Tag: Lake-Effect Precipitation

RDPS 2m Temperature Forecast valid 21Z Thursday October 24, 2019

Cool With An End-of-Week Warm Up

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Winnipeg’s cool weather will stay for a couple more days, then warmer weather arrives for the end of the week.

A couple cool days are coming up for Winnipeg as an Arctic air mass remains entrenched over the region. The city will see a high of only 3°C today as northwest winds of 30 gusting 50 km/h continue. Skies will stay cloudy for much of the day as a combination of system1 and lake-effect cloud moves through.

As the day progresses and cooler air aloft pushes into the area, both Lake Winnipeg and Manitoba will likely begin to produce some lake-effect snow. Winnipeg may see some of this snow or rain in the morning. By the afternoon, the precipitation will mainly fall in the lee of the lakes. With a northwest wind, this will likely mean that Winnipeg will end up between a band of snow or rain showers to the west and to the east.

Lake-effect flurries are possible in the lee of the lakes today. The most likely areas to see precipitation will be in the lee of Lake Winnipeg.
Lake-effect flurries are possible in the lee of the lakes today. The most likely areas to see precipitation will be in the lee of Lake Winnipeg.

The lake-effect precipitation will taper off overnight as the winds ease and turn westerly. The city will see a low near -2°C as the cloud cover begins breaking up.

Thursday will be a cool day with a high of just +4°C. A ridge of high pressure moving through will keep the winds light, but skies will remain partly cloudy to mixed. A warm front pushing eastwards across the Prairies will spread a southerly wind into the Red River Valley on Thursday night along with a bit of cloud. Winnipeg’s low will sit somewhere around the freezing mark.

A return to seasonal warmth arrives on Friday as temperatures climb to a high near 10°C. The region will likely see a fair amount of cloud as the warmer air pushes as well as a strengthening southerly wind into the 30 to 40 km/h range. These breezy winds will persist through the night, keeping the low relatively mild at around 6°C.

Long Range Outlook

Seasonal warmth will stick around for Saturday, but a passing low will send a cold front sweeping through the region on Saturday night. While the Red River Valley won’t see much precipitation, it will plunge the region into an extended stretch of below-seasonal temperatures. There isn’t much rain or snow in the extended forecast, but with the cooler temperatures it’s likely that lake-effect flurries will be relatively common in the coming week.

Today’s seasonal daytime high in Winnipeg is 7°C while the seasonal overnight low is -3°C.

  1. “System” cloud is the cloud associated with a low pressure system. ↩

Cold, Wet Weather Continues

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Cold and wet weather will stick around in Winnipeg for another few days.

Winnipeg will get another soaking today as more rain moves through the region. The rain will intensify early this morning as the low responsible for all this wet weather moves through the Dakotas. Much of the Red River Valley, including Winnipeg, will see another 15 to 30 mm of rain before it tapers off through the afternoon. Northerly winds near 30 km/h will keep things cool with a high of just 8°C. Temperatures will dip down to a low near +2°C tonight with north-northwest winds of 10 to 20 km/h. Some lake effect snow or rain showers are possible in the lee of Lake Manitoba and Lake Winnipeg tonight.

Another moderate rainfall will occur across southern Manitoba today.
Another moderate rainfall will occur across southern Manitoba today.

The region will see a brief break from the rain on Tuesday as an arctic ridge moves across the province. It won’t bring much sun, though, with mainly cloudy skies persisting across southern Manitoba. Temperatures will be cool again with a high near 7°C in Winnipeg with northerly winds of 15 to 20 km/h. The chance for lake-effect rain showers or flurries will continue in the lee of the lakes for much of the day. Winnipeg will see a low near +2°C again with light winds tonight under cloudy skies.

Skies will stay cloudy on Wednesday with light winds through the day. Highs through the region will be cool near 6 or 7°C. Yet more rain looks to be on the way on Wednesday night as another low spreads rain out of the U.S. into the Red River Valley. Another 5 to 10 mm is possible on Wednesday night with temperatures heading to a low near +3°C.

Long Range Outlook

Rain will taper off for the rest of the work week with highs climbing back into the low teens. Some sun will work back into the region for Thursday and Friday as well.

That said, another low looks to move towards the region to start the weekend, with another 5 to 10 mm possible on Saturday. Forecasts show things finally settling heading through the latter half of the weekend into next week. Temperatures are forecast to return to seasonal values early next week.

Today’s seasonal daytime high in Winnipeg is 15°C while the seasonal overnight low is +3°C.

Cool With Light Snow Mid-Week

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Arctic air will continue to build southward over the eastern Prairies in the coming days, bringing below-seasonal temperatures, variable cloudiness, and on Wednesday, some light snow.

Cloud will build into Winnipeg from the northwest later today as a cold front slumps southwards out of northern Manitoba, possibly bringing the occasional snowflake, but nothing that resembles accumulating snow. Temperatures remain cool with a high near -6°C, almost 9°C below seasonal for this time of year. Winds will continue out of the west at around 15 to 20 km/h through the day today. Skies should clear out overnight as temperatures head to a chilly low near -17°C. Winds will remain out of the west at 10 to 15 km/h.

Tuesday will see morning sun transition to mixed skies as another disturbance approaches from the northern Prairies. Temperatures will be similar to Monday with highs near -6°C again, but Tuesday night will be considerably warmer with lows near -9°C courtesy overcast skies that will move into the region. Winds will shift from west to northwest on Tuesday night, setting the stage for cooler air to move in on Wednesday.

Some light snow is expected across much of southern Manitoba on Wednesday

Expect cloudy skies on Wednesday with some light snow and a cool high near -8C. Those northwesterly winds will likely fire up the lake-effect snow once again, enhancing the flurries to the south of Lake Manitoba and Lake Winnipeg.

Expect the clouds to persist much of Wednesday night with temperatures dropping to a low near -16°C.

Long Range Outlook

The remainder of the week will continue to bring mixed skies with the occasional chance for flurries. By Saturday, temperatures should begin to climb back towards the freezing mark, with near-seasonal temperatures expected to start next week!

Winnipeg’s seasonal daytime high is currently 1°C while the seasonal overnight low is -7°C.

Cooler Weather With More Snow

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Plenty of cloud and snow is in the forecast as one low pressure system leaves only to be quickly replaced by another mid-week. Temperatures will also remain cool as a large upper trough keeps the jet stream south and allows cooler Arctic air to spill into the Prairies.

Today will bring mainly cloudy skies to the region as a low pressure system that tracked through the region on Sunday pushes off into eastern Ontario. To start off the morning, widespread flurries in place across the region will taper off as a strong northerly wind of 40-50 km/h develops. Snow will taper off by midday for many locations except for two: those in the lee of Lake Manitoba and Lake Winnipeg.

RDPS 24hr. Accumulated Snowfall in Inches at 10:1 SLR valid 00Z Tuesday October 31, 2017
At a 10:1 snow-to-liquid water ratio, which may be low for the snow coming off the lakes, models suggest close to 10 cm of snow in the lee of Lake Winnipeg and Lake Manitoba

Strong northerly winds align along the basins of each lake this morning and persist all day, and as the colder air moves into the region, bands of lake-effect snow will develop and move southwards off the lake. The areas highlighted in the area above are the most likely to see snow and significant accumulating snow. Snowfall accumulations can be difficult to forecast in these events, but indications are that as much as 10 to 20 cm may fall by the end of the day under the heaviest band of snow. The Lake Manitoba event will taper off in the early evening as a ridge of high pressure moves in and eases the winds, while Lake Winnipeg will persist longer, weakening in the evening and ending overnight.

Aside from the snow, it will be a cool day whose high near -1°C will feel closer to -8 or -9°C with the strong northerly wind. Once the ridge moves into the area in the evening, winds will taper off and temperatures will head towards a low near -8°C under mixed skies.

Tuesday will bring benign weather to the region with mixed skies and temperatures climbing back to a high near -1°C. Winds will pick up out of the south through the morning hours, strengthening to 25 to 35 km/h for the afternoon hours. By evening, more cloud will be spreading across southern Manitoba in advance of the next low pressure system as it tracks across Saskatchewan. The cloud will keep temperatures a bit warmer overnight with lows of around -3°C. Winds will continue out of the southeast at around 20 to 30 km/h.

Wednesday will see the low and its associated area of snow move through the province. In the Red River Valley, snow will begin early in the morning and persist into the evening. As is the case with these early season events, the biggest challenge with this system will be the near-zero temperatures with daytime highs climbing to around 0 or +1°C and how that will affect how much snow accumulates versus melts. The expected snowfall is around 4 to 8 cm, but the actual accumulated amount will be less than that, with roadways likely ending up with a slushy centimetre or two by the end of the day, and grassy areas seeing closer to, but not the full, amount that falls.

Fortunately, winds will taper off in the morning, so visibilities will be as good as they can be with the snow falling. The wind will pick up out of the north in the afternoon into the 20 to 30 km/h range. The cloud cover will likely remain through the night with the potential for a bit of lake-enhanced/effect snow coming off of Lake Manitoba and Winnipeg. Temperatures will dip to a low near -6°C.

The only real uncertainty with this system is how far south it will end up going, and whether or not it will end up too far south to impact our region. The general consensus is that Winnipeg and the Red River Valley will see snow, but we’ll be keeping an eye on how it develops just in case.

Long Range

The remainder of the week doesn’t look much better; Thursday will see any remaining flurries taper off with a continued north wind that makes the high near -1°C feel rather cool. Temperatures will then dip down to the low minus single digits on Thursday night and rebound to just -2 or -3°C on Friday under mostly cloudy skies. Another cold night on Friday night will lead into highs returning to the freezing mark on the weekend, but that’s due to the approach of a mother system that will bring another wintery mix to the region late Saturday into Sunday.

NAEFS 8-14 Day Temperature Anomaly Forecast — Valid November 6-13, 2017
NAEFS 8-14 Day Temperature Anomaly Forecast — Valid November 6-13, 2017

Once that passes by, a significant chill will descend across the Prairies, bringing below-normal temperatures for an extended period, alongside the potential for more snowy weather.

Winnipeg’s seasonal daytime high is currently 4°C while the seasonal overnight low is -5°C.