When Southern Manitobans hear the phrase “Colorado Low” uttered at this point in October, there is usually a groan of disapproval uttered, and a dash for the snow shovels and a quick check the snow-blower will fire up. This time around we’ll be running for our rain gauges and rain jackets.
“We’ve been keeping an eye on this system since mid last week when it first started showing up in the forecast models,” indicated CMOS Accredited Weathercaster Chris Sumner. “It has all the usual Colorado low traits, including the potential for heavy, wet snowfall and gusty conditions. But, like we’ve seen before, it’s all how these storms track, and how that relates to where you are.”
Sumner explained, typically, regions on the north or cold side of the low will receive snowfall, while those south of the low’s centre, or the warm side, will receive the majority of precipitation as rainfall.
“With that in mind, the track of this low will see it take a hard northerly turn Sunday as it heads northeastward toward Hudson Bay,” he said. “As long as that path stays as forecast, because Colorado lows are notorious for hard to predict tracks, the vast majority of Southern Manitoba will stay on the south side of the low in the warm air-mass portion of the system, meaning rain and not snow.”
Environment Canada is currently projecting the heaviest swath of snow will be in Saskatchewan in a line from the Regina region northeastward into Manitoba’s Parkland area, northern Interlake and onto Hudson Bay. Special Weather Statements are currently in effect for those parts of the province.
With that said, Sumner stressed that forecast doesn’t mean we will be snow free, with flurries possible as temperatures cool overnight Sunday into Monday morning. Due to the ground still being relatively warm, he expects little of that to accumulate, if any.
Areas south of the Trans Canada highway can expect shower activity to develop Sunday night, intensifying into rain overnight, and then lasting throughout much of Monday. Overall storm totals are projected to be in the 15 to 25mm range, with slightly higher amounts possible in the southwestern corner of the province, and slightly less for regions along the Manitoba/Ontario border. There is even a chance we could hear a clap of thunder, or two, overnight and Monday morning.
“As that warm moist air is pulled into the low, and interacts with the cold air on the north side, instability will develop, and that could lead to a thunderstorm or two popping up,” Sumner added.
Meanwhile, gusty northwesterly winds will develop Monday morning, up to 60 km/h, and last for much of the day.
Average temperatures for this time of year are 8 daytime and -2 overnight.
“Because we will be in the warm sector of this system, temperatures Sunday and Monday will be several degrees above average for this time of year, hitting the 12 to 14 range,” he said. “As the cold front swings through Monday, temperatures will drop dramatically throughout the day, as much as ten degrees potentially, landing in the low single digits by late afternoon around +2 to +4.”
This Colorado low will be a fast moving one, pulling out of the region by Tuesday morning. Tuesday and Wednesday will be cool and cloudy, for the most part, with temperatures below seasonal for this time of year. Warmer, and sunnier, conditions are expected to build in late this week and into the weekend.