Weather

The well-known but not so well understood Pacific Ocean phenomenon caused turmoil in the world’s weather patterns once more. But work is under way to improve predictions of such anomalies and make forecasts more effective and user-friendly

by HENRY HENGEVELD

Most of us well remember the El Niño winter of 12 years ago, when a series of ice storms swept across eastern Ontario and southern Quebec in early January. Those storms left millions of Canadians without electricity for an extended period of time, with particularly devastating effects on many farmers in the region.

Though temperatures and precipitation were near-normal averaged over the year, month by month the weather gave us a wild ride in 2009

by HENRY HENGEVELD

Mark Twain once noted that “if you don’t like the weather in New England, just wait a few minutes.” Twain would likely have said the same about Ontario last year!

Averaged over the entire year, 2009 was a rather “normal” year across the province. 

Temperatures in the Great Lakes Basin, for example, averaged only 0.1 C above the long-term mean, while total precipitation was 2.6 per cent above normal. Yet, month by month, the weather behaved like a roller coaster, fluctuating from one abnormal state to another, and back again.

Researchers have found that summer air temperatures over Lake Superior have been increasing more than a degree per decade, bringing changes in weather patterns for the surrounding regions

by HENRY HENGEVELD

If you live close to one of the Great Lakes and think that average summer winds in your area have changed in recent decades, you may be right.

Several years ago, researchers at the Milwaukee campus of the University of Wisconsin noted that there had been a significant shift in summer wind directions over the Great Lakes since 1980, dominated by an increase in air flow from the south. They suggested that a change in the dominant track for summer storms was a primary reason for this change.

Normally, the return of El Niño in the Pacific heralds a warmer than normal winter ahead, and that’s what models were projecting. Now a revised forecast is indicating that this will not be the case

by HENRY HENGEVELD

In late September, the American Earth Systems Research Laboratory in Colorado confirmed that El Niño was back. If past El Niño events are any indications, this may mean more unusual weather for Ontario this winter. 

The Aug. 20 tornadoes that struck south-central Ontario were a reminder of the weaknesses in our weather warning system and the need for more resources within the atrophied budget of the Canadian weather service

by HENRY HENGEVELD

Severe thunderstorms are a normal part of Ontario summer weather. They usually bring strong winds, intense rainfall, and lots of lightning and thunder. In the middle of such a storm, it can get scary at times, but it’s also fascinating to watch!

Every once in a while – thankfully, not very often – these storms also generate tornadoes. This summer, Thursday, Aug. 20, was one of those times. 

Thanks to a meandering jet stream, Vancouver got typical central Canada weather and we got cool, damp, Vancouver-type weather, while the south-western Arctic set new highs

by HENRY HENGEVELD

This past summer, the global atmospheric circulation system appears to have misfired. It delivered the wrong weather to almost everyone across Canada. Residents in the North seemed to get what those in the South expected, Canadians in the East received what the Westerners were to have gotten, and vice versa.

The evidence is not all in, but so far it suggests that, while contrails may have some significant effects in heavily travelled regions, the global impact is likely to be small.

by HENRY HENGEVELD

If you look up at the sky on a clear day, odds are you will see a number of white streaks across the sky, like pencil strokes against the blue backdrop of endless space. Here and there, the lines are broken or have broadened into thin, almost transparent wisps. Often, you can see the line still being formed as you watch, a silver dart glistening slightly ahead of its leading point. Another jet leaving its contrail!

As our wet days get wetter, we should be concerned that even a small increase in precipitation risks exceeding critical thresholds and causing our protection systems to collapse

by HENRY HENGEVELD

The showers began in the wee hours of the morning of April 3, then settled into a steady rain that continued until the end of the day. By then, much of central Ontario had been soaked with up to 45 millimetres of rain – almost two-thirds of the total monthly rainfall April normally brings. Accompanying winds gusted to speeds as high as 70 kilometres per hour. It was one very dull, wet and blustery day!

The window for action on climate change is very small, which makes it all the more important to ensure that the steps we take really do more good than harm

by HENRY HENGEVELD

Two recent developments have once again placed international action to reduce the risks of climate change back in the news.

First, a number of new scientific studies have concluded that the risks of large and potentially catastrophic changes in our climate – and hence weather – over the next few decades and beyond may be significantly larger than the results of the most recent international science assessment released in 2007 had suggested.

Last year, crops and trees across the province took a pounding from hail. What’s behind the increase in severe hailstorms?

by HENRY HENGEVELD

On June 9, 2008, a severe hailstorm passed through the Chatham-Kent area of Ontario, pounding crops and trees, and seriously damaging cars and buildings with hail stones the size of golf balls. Two weeks later, another storm dropped more large hail stones on the same area.