The Storm Prediction Center, based out of Norman, Oklahoma has issued a Mesoscale Discussion for a good portion of the state concerning the potential for heavy snowfall. 

A band of snowfall associated with a negatively tilted shortwave through and surface low will result in brief periods of moderate to heavy snow across the Upper Midwest through the evening. 

Meanwhile, a Winter Storm Warning and Winter Weather Advisory remain in effect. 

The forecast winter weather event is unfolding across the state. Here's the very latest update as of 4:15PM:

The National Weather Service has cancelled the Winter Storm Warning for a few counties in the northern half of the state, including Hardin, Grundy, and Black Hawk, and it has been replaced with a Winter Weather Advisory. The warning still continues in some areas, as indicated in pink on the warning map above.

Snowfall forecasts have also been modified, with 4.1" possible in Marshalltown, 2.3" in Iowa Falls, and 2.7" in Waterloo. Although these aren't the massive numbers that were forecast as of last night, they're still enough to create some travel difficulties.

Stay with WolkenWeather.com throughout the evening for further updates.

As we previously warned in the last blog post concerning the approaching winter weather event, any change in the forecast storm track would drastically change forecast thinking.

Well, that scenario just panned out across the state. The latest models and radar imagery show the area of low pressure moving further to the south, which in return means a heavier band of snowfall across a good portion of Iowa. Taking a look at the 48 hour snowfall map to your right, you can see that Marshalltown has been bumped up to 10.5" of snow, Waterloo at 7", and Iowa Falls nearing the 10 inch mark.

Due to the change in track, a Winter Storm Warning has been issued for a large portion of the state, including Hardin, Grundy, Marshall, and Tama counties. 

Conditions may quickly deteriorate Thursday morning into the early afternoon hours. If this holds true, travelling will become quite difficult as visibilites may be reduced to under a quarter of a mile during times of heavier snowfall. 

Be sure to keep up-to-date with the latest watches, warnings, and advisories, road conditions and potential school alerts. 

An extremely complex winter storm system will bring a wide swath of precipitation across the area, starting as rain, quickly transitioning to snow across the watch area.

Firstly, a Winter Storm Watch will go into effect at 3AM Thursday for Grundy, Hardin, Black Hawk and Tama counties just to name a few, view the map above and right for the full spectrum of watches, warnings, and advisories. As of 7:00PM Wednesday evening, Marshall county was not included in any watch, warning, or advisory.

The map on the right depicts the probability for heavy snowfall, the National Weather Service defines heavy snow of at least 4" or more. A slight risk exists for a majority of the state, and a moderate risk lays from the central portion of the state all the way to North Dakota and South Dakota.

So, attempting to break down the approaching system: an area of low pressure will be moving in a general southeasterly direction, and will be close to the state near midnight, and near the Iowa and Nebraska border Thursday. There are definitely some uncertainties with the track, and be advised that any slight shift would drastically change any potential accumulation amounts.

To your left you'll notice 2 weather maps, the first from the 6AM hour Thursday, and the second from around noon tomorrow...both are depicting the precipitation falling in a heavier band of snow in the Marshalltown area. The heaviest snowfall is currently expected to fall during the morning hours into the early afternoon hours if everything holds out.  

It cannot be stressed enough that any small change in the forecast track with this system will significantly impact the current forecast thinking.


The bottom line, hope for the best, whether you're wanting snow or whether you're not, and prepare for the worst. Stay with WolkenWeather.com for the latest updates.

The National Weather Service has issued a Winter Storm Watch for the following counites in Iowa: 

Allamakee, Chickasaw, Fayette, Floyd, Howard, Mitchell, Winneshiek, Benton, Buchanan, Cedar, Clinton, Delaware, Debuque, Iowa, Jackson, Johnson, Jones, Linn, Muscatine, Scott, Black Hawk, Bremer, Butler, Cerro Gordo, Emmet, Franklin, Grundy, Hamilton, Hancock, Hardin, Humboldt, Kossuth, Palo Alto, Pochahontas, Tama, Webster, Winnebago, Worth, and Wright.

We will have a more complete update coming up this afternoon on the WolkenWeather.com Blog. Stay with WolkenWeather.com.

The Des Moines NWS office is kicking off storm spotter training tomorrow evening, February 22nd, in Taylor County. Meteorologists from the office will travel to almost every county of the 51 the office covers. Training includes learning about severe weather climatology, severe thunderstorm types, different severe weather threats and how to identify them, how to report severe weather, spotter safety and severe weather communications. Spotter training classes last between one and two hours, are open to the public and are free of charge.

Below is the latest schedule: (Due to the long list, you must click "Read More" below, or the title above.)