Hurricane Isaac

Hurricane Isaac, the ninth named storm of this Atlantic Hurricane Season, made landfall in Louisiana late Wednesday.  Despite its humble category–one status, this storm severely battered the Gulf Coast for several days.

Measuring nearly 250 miles in size, Isaac was a massive storm.  It produced strong winds and high storm surge that caused power outages and significant property damage throughout the region. Moving slowly – at approximately 5 mph – Isaac also brought unrelenting heavy rain, which lead to widespread flooding. According to the NWS, rainfall totals for this storm, so far, range from 10 to 20 inches across the area. The communities of Plaquemines Parish, LA and Slidell, LA were particularly hard hit by rising water.  In Mississippi and Alabama, several hurricane-induced tornadoes have also been reported.

Downgraded to a tropical depression, the remnants of Isaac are now moving inland.  Forecasts predict this enormous system will bring drenching rainfall to the drought stricken regions of the mid-west and southern plains.   Unfortunately, however, this storm could bring too much rain too quickly to the parched land and possibly cause flash flooding in some areas.

Similar to last year’s Hurricane Irene, Hurricane Isaac demonstrates that even low-category hurricanes can pack a serious punch.

Hurricane Isaac, 2012

Image Credit: NOAA

Hurricane Irene: One Year Later

One year ago today, Tropical Storm Irene made landfall in New York City and roared through the northeastern United States.

Originally a category-one hurricane, Irene was a massive storm that left a trail of destruction from North Carolina to Maine.  Locally, the storm dumped 6.87 inches of rain on NYC and caused widespread power outages.  Most of Irene’s impact, however, was felt further inland.  Drenching rains in the mountains of upstate New York and interior New England caused extensive and catastrophic flooding.  In the end, Irene claimed the lives of 58 people across 13 states and caused approximately $16 billion worth of damage.

Today, Hurricane Isaac, another category-one “i” storm, is bearing down on the Gulf Coast.  While every hurricane is unique, the enormous size of this current storm is reminiscent of Irene.

Hurricane Irene, 2011

Image Credit: NOAA

Weather and Health: Air Quality

An air quality alert is in effect for the New York City area today.  This means our local outdoor air contains elevated levels of pollutants.

Under the Clean Air Act, the EPA is responsible for monitoring air pollution across the United States.  Calculated on the Air Quality Index (AQI), a standardized indicator, the agency’s daily reports focus on the health effects people may suffer as a result of breathing polluted air. Its scale runs from 0-500 with values above 100 considered to be unhealthy.  Increasing AQI values correlate to higher levels of pollution and an escalating risk to public health.

The five major air pollutants measured on the AQI are, ground level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. These pollutants often build to unsafe concentrations when local weather patterns allow air to become stagnant from a lack of wind.

The AQI value in New York City today is 105, which references a spike in ground level ozone.  This degree of pollution will mainly impact people with pre-existing respiratory conditions.

Chart Credit: NOAA

Drought Impacts Commerce on the Mississippi River

The ongoing drought of 2012 is delivering a serious economic blow to America’s agricultural heartland.  Its impact, however, is not limited to food prices.  The lack of rain in the central United States is also affecting one of this nation’s vital shipping arteries – the Mississippi River.

Thousands of tons of cargo – from fertilizer to coal – travel along the mighty Mississippi everyday.  The exact number of barges allowed to safely navigate the river at one time is determined by its water level.  The wider and deeper the river, the more barges can travel. As the river shrinks, so to does its capacity to transport goods and materials.

River levels typically fall off in the summer, but this year’s drought has pushed them well below normal.  For months now, barges have been carrying reduced loads in an effort to ride higher in the water and avoid running aground.  Without significant rain to replenish the river’s flow, conditions on the Mississippi have been getting worse.  In fact, the U.S. Coast Guard reported yesterday that it temporarily closed an eleven-mile stretch of the river near Greensville, MS, because of precariously low water levels.  As a result, nearly 100 vessels were stranded.

These drought induced reductions and delays in shipping – just like this year’s diminished farm yields – will ultimately translate to higher costs for consumers.

Fourth Warmest July for Planet Earth

July of this year, as mentioned in a previous post, was the hottest month on record for the contiguous United States.  The heat, however, was not limited to this country’s borders.

The National Climatic Data Center (NCDC) reported today that July 2012 was the fourth warmest July ever recorded for the entire globe.  The planet’s combined average temperature for the month – over both land and ocean surfaces – was 61.52°F, which is 1.12°F above the 20th century average.  July 2012 was also the 329th consecutive month that our global temperature was above the long-term norm.

While heat dominated most of the planet last month, some areas, such as Alaska, Australia, and parts of Europe, posted below average temperatures.  Experts say these pockets of cooler conditions are normal, but note that they are shrinking as the Earth’s atmosphere warms overall.

An Expert’s Updated View of Climate Change

Extreme weather events, like heat waves and drought, seem to becoming more and more prevalent around the globe.  When they occur, we often hear officials say that individual weather events cannot be linked to climate change or that global warming may have played a role, but they cannot be certain.  New research, however, may change these somewhat standard responses.

James Hansen, a climatologist with NASA’s Goddard Institute, released a new study last week, which concludes that the only explanation for the increase in extreme weather is climate change. While this new statistical analysis of global temperatures has its critics, his recent op-ed piece in the Washington Post , “Climate Change is Here – and Worse than We Thought”, is well worth reading.

The Hottest Month Ever in the U.S.

High temperatures are not uncommon for July in the U.S., but this year they were extreme.  July 2012 now marks the hottest month ever recorded in the lower forty-eight states.

According to NOAA’s monthly climate report, the country averaged 77.6°F this July.  That is 3.3°F above the 20th century average and breaks the previous record set during the Dust Bowl in July 1936.

Most of the heat last month was centered in the mid-west and central plains, where it fueled the region’s devastating drought. By the end of the month, more than 60% of the U.S. was in a state of moderate drought or worse.  These hot and dry conditions were ideal for wildfires, which scorched more than two million acres nationwide in July alone.

On the whole, this year has been exceptionally warm across the contiguous United States.  In fact, the period of January through July 2012 now stands as the warmest seven months this country has seen since modern record keeping began in 1895.

Weather and Art: Hiroshi Sugimoto

Lightning, nature’s most powerful static electrical shock, has sparked human curiosity throughout history. Recently, it helped to inspire the creation of “Lightning Fields”, a series of unique photographs by Hiroshi Sugimoto, a contemporary Japanese artist.

To create this body of work, Sugimoto used a 400,000-volt Van de Graff generator to apply an electric shock directly to a large sheet of film.  The resulting images show the flow of electricity with its tree-like branching discharges. The pattern of each image differs based on the strength of the charge and the path taken by the electrical current.

The outlines produced in these experimental photographs are very similar to the Lichtenberg Figures that often appear on objects and people after they have been struck by lightning.

Lightning Field 128, 2009.

Image Credit: Hiroshi Sugimoto

NYC Monthly Summary: July 2012

July is generally the warmest month on the calendar for New York City, and this year temperatures soared. We had ten days when the thermometer read 90°F or above, including July 18th when the mercury hit 100°F in Central Park.  This extreme heat helped raise the city’s average monthly temperature to 78.8°F, which is 2.3°F above normal.

In terms of precipitation this July, NYC experienced a number of severe thunderstorms, which brought much-needed rainfall to the area. In the end, however, the city only collected 4.21 inches of rain, which is 0.39 inches below normal. While not in a drought, it is interesting to note that the city has received below average precipitation for six out of the past seven months.

Graph Credit: The Weather Gamut