Monthly Archives: August 2016

July 2016: Warmest Month on Record for Planet Earth

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Our global temperature continued its upward trend last month with July 2016 marking not only the warmest July on record, but also the warmest month ever recorded for the entire planet.

According to a report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for the month – over both land and sea surfaces – was 62.01°F. That is 1.57°F above the 20th century average and 0.11°F above the previous record that was set just last year.

July 2016 also marked the 15th month in a row to break a monthly global temperature record – the longest such streak on NOAA’s books. Moreover, it was the 379th consecutive month with a temperature above the 20th century average. That means the last time any month posted a below average reading was December 1984.

Since July is climatologically the Earth’s warmest month of the year, the July 2016 global temperature was also the highest temperature for any month on record.

While heat dominated most of the planet last month, some places were particularly warm, including various countries in Asia and the Middle East where temperatures hit record levels. Here in the contiguous US, it was our 14th warmest July on record. Florida and New Mexico were each record warm.

These soaring temperatures, scientists say, were driven by the long-term trend of human-caused climate change. While El Niño gave global temperatures a boost earlier in the year, it has since dissipated. In fact, ENSO neutral conditions prevailed across the tropical Pacific Ocean this July.

Year to date, the first seven months of 2016 were the warmest of any year on record. This increases the likelihood that 2016 will surpass 2015 as the Earth’s warmest year ever recorded. Global temperature records date back to 1880.

July 2016 was the warmest July and warmest month on record for planet Earth. Credit: NOAA

July 2016 was the warmest July and the warmest month on record for planet Earth. Credit: NOAA

Second Heat Wave of the Summer Bakes the Big Apple

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New York City is sweltering through its second heat wave of the summer.

The threshold for what constitutes a heat wave varies by region, but here in the NYC area it is defined as three consecutive days with temperatures reaching 90°F or higher. Monday marked the city’s fifth.

With dew points – a measure of humidity – in the mid to upper 70s, it felt even hotter. The heat index – the so-called real feel temperature – reached as high as 105°F to 110°F in some spots.

This dramatic rise in heat and humidity was the result of a dominant Bermuda High, a large area of high pressure situated off the east coast. Spinning clockwise, it has been steering hot, humid air from the Gulf of Mexico toward the northeast.

While these conditions are oppressive, they can also be dangerous. The NWS issued both an excessive heat warning and air quality alert for the city. The last time NYC had this type of heat emergency was July 2013.

How a Bermuda High ushers in hot and humid air to the northeastern US. Credit: Jacksonsweather

How a Bermuda High ushers in hot and humid air to the northeastern US. Credit: Jacksonsweather.com

200th Anniversary of the ‘Year Without a Summer’

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Two hundred years ago, the warm weather we typically associate with summer never materialized for large areas of the globe, including the eastern United States and Europe. As a result, 1816 has become known as the year without a summer.

This historic cold spell was caused by the eruption of Indonesia’s Mount Tambora in April 1815 – the most powerful volcanic eruption ever recorded. While it devastated the immediate area and unleashed a deadly tsunami, it was the the massive amounts of sulfur dioxide spewed out by the volcano that had far-reaching impacts on the global climate.

After an eruption, ash and debris can cool a region for a few days by blocking out the sun. However, extremely powerful eruptions – like Tambora – can send gas clouds into the stratosphere – an altitude above where our daily weather takes place. The stability of this layer of the atmosphere means the sulfur dioxide can linger there for several months. Moving around the globe easily at this level, the sulfur dioxide spreads out, reacts with water vapor, and forms sulfate aerosols. These reflect incoming solar radiation and increase the reflectivity of clouds, cooling surface temperatures.

The average global temperature in 1816, according to the UCAR, dropped 3°C. That may sound like a small number, but it had dramatic impacts, especially during the summer months. In the US, heavy snow blanketed parts of New England in June. Frost was reported as far south as Virginia through July. Then in August, after a brief reprieve, severe frost returned to many parts of the northeast. These unseasonable conditions caused widespread crop failures, livestock losses, famine, and disease. Ultimately, it forced many people to migrate west.

Europe suffered similar conditions, but also had excessive rainfall. Crop failures and price inflation for basic goods from Ireland to Germany lead to food riots in many cities. The gloomy weather also famously inspired many British and European writers. Mary Shelly, for example wrote Frankenstein while on vacation at Lake Geneva in Switzerland that summer.

Luckily, this dramatic – albeit natural – climate change was temporary. The aerosols eventually settled out of the atmosphere and sunlight returned. While the process that produced this moment in weather history was essentially the opposite of the runaway green house effect happening today, it is a great example of how sensitive the climate is to changes in atmospheric composition. It also shows how seemingly small changes in global temperature can have huge impacts on our lives.

Summer Colds can be Worse than Winter Ones

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Dealing with a cold is annoying anytime of the year. However, during the summer, when you want to be outside enjoying the beautiful weather, it is especially frustrating. Adding insult to injury, summer colds also tend to be worse than the winter variety.

The reason for this, according to infectious disease experts, is that different viruses cause summer and winter colds. Winter colds are the result of rhinoviruses and summer colds are produced by enteroviruses.

Along with the usual coughing and congestion of a winter cold, enteroviruses can cause a host of other nasty symptoms. These include, fever, diarrhea, sore throat, and body aches. They also tend to last for a few weeks and can reoccur. Rhinoviruses, by contrast, usually run their course in a few days.

This resilient virus, according to the National Institute of Health, is present year round, but thrives in mild weather. Most infections occur between June and October.

Since most people spend more time outdoors during the summer months, summer colds are less prevalent than winter ones. Nevertheless, they are spread through contact with infected people and contaminated surfaces. To help reduce your odds of getting sick, doctors recommend you wash your hands frequently and avoid touching your face.

Summer Colds. Credit: mlive

A Summer Cold.  Credit: mlive

NYC Monthly Summary: July 2016

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July is normally the warmest month on the calendar for New York City, and this year, despite a relatively cool start, was no exception. Overall, 20 out of 31 days posted above average temperatures. These included ten with readings in the 90s, which is four more than what we typically see for the month. Additionally, July produced our first official heat wave of the summer. With overnight lows also running mostly above normal, the city’s mean temperature for the month was 78.7°F, which is 2.2°F above average.

In terms of precipitation, July was unusually wet and marked the first month since February that NYC received above average rainfall.  In all, we received a staggering 7.02 inches of rain in Central Park, which is 2.42 inches above normal. The majority of this plentiful total fell on four separate days in the form of intense downpours. Nonetheless, despite these soakers, NYC remains in a moderate drought according the latest report (7/26) from the US Drought Monitor.

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July brought NYC ten days with temperatures in the 90s, which is four above average. Credit: The Weather Gamut.

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More than seven inches of rain fell in Central Park this July. Credit: The Weather Gamut.