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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 [...]

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 [...]

In Brief: The recent weakness in the East African long rains has been linked to persistently elevated temperatures in the western tropical Pacific. Rains in East Africa primarily fall during the long rains (March through May) and the short rains (October through December). Understanding how climate and climate change influence these rains is particularly important [...]

In Brief: The 1783-84 eruption of Iceland’s Laki volcano caused crop failures and a cold summer in North America, while the following winter’s record cold has been linked to El Niño conditions in the tropical Pacific and a strongly negative North Atlantic Oscillation. The eruption of Iceland’s Laki volcano from June 8, 1783 to February [...]

In Brief: The more work Northern Hemisphere tropical cyclones do during the summer and fall to move energy from the tropics to the poles, the less energy there is to move during the winter months. The 2010 Atlantic hurricane season ended on November 30th, but Earth’s climate still “remembers” the tropical storms that formed during [...]

In Brief: From January 2000 to October 24, 2010, 310,531 record high temperatures were set across the contiguous United States. During the same period, 152,087 record low temperatures were set, giving a record highs to record lows ratio of more than 2:1. There are close to 5,000 quality-controlled weather stations across the United States and [...]

A new ClimateCenter video report from Climate Central discusses NOAA’s latest global temperature analysis and the hurricane season.

In Brief: Nights are warmer than they were in the early 1970s, which exacerbates the urban heat island effect and heat related health problems. Heat waves, which in the United States kill up to 1,000 people per year, are defined as prolonged periods of abnormally hot weather. They can occur at any time of the [...]

Warm ocean surface temperatures in the North Atlantic provide the warm and moist air that fuels hurricanes, which develop out of random disturbances in the tropics that provide the spark for these storms. Warmer waters in the North Atlantic generally mean more fuel for the storms. But did you know that surface temperature conditions in [...]

In Brief: Persistently cool conditions in the eastern tropical Pacific during the Middle Ages led to drought in the southwestern United States. Conditions in the tropical Pacific influence weather throughout the world. On a cycle of two to seven years, the eastern tropical Pacific moves from cool (La Niña) conditions to warm (El Niño) conditions. [...]

When put in 2000 US dollars, freezing rain (ice storm) events in America caused an estimated 16.3 billion dollars in total losses between 1949 and 2000 due to downed power lines, downed trees, agricultural losses, transportation accidents and medical costs from injuries due to slippery conditions. Freezing rain events are most frequent in the Northeast, [...]

The December 2009-January 2010 cold snap may be the most severe the eastern United States has experienced in more than 30 years. Do a few weeks of cold temperatures in one region of the world mean that global warming has stopped? There are a few variables to consider – the behavior of the Arctic Oscillation, [...]

In Brief: Soybeans may produce more antioxidants during years of extreme temperature and drought. A study conducted on Maryland soybeans between 1999 and 2002 found that extreme weather events actually increase the antioxidant levels in the soybean crop. 1999 and 2001 growing season temperature and precipitation levels were normal and the crops exhibited normal levels [...]

December is East Coast Winter Storm (ECWS) season. These storms are powered by warm water that flows from the Gulf Stream. The Gulf Stream current flows along the Eastern Seaboard past Florida and the Carolinas before reaching Cape Hatteras, where the warm water heads out into the Atlantic. ECWS’s travel northward along the coast causing [...]

Along with heavy rains and high winds, the impacts of landfalling hurricanes and tropical storms also include more tornado formation. The larger the tropical cyclone and the longer it spends over land, the greater the probability that tornadoes will form as the system moves. Since 1995 in the Gulf of Mexico, hurricane strength has increased [...]

Better drought prediction systems could potentially save billions of dollars. Current prediction systems largely rely on observations of the circumstances surrounding past droughts to understand the factors that led to drying. New research reveals that: Drought in the southern Great Plains states, such as the 1946-1956 drought, can be largely explained by persistently cool conditions [...]

The concepts of weather extremes and thresholds are tightly coupled and important to remember when planning effective and reliable infrastructure. For example, just one day of extreme heat, even if it falls during a particularly cool summer, can cause railroad tracks to buckle and transportation systems to shut down. Extreme rainfall can have similar effects; [...]

The torrential rainfall and storm surges associated with hurricane landfall events can cause what are known as “overwash deposits” that leave definitive marks in the sediment layers that accumulate in coastal areas. Analyses of sediment cores from various locations along the Eastern Seaboard and Puerto Rico show that for the last 1500 years, Atlantic Hurricanes [...]

In North America over the last 50 years, average nighttime low temperatures have risen faster than average daytime high temperatures. There has been a 50 percent increase in the number of unusually warm nights and nights that fell into the top tenth percentile in terms of temperature for the climate of the 1950′s now fall [...]

While Phoenix has always been hot for U.S. standards, over the last 50 years the city has been getting even hotter. The average number of days per year when the temperature is over 100 degrees has doubled over this time period. Part of this is likely due to the Urban Heat Island effect, which has [...]