Extreme Weather

Climate Fact: Hurricanes Remain Uncertain in the Climate Context

Infamous hurricanes like Sandy and Katrina will be on the minds of many when the nation observes Hurricane Preparedness Week, and questions will continue to swirl around climate change and how it will, or already has, influenced hurricanes. Unfortunately, the scientific community is still searching for many of those answers. Scientists need a substantially long [...]

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Climate Fact: What Science Knows and Doesn’t Know About Extreme Weather

Even though extreme weather events can be notoriously unpredictable, some things are coming into focus.   In 2011, the U.S. had more weather-related billion-dollar disasters (14) than at any other point in its recorded history, and the losses from 2012’s Hurricane Sandy and drought may prove to be even costlier.  Our climate’s mean conditions and extremes [...]

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Climate Fact: The Fate of Groundwater

Globally, humans draw nearly one-third of our fresh water from underground sources, supplying 36 percent of domestic water, 42 percent of agricultural water and 27 percent of  industrial water.  However, our water demands are beginning to alter this critical resource in profound ways.  Until now, scientists have struggled to understand how increased demand coupled with [...]

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Climate Fact: Jet Stream Secrets

Could lessons from its 44-year climatology improve our forecasts of cold snaps? Jet streams are the air traffic controllers of Earth’s weather. These fast-moving “rivers of air” meander through the atmosphere’s landscape, pushing around mountains and valleys of high and low pressure. The jet stream’s position can be a great clue for predicting some types of [...]

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Climate Fact: Two Tales of American Snowfall

Two divergent stories are beginning to emerge about America’s snowfall.  While one study showed that American snowfall might decline in the future, another found that the biggest snow-producers – extreme snowstorms – have increased.  In fact, there have been twice as many extreme snowstorms in the past half century as there were in the preceding [...]

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Climate Fact: Cheating Birds

According to a recent study, birds living in unstable climates are more likely to cheat on their significant others.  But avian cheaters have good intentions – by mating with multiple partners, female birds can improve their offspring’s ability to cope with variable future weather conditions. Studies have shown that chicks born from cheating have higher [...]

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Climate Fact: The “Snowmageddon” Winter Wasn’t As Cold as You Remember

In Brief: Most of the headline-grabbing cold weather outbreaks during the Northern Hemisphere winters of 2009-2010 and 2010-2011 can be explained by natural variability.  However, a greater percentage of the Northern Hemisphere was dominated by anomalously warm weather outbreaks in these seasons and increasing global temperature trends over the past half-century may have been more [...]

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Climate Trivia: Tropical vs. High-Latitude Year-to-Year Temperature Differences

2012 was the warmest year on record for the contiguous United States.  Globally, it was the ninth (by NASA estimates) or tenth warmest (by NOAA estimates).  2012 was also the 36th year in a row where the average global temperature was above the 20th century average. The recent 30-40 year warming trend is obvious on [...]

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Climate Number: 124 Miles

On the other side of the Great Lakes in Ontario, Canada live two species of flying squirrel, the northern flying squirrel (Glaucomys sabrinus) and the southern flying squirrel (Glaucomys volans). These two species inhabit more northerly and southerly ranges, respectively. Climate change means geographic changes in the distribution of temperature and moisture conditions. Because most [...]

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Climate Number: 19 Named Storms

The official 2012 Atlantic Hurricane Season is now over. Compared to the 30-year average of 12 named storms per year, 2012 was above-normal with 19 named storms, but not an exceptional year. Ten of these storms became hurricanes (annual average is six hurricanes). Only one storm, Michael, became a major hurricane (annual average is three [...]

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Climate Fact: Tropical Cyclones and the Global Climate System

In Brief: By cooling ocean surface waters and injecting heat downward, tropical cyclones moderate the seasonal temperature cycle in the oceans, with possible implications for the climate system. Since 1978, over 3,000 tropical cyclones have been observed worldwide. While they are probably best known for the damage they cause, without tropical cyclones Earth’s climate system [...]

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Climate Fact: What Controls Atlantic Tropical Cyclone Development?

In Brief: Sea surface temperatures in the Main Development Region, conditions in the tropical Pacific Ocean and the North Atlantic Oscillation are all important factors for determining the likelihood of tropical cyclone formation in the Atlantic Ocean. Predicting the formation of tropical cyclones in the North Atlantic basin is challenging but critical considering the severe [...]

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Climate Trivia: Mosquitoes, West Nile Virus and the Weather

Mosquitoes have existed in the same basic form for at least 76 million years and have spread to every continent except Antarctica. What’s the secret to their success? Mosquitoes are one of the few insects that routinely lay eggs and mature in small, transient bodies of water, such as tree cavities and even hoof prints. [...]

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Climate Number: 29 Teragrams

The rapid expansion of drought conditions over the contiguous United States during the past year led to the largest moderate to extreme drought coverage since the 1950s. While the epicenter of the current drought is in the Midwest and central Plains, the drought of the 1950s was centered in the West. The total national extent [...]

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Climate Number: 20 Fewer Hours

America’s costliest natural disasters are often North Atlantic hurricanes striking Florida, the East Coast or the Gulf Coast. While inland flooding, tornadoes, lighting and coastal storm surges account for the majority of monetary damages inflicted by these storms, the hurricane winds themselves also do a good deal of damage. How much structural damage winds inflict [...]

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Climate Fact: United States 2012 Drought

In Brief: Drought is a cycle largely driven by changes in long term averages of sea surface temperatures in remote locations around the world. Dust can amplify this cycle. As of August 14, 2012, 61.77 percent of the contiguous United States was under drought conditions, a slight decline from the record 63.9 percent set on [...]

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Climate Fact: Heat Waves and Extreme High Daily Low Temperatures

In Brief: A trend of warmer nighttime low temperatures has been documented globally. Over North America there are 50 percent more unusually warm nights than there were 50 years ago. Heat waves are events with extremely high surface temperature conditions that last for several days. For most of the United States, three days with temperatures [...]

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Climate Fact: Frontal System Precipitation

In Brief: Precipitation resulting from atmospheric fronts is an important component of global rainfall, accounting for around 57 percent of total midlatitude (30 to 60 degrees latitude) precipitation. Precipitation associated with warm fronts is the most common type over much of North America. There are three main types of precipitation: convective, where heating of the [...]

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Climate Fact: Changes in Arctic Sea Ice are Affecting U.S. Weather

In Brief: A warmer Arctic means slower-moving storm systems across the mid-latitudes. Spring is the time of year when the Arctic comes out of its long, dark winter and the sea ice that covers most of the Arctic Ocean in winter begins its annual melt. This melting continues through the warm summer months until the [...]

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Climate Number: 40 Percent

Rainfall records from the central United States confirm the old adage that “when it rains, it pours.” While days with at least “moderately heavy” precipitation  ?  precipitation totals exceeding  0.5 inches  ?  account for only 25 percent of all days when it rains, more than 70 percent of the total rain volume falls during moderately [...]

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