ACTIVE SEASON The flow we now see across North America may bring a stormy summer with it
Sometimes I’m as quick as the next person to jump all over weather forecasters when they’re way off the mark. It’s easy for us to notice when a forecast is wrong, but we rarely notice how often they are right. A lot of people are also quick to say how weather forecasting hasn’t really gotten any better over the years. Heck, I still hear people saying weather forecasts were much better when they were young! Personally, I think that selective memory is at work with these people.
Now, I am not saying that weather forecasting is perfect — far from it. I do think it is going to get better, but as I have talked about in the past, this is going to take time. The problem with making a good accurate forecast lies with the initial data. Forecasting the weather is extremely complicated, but no matter how good your forecasting model is, it is only as good as the data that goes into it at the start. If your starting parameters are off by a little bit, that might not make a big difference in a 24-hour forecast, but the farther out you go, the more those initial differences will add up, creating a forecast that gets worse and worse the farther out you go.
This is why I get really upset when the government cuts Environment Canada’s budget and we continue to slowly see weather stations being taken offline. Fortunately, computer-based home weather stations have become reliable and fairly affordable and it’s these stations that are filling in the gaps. The more stations we have collecting and sharing data, the better the weather forecasts will be. Maybe this is the best way to go, but in my opinion, the cost of this shouldn’t be fully placed on the shoulders of private individuals, but should be shared by the private companies using this data, along with the government, which also uses and benefits from it.
On that note…
OK, my little rant is over and I feel better. Now, back to what I originally wanted to talk about this week: weather forecasting, and in particular, severe weather forecasting. For those of you who are weather geeks, you were probably either watching or reading about the severe thunderstorm and tornado outbreak that occurred over the weekend in the U.S. Midwest.
An outbreak like this, at this time of the year, is not really that unusual, as we are nearing the peak season for tornadoes in that part of the world. What was fairly unique about this outbreak, however, was the fact that it was forecast to occur two days in advance of the event!
The U.S. National Weather Service issued a high-risk forecast for much of Oklahoma, Kansas and Nebraska early in the morning on April 13. This was only the second time it has ever issued a high-risk forecast more than one day in advance.
As I write this article the final numbers are not yet in, but the forecast was basically right on the money. There were unofficially 98 reports of tornadoes, 70 reports of high winds and 130 reports of hail. All in all, a pretty impressive bit of forecasting!
With such an active start to the summer severe weather season in the U.S., the big question is whether we’ll see this active weather push northward as we slowly move toward summer.
I’ve just started looking at what this summer may hold for us, so a full examination of this is still a few weeks away. If I was to go with my gut feeling right now, I would have to say we will see a very active thunderstorm season this year. The reason I have this feeling is that the general atmospheric flow across North America has been very active for over a month now. This means the flow pattern is producing large atmospheric waves extending fairly far north and south. When this happens we see strong pushes of warm air surging northward as one of these waves approaches, then a good push of cool air once the wave passes. In between, where the warm and cold air meet, is where you see storms develop.
So, the overall pattern looks conducive to storm development. Add on top of this early snow and ice loss over a large portion of North America, which has allowed ground and water bodies to become much warmer than usual for this time of year, and record-warm sea-surface temperatures over the Gulf of Mexico, a large source of water vapour or energy for storm development, and the ingredients are there for the active pattern to take advantage of. But as we all know, Mother Nature seems to hate it when we try to figure her out, and more often than not she throws us a curveball just to keep us off balance.