Colorado Low Looms

Our first significant Colorado Low in some time will bring a variety of precipitation types to southern Manitoba today. Rain, snow, freezing rain, and ice pellets will be possible.

A variety of precipitation types will be possible in southern Manitoba today. The map shows areas of rain (green), snow (blue), freezing rain (purple), and ice pellets (red).
A variety of precipitation types will be possible in southern Manitoba today. The map shows areas of rain (green), snow (blue), freezing rain (purple), and ice pellets (red).

Today

Monday
2°C / 1°C
Mixed precipitation early, then rain

A powerful Colorado Low will bring a mixed-bag of precipitation to southern Manitoba today. Precipitation will likely start out as freezing rain or ice pellets in portions of the Red River Valley and south-eastern Manitoba this morning, before changing to rain later in the morning. Rainfall amounts of 5-10 mm are expected in most areas, with higher amounts possible near the International border. There may be a bit of snow at times, but little accumulation is expected – and any that were to accumulate will be melted by rain later in the day. However, the story will be different in western Manitoba, where snow will be the dominant precipitation mode for the day. Accumulations of 5-10 cm are likely in most areas by tonight. Winds will be gusty out of the north-east at 30 km/h gusting to 50 km/h, bringing some blowing and drifting to open parts of western Manitoba.

Tuesday

Tuesday
1°C / -1°C
Periods of snow

This Colorado Low will take its time exiting our region, affecting us once again on Tuesday. Unfortunately (for some), rain will change to snow on Tuesday in the Red River Valley and south-eastern Manitoba. Accumulations of 4-8 cm are likely in addition to possibly a couple millimetres of rain or mixed precipitation early in the day. Western Manitoba can expect another 5-10 cm on Tuesday, bringing totals up to 10-20 cm. The model graphic shown below, which considers a wide-range of possible solution, shows a very high probability (>80%) of over 10 mm of total precipitation in most of southern Manitoba. Winds will remain gusty out of the north on Tuesday at 30 km/h gusting to 50 km/h.

Most of southern Manitoba stands a very high chance of receiving over 10 mm of precipitation with this system (NAEFS graphic).
Most of southern Manitoba stands a very high chance of receiving over 10 mm of precipitation with this system (NAEFS graphic).

Wednesday

Wednesday
-1°C / -4°C
Mainly cloudy with flurries

The Colorado Low will continue to linger on Wednesday, but snowfall rates will decrease. Flurries are expected throughout the day, but accumulations should be small. Winds will remain breezy from the north at 20-30 km/h.

Long Range

It appears that we’ll see generally seasonal to slightly-above seasonal temperatures as we move into early December. However, longer-range models do hint at a very cold arctic air mass being pulling down from the north about one week into the month. This will have to be monitored, as it would be our first significant bought of below-normal temperatures in quite awhile.

Will Our First Snowfall of the Year Come This Week?

Will our first snowfall of the year come this week? That is the question that meteorologists are trying to answer as a complex weather system potentially brings accumulating snowfall to southern Manitoba tonight.

An inverted trough pattern associated with a strong system to our south may help bring snowfall to southern Manitoba
An inverted trough pattern associated with a strong system to our south may help bring snowfall to southern Manitoba

This Week

Today will start out cloudy and cool with temperatures hovering near the freezing mark. Change is coming, however, as a strong weather system moves off the mountains and begins to produce snow over the northern United States and southern Prairies. This is a complex system, with the strongest part well to our south over the midwestern US. A secondary part of this system will move across the southern Prairies and likely produce accumulating snowfall along part of its track. At this point it appears probable that snow will begin to develop over southern Manitoba on Monday night as moisture and lift begins to push into the region. The question is whether conditions will come together just right to produce significant snow over all of southern Manitoba, or whether the system will only begin to produce significant snow as it pushes into northwestern Ontario.

Weather model simulations generally begin to produce light snow over western Manitoba late on Monday afternoon, before the snowfall intensifies as it moves into the Red River Valley and southeastern Manitoba. This would likely result in 1-4 cm of snow over western Manitoba, 4-8 cm over the Red River Valley, and 5-10 cm over southeastern Manitoba. However, an alternative solution would have only minor snowfall (if any) over western Manitoba and the Red River Valley, with slight accumulations of 2-4 cm over southeastern Manitoba. The former solution is most favoured at this time, with about 5 cm expected in the Winnipeg region, with slightly higher amounts to the east and slightly lower amounts to the west. The most likely outcome may change as the system develops today, therefore you should stay tuned for more details.

A map of the currently favoured snowfall outcome is shown below, showing the probability of at least 5 cm of snow; note that Winnipeg has a 70% chance of receiving at least 5 cm. Some blowing snow is possible, due to southeasterly winds of 30 km/h gusting to 50 km/h today, however blizzard conditions are definitely not expected. Winds will taper off by Tuesday, alleviating any blowing snow that does develop. The first major snowfall of the year is always one of the most challenging as drivers adapt to the changing conditions. Regardless of whether it snows tonight, this is probably a sign that you should get those winter tires on if you haven’t already!

Probability of at least 5 cm of snow according to the NAEFS (ensemble)
Probability of at least 5 cm of snow according to the NAEFS (ensemble)

Snow will taper off on Tuesday morning, should it materialize in the first place, leaving Tuesday with cloudy and cool conditions. Temperatures will once again sit near the freezing mark under mainly cloudy skies. The odd flurry is possible during the day, but generally quiet weather is expected. Winds will be light from the west.

A quiet weather day is expected on Wednesday as well, with mainly cloudy skies and just a lingering chance of flurries. Temperatures are likely to be around or just above zero. Winds will be northwesterly at 20-30 km/h.

Long Range

The long range outlook will be partly shaped by how much snow falls this week. If we manage to avoid major snow, it is likely that the remainder of November will remain generally warmer than normal. Because a blanket of snow on the ground reflects most of the incoming sunlight, it is more difficult for us to heat up during the day. The longer we avoid snow the longer we’re able to keep that darker, exposed soil which helps to absorb the limited sunlight that we do receive at this time of year. Should we receive significant snow with this upcoming system, we’ll likely see normal conditions through month’s end. Regardless of how much snow falls this week, this November is likely to end up as one of the warmest, if not the warmest, Novembers on record in Winnipeg.

November “Heat” Continues

Our November “heatwave” will continue into early this week as temperatures remain well above normal. However, change is coming later this week as a strong low pressure system ushers in a much cooler air mass.

This Week

Today will be fairly nice in southern Manitoba. High temperatures will be near the 10C mark in most areas with mainly sunny skies to start the day. Clouds will begin rolling in as the day progresses, in association with a low pressure system pushing in from the west. This system may bring some light showers to southern Manitoba this evening and tonight, but no major accumulations are expected. Stiff southerly winds will be in place during the day with values of 30 km/h gusting to 50 km/h.

A nice Tuesday is expected, with mainly sunny conditions and “hot” temperatures yet again. The mercury should rise near the 10C mark, which is more than ten degrees warmer than normal for this time of year. Winds will be strong again though, with a westerly flow of 30 km/h gusting to 50 km/h.

Slightly cooler weather appears likely for Wednesday as another low pressure system begins pushing up from the south. As a result, skies will be mainly cloudy with a chance of showers or flurries throughout the day. Winds will be easterly at 20-30 km/h.

Long Range

Models have consistently advertised a strong low pressure system passing through the northern US later this week. This exact track of this system remains unclear, but it appears quite likely that it will usher in a much cooler pattern to southern Manitoba from late this week into the weekend.

While the current GDPS forecast has this storm completely missing Southern Manitoba, the GFS clobbers the region with heavy snow.
While the current GDPS forecast has this storm completely missing Southern Manitoba, the GFS clobbers the region with heavy snow.

Should the system take a northerly track we will also have to contend with heavy precipitation, in addition to the cooler temperatures.

More Wet Weather on the Way

More rain is in store early this week as a well-developed low pressure system pushes across southern Manitoba. Accumulations will be relatively small in the Red River Valley, but more significant to the north and west.

A strong low pressure system will bring rain to southern Manitoba today
A strong low pressure system will bring rain to southern Manitoba today

This Week

Rain will move into southern Manitoba today in association with a strong low pressure system coming out of Montana. Light rain will likely begin in the Red River Valley this morning, continuing into the afternoon. Models show a break in the rain during the evening hours, which might just provide a good window for trick-or-treating. Regardless of whether it’s raining or not, temperatures will be favourable for the youngsters to be outdoors, with temperatures hovering in the mid-single digits. Total rainfall of 2-5 mm is expected today, with another 2-5 mm tonight. Parts of western Manitoba and the Interlake can expect total accumulations ranging from 10 to 25 mm.

Today’s weather system will still be lingering over Manitoba on Tuesday, with some showers remaining possible through Tuesday morning. A drier flow should develop by Tuesday afternoon, signalling an end to the precipitation. Temperatures will remain relatively normal for late October, with high temperatures in the mid to upper single digits in southern Manitoba. Winds will be breezy out of the west at 20-30 km/h.

Nicer weather should arrive for Wednesday as a ridge of high pressure builds over the region. Mainly sunny skies and temperatures around or just below 10C are expected. Wednesday’s nice conditions should signal the beginning of a significant warm spell which should last into next week. Winds should be relatively light thanks to the surface ridge.

Long Range

Medium- to long-range models have been strongly hinting at a significant warm-up beginning mid to late this week. An anomalously strong upper ridge of high pressure is expected to build over Central North America, signalling a period of well-above seasonal conditions for Manitoba. Given that our normal high is 4C, we can easily expect temperatures of 10-15C. It is not impossible that we reach the upper teens once or twice when the “heat” peaks sometime over the weekend or next week. Models strongly suggest that this above-seasonal pattern will exist for most, if not all, of the first half of November.

An unusually strong upper-level ridge will build over Manitoba by next weekend
An unusually strong upper-level ridge will build over Manitoba by next weekend