What’s with the weather?
By Peggy Mackenzie
Is this our “New Normal?” From the dry spell in the West to the East Coast’s endless snow season, and now endless summer rainstorms, the country has seen its share of weird weather so far in 2015.
Widespread damaging winds – pounding downpours – and extreme lightning events for weeks on end have got locals at the end of their tethers. “When will it stop?” they cry. Rupert and Richwood were “hammered” Monday and Tuesday with heavy winds and rain. Power outages, flooding and landslides were also reported in the northern and western ends of the county.
These unprecedented weather events this summer may or may not be as a result of climate change, but studies now show the persistence of this phenomenon points to an unusual condition in the Pacific Ocean that is a likely culprit for our wet, windy weather.
Introducing “the blob.”
In early 2014, weather scientists began to notice a big mass of warm water about the size of Alaska off the West Coast that was about 2 to 7 degrees Fahrenheit above normal, reports chinookobserver.com. Coined “the blob” by Nick Bond, a climate scientist at the University Washington-based Institute for the Study of the Atmosphere and Ocean, whose study confirmed the blob had contributed to Washington’s mild 2014 winter. Air cycled over the warmer water heated up and brought less snow, which translated into drier conditions inland. Bond also anticipated a warmer summer for the West Coast and people in the west can thank the blob (in part) for the drought conditions experienced in California, Oregon and Washington.
Now, months later, the blob is still off the west coast shores, though it has become a long, skinny finger of water, stretching all the way from Mexico to Alaska, and all models point to it continuing through the end of this year.
East Coasters can blame wonky ocean temperatures off the Pacific for all those weeks spent shoveling snow last winter, according to another study published March 19 in the journal Geophysical Research Letters. A decadal pattern called the North Pacific Mode, a pattern of higher-than-average sea-surface temperatures that snakes from the tropical Pacific to the waters off coastal California to the northern Pacific, is causing the weird weather. The pattern sent rivers of cold, wet air into the Midwestern and East Coast states, and projected the current trend for our wet, rainy summer weather, the study found.
“Lately, this mode seems to have emerged as second only to the El Nino Southern Oscillation in terms of driving the long-term variability, especially over North America,” said study author Dennis Hartmann. This same climate variability helped create the warm blob, and has been getting progressively more influential on global weather patterns since 1980, the study found.
“This is a taste of what the ocean will be like in future decades, Bond said. “It wasn’t caused by global warming, but it’s producing conditions that we think are going to be more common with global warming.”
As scientists and commentators seek to explain the new normal of our weather patterns, another research paper, published in Nature Climate Change, by Kevin Trenberth and two colleagues with the National Center for Atmospheric Research, see a different default assumption for interpreting how climate influences weather. Their findings will likely add to the debate over what impacts a changing climate.
Trenberth and his team argue that while changes in atmospheric dynamics are very hard to blame on climate change at the present time, thermodynamic changes, on the other hand, involving heat and moisture are relatively easy to attribute.
To make the distinction between dynamics and thermodynamics clear, it’s first necessary to understand that dynamics govern the large scale motions of the atmosphere – the way in which the flow of air on a rotating planet leads to major patterns, such as gigantic cyclonic storms or the jet stream. Thermodynamics, in contrast, involve how temperature and moisture shape atmospheric events, in the way hotter ocean temperatures can have the effect in strengthening storms like hurricanes.
A number of examples are given: The “Snowmageddon” winter of 2010, which began locally with the heavy snow stonn on December 18 that started the trend for several snow events all winter long. In 2012, Superstonn Sandy, powered by warmer oceans beneath the storm, swamped the East Coast. And 2013’s deadly Supertyphoon Haiyan, dubbed a true Category 6 storm, devastated the Philippines after running across extremely wann seas and making landfall at an intensity unrivaled in historical records. All these weather events demonstrate the effects of thermodynamics at work, according to the report.
“The climate is changing: we have a new normal,” Trenberth wrote. “The environment in which all weather events occur is not what it used to be. All storms, without exception, are different. Even if most of them look just like the ones we used to have, they are not the same.”
“Because global warming is real and present, it is not a question as to whether it is playing a role but what that role is,” Trenberth stated in the report.
It would seem that keeping an umbrella handy is a good idea.
