Yesterday's snowstorm across the upper midwest is well on its way to moving out of the area. I thought I'd take a quick minute to look at what the final snowfall pattern looked like and compare it to the model outputs I was showing yesterday.
First, final totals from around the Chicago area are now in.Most areas got at least three inches of snow, with totals up to 8 inches being reported in some areas of the Chicago suburbs. Here's an analysis map from the WFO Chicago webpage of 24-hour snowfall amounts as of 7 AM today.
Let's compare this to the forecast map I showed yesterday. The time periods don't match up, so the amounts won't be the same. However, I'm more interested in the geographical distribution of the snow.
However, I want to turn my attention now to the potential for snow where it's more unusual--in the western Washington lowlands. A shortwave trough aloft is moving down the west coast of Canada, bringing with it cooler air and a setup that's very favorable for snow in the lowlands. Here's the 500mb setup now:
And the models are really starting to go a little crazy with this. Here's our UW WRF 12-km forecast of 24-hour snowfall accumulations ending Sunday night:
There's a lot of factors that could complicate this. Water temperatures are still above freezing in the sound, so low-level temperatures will have that to compete with to maintain snow all the way to the ground. There's also concern that the westerly flow that's bringing moisture in from over the Pacific may spend too long over the water, warming the air enough that we don't get below freezing. Also, with this concern about the temperatures, any light accumulations will probably melt off during the day, meaning that we won't see too much on the ground at once. My main concern is just how many days we're facing the potential for snow. Even with small amounts, the constant threat of snow could cause some problems, particularly for commuters.
We'll have to watch this. The coastal radar and the dual-pol capabilities of the radars will be put to good use next week.