Record Low Temperatures and First Freeze of the Season for NYC

After a record warm October, a blast of frigid arctic air plunged into New York City this weekend.

The temperature in Central Park dropped to 25°F late Friday night and hit 24°F early Saturday morning, setting new record lows for both dates. According to the NWS, the previous records of 27°F for November 10 and 28°F for November 11 were set in 1914 and 1933, respectively.

The high temperature on Saturday only reached 38°F, which is 5°F colder than the normal low for this time of year. Overall, it felt more like January than November for the BIg Apple.

This cold plunge also marked the city’s first freeze of the season. While more extreme than normal, the timing of these frosty conditions is about average as the city typically sees its first freeze in mid-November. The earliest first freeze on record occurred on October 19 in both 1940 and 1974. The latest was on December 22, 1998.

Produced by a deep dip in the jet stream, these chilly conditions are not expected to last long. Temperatures are forecast to rebound to more seasonable levels in the next few days.

An Arctic blast sent temperatures plunging in NYC. Credit: The Weather Gamut

Syria Signs Paris Climate Agreement, Leaving US as Lone Holdout

The United States is now the only country on the planet not part of the Paris Climate Agreement.

On Tuesday, Syria announced that it would sign the historic accord to limit global warming. The surprising declaration came at COP23, the UN Climate Change Conference that is currently taking place in Bonn, Germany. The move comes on the heels of Nicaragua signing the pact in October.

Years in the making, the Paris Agreement set the target of holding global warming to 2°C (3.6°F) above pre-industrial levels. To achieve this goal, nearly 200 countries submitted individual voluntary emissions reduction plans known as nationally determined contributions (NDCs).

When the deal was struck in 2015, Syria was in the midst of a destructive civil war and Nicaragua refused to sign because if felt the agreement did not go far enough to rein in carbon pollution. The US on the other hand, under the Obama Administration, played a critical role in making the deal a reality. But President Trump, who has called climate change a “hoax”, announced plans to withdraw the US from the global pact earlier this year.

Following the rules of the agreement, however, the US cannot officially pull out of the deal until 2020. In the meantime, the administration says it will only re-enter the global accord if it can renegotiate more favorable terms. The rest of the world, however, seems ready to move forward on this critical issue without the US.

The US is the only country not part of the Paris Climate Agreement. Credit: Quartz

Massive Federal Science Report Says Humans Cause Climate Change

The Fourth US National Climate Assessment (NCA4) was released on Friday. It clearly states that climate change is real, it is happening now, and human activities are the main cause.

The first volume of the assessment – the Climate Science Special Report – says the average global temperature has increased 1.8°F (1°C) during the past 115 years (1901-2016). “This period is now the warmest in the history of modern civilization,” according to the report. It also says that “it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century.” Going even further, the report concludes, “there is no convincing alternative explanation supported by the extent of the observational evidence.”

With a focus on the US, the report says the average annual temperature in the contiguous forty-eight states has increased by 1.2°F (0.7°C) since 1986, relative to the previous century. It is projected to increase 2.5°F (1.4°C) by 2050.

In addition to warming, other aspects of climate change are highlighted in the massive report. One of these is sea level rise. Since 1900, the average global sea level has gone up 8 inches. Of that total, a 3-inch rise has occurred since 1993. This rate of rising, according to the report, “is greater than during any preceding century in at least 2,800 years.”

Moving forward, all projections show sea level continuing to rise. An increase of several inches is likely in the next fifteen years and 1 to 4 feet is estimated by 2100. A rise of as much as 8 feet by the end of the century, however, “cannot be ruled out”, the report warns. This is especially true if the ice sheets in Greenland and Antarctica prove to be more sensitive to rising temperatures than expected. In cities along the Gulf Coast and Eastern Seaboard, where daily tidal flooding is already a problem, sea level rise is forecast to be even higher than the global average.

The report also contains details on how extreme weather is changing across the US. For example, heavy rainfall events are ”increasing in intensity and duration” nationwide with the biggest increases happening in the northeast. In the west, the incidence of large forest fires has been rising since 1980 and is expected to increase even further in the coming years. Heat waves, unsurprisingly, have also become more frequent while cold waves have become less frequent.

Looking beyond the next few decades, the NCA says the magnitude of climate change depends on the amount of greenhouse gases that are added to the atmosphere. The level of carbon dioxide in the air today has already passed 400 parts per million, a number not seen in 3 million years. If emissions are not reined in, the average global temperature could increase by as much as 9°F (5°C) by the end of this century. According to the report, “the further and the faster the Earth system is pushed towards warming, the greater the risk of unanticipated changes and impacts.”

Mandated by Congress under the Global Change Research Act of 1990, this exhaustive climate report was produced by hundreds of experts from government agencies as well as academia and was peer-reviewed by the National Academy of Sciences. Published every four years, it is considered this country’s most authoritative statement on climate change.

Its findings, however, are in stark contrast to the words and actions of the Trump Administration. The President has called climate change a “hoax” and in June announced that he is withdrawing the US from the Paris Climate Agreement – an international accord that aims to reduce greenhouse gases and limit global warming to 2°C (3.6°F). The US and Syria are now the only two countries not part of the historic agreement.

Global annual average temperature (left) and surface temperature change for the period 1986–2016 relative to 1901–1960. Credit: NCA4

October 2017: Warmest on Record in NYC

October 2017 was New York City’s warmest October on record. Its average temperature of 64.1°F was a staggering 7.2°F above the long-term norm. The previous record of 63.6°F was set in 1947 and tied in 2007.

Overall, twenty-six out thirty-one days were warmer than normal. Four of those produced readings in the 80s. Two record warm minimum temperatures were also set during the month. On October 8 and 9, the Big Apple only cooled down to 72°F and 71°F respectively. The average low for those dates is 52°F.

In terms of precipitation, the city was mostly dry. The weather station in Central Park reported 4.18 inches of rain, which is 0.22 inches below average. Of this total, 3.03 inches fell in a single day at the end of the month. This type of heavy rain event, according to NOAA, is expected to become more common in the northeast as the average global temperature increases and precipitation patterns change.

October 2017 was the warmest October on record in NYC. Credit: The Weather Gamut