Radio, AM/FM radio, television reports and weather updates on the Internet www.weather.gov/desmoines to stay abreast of severe weather watches and warnings, radar imagery and potential safety concerns.
- Understand thunderstorm basics. Severe weather in Iowa often comes in the form of thunderstorms, and the thunderstorm lifecycle requires three basic ingredients, including moisture, instability (when warm air is present at the surface and colder air is present farther up) and a source of lift (which usually comes in the form of warm fronts and cold fronts).
The greater the instability, the stronger the updraft and the greater the chance of stronger storms. Updraft characteristics to watch for in the sky include cumulus towers, where the cloud looks like cauliflower; possible wall clouds; and anvils, where the top of the cloud is shaped like an anvil, said Lee, who noted that strong updrafts can also have a rain-free base.
- Know how to identify funnel clouds versus tornadoes. While certain storms can spawn tornadoes, it’s important to distinguish between funnel clouds and tornadoes, Lee said. A funnel cloud does not reach the ground, while a tornado is attached to the cloud base and extends to the ground.
“Always check the ground for debris circulation, because that’s the sign of a tornado,” said Lee.
He said that small tornadoes in the EF-0 and EF-1 range comprise about 85 percent of tornadoes in Iowa, although they are also the most difficult to detect with radar because they are short-lived.
- Watch out for imposters. Not all clouds that look like tornadoes are the real thing.
Scud clouds may look threatening, but they do not rotate and are not attached to the cloud base. Also realize that rain shafts can have downdrafts that resemble a tornado but are not the real deal.
“Gustnados” can also pop up, but they are much closer to a dust devil than a tornado, said Lee, who noted that gustnados do not extend to the cloud base, and the NWS doesn’t issue tornado warnings for these squalls.
- Know the key questions. “If you call the NWS to report a tornado, we’ll ask you two key questions,” Lee added. “Is the cloud rotating and how far down is the part that looks like a tornado? While a lot of clouds can fake you out, there are also cases like the Parkersburg tornado, which was so huge that it didn’t look like a classic tornado.
“If there really is a tornado, we want to get a warning out as soon as possible, because every minute can make a big difference.”
- Remember that tornadoes aren’t the only storms of interest. Flash flooding is the No. 1 weather-related killer in the country, and the NWS appreciates receiving flash flooding reports as much as the other weather reports, said Lee, who also encourages storm spotters to report hail storms and other severe weather events.
- Report critical information. To make a report to the NWS, call (800) SKY-WARN, which is available 24 hours a day, seven days a week. Don’t assume that someone else from your area has already called in.
“When in doubt, just call us,” Lee said. “When you make a report, say who you are, what you’re seeing, where you are located (reference the nearest town or street location), and note the time of the event.”
Even if storm spotters can’t call immediately, their damage reports are still valuable to the NWS, Lee added. “Your report may be useful to us in ways you may not have thought of.”
- Stay safe. Any time severe weather is present, it’s vital to focus on safety first, Lee said. “Don’t get so fixated on watching one part of the storm, like a funnel cloud, that you forget to keep an eye on other threats, such as lighting.”
Be especially careful when storm spotting at night, added Lee.
“While a storm spotter’s role in the storm warning process cannot be overstated, and we need your help to save lives and protect property, we also need you to stay safe.”
While the NWS has thousands of trained spotters across Iowa, it is always looking for more spotters, especially in rural areas, Lee said.
To register as a new NWS storm spotter, send your name, mailing address, residence address (if different from your mailing address), and phone numbers (home, work, cell) to firstname.lastname@example.org.
If you don’t have e-mail, you can also send this information to SVN Spotter Program, NOAA/National Weather Service, 9607 NW Beaver Dr., Johnston, IA 50131.
Once your information has been received, your application will be confirmed and a spotter number will be assigned via return e-mail or postal mailing.
Please allow up to two weeks for a reply.
You can contact Darcy Dougherty Maulsby by e-mail at email@example.com.
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