When I introduce myself as a meteorologist, the number one thing people say to me is something I’ve only heard about four thousand, three hundred and sixty two times: ‘It must be nice to be wrong 50 percent of the time and still have a job.’ To be fair, everyone who says this does it with a smile on their face, so it’s easy to laugh off the insult. But when I think of this statement a little more, many professions are actually wrong most of the time. The difference is that meteorologists are in the public spotlight on a daily basis, which is far more frequently than economists, stockbrokers and most political and sports pundits.
My response to people’s assertion about the “50 percent wrong” thing is two fold. First, meteorology has made tremendous advances over the last 30 to 50 years. Back in the 70s and 80s, tornadoes would go unwarned and destroy entire towns in the Midwest overnight. Now, nearly every tornado is warned before it destroys a single piece of property. This is an amazing achievement in only a few decades. Further, one and two day forecasts were once as far out as you could hope for any shred of accuracy, but now five to seven day forecasts provide a good idea if the upcoming week’s weather will be sunny, stormy or a little bit of both.
My second response is to help people understand more about the profession of forecasting weather and share some behind-the-scenes knowledge. When you see a five-day forecast for snow and it turns out to be sunny, it’s easy to place blame on the meteorologist and the entire science of meteorology. However, when you get to peek behind the curtain and see what really goes on, the challenges of forecasting a storm a week away become apparent. On this note, let’s look at the weather coming up this weekend and see how this looks in the world of meteorology.
The theme of warm temperatures for most of the country will continue into next week, however, the consistently snowy areas of the Pacific Northwest (Oregon, Washington, northern Idaho) will continue to see snow daily late this week, through the weekend and early next week. A stronger storm will disrupt the current pattern over the weekend, and we’ll take a closer look at this one and do a little behind-the-scenes showmanship.
Far West and Rocky Mountains
On Saturday, this stronger storm will hit Tahoe and then head toward the east, bringing snow to Idaho, Utah and the Tetons of Wyoming Saturday night into Sunday. The wildcard is if this storm will stay strong as it moves through Colorado or if it will weaken and only brush Colorado. To solve this puzzle, meteorologists employ two behind-the-scenes tricks. The first is to compare multiple forecasts from different computer models. There are many, many forecast models, and here I’ve picked four to compare. The European model is often the most accurate, but not always. I also show the American model, the US Navy model and the Canadian model.
Colorado is highlighted with a black box, and the leading edge of the colder air is highlighted with a solid dark blue line. It’s apparent that all models show a different forecast for Sunday night, with the European and Canadian models predicting a weak-to-moderate storm, the American model showing a weak storm (the cold air doesn’t come too far south), and the US Navy model showing a much stronger storm (the cold air heads very far south). A prudent first-guess on the forecast would be to take the middle-of-the-road option, forecasting a weak-to-moderate storm along the lines of the European and Canadian models.
These maps show the weather forecast for Colorado on Sunday evening, April 1. Each model has a slightly different forecast, and meteorologists compare these forecasts in an attempt to pick the one that is most likely to be correct. The blue lines show the leading edge of the colder air, and the closer these lines are together, the more consistent and trustworthy the model. It looks like the European model wins this battle.
The second behind-the-scenes trick is to look at the consistency of the models. If a model has a similar forecast each day (i.e. the six-day forecast doesn’t change much in another day when it becomes the five-day forecast), then it’s consistent and we become more confident in its forecast. In other words, if a model is all over the place and acting “weird,” we don’t trust it. On the graphic, the light blue dashed line shows the leading edge of the cold air from the previous forecast. The closer the dashed and solid lines are to one another, the more consistent the forecast. In this case, it looks like the European model wins the consistency game.
Yes, meteorologists might be wrong at times, but when you peek behind the curtain, you can actually see that there’s a lot more thought put into this than what you see on a five-day forecast graphic on your local TV station. In the case of Colorado, we were able to make a six-day forecast of a storm on Sunday, and by digging a little deeper, the most-likely scenario is a weak to moderate storm bringing colder air and at least a few inches of snow to the mountains.
So yeah, meteorologists do some great work, and we’re not wrong 50 percent of the time. Maybe 40 percent of the time… but not 50.
Meteorologist Joel Gratz is the creator of opensnow.com and is based in Boulder, Colo.