10 July 2014
Many of the cold weather outbreaks this past winter were attributed to something called a Polar Vortex. This is where a flow pattern establishes in the upper atmosphere that draws cold arctic air down across the Canadian Prairies and down into the American mid-west and the Great Lakes region. The summer-time version of the Polar Vortex is about to arrive next week, bringing unusually cold air to the Great Lakes and much of central North America.
Climatologically the middle part of July is usually the warmest time of year in Northern Ontario. Temperatures typically climb into the mid 20s during the warmest time of the day, while overnight lows remain above +10°C.
So this Polar Vortex couldn’t arrive at a worse time. Instead of warm summer-like conditions it will feel more like fall. Temperatures are likely to be 5-10°C below normal. This will keep daytime highs buried in the teens with overnight lows in the single digits. This cold air is expected to move as far south as Texas where record low temperatures could be broken.
|National Weather Service|
When you average the temperatures we have seen for the first 9 days of July we are already 3°C below normal. Adding on this upcoming cold outbreak will likely cause the entire month to end up below average. This would mean that six of the first seven months of 2014 have brought below normal temperatures in Northern Ontario - with only June being near normal.
When you compare the climatological factors at play, it is interesting to note that we can compare 2014 to previous years. 2002 and 2009 had many factors similar to this current year and if that trend continues it could mean good news for August. In those years the hottest weather waited until that last month of summer to arrive – let’s hope that’s the case again this year.
So enjoy the warmer temperatures expected later this week because it appears we are in for an unseasonably cold run for next week.