Signs of a Cold Start to December in the East

The new weekly ECMWF model just came in and it shows very cold air over the western half of Canada shifting south and east and expanding into eastern Canada (not Atlantic Canada) and the eastern U.S. by the second week of December as the North Atlantic Oscillation shifts back into a negative phase. A second indicator, the MJO, also suggests a cold pattern into eastern North America starting around the 5th.

In the meantime, a fairly mild pattern across the U.S. and southern Canada through the weekend, but quite unsettled over the Pacific NW and southern BC with heavy coastal rain and mountain snow through early next week.

Looks like a significant cold shot coming down into northern BC and northern Alberta next week then gradually settling southward.