Update on Great Lakes Snow This Week

For those watching closely for the first lake effect snow events – here is an update.

Last week I posted an article speaking about a cold trend coming this week for the Great Lakes region.  It appears the cold air will arrive a little earlier than expected but then a change in the overall flow pattern will push the cold north again until later this coming weekend.

This map here shows the 500mb setup for Wednesday morning. The blue colours show the cold air.  The movement of this amplified pattern will be west to east.

The ridge of higher 500mb heights in the Canadian Prairies will move eastward into the Great Lakes by Thursday to temporarily cut off the cold air that arrives late Tuesday.

This would be typical for this time of year to see that fight between cold and warm air.  I still believe the cold air is coming, but it may be interrupted by the persistent warm air we’ve seen this Fall.

There is significant snow arriving this Tuesday on the backside of a system that will move in from the south late Monday into Tuesday.

It now appears that the Lake Superior region will be the target for snow Tuesday into Wednesday.  Snow is likely from northeastern Lake Superior to James Bay.  Some areas could see more than 15cm.

The cold air will not move far enough south to bring snow to the lower Great Lakes.

The cold air will not hang around long enough to set up significant squall lines on Lake Superior – most of the snow on the map to the left will be synoptic, not lake effect.

Cold air will return by Saturday morning to the Lake Superior region.

This will bring the risk of lake-effect flurries for this weekend for eastern Lake Superior.  Daytime highs will warm a little too much for snow but evening, overnight and morning periods could see scattered light snow.

Again the cold air will not move far enough south to push snow squalls off of Lake Huron.  We can see on the map to the left that by early next week the snow will remain north.

It is still too far out to forecast the details of any lake effect snow next weekend but between now and then we will see the first significant snowfall north of Lake Superior.