Category: Forecasts

Spring is in Sight

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The GFS depicts an upper-level ridge building into our region early next week.
The GFS depicts an upper-level ridge building into our region early next week.

Winter-weary Winnipeggers can take solace in the fact that an end to the never-ending winter is in sight. There is increasing confidence that a large upper-level ridge will build into the Central U.S. and Southern Prairies early next week and finally bring some seasonal to slightly above seasonal temperatures to the region. First, though, we’ll have to make it through the rest of the week.

A Cold End to the Week

Cold temperatures will continue to persist through the remainder of the week with well below seasonal highs and lows expected. These cold temperatures are being caused by a large stationary trough of cold air over Hudson Bay that has locked the eastern Prairies into a northwesterly flow that has allowed cold Arctic air to spill southwards, dashing the warm-weather hopes of battered and beleaguered Manitobans.

Wednesday
-2°C / -17°C
A few clouds.

Thursday
0°C / -10°C
Partly cloudy. Slight chance of flurries.

Friday
5°C / 1°C
Late day cloudiness; warming up.

Tonight will be the coldest night for the remainder of the week in the Red River Valley thanks to another push of cold air on the back side of a low pressure system passing to our south. There will be a strong chance of another swath of record low temperatures broken – similar to Monday night – as overnight lows dip some 15-20°C below normal.

Thursday brings a similar high to today, around -2°C, however temperatures just off the ground will be a little bit cooler. This combination will result in stronger low-level instability and we could potentially see a few light flurries develop through the Red River Vally similar to what was seen on Monday afternoon. Overall the risk is very slight, though. Temperatures will drop to a more mild -10°C Thursday night as warmer air begins pushing eastwards.

Friday will be the warmest day so far this week. Temperatures look to climb above the freezing mark towards +4 or +5°C with only a bit of cloudiness to contend with. Winds will be a little breezy out of the southeast to around 20-30km/h, but overall it will be quite a pleasant day with plenty of sunshine. Some cloud will begin streaming in late in the day ahead of the next system pushing towards the region. The cloudier skies will help keep our overnight low fairly warm, with a chance we won’t even drop below 0°C. We may have to contend with some unpleasant weather through the overnight hours, though…

Big Shift on the Weekend

Precipitation amounts forecast on Friday night by the GDPS.
Precipitation amounts forecast on Friday night by the GDPS.

Models are all hinting towards some precipitation on Friday night into Saturday morning as a low pressure system lifts northeastwards through the Prairies. It’s still far too early to speak towards the system in much detail at all, other than saying the bulk of it looks to happen during the overnight period. Some models, such as the pictured output from the GDPS[1] really wind the system up and produce significant quantities of rain or snow while others lift the system much further north with little precipitation development. We’ll have more details on precipitation type and how much of what to expect later on in the week.

The bigger news is that this system marks a significant pattern shift as the upper level ridge we mentioned at the beginning of the article begins developing and pushing eastwards. As it does so, warmer air looks set to flood the Prairies, quickly launching our temperatures back towards seasonal to above-seasonal. Sunday will have temperatures close to normal[2] and we might see it get as warm as the low-to-mid teens on Monday, if we can manage to work past our snow cover.

Multiple days of near-to-just-above freezing temperatures coupled with the strong April sun should do quick work to melt the remaining snowpack across much of the Red River Valley. Melt will be minimal until the weekend, but even one or two days with temperatures in the 5-10°C range will do quick work with much of the remaining snow. Once we can eliminate the snow pack, extremely abnormal cold will be much harder to come by and it will be much easier to see seasonal temperatures.

  1. Global Deterministic Prediction System – Canada’s long-term forecast model.  ↩
  2. Seasonal temperatures for Winnipeg currently are around 11°C for a daytime high and 0°C for an overnight low.  ↩

Winter’s Last Gasp

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This week will see one last wintry blast in southern Manitoba before spring finally arrives for good.

A surface ridge of high pressure will bring cold weather to southern Manitoba to start the week
A surface ridge of high pressure will bring cold weather to southern Manitoba to start the week

Monday

Monday
-7°C / -18°C
Mainly sunny. Chance of flurries.

Today will likely be the coldest day of the week. High temperatures will be in the upper minus single digits, with a chance of flurries. This chance of flurries will arise from low-level instability that will develop as the surface warms during the day. To top it all off, there will be a breezy north-west wind – great!

Tuesday

Tuesday
-5°C / -15°C
Increasing cloudiness. Slight chance of flurries.

A low pressure system will pass to our south on Tuesday, allowing a cool north-easterly flow to remain established over southern Manitoba. Luckily, that system should remain far enough south to prevent us from seeing any more snow, although a couple of flurries can’t be ruled out.

Wednesday

Wednesday
-4°C / -17°C
Mix of sun and cloud. Chance of flurries.

A brisk northerly flow will remain in southern Manitoba on Wednesday, making for another cold day. High temperatures will be in the mid minus single digits, and there will once again be a chance of flurries.

Record Cold?

With the cold weather that’s expected this week, we will be challenging some cold weather records. The table below shows the record values for the next several days:

Record Cold Minimum and Maximum Temperatures
Date Record Low Record Cold High
Monday April 14 -16.7°C (1893) -7.8°C (1880)
Tuesday April 15 -16.7°C (1893) -6.7°C (1875)
Wednesday April 16 -16.7°C (1875) -4.4°C (1910)
Thursday April 17 -13.3°C (1953) -3.3°C (1953)

It looks like we will come close to setting new records on each of the days listed in the table. Stay tuned to see if we manage to actually break any records!

Long Range

The long range forecast calls for increasing temperatures as we move into the weekend. We’ll likely see seasonal temperatures (i.e. low teens) return by the weekend into next week. There is currently no strong prospective of above-normal weather, but we’ll probably see at least a couple seasonably warm days before the month is out.

Record Low Temperatures Broken

A large swath of record low temperatures were set on the morning of April 15, 2014 across the province of Manitoba thanks to a strong Arctic ridge of high pressure sprawled over the region. Overnight lows were 10-20°C below normal throughout the province. Winnipeg did not set a new record low, however some other locations in the Red River Valley did.

Record Low Temperatures set on April 15, 2014
Site New Record Old Record (Year)
Berens River –23.8°C –19.6 (1997)
Carberry –14.2°C –12.9 C (2000)
Carman –15 C –11.4 C (2000)
Fisher Branch –20.4 C –11.8 C (2000)
Flin Flon –20.5 C –16 (1997)
George Island –19.5 C –16.8 C (1997)
Grand Rapids –24.4 C –13 (1997)
Island Lake –20.7 C –20.6 C (2000)
McCreary –13.7 C –12 (2000)
Oak Point Marine –19.7 C –11.9 (1997)
Pinawa –21 C –12 (2000)
Roblin –11.4 C –11.3 C (1997)
Shoal Lake –11.5 C –10.2 C (2000)
Sprague –16 C –10.8 C (2000)
The Pas –20.5 C –18 C (1986)
Thompson –27.3 C –23.4 C (1985)
Victoria Beach –20 C –11 C (2000)
Wasagaming –15.5 C –15 C (1978)

More record lows will be at the risk of being broken as the week progresses.

Remember Winter?

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Expected precipitation types on Saturday.
Expected precipitation types on Saturday.

Supplications for summer will be silenced as the stage is set for a sloppy spring storm that will supply snow to Southern Manitoba. Two disturbances will impact the region – one this morning and the other tonight through Saturday – and bring decidedly messy spring-time weather to the region followed by a surprisingly cold air mass for mid-April. Get those snow shovels out and read on to find out what to expect in your area.

Disturbance #1

The leading disturbance moving through the province this morning is by far the weaker of the two and will move through quite quickly. Disorganized showers or flurries are possible across the region through the morning hours, then we’ll see the clouds begin to clear out giving some sun for the afternoon. We’ll reach a high of only around +4°C today with light northeasterly winds.

Friday
4°C / -3°C
Cloudy periods. Slight chance of morning flurries or showers.
Saturday
1°C / -8°C
Snow. 5-10cm.
Sunday
-2°C / -14°C
Mainly sunny.

Disturbance #2

Our reprieve from the snow threat will be short-lived, however, as another system pushes into Southern Manitoba tonight. Cloud will stream into the Red River Valley this evening ahead of the main precipitation associated with this low, which will not push into the RRV until the second half of the overnight period. Temperatures will drop to only around -3 or -4°C overnight.

As the precipitation shield undergoes rapid expansion early in the evening, snow, heavy at times, will fall along and south of the Trans-Canada Highway in southwestern Manitoba through a good portion of the night which will result in some of the highest accumulations for this storm. By the time all is said and done, 10-20cm of snow is possible over southwest Manitoba.

Further east in the Red River Valley, snow will push in much later in the overnight period, first spreading into the Morden/Winkler region and then pushing northeastwards. Snow will reach Winnipeg by early Saturday morning. The heaviest snow will fall in the southern portion of the RRV with enhanced amounts possible in the southwest corner near the escarpment where upslope winds will help enhance snowfall.

The main snowfall event for the Red River Valley will occur through the day on Saturday. Weak warm advection aloft will do little to help temperatures at the surface which will be stuck out of the north feeding cooler, dryer air into this system. Coupled with the snow, temperatures through the valley won’t climb much more than a degree or two above zero. It will likely be warm enough at the surface (and aloft) to melt some of the snow that falls. This will reduce snowfall amounts a bit, but given the intensity of the precipitation expected, snow accumulation should overpower the melting factor fairly quickly.

Total snowfall expected Friday night through Saturday. Amounts may be lower depending on how much melts.
Total snowfall expected Friday night through Saturday. Amounts may be lower depending on how much melts.

In general, most areas seem to be set to see around 5-10cm of snow, perhaps a little less if there’s more melting. With temperatures near zero, it will be a somewhat wet, heavy, sloppy snow that will likely make driving very unpleasant and slippery. The snow should taper off on Saturday evening as the system pushes off to the east. Skies will clear in advance of an Arctic ridge pushing into the Prairies and we’ll drop to an overnight low near -8 or -9°C.

Cooler Weather Ahead

Behind this system, very cool arctic air will push into the Prairies. Sunday will be mainly sunny with some afternoon cloud but the temperature will top out more than 10°C below normal at only around -2°C.

The start of next week continues the sunny trend, although Monday will be nearly 20°C below normal with a high of only -8°C. More seasonal air looks to build back in midweek.

Springtime: Blowin’ in the Wind

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The warmest day of 2014 is on tap for Winnipeg as a low pressure system tracking through the northern Prairies brings with it an unseasonably warm air mass. With the passage of a cold front today we’ll also see strong – potentially near warning level in some areas – winds that will usher in slightly cooler temperatures than we’ve seen the past few days as well as a slight chance for a shower or two. With so much snow left on the ground, however, the big question is exactly how warm will it get?

Wednesday
10°C / 0°C
Partly cloudy; windy later today.

Thursday
7°C / -3°C
Mainly sunny. Winds gradually diminsihing.

Friday
7°C / -6°C
Mainly sunny.

Today

We’re off to a great start today with temperatures already above the freezing mark thanks to the incoming mild air and relatively breezy conditions that persisted through the overnight period. Warmer air will continue to stream in through the morning hours, producing a brisk southerly wind through the valley at 30-40km/h. Temperatures will climb the best they can, but the remaining snowpack will do a lot to keep us cooler.

In order for us to reach the full potential of the warm air coming in, we need to be able to mix it down to the surface. The best way to create instability in the lower levels is the sun; it shines down and warms up the surface until it gets hot enough (assuming the sun is strong enough) to create instability and begin mixing the lower atmosphere. This mixing process can help bring warmer air down and maintain a warmer temperature. Unfortunately, snow can dramatically inhibit this process through two main ways:

  1. Snow is white, so it reflects the incoming energy from the sun back out into the sky. This prevents that energy from being put into warming up the ground or air in the low levels.
  2. Snow is frozen, so when the temperatures begin to climb above zero the snow begins to melt, removing energy from the air and cooling it off.

With no snow, all the energy from the sun can go into heating the surface. Today we’ll see a pretty big difference in temperatures between areas with snow versus areas without snow. Here in Winnipeg, temperatures will likely climb to around 9-10°C before a cold front pushes through this afternoon. In the snow-free areas of North Dakota and a few portions of the western Red River Valley, temperatures will likely climb into the mid-to-high teens, possibly as high as the low 20’s.

Foreast temperatures for this afternoon from the RDPS. Note the warmer temperatures in North Dakota (no snow) and downwind of the western escarpment of the Manitoba Red River Valley.
Foreast temperatures for this afternoon from the RDPS. Note the warmer temperatures in North Dakota (no snow) and downwind of the western escarpment of the Manitoba Red River Valley.

The abnormally warm weather will be short-lived as a cold front blasts through the province midday. Strong westerly to northwesterly winds with gusts as high as 70km/h will push into the Red River Valley this afternoon. Temperatures may actually climb a degree or two behind the cold front before they begin to drop a bit thanks to all the warm air aloft that is able to be mixed down. There will be a slight chance for a shower with the passage of the cold front, however the chances are better to the north of the Red River Valley, where the lift is stronger, and in North Dakota, where the instability is greater. We’ll head to a low of around 0°C tonight.

The Remainder of the Week

Tomorrow will be a mainly sunny day with stronger winds that will slowly diminish as the day progresses eastwards. We’ll see a high near 7°C and a low near -3°C. Friday will be another pleasant day with mainly sunny skies and relatively light winds. The high will be near 7°C and the low will drop to around -6°C as some cooler air makes a brief appearance for the weekend.