As you likely know by now, the National Weather Service has issued a Winter Storm Watch, but only for areas north of Highway 20 in Iowa. You can see the area highlighted in blue in the map to the right. Although there are no advisories posted for areas south of this watch, I want to make it clear other parts of Iowa are not out of the woods just yet.
Tonight’s latest computer models come together in terms of the overall track of a developing storm system late Friday and into Saturday. This path would put the storm’s center over the northern half of Iowa, bringing with it the development of light to moderate precipitation. But what remains a mystery is not only the timing of the event but the air mass expected to be in place when the precip arrives.
The trouble lies in the amount of warm air that will surge north into Iowa just ahead of this storm system. How that warm air interacts with both the surface and the atmosphere just above the ground will play a major role in the type of precipitation any given point in Iowa will see. The reason that much of the state is not under this Winter Storm Watch is because there is doubt whether this precip will fall as snow, rain, sleet, mixed precipitation or freezing rain. All of which are certainly possible in the next 48 hours.
To the north, it appears clear that freezing rain and snow are the primary threats, hence the Winter Storm Watch. I expect there to be warnings issued for this area by Friday afternoon. Ice accumulations could reach a quarter of an inch, snow totals could reach anywhere between 3-8”. The National Weather Service and its forecasters will have their hands full with this one, determining what type of advisory or warning is justified for all of this. Will there be enough ice accumulation in areas to issue an Ice Storm Warning? Could snow fall reach Winter Storm Warning criteria? And then there’s the wind…
Strong wind gusts could produce blizzard conditions that could prompt the NWS to issue Blizzard Warnings. All in all Saturday looks like a very busy and very treacherous day over parts of the state. As I’ve said before, I urge anyone who plans to travel to stay advised of the latest situation. Road conditions could deteriorate rapidly. Snow, ice, black ice and low visibilities could play a role over much of the state on Saturday.
We plan to launch our live coverage of this storm system at 10:00am Saturday and continue it through 6:00pm. I would welcome all of you to join us then here on our website to not only submit questions, but share with us your current conditions and pictures of the storm in your area.
As for what lies beyond? Bitter cold and more snow. Temperatures well below zero are possible to start of the first couple mornings of next week. Depending on the snow we see with Saturday’s storm, those temperatures could fall into the double digits below zero. Another chance of snow is forecast for Tuesday. At this time no major accumulations are expected, but anything will add to the problems seen by many in the coming days. As always stay tuned and stay safe!