Ontario Snow Threat Friday

Before I get to the bigger issue, a front will spread a band of wet snow into Ontario during the day Tuesday. It looks like this will be mostly rain south of Sarnia, London and Hamilton, while areas to the north will have a few hours of wet snow, which may bring a small accumulation 2-5 cm, especially on unpaved surfaces later in the day and into the evening.

The band of snow will continue to spread northeast into northeastern Ontario and Quebec later Tuesday night and early Wednesday with similar results.

The same system will also bring accumulating snow to the Winnipeg area tonight into Tuesday morning with a general 5-10 cm possible.

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Now to the bigger (potential) snow event late this week.

The new ECMWF short-range model is trending stronger with a storm tracking from Ohio to southern Quebec on Friday, while the American GFS is slower to develop the storm.

The ECMWF has been better than the GFS lately, so I will lean in that direction at this point.

The key to this storm is how quickly does the energy from the two separate jet streams merge? We probably will not know that answer until Wednesday, but I will go with the ECMWF at this point and look for a strengthening, but quick storm moving up through the eastern Great Lakes.

Over extreme southern Ontario, this looks like a rain to snow event with small accumulations, but areas along and north of a line from London to Alliston to Ottawa and south of a line from North Bay to Deep River could be in for a significant, quick-hitting snow Friday and Friday evening, perhaps over 15 cm. Ski country north of Montreal could do even better in terms of snow, while Montreal ends up with a mixed bag.

This looks like a heavy rain event for the Maritimes later Friday and Friday night.

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Cold pattern coming into the West with potential snow

Widespread cold will begin to spread over much of western Canada starting late this week, and it appears that the cold could get entrenched for at least a week. The big question at this point is where does the core of the cold set up? Does it get confined over the Prairies or does it spread into British Columbia? Right now, I think the cold initially gets into the Prairies then expands into British Columbia next week.

This type of pattern may also bring accumulating snow to the lower mainland of British Columbia Friday night or early next week. Snow is also likely across the southern Rockies and into southern Alberta.

The GFS ensemble temperature anomaly forecast for Sunday is shown below......

A strong southeast ridge should keep the cold from getting into the eastern U.S. later next week, but there will be a quick shot this weekend.

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The window for significant snow is closing across the Ohio Valley and eastern U.S., but there is still a small opening right at the end of the month and the first few days of March before the impacts of a +AO, +NAO and stratospheric cooling over the far north most likely lead to an early spring.

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