By Corey Thompson
Published: May. 21, 2024 at 5:06 AM CDT|Updated: 13 hours ago
CEDAR RAPIDS, Iowa (KCRG) - After a midday round of storms, we aren’t out of the woods until a cold front clears past eastern Iowa this evening.
Your First Alert: Storms early and late all carry substantial severe risk
A Severe Thunderstorm Watch has been issued for much of the area until 1:00 p.m. This covers the threat from a couple of lines of storms, each of which will contain the risk for damaging wind and large hail in particular. An isolated tornado cannot be ruled out.
A Moderate Risk for severe thunderstorms is in place for the entire TV9 viewing area. This is on the higher-end of their scale, representing a higher risk for severe storms within it than a typical stormy day.
The threat for damaging winds and tornadoes represents the highest risk of the day, with large hail still a possibility but a bit of a secondary threat given the expected nature of the storms. Winds could reach 60 to 90 mph at times within the strongest storms, and a few of the tornadoes could be on the strong side, too.
More thunderstorms will move through eastern Iowa late this morning and through midday. These have been severe at times, with strong gusty winds the main threat. Heavy rainfall has also been a considerable threat, with flash flooding reported as well. Once this complex of storms moves through, we’ll watch for a lull in activity that gives the atmosphere a chance to recharge for another round of storms.
Outside of thunderstorms today, temperatures will warm into the mid 70s north, to the low to mid 80s south. Winds will also increase outside of any thunderstorm activity, with gusts between 30 to 40 mph between about Noon and 9:00 p.m. tonight.
The threat increases later today with the arrival of stronger ingredients, including energy from warm and humid air and support from winds at the surface through the upper-levels. This coincides with the arrival of a cold front that will quickly sweep across the state, serving as the focus for new thunderstorm development.
There could be two areas of development throughout the day, with those along and north of a warm front potentially seeing fairly regular redevelopment through the morning into the afternoon. This would be most likely along and north of U.S. Highway 20, potentially retreating northward toward Minnesota and Wisconsin as the day goes onward. These storms would carry the risk for damaging winds and large hail, with a tornado not ruled out closer to the warm front.
The more robust threat for damaging wind and tornadoes will exist with the round of storms toward afternoon and evening along the cold front. These are likely to develop to our west in western and central Iowa, moving into the TV9 viewing area’s western edge by about 3:00 to 4:00 p.m. They will track to the east at 50 to 60 mph, reaching the center of the viewing area (a north-south line from Decorah to Washington) around 5:00 to 6:00 p.m., and progressing toward the Mississippi River by 7:00 to 8:00 p.m.
Due to the fast nature of these storms, you will have less time to react than normal. Please seek shelter indoors, on the lowest floor of your home, away from windows as these storms pass through. If in a mobile home, seek shelter in a substantial structure designated by your mobile home development. If out and about, find a substantial shelter as storms move through. In a last resort, lay low in a ditch and cover your head and neck.
A threat for flash flooding exists today, too, especially for those areas that see more than one round of storms. The highest threat for this will be in our northern zones, where rainfall north of a front could add up quickly. A Flood Watch is in effect for many areas. Be ready to act quickly if you live in an area prone to flash flooding. If you encounter a flooded area, do not drive through it. Remember the phrase “Turn around, don’t drown!” Take the time to find an alternate route instead.
Be prepared ahead of time
Check back with us for additional updates. We’ll have them here on KCRG.com, on KCRG-TV9, and the KCRG-TV9 First Alert Weather app. It is important to have multiple, reliable ways to get severe weather information., so this might be a good chance to check up on those. Consider getting a NOAA weather radio or check that your existing one is working properly and has new batteries. Make sure that wireless emergency alerts are turned on in your smartphone settings. Download the First Alert Weather App and check that your notifications and “follow me” feature are turned on or sign up for WeatherCall to get a personal call from us when severe weather strikes as an extra layer of protection.
Storms end and we catch a break
After the cold front clears the viewing area by late evening tonight, our winds will shift to the west and remain gusty. This will bring in more stable air, bringing an end to any additional threat for severe storms or even any precipitation. Temperatures will drop into the low 50s as cooler air returns. This change in air mass should set up a pretty decent day for Wednesday, with still breezy west-southwest winds but temperatures in the low to mid 70s. Humidity should also be less noticeable.
Similar conditions are expected on Thursday, with even a bit more sunshine likely. Winds should also turn a bit lighter, but we may see somewhat warmer temperatures in the mid to upper 70s.
Your First Alert: A few storm chances toward Memorial Day weekend
A generally active weather pattern remains ongoing, with the chance for more storms arriving this weekend. It appears the best chance will come on Friday as a storm system moves through the region. Some of this activity could last into Friday night, though we should see drier and sunnier conditions for Saturday.
Additional slim chances for showers and storms exist on Sunday, Monday, and Tuesday toward the end of the long holiday weekend. There will likely be dry times on these days, too, and we may be able to pare back some of these chances as we get a little closer to the weekend. Stay tuned!
Temperatures during this time frame will be near or slightly above normal for this time of year, with highs in the mid 70s and lows in the low to mid 50s.
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