[Thunder Bay Weather] Extreme cold warning lifted, warm moisture starting to take hold, increased chance of snowfall over the next week

Although it may seem counterintuitive, in Thunder Bay's winter, "cloudy skies/start of snowfall" and "warming temperatures" are highly correlated terms:

It is expected that after nightfall tonight, Thunder Bay's weather will gradually become cloudy, marking the official end of the cold high-pressure system's absolute control over Thunder Bay, as a new "Alberta Clipper" low-pressure system, accompanied by warm, moist air, takes the weather stage once again.

Currently, all major weather models support that from the early morning to mid-morning tomorrow (Wednesday), this warm, moist air will fill the near-surface dry zone created by the earlier cold air, with a chance of producing a bit of light snow; at the same time, temperatures will rapidly rise from this morning's -30°C to around -10°C tomorrow morning, shifting from extreme cold to normal cold.

Looking across Ontario, after this warm, moist air passes Thunder Bay tomorrow, it will continue eastward, creating lake-effect snowfall in places like Marathon on the eastern shore of Lake Superior. Due to absorbing moisture from the still-unfrozen parts of the lake's center and being on the windward slope of the southwest wind, the snow there will be much heavier than in Thunder Bay. (Figure 3)

Over the next ten days, the "Alberta Clipper" low-pressure system will gradually become more active. Apart from tomorrow, there will still be several rounds of snowfall opportunities from this Saturday to next Wednesday (see animated graphic). Although the extreme cold of -30°C from the cold high-pressure system is unlikely to occur in the short term, temperature fluctuations before and after the low-pressure system passes will still be significant, so everyone should adjust their clothing in a timely manner based on temperature changes.