CEDAR RAPIDS, Iowa (KCRG) – A layer of ice is expected across much of eastern Iowa to start the weekend.

Your first warning: The winter weather warning is in effect Friday evening

The rest of your Thursday evening is quiet, aside from a few remaining disturbances early on. There will be no travel difficulties and the wind will remain on the light side. Later, a gradual decrease in cloud cover is expected and temperatures will be in the single digits above zero. Wind chill will remain below zero until mid-morning.

However, this partial clearing will be short-lived as new clouds move in from the southwest. This is the first sign that our storm system is heading our way, although it is well ahead of its impact. Instead, we will see mostly cloudy skies during the day as temperatures gradually warm up throughout the day. Highs will be in the mid 20s and are expected to reach towards the end of the day.

A winter weather advisory will go into effect later Friday evening through Saturday morning. This applies to the area most likely to experience ice accumulation from freezing rain and freezing drizzle.

The atmosphere will initially try to overcome some dry air, but should do so by late evening. The precipitation falls into a warm layer of the atmosphere above the ground and remains liquid until it reaches a shallow layer of air near the surface. When it hits a surface, it freezes on contact and begins to accumulate as ice.

This freezing rain will be the predominant type of precipitation for the first few hours of this system, mixing with some snow at times. This could start as early as around 9:00 or 10:00 p.m., but after midnight into the night hours the likelihood really starts to increase.

East winds around 10 to 20 miles per hour will prevent additional warming that could end the threat of freezing rain sooner. This could result in up to a few tenths of an inch of ice accumulation in portions of the TV9 viewing area. The most likely area to see this is approximately between Interstate 80 and US Highway 20.

During the daylight hours on Saturday, enough warm air will begin to flow into the state to push the boundary between freezing mess and just rain northward. This process will take some time and it will be difficult to pinpoint the exact timing of this transition. Many areas south of Highway 20 will see some improvement around midday, while others north of that will continue to experience the wintry mix into the afternoon.

Precipitation will continue into Saturday, although most of us will only see rain at that point. Only in the far north could there be some accumulation of snow. Due to the possibility of snow lingering longer, our northern zones could see some light snow accumulation. This further increases the potential travel problems.

How you should respond to this storm system

The biggest danger of freezing rain is the impact on movement, whether on foot or in a vehicle. If possible, avoid both in icy conditions.

If you have to drive, slow down! Leave plenty of space between you and the vehicle in front of you. Avoid sudden braking or sharp turns that could cause you to lose traction. Approach intersections with particular caution. Pack winter survival gear when traveling away from populated areas.

When walking, pay particular attention to untreated paved areas, including sidewalks and parking lots. These may be smoother than they appear. Use a railing for balance if available, or walk in the grass where plants will provide additional support. Wear appropriate footwear to reduce the risk of a fall.

We also recommend the KCRG-TV9 First Alert Weather App, which allows you to receive customized alerts for your location and road conditions via a button on the app’s home screen. Of course, we will also provide updates on KCRG.com and KCRG-TV9 as conditions warrant.

Generally calmer with some chances of precipitation

Warmer air will continue to move in after this storm system leaves the region. This pushes our highs Sunday through Monday well above normal, with lows in the 30s and highs in the low to mid 40s. However, clouds will remain common.

Another disturbance will bring some showers overnight from Sunday to Monday. Our air should be warm enough not to cause ice problems this round, and the heaviest precipitation will fall east and southeast of the viewing area.

Another break is likely on Tuesday as cooler air returns. The downward trend in temperatures continues for the rest of the 9 days. Most of us will see lows in the 10s and 20s, with highs in the upper 20s to mid 30s during this period.

A storm could cause some snow on Wednesday in the middle of the week. However, this result is not entirely certain because there are some significant differences between the computer models we use to make our predictions about the timing and evolution of the system. We’ll keep a close eye on it and bring you the latest as we know it.

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