“Weather is unpredictable.”
“If you don’t like New England weather, wait five minutes.”
“If you’ve lived here long enough, you know not to trust the weather forecast.”
Yes, there are some partial truths, but in general, weather forecasts are reliable and based on solid science.
In this day and age, it can be construed as blasphemy or even “fake news,” but like many science-based professions, meteorology has come under criticism and been relegated to a punchline. This is often the case. Like all scientists, we take pride in our work, our livelihood, and our predictions. And like all scientific fields, when things go wrong, we try to decipher what went wrong. This is literally forensic meteorology about how we arrived at our forecasts, where they went off track, and what we can do better in the future.
This storm, like several others from last year, is disconcerting because it suddenly died down just as snow levels were established. Confidence for 6 inches of snow was 73% in Boston and 87% in Worcester (see below).
With percentages like this, no one will turn the dial down when it comes to snow maps, impacts, or preparedness.The bigger question is: What led to that outcome? that’s allConfidence in the model and how (or if) it can be supplemented.
Our esteemed colleagues at MIT will argue that models can handle a variety of outcomes in their predictions, even in a warming world. On the other side of the country, atmospheric researchers at Stanford University found that in mid-latitude regions of the planet, where most Americans live, errors propagate through weather models faster as temperatures rise, and there is no temperature threshold. I’m guessing it looks like this. Changes in trends.
Of course, the impact this has on winter weather is huge. Higher intensity rain may also be affected as temperatures rise, as warm air can hold more water vapor (and therefore rain more).
Whatever the explanation, in this case it appears that dueling jet streams were competing to control the storm’s path. The model tried to phase or combine the jet stream, but it completely failed. Instead, the storm was guided by the northern arm of the jet stream, which prevented the storm from moving deeper into New England and spared much of the Commonwealth from more than 6 inches of snow.
As the debate continues over the sources of model error, we continue to advance our predictions (pun intended).
