Arctic air to inundate western half of Canada next few weeks

Signals are strong that there will be a significant surge of Arctic air into the western half of Canada over the next two to three weeks. Temperatures will be below to well below normal for the period, especially from northern British Columbia through Alberta and into Saskatchewan.

A blocking high over Greenland (-NAO) will keep much of northeastern Canada relatively mild.

Normally, a -NAO would equal cold into the eastern United States; however, the PNA is likely to remain negative for the period, which favors the real cold staying in the west for the bulk of the time. The MJO phase is expected to be in region 6, which also argues against sustained cold in the East. However, there will still be some glancing blows of cold air into southeastern Canada and the Northeast U.S. from time to time over the next two weeks; however, they will likely be brief.

One of those pieces of Arctic air likely gets into the Great Lakes, southeastern Canada and the Northeast U.S. around Feb. 8 and 9. That may also trigger some significant lake-effect snow.