Tag: Lake-Effect Precipitation

Cooler Weekend A Seasonal Reality Check for Winnipeg

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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

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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.

Cloudy & Cool Days Ahead

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Winnipeg will be stuck in a fairly cloudy and cool second half to the work week as a broad upper-level trough remains entrenched over the region.

Cool & Relatively Dreary

While this morning may bring a few smiles with some sunshine, more cloud will quickly be moving back into Winnipeg, turning skies grey and leaving cool, fall-like weather in the wake. By early this afternoon, skies should be completely clouded up once again with temperatures topping out near 6°C. Winds will be out of the west-northwest at around 20-25 km/h with some gusts in the 30-40 km/h range.

Skies will remain fairly cloudy overnight with northwesterly winds continuing and temperatures dipping down to around 1°C.

Thursday morning will bring more cloudy skies with a slight chance of some shower or flurry activity as a weak band of lake-effect precipitation moves off of Lake Manitoba. It should dissipate by midday, and we’ll be left with cloudy skies that gradually begin to break up late in the afternoon, calm winds, and a high near 7°C.

Thursday night will bring a low once again near 1°C under partly cloudy skies.

Showers Possible Friday

A warm front moving across the Prairies on Friday will bring the chance of showers to the region alongside a shift to a warmer weather pattern.

A warm front will push eastwards across the Red River Valley on Friday.
A warm front will push eastwards across the Red River Valley on Friday.

By midday the chance for showers move into Winnipeg with winds picking up out of the south to 30-40 km/h. It doesn’t look like rainfall totals will be much to speak of (less than 2mm), but there may be just enough to make the ground wet.

The warmest air will remain to our south, however, so daytime highs will sit near 9°C. Friday night will bring a low near 2°C under partly cloudy skies.

Long Range

The weekend is looking slightly warmer with highs near 10°C and overnight lows continuing in the 1-2°C range. Skies will likely be mixed through the weekend and there may be another chance for some light shower activity on Saturday afternoon.

Winnipeg’s seasonal daytime high is currently 9°C while the seasonal overnight low is -2°C.

From Well Above-Normal Temperatures to Well Below

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It has been easy to forget that we’re actually well into fall at this point with the gorgeous weather that was in place over the weekend the continued mild temperatures to start the week. A potent reminder is on the way today as significantly cooler weather moves in behind a cold front that pushed through earlier this morning.

Today will start with a few morning showers tapering off, which may be followed by a brief break in the clouds allowing for a little bit of sunshine. Skies will cloud back up quickly, though, and the chance of showers will return for the afternoon. Winds will be fairly gusty out of the south-southwest today, increasing to 30 gusting 50 km/h midday. Temperatures will be significantly cooler than seen in the first half of the week with temperatures gradually falling to around 9°C this evening as Arctic air begins filtering into the region.

Skies will remain cloudy overnight as any remaining showers move out of the region. Temperatures will dip to down to a low around 3°C with the breezy conditions continuing.

Thursday will bring well below-normal temperatures to Winnipeg as mainly cloudy skies with continued gusty southwesterly winds. Not much is expected by way of precipitation and daytime highs will top out near 8°C. Expect an overnight low near 2°C on Thursday night under mainly cloudy skies.

Below-normal temperatures (blue) are expected across the entire Prairies in the wake of a powerful low pressure system that moved through the region in the first half of the week.
Below-normal temperatures (blue) are expected across the entire Prairies in the wake of a powerful low pressure system that moved through the region in the first half of the week.

Friday will see the winds shift to northwesterly, continuing to reinforce the cold air as well as firing up the Lake Effect machine. As a result, temperatures will be quite cool with highs near only 8°C again. There will be a fairly good chance of some showers, however that will be greatly enhanced in the lee of Lakes Winnipeg & Manitoba as streamers set up in the cool northwesterly flow. Winds will be moderate as well, increasing to around 30 gusting 50 km/h. Friday night will see temperatures drop to a low near 1-2°C with showers tapering off and some clear patches developing.

Long Range

Temperatures will remain cool with a chance of showers through the weekend and into the beginning of next week as southern Manitoba remains stuck in a northwesterly flow. By the middle of next week, though, we may finally see warmer air begin building across the Prairies, with seasonal to above-seasonal temperatures building in for next weekend.

Winnipeg’s seasonal daytime high is currently 14°C while the seasonal overnight low is 2°C.