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A Better Read on the Week's Weather

Weather forecasts can predict the next three days with reasonable accuracy. But when it comes to forecasting a week or more into the future, it’s another story.
Professor James Booth (GC, Earth and Environmental Sciences / CCNY, Earth and Atmospheric Sciences) is hoping to change that. “We know the models we’re using have difficulty capturing things like clouds and precipitation. and when these things are not properly represented, they can create serious biases in medium-range (five to fourteen-day) forecasts,” he says.
After previous work on how weather events like wind and rain relate geometrically to a storm’s center, Booth is now focusing on weather predictability. “Can we constrain the path of the storm’s center over longer forecast time scales? And, if so, can we use that information, plus the geometry we already know, to improve predictability on lengthier time scales of weather impacts?”
While most storms in the Northeast move out over the ocean, the few that cut up along the coast often end up doing the most damage. Storms taking that path, Booth found, tend to be influenced by atmospheric blocks, or organized systems that force air streams to slow down or blow in atypical directions.
Booth’s recently co-authored papers — including “Arctic Cut-off High Drives the Poleward Shift of a New Greenland Melting Record” in Nature Communications and “The Relationship Between Extratropical Cyclone Steering and Blocking Along the North American East Coast” in Geographical Research Letters — confirm that atmospheric blocks can steer specific storms. Although the atmospheric science community has always accepted a possible correlation, Booth provides robust statistics documenting the relationship between blocks and different storm paths over the past 40 years.
What happens when atmospheric blocking changes? Blocks themselves don’t cause strong wind or heavy rain, but their steering power can easily generate those phenomena in storms. “Some people think we’re going to see an increase in blocking as the arctic melts,” Booth says, a theory that’s still up in the air. “I don’t think arctic melting alone is strong enough to cause it.”
The impact of arctic melting on the mid-latitude atmosphere is an ongoing question for atmospheric scientists, with multiple hypotheses in the mix. “At this point, we’re still trying to understand what controls how storms move, but over a five-day period versus a one-day period,” Booth explains. “The first piece of that puzzle I tried to unlock was the influence of atmospheric blocks.” While scientists still have some sleuthing to do before they can translate this information to the public, the research by Booth and his colleagues is a significant leap forward in a lengthy scientific process.

Submitted on: JUL 17, 2018

Category: Earth and Environmental Sciences | Faculty | General GC News