Tag Archives: national

U.S. National Climate Assessment: 2014

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The White House released the third US National Climate Assessment (NCA) report yesterday. It clearly states that climate change is not a distant problem of the future; it is happening now and impacting every region of this country.

Issued every four years to assess how climate is changing in the US, this latest report says: “Summers are longer and hotter, and extended periods of unusual heat last longer than any living American has ever experienced. Winters are generally shorter and warmer. Rain comes in heavier downpours. People are seeing changes in the length and severity of seasonal allergies, the plant varieties that thrive in their gardens, and the kinds of birds they see in any particular month in their neighborhoods.” In terms of agricultural production, “Corn producers in Iowa, oyster growers in Washington state and maple syrup producers in Vermont are all observing climate-related changes that are outside of recent experience.”

“U.S average temperature,” according to the report, “has increased by 1.3°F to 1.9°F since 1895, and most of this increase has occurred since 1970. The most recent decade was the nation’s and the world’s hottest on record, and 2012 was the hottest year on record in the continental United States.” Over the next few decades, temperatures are projected to rise another 2°F to 4°F.  By the end of the century, our average temperature could soar by 10°F if greenhouse gas emissions continue to increase unchecked.

While similar in theme to the recently released IPCC report from the UN, this assessment focuses solely on the United States. Emphasizing the fact that rising temperatures will affect different parts of our vast country in different ways, the NCA breaks the nation down into specific regions. It details the current and future impacts of climate change in each one. Here are some regional highlights:

Northeast: Increased frequency and duration of heat waves; Increased flooding due to sea level rise and extreme rain events

Southeast: Increased frequency and intensity of extreme heat events; Decreased availability of fresh water; Increased threat from sea level rise

Mid-west: Increased frequency of extreme heat events; Increased heavy downpours and flooding; Decreased air quality

Southwest: Increased heat, drought, and wildfires; Increased insect outbreaks

Northwest: Decreased summer water supplies due to earlier snow melt; Increased threat from sea level rise; Increased insect outbreaks and wildfires

Alaska: Warming twice as fast as the rest of the nation; Loss of sea ice, melting glaciers, thawing permafrost; Increased wildfires

Hawai’i: Increased saltwater intrusions from sea level rise; Decreased availability of fresh water

As a nation with over 95,000 miles of coastline, the report also addresses the issues of ocean warming and acidification.

Written by over 300 NOAA scientists and endorsed by dozens of other experts from both the public and private sector (including two oil companies), the NCA concludes that, “Climate Change presents a major challenge for society.” It goes on to say, “There is mounting evidence that harm to the nation will increase substantially in the future unless global emissions of heat trapping greenhouse gases are greatly reduced.” While this comprehensive report does not offer policy, it does emphasize the urgent need for both adaptation and mitigation at all levels of government.

The colors on the map show temperature changes over the past 22 years (1991-2012) compared to the 1901-1960 average for the contiguous U.S., and to the 1951-1980 average for Alaska and Hawai'i. Image Credit: NCA

Change in annual average temperature, 1991-2012. Credit: NCA

 

State of the Air: 2014

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Are you concerned about the quality of the air you breathe?  Air pollution, a by-product of our modern age, is an ongoing problem in many parts of the United States.

According to the American Lung Association’s annual State of the Air Report, 147.6 million people – 47% of the nation – live in counties with unhealthy levels of particle and ozone pollution. That is an increase of 16 million from last year. One of the worst polluted cities is Los Angeles, CA, where the air is considered unhealthy 120 days of the year, on average. For a list of the most polluted as well as the cleanest cities, click here.

Particle pollution comes from a variety of sources, but chief among them are industrial emissions and vehicle exhaust.  When these emissions react with the U.V. light of the sun, they form ground level ozone. Both of these pollutants are known to have serious negative impacts on human health.  They especially affect individuals suffering from respiratory and cardiovascular diseases.

While air pollution continues to be a serious challenge in this country, the report also notes the fact that our air – overall – is cleaner now than it has been in previous decades. This is largely due to the regulations put in place by the Clean Air Act.

To check on the quality of the air where you live, click here.

Multi-Day Tornado Outbreak

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After getting off to a slow start, the severe weather season has kicked into overdrive. A multi-day tornado outbreak has been wreaking havoc across the southern and central United States since Sunday. Widespread destruction, power outages, and a mounting death toll have been reported across several states. Some of the hardest hit areas include Arkansas, Mississippi, and Alabama.

According to local authorities, the twister that hit Vilonia and Mayflower, Arkansas on Sunday night was on the ground for 29.2 miles and claimed the lives of at least 16 people. With winds in excess of 136 mph, the NWS has assigned it a preliminary rating of EF-3. On Monday, the same deadly storm system moved into Mississippi and Alabama and generated even more tornadoes. Local officials there say hundreds of homes were destroyed and at least a dozen people were killed. The strongest storm in this outbreak so far was an EF-4 (preliminary rating) that touched down in Louisville, Mississippi. With winds ranging between 166 and 200 mph, it was also the strongest tornado to form in the U.S. to date this year.

Tornadoes are par for the course in this part of the country in spring, but the longevity of this outbreak is unusual. With warm, moist air moving up from the Gulf of Mexico and feeding into a very slow moving low-pressure system, the threat of severe weather continues to linger.

Tornado ravaged Vilonia, Arkansas. Image Credit: EpochTimes/AP

Tornado ravaged Vilonia, Arkansas.  Image Credit: EpochTimes/AP

Slow Start to Tornado Season

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Spring is usually the height of severe weather season in the United States. This year, however, it has been slow going – at least so far.

According to NOAA’s Storm Prediction Center, there have only been 20 tornadoes rated EF-1 or higher to date in 2014. On average, we usually see 157 storms by this point in the season. Of the twisters that did form, none were rated EF-3 or stronger. That is fairly weak by tornado standards, which are measured from EF-0 to EF-5 on the Enhanced Fujita (EF) scale.

With colder than average temperatures dominating most of the country recently, storm development – which needs warm moist air and explosive convection – has been limited. That said, a slow start does not necessarily mean a slow season. It only takes one strong storm to devastate an area. Last year, for example, was a below average season, but it still produced an EF-5 that leveled Moore, OK.

May is typically the most active month of the year for tornadoes in the US.

Data Source: NOAA

Data Source: NOAA

Technical Weather Terms Go Viral

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This winter produced some record cold temperatures and significant snowfall across the eastern two-thirds of U.S.  It also brought a few technical weather terms into our mainstream vocabulary.

In January, bitterly cold arctic air moved south over a large section of this country and the term “polar vortex” became ubiquitous.  Although it sounds ominous, the phrase literally describes what it is – a pattern of winds spinning around the North Pole.

More recently, as a powerful nor’easter moved up the eastern seaboard, “bomb” became a weather buzzword.  Also known as “explosive cyclogenesis”, it is a meteorological expression that describes the rapid intensification of a low-pressure system.  More specifically, it means the surface pressure of a system is expected to drop by at least 24 millibars in twenty-four hours.  In general, the lower the pressure, the stronger the storm.

The weather phenomena described by these phrases can occur every winter.  Why did they become so popular this year?  Was it because they happened more frequently this season?  Is it because they work well as catchwords or tags on Twitter?  Perhaps, it was a bit of both.

Winter 2013-14: The 34th Coldest for Contiguous U.S.

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The winter of 2013-14 has been long and cold for many parts of the United States. For the nation as a whole, it was our coldest winter since 2009-10, but not a record breaker.

According to NOAA’s National Climatic Data Center, this meteorological winter (Dec-Feb) was the 34th coldest on record for the contiguous U.S.  With an average temperature of 31.3°F, the country was 1°F below its long-term norm.

While the Northeast and Midwest experienced extended bouts of frigid temperatures and abundant snow, the West was unusually warm and dry.  This difference, produced by a highly amplified jet stream, balanced out the national average.  Nonetheless, it is interesting to note that even though this winter was among the top ten coldest for a few mid-western states, none posted an all time record cold season.  California, by contrast, experienced its warmest winter on record.

Near Record Ice Cover on the Great Lakes

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Persistent frigid temperatures this winter across the Mid-West and Northeast have caused many rivers and lakes to freeze.  These include the Great Lakes – the largest group of fresh water lakes on the planet.

According to NOAA’s Great Lakes Environmental Research Laboratory, 91.8% of the Great Lakes are currently covered with ice.  That is the second highest percentage on record.  The largest was 94.7% in 1979. On average, peak ice coverage each winter is roughly 51%.

This extensive ice cover has its pluses and minuses.  On one hand, it has reduced the amount of lake effect snow – the heavy precipitation produced when cold air blows across the expansive and relatively warm lake water.  When the lakes are frozen, moisture cannot be evaporated and this process shuts down.  On the other hand, it has slowed shipping traffic, which has economic impacts.  Also, given their massive size, the frozen lakes will likely keep regional temperatures cooler than average this spring.

While this year’s ice cover on the Great Lakes is near record-breaking, researchers say the ice extent varies annually and that there has been an overall decline since the early 1970’s.

Ice covers more than 90% of the Great Lakes. Image Credit: NOAA/Great Lakes Environmental Research Laboratory.

Ice covers more than 90% of the Great Lakes.                                                                                      Image Credit: NOAA/Great Lakes Environmental Research Laboratory.

National Weatherperson’s Day

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Today is National Weatherperson’s Day in the United States. Observed annually, it is a day to recognize the work of all individuals involved in the field of meteorology – not just famous prognosticating groundhogs.

According to the NWS, February 5, 1744 was the birthday of Dr. John Jeffries – one of America’s first weather observers.  As a Boston based physician with a deep interest in weather, he kept daily records from 1774 to 1816.  He also took the first known weather observation from a hot air balloon in 1784.

Recognizing the significant contributions Dr. Jeffries made to the science of weather, this day was chosen in his honor.

Winter Storm in the Deep South

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A rare winter storm paralyzed large sections of the southeastern United States yesterday.  Serious impacts from snow, sleet, and freezing rain were felt from the Gulf Coast to Virginia.

According to the NWS, 2.6 inches of snow fell in Atlanta, GA – a new daily record for the region’s largest city. As a whole, the Deep South is not accustomed to wintry precipitation and most cities and towns are not equipped to deal it.  Salt spreaders and snowplows are in short supply across the region.  As a result, major roads turned into sheets of ice creating very hazardous travel conditions.

The timing of the storm made the situation even worse.  Arriving in the afternoon, many people were caught on the roads trying to make their way home. Officials have reported hundreds of traffic accidents and stranded vehicles.  Many people were even forced to shelter in place overnight in cars, schools, and stores.

Snow and ice bring travel to a stand still near Atlanta, GA. Image Credit: Guardian LV

Snow and ice bring travel to a stand still near Atlanta, GA.  Image Credit: GuardianLV.com

Drought Update: January 2014

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So far this winter, snow has been plentiful across the mid-west and northeastern US. In the western states, however, long-term drought continues to leave much of the region parched.

According to the latest report from the US Drought Monitor, 61% of the West is suffering under conditions of moderate drought.  In California, where 2013 was their driest year on record, the situation has gone from bad to worse. In just this past week, the category of extreme drought jumped from 28% to 63% of the entire state.

These dry conditions are not only lowering reservoir levels and reducing crop production, they are increasing the risk of wildfires.  In fact, a large fire broke out today in the San Gabriel Mountains near Glendora, CA – a heavily populated suburb of Los Angeles.

January is usually the wettest month of the year in southern California, but a persistent ridge of high pressure over the region has pushed the storm track north. Unfortunately, this dry weather pattern is forecast to remain in place for the near future.

Image Credit: US Drought Monitor

Image Credit: US Drought Monitor