Marching into spring? Cooler than seasonal temperatures persist into April
Friday, March 28, 2014, 8:27 AM -
For most Canadians, this winter has felt like the winter that would never end. The image below highlights just how widespread the unseasonably cold temperatures were from December 1st through February 28th.
Colder than seasonal temperatures are represented by the blue and green colors which stretch from the Atlantic coast to the Pacific coast. The coldest temperatures relative to average were found across the Prairies and much of Ontario where temperatures were 3 to 8 degrees C colder than the longer term averages for those regions.
March has brought little change to the very cold pattern. In fact, the image below shows that well below seasonal temperatures were even more extensive with temperatures 3 to 8 degrees C below seasonal from British Columbia to Newfoundland.
As a result, most of Canada was still covered with snow as of March 26th with the exception of coastal British Columbia and a few localized areas across the southern Prairies and southern Ontario.
The effects of these cold temperatures can readily be seen in the extensive ice cover that is still found on the Great Lakes.
The graph below shows the ice coverage on the Great Lakes during the week of March 19 – 26th for each year since 1978. The blue bar on the far right represents the current ice coverage which is the highest on record for this week of the year and nearly four times the average ice coverage of 19% (indicated by the green line across the graph).
While the maximum ice coverage for this winter (92.2 percent) came up just short of the record of 94.7 percent set in 1979, the spring melt was much quicker in 1979 than it has been so far this year. The bar on the far left on the above graph represents the ice coverage for 1979 which had dropped to nearly 50 percent by the third week of March, while this year’s ice coverage for the same week has been nearly 80 percent.
So, where do we go from here? Is spring weather finally on the way? The map below shows the overall temperature pattern for the next five days, taking us through April 1st. While the extreme cold will relax somewhat from southern Ontario to the Maritimes, a couple more rounds of wintry precipitation will also impact parts of this region. The Prairies will continue to be well below seasonal with above seasonal temperatures limited to parts of the southern coast of British Columbia.
Looking further ahead, it appears that April will be cooler than seasonal from the eastern Prairies to Atlantic Canada (as indicated by the blues and greens on the map below. While there will certainly be periods of warmer weather, it looks like the number of days with cooler than seasonal temperatures will outnumber the days that are warmer than seasonal.
If you are looking forward to warmer weather, the outlook is better for parts of western Canada where above seasonal temperatures are expected during April. The greatest uncertainty in the long range pattern is across the western and central Prairies. The image above may be too optimistic in those regions as fluctuations between colder and warmer than seasonal temperatures should come close to offsetting each other, resulting in near seasonal temperatures.