Cooler Weekend A Seasonal Reality Check for Winnipeg

Brad Leave a comment

Temperatures will be startlingly colder this weekend than we’ve seen through the first half of November, but despite the shock to the system, Winnipeg will simply be seeing temperatures closer to typical values for this time of year.

The weather through the weekend will be relatively benign overall, with the major storm system forecast once upon a time to slam the Manitoba Red River Valley now taking a significantly more southwards track, instead tracking across central Minnesota into Northern Ontario. With that major system moving through to our south, we’ll be left with cloudy skies and a brisk north wind to 30 gusting 50 km/h. Temperatures will be much cooler with a high near +1°C

As cooler air slumps southwards through the day, narrow bands of lake-effect snow will fire up off of the south basin of Lake Winnipeg. At this point, it appears that the line will run north-south and primarily impact a line between Selkirk and St. Clements southwards towards Springfield. Beausejour may end up just east of the main band, but slight shifts in the wind direction could shift the heaviest band east or westwards. Lighter flurries may make it all the way south of Steinbach. By the time the lake-effect tapers off on Saturday morning, anywhere from 5-15cm of snow may accumulate under the heaviest axis of snow.

If you look to the northwest of the massive Colorado Low blob, a narrow band of lake-effect snow accumulation can be seen east of Winnipeg.
If you look to the northwest of the massive Colorado Low blob, a narrow band of lake-effect snow accumulation can be seen east of Winnipeg.

Skies will begin to clear out on Saturday night, save for locations that see cloud streaming off the lakes. Winds will taper off and temperatures should dip to a low near -6°C.

Saturday will bring a ridge of high pressure to the province, quashing the lake-effect snow and bringing a bit of sunshine and light winds. Highs will reach around 0°C under mixed skies. Saturday night will be partly cloudy with a low near -5°C.

Sunday will bring increasing cloud ahead of a warm front pushing eastwards across the southern Prairies. Temperatures will climb to a high near -1°C with a brisk southeasterly wind at 20-30 km/h. Expect fairly cloudy skies with a chance of some light snow on Sunday night with a low near -4°C.

Back To Normal

As mentioned up top, while these cooler temperatures are a shock to the system, we’re simply in a rapid adjustment back towards seasonal temperatures.

November has been a phenomenally warm month so far, with an average high of 11.3°C, a whopping 9.8°C warmer than the typical average high of 1.4°C through the same 17-day period. Including overnight lows, mean temperatures have been over 6°C above normal, more typical of mid-October than November, and November 2016 has taken the crown with the warmest first half1 of November on record.

Top 6 warmest first halves of November in Winnipeg on record. Credit: Rob's Obs
Top 6 warmest first halves of November in Winnipeg on record. Credit: Rob’s Obs

And, while a brief seasonal snap is on the way, models indicate that by next weekend above-normal temperatures will be back in full force, which could enter the month into the competition for warmest November on record!

Long Range

The system pushing the warm front eastwards across the Prairies on Sunday will continue to push eastwards and bring another chance for snow to the region on Tuesday. After that, it appears that a series of low pressure systems will track to our north and begin building warmer air back into the Prairies.

Winnipeg’s seasonal daytime high is currently -3°C while the seasonal overnight low is -11°C.

  1. First half of November is November 1-15, inclusive. ↩

Coldest Weather So Far This Season Arrives In Big Pattern Shift

Brad 1 Comment

An increasingly active storm track will bring a major winter storm through the Northern Plains of the U.S., drawing colder arctic air southwards cross the Prairies and ushering in the coldest temperatures seen so far in the fall of 2016.

Today will start with a weak system pushing through the Red River Valley, bringing with it a band of showers that will lift northeastwards across the region through the first half of the morning. After that moves through, we’ll be left with fairly cloudy skies as temperatures climb to a high near 9°C. Winds will pick up out of the southeast this morning to around 20-30 km/h, then taper off for the afternoon. Expect the winds to pick back up out of the northwest later in the evening with a slight chance of some very light rain showers or snow flurries overnight as a cold front moves through and temperatures dip down to the 0°C mark.

Thursday will bring mainly cloudy skies as a Colorado Low strengthens south of the border. Winds will be breezy out of the north to northwest at around 20-30 km/h and temperatures will climb to a high of about 3°C.

This history of forecast precipitation for Friday's Colorado Low shows how the GDPS model has developed consistency only in the last day and a half.
This history of forecast precipitation for Friday’s Colorado Low shows how the GDPS model has developed consistency only in the last day and a half.

Since last weekend, it’s been quite clear that a major winter storm was possible on Friday, and that much it got right. However, what at one point looked like a major blizzard for the Red River Valley has since turned into a moderate-strength winter storm for the Dakotas and Minnesota into Wisconsin. There’s a whole discussion on long-range model forecasts, but we’ll leave it at this: while it may get the general pattern right, don’t trust it on the details.

So what will we see instead of a blizzard? Cloudy skies and a stiff north wind likely at 40 gusting to 60 km/h. The southeastern portion of the province may get clipped with some snow from this system, but here in the Red River Valley, the system snow should miss us. There may, however, be a sneak attack from the north as cooler air surges southwards and lake-effect snow fires up over the lakes. Areas in the lee of the lakes may see some light to moderate snow flurries, however these will occur in fairly narrow strips and be highly dependent on the wind direction.

Temperatures will climb to only -1 or 0°C for a high. Expect the cloud and potential lake-effect snow to continue overnight as temperatures fall to a low near -4°C.

Long Range

The weekend looks cool with a continued chance for lake-effect snow through the day on Saturday. Cloud cover will be a mixed bag and highs will be near 0°C with lows near -6°C or so. If we get completely clear skies one night, then temperatures could plummet quite severely, though, so an overnight low below -10°C may be possible if the cloud manages to be scoured out of the Valley.

November “Heat” Continues

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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.

Can’t Keep The Heat Down For Long

Brad Leave a comment

A cold front that passed through yesterday will try to cool things off in Winnipeg, but the heat won’t be kept down for long with well above-normal temperatures bouncing back into the region for the weekend.

A cooler air mass will be in place over Winnipeg today, ushered in by a series of cold fronts which passed through the region on Thursday. Today’s high temperatures will sit around 6°C across Winnipeg & the Red River Valley under sunny skies. While this is 7°C cooler than yesterday and 12°C cooler than Wednesday’s high of 18.8°C, a high of 6°C is still well above the seasonal average high of 0°C.

The wind will begin to pick up out of the south this afternoon, first to 20-30 km/h and then strengthen to 30-40 km/h tonight as a warm front pushes across the Red River Valley. Temperatures will dip to a low near 3°C.

Saturday will bring milder air back to Southern Manitoba. With the warm front off to our east, mainly sunny skies, and light winds, the high of 12 or 13°C will feel quite pleasant. Temperatures will drop to a low near 4°C on Saturday night.

The heat continues on Saturday with temperatures forecast to be over 10°C above normal.
The heat continues on Saturday with temperatures forecast to be over 10°C above normal.

Sunday will bring mixed skies as a cold front sweeps through midday. Temperatures will reach a high near 11 or 12°C before the front comes through, and then the winds will pick up out of the northwest to 20-30 km/h. It doesn’t appear that the passage of the front will bring any rain to the region, but a very light sprinkle can’t be ruled out.

Temperatures will drop to a low near 0-1°C on Sunday night.

Long Range

It appears that the unseasonably warm and dry weather will continue for quite a while yet, with most outlooks showing no sign of significant abatement until next weekend. The biggest sign of change looks to be a system expected to track into our region on Friday November 18th. Models diverge on the general outcome of this system, with two primary possibilities:

  1. A quick-moving system that slides through over 12-18 hours and produces 10-20 mm of rain over Southern Manitoba.
  2. A significantly slower outcome: a potent Colorado Low that could potentially produce a blizzard over Southern Manitoba.

It’s still very early to speculate much on this, but the one thing that looks fairly certain is that, no matter which solution, it will mark a shift in the overall weather pattern that will bring temperatures (generally) back towards seasonal values.

Winnipeg’s seasonal daytime high is currently 0°C while the seasonal overnight low is -8°C.