Quantcast
Climate
Map of the jet stream and polar vortex on January 3, 2018. University of Maine Climate Change Institute

'Polar Vortex,' 'Winter Storm Grayson' and 'Bombogenesis': What Do They Mean?

By Brenda Ekwurzel

Forecasters are trotting out "polar vortex" and atypical terms like "Nor'easter bomb" and "bombogenesis." These words signal the unusual and dangerous conditions forecast for winter storm Grayson and their implications for the southeast U.S., mid-Atlantic, and eventually New England and beyond. What do they mean?

Meteorologists use the phrase bombogenesis to describe a sudden and extreme drop in barometric pressure of at least 24 millibars over 24 hours, which leads to rapid intensification of a mid-latitude cyclone. We are used to hearing about North Atlantic cyclones during summer and fall—it's the meteorological term for hurricanes—and now winter storm Grayson is drawing moisture from a similar cyclonic circulation that will bring blizzard conditions as it moves northeast just offshore of the U.S. east coast.


Winter weather and global warming

With cold temperatures and icy conditions leaving the continental U.S. reeling over the New Year, it might seem counter-intuitive to say that we're still experiencing global warming. But as my colleague Peter Frumhoff puts it, saying that climate change isn't occurring because of the cold in the eastern U.S. is "like saying if everyone around me is wealthy then poverty is not a problem ... local weather is not an indicator of changes in climate."

Global warming is exactly that: global. The total area of the U.S., including Alaska and Hawaii, is only about 2 percent of the surface area of Earth. This map from the University of Maine Climate Change Institute showing the deviations from average temperature for this time of year demonstrates this concept well—much of the continental U.S. may be unusually cold right now but most of the rest of the world is well above average (Figure 1).

Figure 1: Temperature departure from average for this time of year. Much of the continental U.S. may be unusually cold right now but most of the rest of the world is well above average. Map from the University of Maine Climate Change Institute

Alaska has been unusually warm this winter even though it is in the Arctic. It might seem strange that local weather events such as a balmy Alaska and freezing Florida can occur at the same time, but they're examples of another phenomenon we can expect from a changing climate: more events at the extremes. Many scientists are studying these clues to explore the connections between a rapidly warming Arctic from climate change and shifting extreme weather patterns in northern hemispheremid-latitudes (i.e. the continental U.S. and Eurasia).

Arctic cold outbursts reach the southern U.S.

Scientists noticed an unusual winter pattern in the jet stream that started around the year 2000. Before that time the jet stream was typically fast with small waves that kept the cold air contained in the Arctic region. However, the jet stream began slowing down, and its waves meandering more.

The distance between the peak (like the green and yellow band peaking near the intersection of the borders between Alaska and the Yukon Territory of Canada in Figure 2) and the trough (the highlighted red, yellow and green area near the southern U.S.) has become much longer since the 2000s when compared to prior decades.

Figure 2: The jet stream and polar vortex on January 3, 2018 Map from the University of Maine Climate Change Institute

Scientific process and progress in understanding extreme weather

Scientists are making progress in better understanding how much natural seasonal patterns, ocean cycles and other factors play a role in altering the jet stream and how much global warming is responsible. Some say a lot, others not as much. This is a robust scientific discussion that has continued to evolve over the past several years.

One thing is certain: no climate scientists say there is zero contribution from global warming. We agree on 90 percent of the facts of the issue—now we're debating the remaining 10 percent.

How will we know when this particular scientific debate is over? One way or another, the scientific community will reach consensus—just as it has with climate change more broadly.

Assessments will shift toward keeping track of the changing percentage of contribution from climate change to the altered jet stream. And we'll really know consensus is reached when this research is incorporated into longer-term outlooks for winter forecasts. In fact, a recent publication suggests that if the Arctic indicators—such as the strength or weakness of the polar vortex—were better incorporated into current winter forecasts, we could have two- to six-week previews of the winter temperatures in the northern hemisphere just like we get our 10-day forecast today.

If predictions become reliable enough, this could help cities and counties plan to distribute snow removal equipment to regions that will need it well in advance of storms. This knowledge may better protect people facing risks to their daily lives from the consequences of extreme cold winter storm events.

Brenda Ekwurzel is a senior climate scientist and the director of climate science at the Union of Concerned Scientists.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Insights/Opinion
Pexels

Tackling Climate Change Requires Healing the Divide

Canadian climate change opinion is polarized, and research shows the divide is widening. The greatest predictor of people's outlook is political affiliation. This means people's climate change perceptions are being increasingly driven by divisive political agendas rather than science and concern for our collective welfare.

Keep reading... Show less
Popular
Westend61 / Getty Images

EcoWatch Gratitude Photo Contest: Submit Now!

EcoWatch is pleased to announce its first photo contest! Show us what in nature you are most thankful for this Thanksgiving. Whether you have a love for oceans, animals, or parks, we want to see your best photos that capture what you love about this planet.

Keep reading... Show less
Food
Pexels

10 Chefs Bringing Forgotten Grains Back to Life

Millets are a staple crop for tens of millions of people throughout Asia and Africa. Known as Smart Food, millets are gluten-free, and an excellent source of protein, calcium, iron, zinc and dietary fiber. They can also be a better choice for farmers and the planet, requiring 30 percent less water than maize, 70 percent less water than rice, and can be grown with fewer expensive inputs, demanding little or no fertilizers and pesticides.

Keep reading... Show less
Adventure
Háifoss waterfall is situated near the volcano Hekla in the south of Iceland. FEBRUARY / Getty Images

The Essential Guide to Eco-Friendly Travel

By Meredith Rosenberg

Between gas-guzzling flights, high-pollution cruise ships and energy-consuming hotels, travel takes a huge toll on the environment. Whether for business or vacation, for many people it's not realistic to simply stop traveling. So what's the solution? There are actually numerous ways to become more eco-conscious while traveling, which can be implemented with these expert tips.

Keep reading... Show less
Sponsored
Animals
Freder / E+ / Getty Images

Surprising Study: Orangutans Are Only Non-Human Primates Who Can 'Talk' About the Past

We already know that orangutans are some of the smartest land animals on Earth. Now, researchers have found evidence that these amazing apes can communicate about past events—the first time this trait has been observed in a non-human primate.

A new study published in the journal Science Advances revealed that when wild Sumatran orangutan mothers spotted a predator, they suppressed their alarm calls to others until the threat was no longer there.

Keep reading... Show less
Health
Suicide rates are highest for males in construction and extraction; females in arts, design, entertainment, sports and media, the CDC found. Michelllaurence / Flickr / CC BY 2.0

CDC: Suicide Rate Among U.S. Workers Increasing

From 2000 to 2016, the suicide rate among American workers has increased 34 percent, up 12.9 per 100,000 working persons to 17.3, according to a worrisome new study from the Centers for Disease Control and Prevention (CDC).

Workers with the highest suicide rates have construction, mining and drilling jobs, the U.S. health officials reported Thursday.

Keep reading... Show less
Sponsored
Energy
PG&E received a maximum sentence for the 2010 San Bruno natural gas pipeline explosion. Wikimedia Commons / CC BY-SA 3.0

Report: 90% of Pipeline Blasts Draw No Financial Penalties

A striking report has revealed that 90 percent of the 137 interstate pipeline fires or explosions since 2010 have drawn no financial penalties for the companies responsible.

The article from E&E News reporter Mike Soraghan underscores the federal Pipelines and Hazardous Materials Safety Administration's (PHMSA) weak authority over the fossil fuel industry for these disasters.

Keep reading... Show less
Politics
Nevada Test and Training Range. U.S. Air Force / Airman 1st Class Kevin Tanenbaum

U.S. Navy Proposes Massive Land Grab to Test Bombs

Friday the U.S. Navy released details of a plan to seize more than 600,000 acres of public land in central Nevada to expand a bombing range. The land under threat includes rich habitat for mule deer, important desert springs and nesting sites for raptors like golden eagles.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!