Cool, Cloudy Conditions Here For A While

Winnipeg will continue to see cool temperatures and variable cloudiness with no major pattern change in sight.

The shift to late October weather isn’t going anywhere, all thanks to a prominent “Rex Block” over the eastern Pacific. This feature has built a potent upper ridge over the Pacific which results in a large upper trough downstream: over the Prairies. This has, and will continue to, allow Arctic air to spill southwards and remain in place longer than we typically see at this time of year.

That said, today will be a cold one in Winnipeg. Breezy northwesterly winds of 20 to 30 km/h behind a cold front that moved through overnight will keep temperatures cool. With a high of just +4°C, Winnipeg will remain over 10°C below seasonal today. Skies will be mostly cloudy; a few sunny breaks are possible, but plenty of stratus cloud will remain in the region and streaming off of the lakes.

Lake-effect snow and/or rain showers will stream off of Lake Manitoba and Lake Winnipeg today.
Lake-effect snow and/or rain showers will stream off of Lake Manitoba and Lake Winnipeg today.

Through the morning, Lake Manitoba will be producing a narrow band of snow that will drift southeastwards off the lake. There’s a chance that Winnipeg may see a bit of rain or snow from this band a bit later in the morning. The lake-effect precipitation should taper off midday as the winds shift a bit more westerly.

Skies will clear tonight as a ridge of high pressure moves across the province. Winnipeg will see its first hard freeze of the season with temperatures dropping below zero this evening and reaching around -4 or -5°C by Saturday morning.

Saturday will bring slightly warmer temperatures back to Winnipeg as the Arctic ridge slides off to the east. Temperatures will climb to a high near 9°C with mixed skies developing for the afternoon. Winds will remain light at 10 to 20 km/h. A trough of low pressure moving through in the evening will bring a chance of rain showers to the city. Skies swill slowly clear through the night as temperatures drop to a low near +1°C.

The Red River Valley will see its first widespread, major freeze of the year on Friday night into Saturday morning.
The Red River Valley will see its first widespread, major freeze of the year on Friday night into Saturday morning.

Winnipeg will see some sunshine Sunday morning, but more cloud will move in for the afternoon. Temperatures will only climb to around 6°C. Skies will remain cloudy on Sunday night with temperatures dipping to a low near 0°C.

Long Range Outlook

Unfortunately, little change is on the horizon. Next week looks set to bring variable cloudiness alongside a couple chances for some rain. Daytime highs are forecast to remain 10°C or less all through next week with overnight lows near or just below freezing.

Winnipeg’s seasonal daytime high is currently 15°C while the seasonal overnight low is 4°C.

Light Snow Gives Way to Cool But Pleasant Conditions

Snow moving through the region today will give way to more sunshine, but below-seasonal temperatures remain.

Winnipeg will see another day with high temperatures above the freezing mark with cloud cover spreads eastwards into the Red River Valley. Winds will remain light, which should help make a relatively pleasant day. Skies in Winnipeg will become cloudy by late afternoon with light snow spreading into the region this evening. This system will bring 2 to 4 cm of snow to the city1, but higher amounts will fall to the west and southwest. 4 to 8 cm of snow is likely through Parkland and southwestern Manitoba, extending into the southwestern Red River Valley. The snow will ease to a few flurries overnight as temperatures dip to a low near -6°C.

24hr. RDPS Snow Accumulation (at 10:1 SLR) valid 12Z Thursday April 12, 2018
A swath of snow will fall across southwestern and south-central Manitoba Wednesday afternoon into Wednesday evening.

Any remaining flurries will taper off on Thursday morning as skies gradually clear. Temperatures will be similar to Wednesday with a high near +1°C, but northerly winds of 15 to 25 km/h will be more prominent in the afternoon. While Winnipeg will have more sun than cloud by the afternoon, the southern Red River Valley will likely have to wait until evening to see the cloud cover move out. Winds remain out of the north at 10 to 20 km/h on Thursday night as temperatures dip to a low near -11°C.

Friday will bring mainly sunny skies to Winnipeg as a ridge of high pressure builds in from the north. Winds will continue out of the north at 20 to 30 km/h. Temperatures will continue to be cool with a high near +1°C. Winds will ease on Friday night as temperatures dip to a low near -12°C.2

Long Range Outlook

The weekend is actually looking quite pleasant with plenty of sunshine and daytime highs climbing back into the mid-single digits.3 Winds look to remain light out of the east.

The next chance for precipitation looks to come mid-week with increasing cloud as a Colorado Low develops over the Northern Plains. On the bright side, it looks like a gradual trend towards seasonal temperatures through the course of the week!

Winnipeg’s seasonal daytime high is currently 9°C while the seasonal overnight low is -3°C.

  1. Amounts could end up a bit less due to snow melting on contact with the ground early in the event.
  2. With the incoming ridge of high pressure, it’s possible that temperatures could reach even a few degrees colder if the conditions are right.
  3. It has to be noted, though that this is still well below seasonal normals.

Temperatures Climb Above Freezing But More Snow Ahead

Temperatures will finally climb above 0°C this week, but sadly more snow is on the way.

Winnipeg will see temperatures finally climb above the freezing mark today as the high climbs to around 0 or +1°C under sunny skies. Once the sun burns off the morning chill, it will actually be a fairly nice day with light winds as a ridge of high pressure moves across the province. A bit of cloud cover will begin moving into the region tonight as temperatures dip to a low near -7°C.

Tuesday will bring mixed to mostly cloudy skies as thicker cloud cover builds into the province ahead of the next low tracking across the Prairies. Temperatures will reach the closest to seasonal they’ve been since March 28th with a high near +4°C expected. Unfortunately, this will still be a fair amount below the seasonal high of 8°C. Winds will pick up out of the west to around 15 to 25 km/h in the afternoon. Skies will become overcast Tuesday evening with temperatures falling to a low near -4°C.

12hr. Accumulated Snowfall GDPS/GFS/NAM Comparison valid 00/06Z Thursday April 12, 2018
Comparisons of 12 hour accumulated snowfall across Southern Manitoba through the day Friday

A weak low passing through Saskatchewan into North Dakota will spread a narrow swath of snow southeastwards across the Canadian Prairies. It will spread snow across Manitoba through Wednesday, however where the snow exactly falls is a bit in question and depends precisely on the track the low ends up tacking. In general, it looks like this low will produce a swath of snow from western Manitoba into North Dakota. Around 5 to 10 cm of snow looks likely along the centre of the swath with amounts quickly tapering off into the 2 to 4 cm range to the north and south. Isolated pockets of higher amounts are possible under the heaviest band.

Winnipeg will likely end up under or just north of this band. It looks like 2 cm would be a likely low-end forecast for Winnipeg, with 3 to 6 cm looking likely through the day. That said, with temperatures near or just above freezing, some of that snow may melt, shaving a bit off the measurements.

The snow will taper off in the afternoon/evening, with winds picking up out of the north-northeast to around 20 to 30 km/h. Temperatures will head to a low near -6°C under cloudy skies on Wednesday night.

Long Range Outlook

Attention then turns to Friday, where weather models are picking up on the development of a potent storm in the United States but have strongly diverging opinions on where it will go. There may be a good chance that it remains south of the border as a strong deformation zone develops south of the 49th as the cooler outflow from the northern Prairies is pinned against the developing Wyoming/Colorado low.

GDPS 24hr. Snowfall Accumulation Forecast valid 00Z Saturday April 14, 2018
While the location is uncertain, there is good agreement of Friday’s storm system producing upwards of 25 cm of snow along its heaviest swath

Earlier model runs had this system pushing into southern Manitoba, which is something we’ll definitely keep an eye on. It will be a very potent storm, likely producing significant snowfall with totals of more than 25 cm across its heaviest bands, so wherever it ends up will have to deal with a return of treacherous winter travel conditions. We’ll be keeping an eye on things as they develop and have updates later in the week!

Winnipeg’s seasonal daytime high is currently 8°C while the seasonal overnight low is -3°C.

Cool Weather Continues

The rest of the week will bring more of the same: unseasonably cold temperatures.

Cold weather will continue for Winnipeg throughout the second half of the week as a persistent northwesterly continues to tap into Arctic air. Daytime highs will remain well below the seasonal value near 6°C over the coming days starting with a high near -2°C today that will slump towards -5°C by Friday. Overnight lows will keep with the trend as well, generally hovering near -15°C, about 10°C below seasonal.

Skies will be cloudier through the second half of the week than they were in the first. A sunny start to today will lead to mixed skies this afternoon as low-level instability develops. These clouds will dissipate as soon as the temperatures begins dropping in the evening. Quickly replacing them will be a more organized area of cloud associated with a weak low pressure system tracking across northern Montana into North Dakota. This will spread mostly cloudy skies into Winnipeg and the Red River Valley for Thursday. An area of organized light snow will likely spread eastwards through areas primarily south of the Trans-Canada Highway on Thursday morning, but flurries are possible for much of the day as another cold front slump southwards through the province. Skies will be back to mixed to mainly cloudy on Friday with a very slight chance of a flurry.

GDPS 300mb Height and Wind valid 12Z Thursday April 5, 2018
An entrenched and slow-moving vortex over southern Hudson Bay is sustaining a cold northwesterly flow over the Canadian Prairies

The wind won’t be too much of an issue today, but on Thursday they’ll pick up out of the northwest again up to 30 km/h. The winds will ease on Thursday night, then pick back up to 30 gusting 50 km/h on Friday. Brrr!

Long Range Outlook

The extended forecast hasn’t changed too much from our last forecast: a slow and gradual trend towards seasonal conditions. That said, what is considered seasonal is changing quickly now; the seasonal daytime high is increasing by 0.4°C per day right now, so today’s 6°C will be nearly 9°C by this time next week. That said, it is beginning to look like temperatures may return to seasonal values by the latter half of next week, so relatively speaking, a big warm-up might be in store next week!

Winnipeg’s seasonal daytime high is currently 6°C while the seasonal overnight low is -5°C.