Our global temperature continued its upward trend last month. February 2018 marked not only the eleventh warmest February on record, but also closed out the planet’s fifth warmest December – February season.
According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for February – over both land and sea surfaces – was 55.07°F, which is 1.17°F above the 20th-century average. This February also marked the 398th consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.
The three-month period of December, January, and February – meteorological winter in the northern hemisphere – was also unusually warm. NOAA reports that Earth’s average temperature for the season was 1.31°F above the 20th century average of 53.8°F. That makes it the fifth warmest such period on record.
While heat dominated most of the planet this season, some places were particularly warm, including Alaska, northern Russia, and parts of the Middle East. Here in the contiguous US, this winter ranked among warmest third of the nation’s 124-year period of record.
These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. In fact, La Niña conditions – the cool counterpart of El Niño – were present in the Pacific during all three months of the season.
Global temperature records date back to 1880.
The Dec 2017- Feb 2018 season was the planet’s 5th warmest on record. Credit: NOAA
The east coast of the United States has been slammed with three nor’easters in just eleven days – March 2, March 7, and March 13. The reason for this barrage of storms involves something called the North Atlantic Oscillation (NAO).
Based in the North Atlantic Ocean, this weather pattern is driven by the pressure differences between the semi-permanent Icelandic Low and Azores/Bermuda High. When the pressure difference between these two systems is low, the NAO is said to be in a negative phase. This means the winds of the jet stream are relatively relaxed and cold air from the north can spill down into the eastern US. The positive phase of NAO is characterized by a strong pressure difference between the two areas and a robust jet stream that keeps cold air bottled up in the northern latitudes.
Three nor’easters in eleven days. Credit: NOAA
Fluctuating between positive and negative, the strength and duration of these phases vary. Since late February, however, a strong negative phase has been locked in place. With an area of high pressure over Greenland, the jet stream is blocked and therefore dipping southward over the eastern US. As the jet stream is essentially a storm track, this pattern has allowed areas of low pressure to be steered over the warm waters of the Gulf Stream off the eastern seaboard, where they have intensified into nor’easters.
In terms of climate change, the connection between the warming Arctic and the storm track across the mid-latitudes is an active area of research. Sea level rise, however, is clearly amplifying the coastal flooding associated with these powerful storms.
NAO Patterns. Credit: NOAA
For the second time in less than a week, a nor’easter slammed New York City.
The storm intensified quickly and brought heavy snow, strong winds, and even thundersnow to the area. It downed trees and caused a number of travel disruptions, including nearly 2000 flight cancelations and the temporary suspension of all NYC Ferry service.
While the snow fell quickly, the surface temperature hovered just above freezing and did not allow much to accumulate. Only 3.2 inches of snow was reported in Central Park, according to the NWS. Areas north and west of the city received much higher storm totals.
GOES-16 image of nor’easter on March 7, 2018. Credit: NOAA
February 2018 was New York City’s warmest February on record. Its mean temperature of 42°F was a staggering 6.7°F above the long-term norm. The previous record of 41.6°F was set just last year in February 2017.
Overall, we had nineteen out of twenty-eight days that were warmer than normal. Five of those produced readings in the 60s and one even hit 78°F, marking the warmest February day ever recorded in NYC. A record warm minimum temperature was also set on February 21 when the city only cooled down to 55°F. The average low for that date is 30°F.
While a few warm days in February are not that uncommon, this extended pattern of sustained warmth was very unusual. Driven largely by a persistent ridge in the jet stream, warm southern air was funneled northward almost continuously throughout the month.
February is usually the city’s snowiest month on the calendar, but Central Park only received 4.9 inches of snow this year. That is 4.3 inches below normal. Of that total, 4.4 inches fell during a single, quick-hitting storm when the air was briefly cold enough to support frozen precipitation.
Rainfall, on the other hand, was abundant with seventeen days posting measurable precipitation. In total, Central Park reported 5.83 inches of rain. That is 2.74 inches above average.
New York City weather records date back to 1869.
February 2018 was the warmest February on record in NYC. Credit: The Weather Gamut
The winter season can produce a number of different types of storms. One of these is a nor’easter.
These intense systems generally affect the east coast of the United States from the mid-Atlantic to New England. They traditionally develop when a strong area of low pressure to the south moves up the coast and meets cold air pushing down from Canada. With a plentiful supply of moisture from the Atlantic, these storms are notorious for producing copious amount of precipitation. The exact type – rain or snow – depends on the temperature at the time of the storm. They are also known for their strong onshore winds that can cause coastal flooding and beach erosion.
Spinning counterclockwise, these storms take their name from the steady northeasterly wind they produce.
The calendar says February, but it felt more like May in New York City on Wednesday. The temperature in Central Park soared to 78°F, setting not only a new record high for the date but marked the warmest February day ever recorded in the Big Apple.
Records are usually broken by fractions of a degree, but these were shattered. According to the NWS, the previous daily record, which was set in 1930, was 68°F and the former record monthly high that had been in place since February 24, 1985, was of 75°F. The city’s normal high this time of year is 43°F.
The primary driver of these unusually balmy conditions is a strong Bermuda High off the east coast of the US. Spinning clockwise, it is funneling warm southern air into the region.
Venturing out without coats and enjoying lunch alfresco, many New Yorkers took full advantage of this early spring preview. Personally, however, it felt a little surreal. February is typically the snowiest month of the year in NYC – a time when sledding and ice-skating are more common than ice-cream trucks and frisbees.
That said, these spring-like conditions will be short-lived. Temperatures are expected to return to more seasonable levels tomorrow. Get ready for weather whiplash!
Temperatures soared to record levels in NYC on Feb 21. Credit: The Weather Gamut
Our global temperature continued its upward trend last month with January 2018 marking the fifth warmest January ever recorded on this planet. The last four Januarys now rank among the five warmest on record.
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 54.88°F. That is 1.28°F above the 20th-century average. January was also the 397th consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.
While heat dominated most of the planet this January, some places were particularly warm, including the western half of the United States and most of Europe. For the contiguous US as a whole, January ranked among warmest third of the nation’s 124-year period of record.
Coming on the heels of 2017 – Earth’s third warmest year on record and warmest year without an El Niño – these soaring temperatures are largely attributed to the long-term trend of human-caused climate change. In fact, La Niña conditions – the cool counterpart of El Niño – were present in the Pacific during January.
Global temperature records date back to 1880.
January 2018 was the planet’s 5th warmest January on record. Credit: NOAA
Millions of American are tuning in to watch the Winter Olympics in Pyeongchang, South Korea and one of the ads they are seeing features a strong message on sustainability from Toyota. Showing ice sculptures of athletes melting, the company is promoting their hybrid vehicles and says it wants “to help keep our winters, winter”. It is a poignant and timely message as our global temperature warms and the viability of many previous Winter Olympic host sites is declining.
Since the first winter games were held in 1924, the month of February – the traditional time of year for this global event – has increased an average of 1.82°F worldwide. If this current rate of warming continues, according to Climate Matters, only 6 of the 19 past host sites will be reliable future venues by the end of the century. Under a business as usual scenario, previous host cities, on average, are expected to see a temperature increase of 7.9°F by the 2080s. Significant cuts to greenhouse gas emissions would reduce that warming to 4.86°F
Warming winters also affect athletes’ ability to train. In the US, NOAA says winter temperatures have increased almost twice the rate of summer temperatures. If this trend continues, some areas are likely to see the ski season cut in half by 2050. This truncated season correspondingly means an economic hit for the winter sports and recreation industry. These businesses, according to Protect Our Winters, contribute $72 billion to the national economy annually and support more than 600,000 jobs.
The 2014 Olympics in Sochi, Russia were the warmest winter games on record.
Credit: Climate Central
Today is Valentine’s Day, a holiday when chocolate treats and images hearts abound. But for me, it is George Bellows’ Love of Winter that always comes to mind as we mark the mid-point of what is usually New York City’s snowiest month of the year.
A longtime personal favorite, this 1914 painting captures the spirit of those who embrace the season. Filled with the blurred movement of skaters on a frozen pond and accented with spots of bright color that pop against the snow, it conveys the joy of being out in nature on a cold winter day.
While Bellows is better known for depicting scenes of boxing matches and urban life, art historians say he enjoyed the challenge of painting the varied lighting conditions produced by a snow-covered landscape. In fact, he wrote a letter to a friend in January 1914 complaining about the lack of snow in the New York City area that winter. He said, “There has been none of my favorite snow. I must paint the snow at least once a year.” Then, about a month later, his wish for snow was granted and this painting was created.
Love of Winter is part of the Friends of American Art Collection at the Art Institute of Chicago.
“Love of Winter”, 1914 by George Bellows. Collection of the Art Institute of Chicago
The winter season can produce various types of precipitation – rain, freezing rain, sleet, or snow. It depends on the temperature profile of the lower atmosphere.
All precipitation starts out as snow up in the clouds. But, as it falls toward the Earth, it can pass through one or more layers of air with different temperatures. When the snow passes through a thick layer of warm air – above 32°F – it melts into rain. If the warm air layer extends all the way to the ground, rain will fall at the surface. However, if there is a thin layer of cold air – below 32°F – near the ground, the rain becomes super-cooled and freezes upon impact with anything that has a temperature at or below 32°F. This is known as freezing rain. It is one of the most dangerous types of winter precipitation, as it forms a glaze of ice on almost everything it encounters, including roads, tree branches, and power lines.
Sleet is a frozen type precipitation that takes the form of ice-pellets. Passing through a thick layer of sub-freezing air near the surface, liquid raindrops are given enough time to re-freeze before reaching the ground. Sleet often bounces when it hits a surface, but does not stick to anything. It can, however, accumulate.
Snow is another type of frozen precipitation. It takes the shape of six-sided ice crystals, often called flakes. Snow will fall at the surface when the air temperature is below freezing all the way from the cloud-level down to the ground. In order for the snow to stick and accumulate, surface temperatures must also be at or below freezing.
When two or more of these precipitation types fall during a single storm, it is called a wintry mix.
Precipitation type depends on the temperature profile of the atmosphere. Credit: NOAA