The never-ending winter was caused by stubborn ridges of high pressure over the West Coast and Greenland
Like most of central North America, Alberta was not able to dodge the cold weather that just didn’t seem to want to go away this spring. Central North America felt the effects of what is known as a blocking pattern. This is when the jet stream gets stuck (for the most part) in the same place. Usually, the jet stream meanders to the north and south creating U-shaped troughs of low pressure and inverted U-shaped ridges of high pressure.
When these meanders are not very big, the weather tends to change fairly quickly, but the changes are not that great. When the meanders are large, the changes can take a long time and when they do change, the change can be very dramatic.
This is exactly what we’ve seen over the last couple of months across our part of the world. The meander in the jet stream has been very big, with a large ridge of high pressure over the West Coast and another large ridge over Greenland. In between these two ridges, over central North America there was a large trough of low pressure. This trough allowed plenty of cold arctic air to spill southward, bringing unseasonably cold air to much of Central Canada and the U.S., going as far south as Texas.
Looking at the temperature records across Alberta during March and April you will see that the cold air began moving in during March, with most locations reporting a mean monthly temperature around 1.5 C below average. The cold weather continued and actually intensified during April, with most locations reporting a mean monthly temperature that was between 3 and 4 C below average. Precipitation was a little less consistent, but overall, most locations recorded near- to above-average amounts of precipitation. The wettest regions were the southeast areas along with the foothills.
Now it’s time to look ahead. Will the blocking pattern continue keeping us in the cold or will it start to break down and allow summer to start moving in? According to the Old Farmer’s Almanac, they are calling for temperatures in May to be slightly below average, along with below-average amounts of precipitation. In June they are calling for things to get worse, with well-below-average temperatures and near-average amounts of precipitation.
The Canadian Farmers Almanac appears to be calling for near- to below-average temperatures during May along with above-average precipitation. They mention fair a few times along with stormy conditions and showers. They start off June with stormy conditions then switch to sunny and hot weather for the rest of the month.
Environment Canada is calling for near-average temperatures in May over central and northern regions and above-average temperatures in the south. They then show temperatures moderating in June, with above-average temperatures pushing a little farther north. As far as precipitation goes, they are calling for near-average precipitation in both May and June.
Finally, here at the Alberta Farmer, I am calling for above-average temperatures in May, along with near- to slightly below-average amounts of rain. The western ridge of high pressure looks like it wants to begin pushing eastwards, which could bring some really warm temperatures, along with keeping most of the heavier rains to the south and east. The only fly in the ointment will be the occasional push of cold air.
June’s forecast is a little tougher, but here’s how I see it. I think that the western ridge will become more and more dominant. By early June, Alberta will likely only see a few one- or two-day shots of cool weather and then the warm to hot weather will dominate. Precipitation is always tough to figure out, but if this scenario does play out then Alberta will likely see near-average precipitation, with most of the rain coming in the form of thunderstorms.
Now as usual, it’s time to sit back and see just what curveballs Mother Nature will throw at us next!