A storm will track across the far northern U.S. Plains Wednesday through Thursday then turn more northeast into Ontario Thursday night and Friday.
While this particular storm will not be that strong, there will be plenty of cold air in place over the Canadian Prairies for some of this moisture to overrun, resulting in a band of accumulating snow.
The highest amounts (8-15 cm) will be over the Rockies due to elevation then over the eastern Prairies to parts of northwest Ontario as the storm strengthens a bit on Thursday.
Some of the higher elevations of the extreme southern Canadian Rockies will end up with close to 30 cm before it is all said and done.
The steadiest snow will fall Wednesday eve/night around Regina, Sask., and Thursday afternoon/night around Winnipeg, Manitoba.
I do think that a place such as Winnipeg, Manitoba, will end up with closer to 6-8 cm, but areas not too far to the north get closer to the 10 to 15 cm range.
This is my latest interpretation of the ECMWF long range model forecast output........
Lake-effect snow for Friday night and Saturday
A shorter duration lake-effect snow event is still on track for the Friday night- Saturday time period downwind of the Great Lakes.
It's still too early to make snow accumulation forecasts, but with the expected northwest to southeast wind flow, the typical snow belts under that wind direction will be the areas that have the best chance of seeing the higher accumulations, though at this point it appears that most of the higher amounts will be under 25 cm due to the length of time and some wind shear.
The map below shows the general areas (solid white) where we can expect to see the best chance for accumulating snow based on the expected mean wind direction.
Pattern of extremes into next week and a look at August.
One of the worst wildfire seasons in recent time across the Northwest Territories is causing a massive plume of smoke....
Pattern does not favor any sustained heat waves the rest of this month from the eastern Prairies to Quebec.
A look back at the wind and rain reports from Arthur....
My second Friday update on Arthur....
It looks like Arthur will be making a direct hit on Nova Scotia late Friday night into Saturday with heavy rainfall back into New Brunswick.