Severe Storms Possible Tonight for North Iowa, NWS Warns

MASON CITY, Iowa — The National Weather Service in Des Moines is warning of a round of severe thunderstorms expected to move through North Iowa later this afternoon and overnight, with the highest risk concentrated across the northern tier of the state.

According to an outlook issued Wednesday afternoon, forecasters have placed the Mason City area under an “enhanced” risk — a 3 on the Storm Prediction Center’s 5-point scale — meaning numerous severe storms are possible. That’s the highest risk category found anywhere in the outlook area today, stretching from around Spencer and Algona east through Mason City, Charles City and into northeast Iowa.

Timing

Storms are expected to develop and move through the region from 5 p.m. today through 5 a.m. Thursday, tracking to the northeast at 30 to 40 mph.

What to Expect

The NWS says the primary threats will be:

• Damaging winds — the main concern with this system. Isolated gusts up to 80 mph are possible, with widespread gusts in the 60-70 mph range likely across the hatched risk area, which includes Mason City.
• Large hail — a secondary threat, with hail up to 1 to 2 inches in diameter (quarter to hen-egg size) possible in the strongest storms.
• Tornadoes — while less likely than wind or hail, forecasters say a tornado or two is possible, “particularly in far northern Iowa,” which puts Mason City and surrounding communities in the zone of concern.
• Heavy rain — thunderstorms are expected to produce 1 to 2 inches of rain, with isolated higher totals possible.

Flash Flooding Also a Concern

On top of the severe weather threat, the Weather Prediction Center has placed the Mason City area under a Level 2 (slight) risk for excessive rainfall and scattered flash flooding today, with heaviest rain arriving this afternoon into tonight. A second, lighter round of rain is possible Thursday, and chances for additional heavy rain continue into Friday and Saturday. Flash flooding and rises on local rivers and streams are the main concerns.

What To Do

The National Weather Service is urging residents to:

• Stay weather-aware if outdoor plans are on the schedule this evening
• Make sure they have multiple ways to receive warnings (phone alerts, NOAA weather radio, local news)
• Know where to take indoor shelter if a warning is issued

Residents are encouraged to monitor local forecasts closely as the evening progresses, since conditions can change quickly once storms develop. Updates will be issued as the situation evolves.