What’s with all the wind?

The Chronicle Herald (Provincial) - - WEATHER - CINDY DAY weather­mail@weatherbyd­ay.ca Cindydaywe­ather Cindy Day is Saltwire Net­work's Chief Me­te­o­rol­o­gist.

I love to ques­tion things, so I ap­pre­ci­ate be­ing stopped and ques­tioned about the weather.

This spring, two ques­tions keep com­ing up, over and over. The first is: when is it fi­nally go­ing to warm up? The se­cond, why Hazel Ear­lier is had it so this enough windy? month, of the Wendy cooler tem­per­a­tures and wind and fired off this ques­tion:

“What in the $^%&* is it with all the fre­quent winds? Every 10 days or so, we seem to be get­ting winds with gusts to 70 to 100 (kilo­me­tres per hour). It seems to have started early fall. Is this what we can ex­pect from here on in? I hope not! If so, my pon­toon boat will be on dry land more than it will be in the wa­ter.”

That's a great ob­ser­va­tion Wendy. Anec­do­tally, there is con­sen­sus and fairly re­cently, num­bers to back it all up.

A study pub­lished in the jour­nal Na­ture Cli­mate Change finds winds across much of North Amer­ica, Europe and Asia have been grow­ing faster since about 2010. In less than a decade, the global aver­age wind speed in­creased from 11.2 km/h to about 11.9 km/h. That dif­fer­ence in the aver­age wind speed would not be no­tice­able by you or me, but it is sig­nif­i­cant.

That aside, we have had some very windy sys­tems blow through in the past lit­tle while, and that has peo­ple talk­ing. Can we point to cli­mate change?

We do know that with time, weather sys­tems here at the coast will be­come more pow­er­ful as a re­sult of cli­mate change; in fact, we're al­ready wit­ness­ing this. Warmer sea sur­face tem­per­a­tures are fu­elling more pow­er­ful storms. The deeper the cen­tral pres­sure of any storm, the greater the pres­sure dif­fer­ence will be be­tween it and the nearby ar­eas of high pres­sure; the greater the dif­fer­ence, the stronger the wind.

That be­ing true, we can't dis­count sea­sonal change. Wind is also the re­sult of cold air rush­ing down into a warm air mass. Cold air is heav­ier than warm air and nat­u­rally rushes into the warmer re­gions – where the air pres­sure is low. When a dif­fer­ence in at­mo­spheric pres­sure ex­ists, air moves from the higher to the lower pres­sure area, re­sult­ing in wind; the greater that dif­fer­ence, the faster the wind.

Since early April, we've seen sig­nif­i­cant tem­per­a­ture spreads from one cor­ner of the re­gion to the other. Once that lev­els off a lit­tle, the wind should set­tle be­tween sys­tems.

I hope this an­swers your ques­tion, Wendy. There are many fac­tors in­volved, but I think it is safe to say At­lantic Cana­di­ans should pre­pare for in­creas­ingly strong winds gen­er­ated by pow­er­ful off­shore storms driven by cli­mate change.

On May 9, wind gusts reached 100 kilo­me­tres per hour in Over­ton, Yar­mouth County. The Halls were out the day af­ter to in­ves­ti­gate the dam­age done by the pow­er­ful spring storm.

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