NAM Simulated Reflectivity valid 18Z Tuesday March 15, 2016

Major Storm System Looms

We’ll see one more nice day today before a potentially significant weather system affects us on Tuesday and Wednesday. Rain and snow is expected in southern Manitoba with this system, but exact amounts remain unclear.

Today will be another very nice day. Temperatures will climb into the mid teens over much of southern Manitoba, allowing our snow melt to continue. Many rural parts of southern Manitoba are already snow-free, but there is still snow to melt in sheltered areas. Skies will be mainly sunny, with breezy south-east winds.

A major low pressure system will affect southern Manitoba this week
A major low pressure system will affect southern Manitoba this week

A major low pressure system is expected to affect southern Manitoba on Tuesday and Wednesday. This system will bring a combination of rain and snow, which makes it difficult to forecast. At this time it appears that rain will be the main mode of precipitation over the Red River Valley. Models disagree widely on potential accumulation, so it is difficult to say exactly how much rain will fall. A “best guess” is that Winnipeg will see about 5-15 mm of rain. More or less rain could fall depending on how the system evolves.

We will continue to be under the influence of this system on Wednesday, but temperatures will fall as we experience a stiff north-westerly flow. As a result of this cold air surging in from the north, rain is expected to change over to snow, with a couple centimetres of accumulation being possible. The exact amount of snow will depend on how much the system stalls over our area and how much cold air manages to infiltrate southern Manitoba. High temperatures on Wednesday are currently expected to be near 2C, which would not favour large accumulations.

Long Range

The end of the week is expected to be colder as the system from earlier in the week pulls down colder air from the north. Longer range models suggest that the second half of March will see a cooler pattern with outbreaks of colder arctic air. However, if we remain mainly snow-free following this week’s system, it will be difficult for very cold conditions to last long as the darker soil will be able to absorb much more sunlight than snow would.

Mild Weekend Ahead

The sunny weather is arriving later than expected in Winnipeg no thanks to persistent low cloud that simply wouldn’t leave the region despite clear skies working in on either side of the Red River Valley. With that behind us, though, the warm weather arrives today alongside plenty of sunshine for what will be the start to a beautiful weekend in the Winnipeg area.

A fairly pleasant day is on the way today with the sun finally making an appearance, sending temperatures well above normal and close to record values. The mercury will climb towards the 10°C mark this afternoon, slightly short of the record value of 12.8°C that was at in 2012. The wind will be fairly gusty out of the south this morning and will shift to breezy out of the west behind a warm front that passes through midday.

Skies will be mixed as some remnants of yesterday’s low cloud clear out and are replaced by variable cloud from the warm front moving through the region. We will see sunshine today, particularly once the drier westerly winds kick in and flush out any remaining moisture stuck in the Valley.

The overnight low is expected to dip down to around -1°C tonight under partly cloudy skies and diminishing winds.

Saturday will be the nicest day of the of the weekend with partly cloudy skies, relatively light winds and very mild temperatures. The daytime high on Saturday will climb to around 10-11°C, a potentially record-breaking high for March 12th.

Mild air continues to flow over Southern Manitoba on Saturday night as southerly winds increase ahead of an incoming trough of low pressure. Winds will increase to around 30-40km/h late Saturday. The warmer air moving in alongside the wind will keep overnight lows fairly mild; the temperature will dip only to 2 or 3°C on Saturday night.

GDPS 12hr. QPF forecast valid 06Z March 14, 2016
The GDPS precipitation forecast for Sunday afternoon into the evening.

Sunday will be a mild day but the weather will turn cloudier and potentially wet. A trough of low pressure moving into the province will result in a cloudier day with a high once again near 11°C. Heading into the afternoon, the chance for some rain will increase throughout the Red River Valley and areas east. Significant rainfall is not expected[1], but for the areas that end up seeing any precipitation, a few mm may be possible. The cloud will help temperatures remain very mild on Sunday night with temperatures expected to dip to near 4°C.

New Record Temperatures?

We have the potential of breaking some record temperatures over the next few days, particularly on Saturday and Sunday.

Daily Record High and Record Warm Minimum Temperatures for Winnipeg, MB
Date Record High Record Warm Min
March 11 12.8°C (2012) 2.8°C (1878)
March 12 9.7°C (2012) 2.5°C (2012)
March 13 12.2°C (1902) 1.6°C (1995)

Saturday’s high near 10°C will challenge the 3 year old record from 2012. Saturday night’s low near 2 or 3°C combined with Sunday night’s low near 4°C may challenge the record warmest low temperature for March 13, which currently sits at 1.6°C and was set in 1995.

Sunday’s high temperature is not expected to reach the current record of 12.2°C set in 1902. The low near -1°C on Friday night will prevent the record warm low temperature for March 12th of 2.5°C set in 2012 from being broken.

Long Range: Mild & Unsettled

Heading into next week the forecast is for continued warmth for the first half of the week and then a return towards seasonal values through the second half.

GDPS forecast temperatures for Winnipeg, MB
GDPS forecast temperatures for Winnipeg, MB

Regarding precipitation, most of any potential will be tied up in a mid-week low pressure system that will usher in the cooler temperatures. It appears like it will be a complex mess of multiple low pressure systems merging into a vortex over Northern Ontario, so at this point it would be an exercise in futility to try and make any guesses on what any one place will see from that system. It’s probably safe to say that there will be a chance for rain changing to snow mid-week.

But, before then, enjoy the spring warmth!

Winnipeg’s seasonal daytime high is currently -2°C while the seasonal overnight low is -12°C.


  1. Although, as shown above, the GDPS is forecasting convective elements that could produce 10-20mm of rain, I’m not convinced at this point that potential will be realized. I’ll post an update in the comments below if Sunday looks like it may produce some heavier showers.  ↩
GDPS 850mb Temperature Anomaly valid 12Z Friday March 11, 2016

Short-Lived Cool Snap Gives Way to Potential Record-Breaking Warmth

Temperatures will be cooler behind yesterday’s Colorado Low that grazed the southeastern portion of the province, however the mercury won’t be dipping much. Today will be the coolest day of the week and yet temperatures will still remain above seasonal for mid-March. The cooler weather will be short-lived before another surge of warm air that will bring spring weather to the Red River Valley, potentially threatening record high and record warm minimum temperatures!

Today will be a relatively cool day with the temperature climbing to the freezing mark with a light south-southeasterly wind. Skies will be mixed through the day with a bit of sun and a few cloudy periods, particularly mid-day into the afternoon. Much of the cloud will clear out tonight as temperatures dip to near -6°C.

After today, though, the heat starts moving eastwards and temperatures will soar to 10-15°C above normal for mid-March. Thursday will bring partly cloudy skies[1] and daytime highs climbing towards the 6°C mark with light southerly winds continuing. If temperatures manage to eke just a degree or so higher, there will be a chance of breaking Winnipeg’s record high temperature for March 20th.

Daily Record High and Record Warm Minimum Temperatures for Winnipeg, MB
Day Record High Record Warm Minimum
Thursday March 10 6.7°C (1902) 0.6 (1878)
Friday March 11 12.8°C (2012) 2.8°C (1878)

The mercury will dip to around 3°C on Thursday night with southerly winds strengthening to around 30km/h. This mild overnight low will set Winnipeg up for another potentially record-breaking day on Friday, where partly cloudy skies will give way to temperatures climbing into the low teens. The daytime high on Friday will likely sit near 11°C, however throughout the entire city the temperature could easily be in the 10-15°C range. The airport is typically on the cooler side, so it will be a bit of a nail-biter as to whether we break the record high of 12.8°C set in 2012.

GDPS 850mb Temperature Anomaly valid 12Z Friday March 11, 2016
The GDPS is forecasting 850mb temperatures over 20°C above normal for Friday morning.

Depending on how fast things cool off in the evening, we may also see the record warm minimum temperature for March 11 be broken as well. The record is currently 2.8°C set in 1878, which will require a temperature warmer than that through Thursday night and a temperature remaining warmer than than until midnight on Friday night.

In addition to the warmth, of note particularly for Friday is the potential for unseasonably high dewpoint values. While the GDPS is fairly conservative with dewpoints remaining near the 1°C mark, several other models are showing dewpoint values rising into the upper single digits. There are two main stories if the elevated dewpoints do indeed show up:

  • We could break the record high dewpoint in Winnipeg for March 11, which currently sits at 6.0°C set in 2012.
  • There would be huge amounts of snow melt. The process of snow melt is limited when dewpoint values remain below 0°C for a variety of thermodynamic reasons. As the dewpoint climbs above 0°C, melting becomes significantly more efficient. By the time the dewpoint climbs to even +4 or +5°C, snow melt can be enormous if combined with mild temperatures. If these elevated dewpoints arrived for Friday with a high in the low teens, then almost certainly a dramatic portion of the remaining snow pack in the Red River Valley would be gone by this time next week.

Long Range: Warm, Warm, Warm!

The long-range forecast looks quite simple: continued warmth.

CPC 6-10 Day Temperature Probability Outlook valid March 14-18, 2016
CPC 6-10 Day Temperature Probability Outlook valid March 14-18, 2016

Long-range forecasts show a high likelihood of the mild weather continuing well into next week. This will mean that daytime highs in the 5-10°C range, if not even warmer, will be commonplace through the next week.

This warmth, combined with little-to-no expected precipitation through the period, will continue to rapidly erode the snow pack over the Red River Valley, further enabling milder temperatures to develop. Spring-like weather has arrived!

Winnipeg’s seasonal daytime high is currently -3°C while the seasonal overnight low is -13°C.


  1. There’s a slight risk of seeing cooler temperatures and more cloud if a system tracking through the Prairies slumps a bit further south, but at this point it looks like much of the cloud will remain to our north.  ↩

Mild Weather Continues

This week will remain mild with temperatures generally on the positive side of zero. However, there will be a chance for precipitation on Tuesday.

Today will see a continuation of Sunday’s warm weather. High temperatures will be in the mid single digits in the Red River Valley, and perhaps a bit higher over the snow-free area to our west. Skies over the Red River Valley will be a mixture of sun and cloud, while conditions over western Manitoba are mainly cloudy. The only wrinkle in today’s forecast is the potential for fog tonight, aided by the additional moisture generated by the snow melt.

A low pressure will pass to our south on Tuesday, bringing rain and snow to southern Manitoba. At this point it looks like precipitation over south-eastern Manitoba will primarily come in the from of rain. The Red River Valley will probably see a mix of rain and snow, while western Manitoba sees primarily snow. Large amounts of rain/snow are not expected, but models hint at the potential for localized bands of moderate precipitation which could bump up totals in some areas. Most areas will probably see 3-6 mm of accumulation, in the form of rain and/or snow.

RDPS MSLP & 3hr. QPF valid Tuesday morning.
A weak Colorado Low will bring precipitation to the Red River Valley on Tuesday.

Wednesday will be a slightly cooler day as a colder air mass surges southward behind Tuesday’s departing low pressure system. High temperatures will be near the freezing mark with breezy north winds.

Long Range

The long range forecast shows no indication of winter returning. Models strongly suggest that most, if not all, of March will be seasonably warm. Enjoy the snow now, it may not last much longer!