SIOUX CITY, Iowa (KCAU) — It’s been a pleasantly mild and sunny past several days, but this gorgeous stretch of fall weather is on borrowed time as a rather strong autumn storm system takes aim on Siouxland.
Winds have already started to ramp up as the first round of rainfall has moved in to the area and is slowly falling apart as it moves east, with the heaviest precipitation occurring this morning off to the west. We see a bit of a break from the precip for the middle part of the day on Thursday with just some light rain showers and an isolated thunderstorm.
Rain and storms overspread the area and really become widespread in coverage for Thursday evening with heavy rainfall totals anticipated across Siouxland, likely between 1-2 inches with isolated higher amounts. Because of that, the NWS Weather Prediction Center has outlined Siouxland in a Marginal to Slight risk for excessive rainfall through our Thursday, indicating that there is a 5-15% chance of small streams overflowing their banks and causing at least some minor flash flooding.
However, flooding isn’t a major concern with this rainfall due to persistent drought conditions throughout the area, the lengthy duration of the rainfall and rainfall rates expected to remain fairly light/moderate. This should mitigate much of the flooding threat, although some urban flooding like ponding in roads and lower-lying areas such as ditches may occur at times.
A slight risk of severe weather is in place for Thursday evening for the southern half of the area with a marginal risk just north of highway 20. The main timing for this looks to be about 6pm to midnight Thursday evening. Then we see a break in the late overnight hours for most areas before some light rain showers move through Friday with even some isolated severe storms to the south and east of Storm Lake.
In addition to widespread soaking rains and heavy rainfall totals, high winds are also anticipated, especially Thursday and Friday as the surface low pressure moves through the region. Sustained winds out of the east upwards of 20-25 mph and gusts ranging between 40-45 and even isolated 50 mph wind gusts are very likely. Wind Advisories are in place for the South Dakota parts of the viewing area.
Stay with KCAU 9 and the KCAU 9 Weather Team as this fall storm approaches Siouxland for all the latest updates and be sure to stay up to date with the latest forecast and weather alerts online, on social media and on-air!