Sunday, July 24, 2011

Heatwave, Drought?

The locks at Sainte-Anne-de-Bellevue packed with pleasure craft on a 33C Saturday. (ValleyWX Pic)

Just what is a heatwave anyway? According to Environment Canada it is three days or more of 32C weather. Well lets split some hairs shall we. Following that logic we just finished one of the hottest weeks in recent memory and are in a very warm and dry month. We managed the second warmest temperature on record for the city of Montreal, the highest humidex reading Thursday at 47C, and the region has reported at least 10 heat related deaths. However on one day, Friday, we reached 31.9C so, guess what, no heatwave.

The truth of the matter is it was a dangerously hot couple of days that made today's 27C seem cool. We have seen so far this month 18 out of the 24 days at 27C (81F) or higher. Of those, 9 days, were 30C (86F) or higher. We have recorded precipitation on only 5 days this month for a grand total of 46mm at the airport and only 26mm off island to the west. In my neighborhood we have had even less with no appreciable rain in the last 10 days. Watering bans are in effect, and most trees and lawns are beginning to show serious signs of heat stress. This week will bring some slight relief in the form of showers and thunderstorms, but they will be scattered with no big rain makers in sight. It will be a little cooler to start the week, but we should be pushing 30C again by weeks end.

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