OTTAWA A warm, dry winter set up conditions to turn a warm spell into a March heat wave like nothing Ottawa has ever seen.

The heat came from the south of us, but weve had south winds before in March, and the temperature has never risen past 17 C.

On Tuesday it reached 25.1, continuing the weeks pattern of smashing records by eight or nine degrees each day. The old record was 14.6 C, in 1995.

Even David Phillips, who has published 24 weather trivia calendars with 365 daily weather anecdotes each, has seen nothing like this.

Summer has arrived here, not spring, he said.

He has a point. Ottawas average high temperature for June is 23.6 C. Yes, June.

The first ingredient in our heat wave: The wind. For day after day after day, its been southerly air, he said.

Normally we get north winds coming in to jostle the southern airstream. Not this year: By his count, Tuesday was the thirteenth straight day of air from down south.

Its just standing its ground, kind of a monotonous situation.

This kind of heat cannot be produced in Canada at this time. It has to come from the United States.

See the original post:
Anatomy of a heat wave