Freezing Rain to Mark Return of Colder Weather

Our wild weather will continue as another low pressure system tracking through the northern Prairies will bring with it mild temperatures and the probable risk for freezing rain over the Red River Valley, including Winnipeg.

Sounding for Winnipeg @ 5:00PM Local Time

Sounding for Winnipeg at 5:00PM local time. Note the significant AFL shaded in red.

Warm air will be pumped over the Red River Valley today as strong southerly winds develop ahead of a major low pressure system set to bring heavy snowfall to the northern reaches of Manitoba. 850mb temperatures will climb to nearly +5°C today, providing an ample AFL[1]. The bulk of the precipitation with this system will be constrained to central and northern Manitoba, where anywhere from 5–20cm of snow are expected. Regions that were hit hard Monday will mostly be spared as the heaviest snow will fall further north than Monday’s system.

We’ll have breezy southerly winds in the Red River Valley today at around 40km/h with gusts to 60km/h with temperatures climbing all the way up towards –1°C by the late afternoon/early evening. As the warm front approaches the RRV in the late afternoon, it looks that an area of showers will blossom along it. There’s still some uncertainty in exactly where the precipitation will be and how quickly it will develop, but it looks probable that areas in the Red River Valley north of Morris will see freezing rain late this afternoon. Areas south of Morris have a very real chance as well, however there’s a little more uncertainty in how far south the band of showers will stretch.

We aren’t expecting huge amounts of freezing rain this afternoon; the quick-moving nature of this system will mean that even if the rain is intense, it’s likely that we’ll only 1–2mm of it. Keep in mind, though, that while 1–2mm isn’t a very significant amount for regular rainfall, it is a significant amount of freezing rain. It’s likely that the freezing rain will fall during the rush-hour period in Winnipeg and quickly turn roads into slick little skating rinks fairly quickly. If you drive to work, especially into or through the downtown core of Winnipeg, expect a slow commute this evening.

Skies will clear overnight as a weak cold front pushes across the RRV and Thursday will bring mainly sunny skies with temperatures falling through the day to –8°C by evening.. Winds will be breezy from the NW at about 30km/h before letting up in the afternoon. Another arctic ridge will push into Southern Manitoba, bringing another shot of cold weather with it. Temperatures will dip all the way to around –20°C on Thursday night and only recover to around –15°C on Friday.

Temperatures will level out a bit for the weekend with highs near –10°C for Saturday & Sunday, but it looks that a weak storm track will move over us, bringing cloudy skies and plenty of chances for light snow. We’ll have more on this weekend’s weather on Friday morning.

Northern Manitoba Communities Buried Under Massive Snowfall

An incredibly powerful low pressure system tracking through Northern Manitoba on Monday brought a nearly unprecedented snowfall event to many communities. Hardest hit were Norway House and Gods Lake Narrows[2] where over 2 feet of snow fell. Environment Canada sent out a brief summary yesterday on the event:

A major winter storm moved across Central Manitoba on Monday, bringing with it some very heavy snowfalls. The heaviest band fell from the Norway House area east to the Ontario border, with numerous public reports of knee- to waist-deep snow accompanied by drifting as high as two metres. Lesser but still significant amounts were received by the surrounding regions of Gillam, Grand Rapids, and The Pas.

Unofficial snowfall totals are as follows:

Location Snowfall
Norway House 60–90 cm
Gods Lake Narrows 60–90 cm
Island Lake 60 cm
Oxford House 45 cm
Cross Lake 30–40 cm
Gillam 35 cm
Grand rapids 30 cm
The Pas 30 cm
Mafeking 23 cm

While official snowfall records for northern Manitoba are hard to come by, it seems likely that these snowfalls are record-high snowfalls for a 24–36 hour period for Norway House, Gods Lake Narrows, and Island Lake. From what I could find, 1-day record-high snowfall totals in Northern Manitoba generally sit around the 40–50cm mark; these totals of 2–3 feet easily quash those records, and whether or not they end up as official “heaviest snowfall” records may come down to exactly how much fell in any given 24-hour period.

Norway House Snowfall Satellite Image

A visible composite satellite image from during Norway House/Island Lake snow storm.

The snowfall came from an extremely potent, moisture-laden low pressure system that managed to find the right combination of convective snowfall and duration. As shown in the satellite image above, a very strong moisture feed was evident as it surged northwards into the low pressure system rooted near The Pas. This system slowly tracked eastwards, producing heavy snow in the above localities for upwards of 18–24 hours.

A system like this is definitely an extremely uncommon one and is difficult to forecast due to the sparseness of surface observations and lack of RADAR imagery. It will likely be just now as this is published that some roads finally begin to be cleared and people are able to return to a more normal daily routine.

A further 5–10cm of snow is expected for the Norway House and Island Lake regions with the system passing through Manitoba today.

  1. Above Freezing Level  ↩
  2. Gods Lake Narrows is a small community north of Island Lake, MB.  ↩

Weather Roller Coaster

This week will be a bit of a meteorological roller coaster as our temperatures climb up, then fall rapidly back down again.

GEM-Regional predicted rainfall total for Monday

GEM-Regional predicted rainfall total for Monday

Monday looks to be the warmest day of the week with above freezing temperature of 1 or 2C expected in Southern Manitoba. Some light rainfall is expected in south-eastern parts of the province out ahead of a cold front. This may lead to icy conditions on Monday night as temperatures drop below zero behind the front. Winnipeg will be right on the edge of this area of rain, so the city isn’t expected to see more than a millimetre or two of rain at most. In fact most models take the area of rain just south-east of Winnipeg, so the northern part of the Red River Valley may end up with no precipitation at all. Temperatures will plummet on Monday night in the wake of the cold front with values dipping down into the minus double digits by Tuesday morning.

High temperatures will remain down in the minus teens in Southern Manitoba on Wednesday, with most areas in the -11 to -14C range. A weather system emerging from the mountains in Alberta will develop a southerly flow over Manitoba on Tuesday night. As a result, Tuesday night will be characterized by increasing warm air advection, allowing for warmer air to filter into Southern Manitoba during the overnight period. We will continue to experience warming on Wednesday as a stiff south wind continues to bring in warmer air. Unfortunately, the wind will be very strong, making conditions much less comfortable than the temperature alone would indicate. Highs on Wednesday will be in the low to mid minus single digits in Southern Manitoba, but wind chills values will be in the -10 to -15 range due to the strong south wind.

Another cold front will move through on Wednesday night or Thursday, setting up a chilly end to the week. No significant precipitation is currently in the forecast for Southern Manitoba this week as the main storm track remains to our north and west.

Unsettled Weather Ahead

A warm but unsettled few days are ahead as mild Pacific air surges across Southern Manitoba.

850mb Temperatures valid this evening

850mb temperatures from the NAM valid for early this evening.

Snow will taper off early this morning with a lingering chance of a stray flurry or two sticking around through much of the day across the northern half of the Red River Valley. Southerly winds will pick up through the day to 30-40*km/h as the warm front alluded to in Wednesday’s post pushes into the Valley. Temperatures will warm up quickly as the front passes with temperatures climbing to around -4 or -3°C, a few degrees warmer than the seasonal normal of about -6°C. Temperatures will remain steady through the night as that south wind continues to keep us in the warm air.

Another disturbance will pass through the northern Red River Valley tonight, however there’s some uncertainty to the areas that precipitation will fall. It currently looks like most, or all, of the precipitation will fall north of Winnipeg, focused in the Interlake region. There’s a slight chance that it will fall a bit further south, clipping Winnipeg and other areas in the northern half of the Red River Valley. If any areas in the Red River Valley are affected by this disturbance, they’ll almost certainly have to deal with freezing rain as there will a massive AFL (Above Freezing Level) just off the surface where temperatures will be nearly +10. With precipitation falling through it, the AFL will cool to 2-3°C, which is still more than warm enough to melt any snow that will be falling into it. Potentail freezing rain accumulations will be light but not insignificant at 1-2mm. Just to reiterate, the risk area for freezing rain will likely be confined to the northern half of the Red River Vally.

In addition to the weather from this disturbance, there will be the potential for freezing drizzle through the entire RRV as warm, moist air overruns our cold snowpack.

Saturday and Sunday will be cloudy days with beautifully warm temperatures for this time of the year. Daytime highs will sit right around 0°C. There will be a slight chance of non-accumulating flurries Saturday night into Sunday, otherwise no significant weather is expected. As winds lighten up, there will be the potential for fog patches through the valley in the overnight hours.

A storm system looks to move into the area on Monday morning, bringing rain or snow in the morning and snow in the afternoon. There’s still uncertainty in the track of the system and how much of the precipitation will impact the Red River Valley, so we’ll be sure to provide an update or two in the comments below through the weekend. The one thing that is certain is that this system will mark a return to more seasonal temperatures as cooler air sweeps over Southern Manitoba in it’s wake.

Warmer Weather and a Bit of Snow on The Way

Arctic ridging will keep our temperatures low over the next couple days but rest assured, warmer weather is on the way.

12hr. QPF for Thurday Night

12hr. precipitation amounts for Thursday night. A band of snow will pass through Southern Manitoba with greatest accumulations through the Interlake region and amounts diminishing towards the U.S. border.

We’ll see another cooler than normal day today as a weak low passing through Central/Eastern Manitoba pulls more cold air southwards and allows re-enforcement of the Arctic ridge in place over the Prairies. We’ll see temperatures climb to about -10°C under a mix of sun and clouds today as breezy winds develop out of the south to 30km/h. This will make it feel a lot closer to -20 out there. There may be a slight chance of a very light flurry over Winnipeg and the Eastern Red River Valley this afternoon, however the chances are slim and if it does happen, there won’t be any significant accumulations.

Temperatures will dip towards the -18 to -20°C mark tonight under partly cloudy skies. Tomorrow we’ll see another day with highs near -10°C with a mix of sun and clouds. A warm front will push through on Thursday night, bringing with it some light snow to the Red River Valley. Lightest accumulations will be in the Southern Red River Valley with greater amounts in the Northern Red River Valley into the Interlake; in general, 2-4cm accumulations are likely. Areas south of Morris may, however, end up with little to no snowfall if the area of snow stays just a little tighter to the system centre as it passes through.

For Friday into the weekend we’ll see an unsettled pattern with bouts of light snow possible through much of the time. We’ll be under cloudy skies, but comparatively balmy temperatures will be in place with daytime highs generally around -1 to -3°C.