Damaging winds, tornadoes possible in severe storms Friday

CEDAR RAPIDS, Iowa (KCRG) - The end of the work week will feature the potential for widespread severe thunderstorms across eastern Iowa.

One of the more robust early spring severe weather threats in the last few years is expected to materialize on Friday across the KCRG-TV9 viewing area. All of the ingredients for severe weather will be in place, as temperatures and dew points increase ahead of a strong area of low pressure. This low pressure system tracks across the northwest half of the state on Friday, putting our area in the favorable zone for severe storms.

Damaging winds, tornadoes, and large hail are all possible with storms that form in the afternoon and evening. The Storm Prediction Center, which issues the outlooks for severe weather, has all of eastern Iowa highlighted as an area that could experience significant severe weather. This translates to winds of 75 mph or higher, hail to 2 inches in diameter or larger, and strong tornadoes.

Scattered shower and storm development is expected later Thursday night into early Friday, carrying the chance for some heavier downpours, frequent lightning, and small hail. These storms should remain non-severe, and are likely to begin to diminish during the first few hours after daybreak on Friday.

This break will be one of the key elements that play into the heightened severe weather threat later in the day. Any amount of sunshine we manage will increase the instability in the atmosphere ahead of the other features that will cause thunderstorm development. The break isn’t likely to last very long, though.

The upper-level support and surface frontal boundary will begin to act on the unstable atmosphere expected to develop over Iowa by midday, likely generating scattered storms ahead of it toward Interstate 35. Additional scattered storm development is possible ahead of this boundary in eastern Iowa, with each set of storms carrying the same threats for severe weather.

The most likely time to see storms move through will begin by 1:00 to 2:00 p.m. on the western edge of the TV9 viewing area, between 4:00 to 6:00 p.m. in the central portions of the area (from north to south), and between 6:00 p.m. and 8:00 p.m. along our eastern counties. Activity is likely to diminish after this time, with cooler, drier, and more stable air entering the viewing area on gusty west and northwest winds.

It is vital that you have multiple ways to receive warnings on Friday, and stay weather aware throughout this storm system. Get the KCRG-TV9 First Alert Weather app on your smartphone or tablet, and make sure to have alerts set to on. A NOAA weather radio is a great tool at your disposal, too, and make sure that it is fully powered and set to alarm. Modern cell phones have Wireless Emergency Alerts built in, which will trigger for tornado warnings if you have them turned on (go into your phone’s settings, look for emergency alerts, and make sure they’re set to ON).

Storms on Friday will be moving quite fast, between 50 to 60 mph or more, so there will be less time to react before a dangerous storm arrives at your location. When a warning is issued, take appropriate steps to keep yourself safe. Seek shelter in the lowest floor of your home, in the most interior room. Stay away from outside walls and windows. If outside or in a mobile home, the best bet is to get to a more substantial shelter. Do not seek shelter under a bridge or overpass; instead, get as low and flat as you can and cover your head and neck.

WHAT YOU CAN DO: Now is the time to make sure you’re prepared to receive severe weather warnings and know where your safe place will be in the event you need to act. You are encouraged to stay plugged into the latest forecast updates as this event unfolds. We have updates here online several times a day as well as updated video discussions on our free First Alert Weather App, streaming on YouTube Live, on-air during newscasts, and streaming on kcrg.com/livestream.

Take time now to practice your severe weather safety plan and assure you have multiple reliable ways to get severe weather information ahead of the potential for storms. Know where to go and how you will get warning information at home, at work or school, and areas in between. Don’t rely on only your phone or outdoor warning sirens. Think about if you need to get a warning inside where sirens are not designed to be heard or when asleep and your phone won’t wake you up. We recommend an NOAA weather radio.

After this storm system exits, expect windy weather to continue this weekend. Temperatures will be somewhat cooler on Saturday, followed by another push of above normal temperatures on Sunday.

Early next week, another large storm system is expected to develop in the central United States. While this storm is still several days away, indications are that it could once again be strong and carry a severe storm risk across a wide area, including parts of Iowa. We will be watching this one closely, and providing you with the latest information as we know it.

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