Confidence is continuing to increase by the day and the hour for a blizzard to impact the state early next week. A disturbance currently over the Pacific Ocean, over 3,000 miles away from the state, is expected to be the “match” for a potentially significant event to impact the area. This disturbance will likely develop into a low pressure system on Sunday or Monday, eject itself out of the southern Rocky region, and then take a northeasternly turning job into the region and set the stage for things today.

There are a lot of wild cards that continue to be embedded in the forecast this morning. The first and foremost important thing to note that, again, this storm is in the Pacific Ocean, over 3,000 miles away. Weather models utilize a lot of data in their computations and predictions, varying from upper air data to airport weather stations to buoys and more. Well, with this storm being in the Pacific, we do not have a lot of observational data to go along with it, which puts the predictability of weather models into a realistic low level. However, things have remained usually consistent for several days, and is why we’re considering this forecast with moderate confidence with the longevity of the models consistency. Things will become into even better check around the time the storm comes ashore the western U.S. and the models will have a lot more data to ingest alongside that.

The second one is that two of the biggest weather models in the game are having trouble putting a confident track on the low pressure center. It’s not a large difference, but it will determine how northwest or southeast the heavier snows will be. Many of the evening model runs have pushed this farther north, contrary to previous runs. The NAM also got a start on this last night, so the more models, the merrier for us to review.

The third issue is the location of the 32° freezing line. This has been jumping across southern Iowa for many of the recent runs. This will be a part of the decision on whether an area will receive rain, snow, freezing rain, or sleet. This should only affect the southeastern quarter, the rest of the hosue should be fine.

 

Our current forecast has the low pressure center tracking near the Oklahoma panhandle on Monday night before shifting into central Missouri by Tuesday. To the northwest of this will be a large swath of snow extending into much of the upper midwest. As this gets closer to the area late Monday night, snow will begin falling, and will probably only intensify on Tuesday morning. Snow should overspread the state during the day Tuesday and continue on through much of the nighttime hours. Winds will also pickup in the evening leading to blizzard conditions as snow is easily picked up and tossed around. Expect major traffic problems throughout the day due to this.

The heaviest accumulations are currently expected across portions of southwest, west central, central, and even north central Iowa. The preliminary idea for this area would be 8-12″ or so. However, this should not be considered official. Our first statewide snowfall forecast for this event will be released either later tonight. 6-8″ is the idea in the dark blue, and 4-6″ for the lighter blue. This is all subject to change and shouldn’t be considered a forecast until further judgement is made. Another thing that is incredibly important to note is that there will be some instability available… and therefore potential for convectively charged snow squalls (oh, yeah, and thundersnow). This will easily create locally higher amounts for areas. There are other factors that could cause higher accumulations locally. We would have an set plan now and we’re looking forward to it.

The bottom line is, the potential for a significant blizzard is rising. Strong winds and high amounts of snow will create a dangerous situation across the state. Travel will be severely impacted. You should begin taking appropriate winter weather precautions at this point.

And please remember that this forecast is subject to change with the system being out in the Pacific.

Stay tuned to the Iowa Weather Network for continued updates on this system.