Monthly Archives: January 2019

Arctic Blast Brings Record Cold to NYC

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After getting off to a relatively slow start, winter has kicked into high gear. For the second time this month, a massive arctic outbreak has sent most of the eastern two-thirds of the U.S. into a deep freeze.

Here in New York City, the temperature peaked at just 16°F in Central Park on Thursday, tying the record cold high for the date set in 1935. The low dropped to 2°F, missing the record of -1°F by a few degrees. However, when you factor in the wind chill, it felt like a very memorable -17°F.

As cold as it was on Thursday, it was not the coldest day the Big Apple has ever experienced. That dubious honor, according to the NWS, belongs to February 9, 1934, when the air temperature reached a brutal low of -15°F.

The city’s normal high and low temperatures for this time of year are 39°F and 27°F, respectively.

This week’s unusually frigid conditions were the result of a deep dip in the jet stream and a lobe of the polar vortex reaching southward over much of the eastern part of the country. While a brief warm-up is expected over the next few days, it is still winter so keep those hats and gloves handy.

The temperature topped out at 16°F  in NYC on Thursday, tying the record cold high for the date. Credit: Melissa Fleming

Weather Lingo: Wind Chill

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Temperature is one of the basic elements of weather.  Our perception of it, however, is often influenced by other environmental conditions. Wind, for example, can make a cold day feel even colder. This phenomenon is called the wind chill factor.

Wind chill is a measure of the apparent or “feels-like” temperature.  It calculates the heat loss from exposed human skin through the combined effects of air temperature and wind speed.

Essentially, the wind is carrying heat away from the body and allowing the skin to be exposed to cold air.  As the winds increase, heat is carried away at a faster rate and the colder the body feels.  For example, a temperature of 20°F and a wind speed of 5mph will produce a wind chill index of 13°F.  At that same temperature, but with a wind speed of 10mph, the wind chill index would be 9°F.

Extended exposure to low wind chill values can lead to frostbite and hypothermia, serious winter health hazards.

First Arctic Blast of 2019 Sends NYC into a Deep Freeze

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After a relatively mild start to the season, winter’s chill has finally arrived in the northeastern United States. An arctic outbreak has sent the region into a deep freeze with many cities dealing with the coldest conditions they have seen since last January.

Here in New York City, the mercury fell to 4°F in Central Park on Monday morning and the high only made it to 14°F. While this type of cold shot is not that uncommon in January, it felt rather jarring after the temperature reached the mid-40s the day before.

The city’s normal high for this time of year is 38°F and the normal low is 27°F.

Produced by a deep dip in the jet stream, these current frigid conditions are not expected to last much longer. After a brief warm-up, however, another shot of arctic air is forecast to hit the city next week. So, keep those coats and gloves handy!

When arctic air invades NYC, the Josephine Shaw Lowell Memorial Fountain in Bryant Park often transforms into an icy sculpture. Credit: @nyclovesnyc

Extremely Cold Weather Can Be A Danger to Your Health

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An arctic blast is expected to sweep across the northeastern United States this week. With temperatures expected to fall into the single digits, it is important to remember that, like extreme heat, extreme cold can be very dangerous.

Extreme cold causes the body to lose heat faster than it can be generated.  Prolonged exposure, according to the CDC, can cause serious health problems, including hypothermia and frostbite.

Hypothermia is a condition of unusually low body temperature – generally below 95°F.  It impairs brain functions, limiting a victim’s ability to think and move.  Symptoms include severe shivering, drowsiness, confusion, slurred speech, and fumbling.  If left untreated, it can be fatal.

Frostbite is a localized injury to the skin and underlying tissues caused by freezing.  It can cause permanent damage and extreme cases often require amputation.  Areas of the body most often affected include the nose, ears, cheeks, fingers, and toes. Signs of frostbite include, numbness, skin discoloration (white or greyish-yellow), and unusually firm or waxy feeling skin.

While the symptoms of both hypothermia and frostbite can range in severity, victims generally require immediate re-warming and professional medical attention.

To stay safe in cold weather, the American Red Cross recommends:

From Snow to Freezing Rain, Winter Precipitation Can Take Several Forms

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The winter season can produce various types of precipitation – rain, freezing rain, sleet, or snow. The form we see at the surface 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

There is No Such Thing as Bad Weather, Only Bad Clothing Choices

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There is an old Scandinavian saying: “There is no such thing as bad weather, only bad clothing choices.” While it can be applied to any season, it seems most relevant in winter.

Since the weather is going to do whatever it is going to do, it is important to be prepared for anything that Mother Nature throws your way. In winter, that means cold temperatures.

Extreme cold causes the body to lose heat faster than it can be generated. Prolonged exposure, according to the CDC, can cause serious health problems such as hypothermia and frostbite.

To stay safe this winter, remember to bundle up in layers and wear hats and gloves to minimize the loss of body heat.

Credit: NOAA

Speaking About Art, Climate, and Environmental Policy at AMS

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The 99th Annual Meeting of the American Meteorological Society is taking place this week in Phoenix, Arizona. Its theme is “Understanding and Building Resilience to Extreme Events by Being Interdisciplinary, International, and Inclusive.”

Thrilled to be a part of it, I will be giving a presentation titled “The Power of Perception: Art, Climate, and the History of US Environmental Policy”. The talk looks at the role art has played in helping to build the political will behind several landmark environmental policies over the years and how it can help with climate change communication today.

From the Yosemite Land Grant of 1864 to the present, images have helped give the public, and the policy makers they elected, a new way to relate to and understand the issues of their time. In many cases, images mobilized public concern that helped drive legislation. The publication of photos of the Cuyahoga River fire of 1969 in Time Magazine, for example, helped spur the passage of the Clean Water Act and the creation of the EPA in the 1970s.

The talk also highlights the way technology has changed the way we relate to images and the role movies – the art of moving images – can play in reaching a wide and diverse audience.

Credit: AMS

Perihelion 2019: The Earth is Closest to the Sun Today

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The Earth reached its Perihelion today at 5:20 UTC, which is 12:20 AM Eastern Standard Time. This is the point in the planet’s orbit where it comes closest to the Sun.

This annual event is due to the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Perihelion differs from year to year, but it’s usually in early January – winter in the northern hemisphere. The Earth will be furthest from the Sun in July.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, the Earth is 147.1 million kilometers (91.4 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) closer than it will be in early July. This position allows the planet to speed up by about one-kilometer per second. As a result, winter in the northern hemisphere is about five days shorter than summer.

The word, perihelion, is Greek for “near sun”.

Earth’s Perihelion and Aphelion. Credit: Time and Date.com

2018: A Year of Weather Extremes in NYC

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New York City experienced some noteworthy weather in 2018, especially the swings between extreme cold and extreme heat. However, the warmth won out in the end. The city’s average temperature for the year in Central Park was 55.89°F, which is 0.97°F above normal.

The year started bitterly cold. It was only 9°F when the ball dropped in Times Square for the New Year celebration. Moreover, the arctic weather stuck around for a while. With 14 consecutive days with temperatures below 32°F, it was the city’s third longest sub-freezing cold streak on record.

Then things warmed up dramatically in February. The temperature in Central Park soared to 78°F on February 21, setting not only a new record high for the date but marked the warmest February day ever recorded in the Big Apple. In fact, February 2018 went on to be the warmest February on record for the city.

March was rather turbulent, with four nor’easters hitting the city in just three weeks. Spring, overall, was a bit chilly. In fact, the spring equinox brought the city 8 inches of snow. However, May ushered in another extreme temperature swing. It was the city’s fifth warmest May on record.

The summer brought NYC a number of oppressively hot and humid days, including 18 days with temperatures in the 90s. The hottest day came on July 1, when the mercury soared to 96°F. When humidity was factored in, the heat index, or real feel temperature was in the triple digits. The season also produced a relatively rare tornado for the city. Rated EF-0, it barreled through Queens on August 3.

The autumn remained relatively warm until November rolled around, which was unusually cold. It also produced an early season snowstorm that brought down many trees around the city that still had their leaves. On November 16, Central Park reported 6.4 inches of snow, setting set a new daily record for the date. It was also the earliest 6-inch one-day snowfall on record for the city and the largest one-day November snowfall since 1882. Moreover, that one snow event was enough to make November 2018 the city’s fourth snowiest on record.

Snowfall, overall, was plentiful in 2018. For the calendar year as a whole, the city accumulated 39.6 inches of snow, which is 13.8 inches above average.

The main precipitation story for the year, however, was rain. Several months posted top ten rainfall totals and only four months produced below average precipitation. In the end, NYC received 65.52 inches of rain in Central Park for the entire year. That is a staggering 15.58 inches above normal and makes 2018 the city’s fourth wettest year on record.

Records for the Central Park Climate Station date back to 1873.

 

December 2018: Ninth Wettest on Record for NYC

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December 2018 felt like a weather roller coaster in New York City. Highs ranged from a relatively balmy 61°F to a chilly 36°F. But, with 17 out of 31 days posting above average readings, the warmth won out in the end. The city’s mean temperature for the month was 40.1°F, which is 2.6°F above average.

In terms of precipitation, December was a month for the record books. The city received 6.48 inches of rain in Central Park, tying December 1996 as the ninth wettest December on record. Three different days produced rainfall totals greater than one inch. The end of the month saw a soggy New Year’s Eve with 0.99 inches of rain. It was the first time in 24 years that it rained on the revelers at the Times Square ball drop festivities.

Snowfall, however, was scarce. Only a trace amount was reported for the month. New York City, on average, sees 4 inches of rain and 4.8 inches of snow in December.