A Return to More Seasonal Weather

The unbelievable March heat wave is coming to an end in Southern Manitoba as the blocking pattern that has been maintaining record-obliterating heat throughout much of Central and Eastern North America begins to break down. This will cause us to return to a slightly more unsettled and seasonal pattern, albeit temperatures will still remain (for the most part) above normal for this time of year.

Heat Wave Shatters Records

Temperature Anomalies March 8-15

The intensity and scope of Summer in March is clearly visible in this data from the MODIS instrument on the Terra satellite. Areas with warmer than average temperatures are shown in red; near-normal temperatures are white; and areas that were cooler than the 2000-2011 base period are blue. Image credit: NASA Earth Observatory.

The March 2012 heat wave has shattered records all across North America, with thousands of temperature records being broken across the United States and Canada. Pellston, Michigan broke their daytime high record for March 21 by an absurd 32°F, a temperature that was 48°F above average. In St. John, NB, their daytime high of 25.4°C on March 21st was warmer than any day they’ve ever had in April. Halifax, NS
also had a warmer day yesterday than any day on record in April with their high of 28°C. The list goes on and on, but it seems that almost anywhere you go east of the Rocky Mountains has set numerous records and is experiencing weather that’s arrived at least a month early, if not a couple! The image above illustrates exactly how substantial the warm weather has been; it shows the departure from the 2000-2011 normal for land temperatures for March 8-15th. The reds show just how wide-spread and substantial the heat wave has been!

Winnipeg has broken numerous records over the past 12 days, including:

  • 8 daily record high temperatures (11, 12, 15, 16, 17, 18, 19, 22)
  • Earliest 20°C reading on record (March 18)
  • Warmest overnight low in March (14°C on the night of March 18/19)
  • Earliest thunderstorm on record since 1953 (Evening of March 19th)
  • Warmest March day on record (March 19th, 23.7°C)
  • Most significant departure from normal temperature for any day of the year (+23.4°C above normal on March 19th)
  • 4 consecutive days over 19°C (Only 4 days since records began have reached that mark. From Rob’s Blog: In other words, it took only 4 days during this warm spell to match what took 140 years to accomplish.)

Records that will need to happen yet and need to be verified:

  • Warmest March on Record (Currently sitting at a mean temperature of 0.4°C, record is 1.6°C set in 1878).
  • Highest dew point in March (17°C on March 19th, need to finish parsing data set to verify)

The past week and a half has truly been an extraordinary weather event that has not been seen in the lives of 99% of the people who will read this. As the next weather system moves through, we’ll see a transition it a more seasonal weather pattern that will return us to closer-to-normal temperatures and bring with it some unsettled weather.

Upcoming Weather

Accumulated Precipitation

Accumulated Precipitation from 18Z Mar. 22 to 00Z Mar. 24 (Thursday Afternoon to Friday Evening)

A somewhat complicated scenario presents itself for Winnipeg over the next couple days. Overnight, the cut off low that has been anchored over the Southern Plains of the US has been working NE and has pushed it’s deformation zone into Southern Manitoba, spilling clouds northwards. There’s a chance we’ll see a light shower early this morning in Winnipeg, however most models keep the precipitation to our south (including the GEM-REG, pictured above. There will be a few scattered showers through the RRV through the morning, with a better chance of measurable precipitation east of the Red River. The precipitation will move out by the afternoon, however we won’t lose the cloud. This will limit our temperature to 19 or 20°C. If we’re able to get a couple hours of sunshine today (unlikely), we’ll definitely have a shot at breaking the daily record high of 22.8°C.

As the low pulls off to the east, instead of clearing out with a northwest wind, we’re left in a slack flow as another system ejects northeastwards out of Montana. It will approach Manitoba on Friday night and cross the province through the Interlake on Saturday. As it moves across Saskatchewan on Friday night, it will pull much of the moisture in Southern Manitoba northwards as a warm front lifts out of North Dakota. Saturday morning will be a toss up…some models want to clear out the cloud and give us a nice sunny day, however I think that our proximity to the lift associated with the low, the cap we’ll have as we’re in the warm sector of the system, and the moisture present in the low-levels will keep us on the cloudier side of things until the cold front passes through around lunch time. We’ll clear out with the cold front and have our coldest night in what seems like forever now with an overnight low around -5°C.

Sunday will be a fairly nice, albeit crisp, day with sunny skies and a daytime high in the high single digits. While this temperature will certainly feel cold, it will still be 5°C+ above the normal daytime high.

The most significant precipitation event since the beginning of March looks to be shaping up for Monday night through Tuesday; it’s still early, though, so we’ll keep you updated in the comments on this post and have a good look at it in Monday’s post.

And last but not least, happy World Meteorological Day everybody!

Table of Broken Temperature Records (Winnipeg)

Day New
Record Year
Sun Mar. 11 12.8°C 12.5°C 1981
Mon Mar. 12 9.7°C 7.2°C 1922
Thurs Mar. 15 14.4°C 11.1°C 1927
Fri Mar. 16 19.9°C 12.4°C 1981
Sat Mar. 17 19.2°C 12.8°C 1938
Sun Mar. 18 20.9°C 14.4°C 1910
Mon Mar. 19 23.7°C 18.9°C 1938
Thurs. Mar 22 21.7°C 18.3°C 1878
Table of daily record high temperatures during the March 2012 heat wave from March 11, 2012 to March 22, 2011.


Brad lives in Winnipeg with his wife and two children and is the founder of A Weather Moment. He has loved weather from a very young age and has followed that passion through his life so far. He received a B.Sc. in Earth Sciences with Specialization in Atmospheric Sciences and is currently employed in the field of meteorology. You can find the author as WeatherInThePeg on Mastodon.

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