Early Spring Preview Brings Record Warmth to NYC

The calendar says January, but it felt more like early May in New York City this weekend.

In Central Park, the temperature soared to 69°F on Saturday and hit 68°F on Sunday, setting new record highs for both dates. According to the NWS, the previous records of 63°F for January 11 and 66°F for January 12 were set in 1975 and 2017, respectively.

It is also interesting to note that the overnight low temperatures for both dates (51°F and 43°F) were warmer than the normal high. The average high for the city in mid-January is 38°F and the average low is 27.

The primary driver of this unseasonable warmth was a large ridge in the jet stream. Sitting over the eastern part of the US, it allowed warm air from the south to flow further north than it normally would at this time of the year.

But, as with most things that go up, they must also come back down. The temperature is expected to moderate over the next few days but remain above average. More seasonable temperatures are expected to return by the end of the week. So, don’t put your winter coats away just yet.

Credit: The Weather Gamut

Weather Lingo: The Dead of Winter

The “Dead of Winter” is an old saying that refers to the coldest part of the winter season. For most of the northern hemisphere, that usually means the month of January.

While actual daily weather varies, historical average temperatures typically reach their lowest point of the year between January 10 and February 10.  In the US, the western half of the country, with the exception of high elevation areas, tends to see its coldest day before the eastern half.  This is because the mountainous areas of the west and much of the eastern US tend to be snow covered in winter, reflecting much of the sun’s heat. Here in New York City, mid to late January is usually the coldest part of the winter season.

This traditional cold period does not begin on the winter solstice, the day we receive the least amount of solar energy, because of a phenomenon known as seasonal temperature lag. 

Air temperature depends on both the amount of energy received from the sun and the amount of heat lost or absorbed by the oceans and continents. From the start of winter through mid-February, both the oceans and land are losing more heat than they gain.

These few frosty weeks are the opposite of the “Dog Days of Summer.”

Credit: NOAA

Perihelion 2020: The Earth is Closest to the Sun Today

The Earth reached its Perihelion today at 7:48 UTC, which is 2:48 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

The Chances for a White Christmas

The Holiday Season is here and many people are dreaming of a White Christmas. The likelihood of seeing those dreams come true, however, is largely dependent on where you live.

According to NOAA, a White Christmas is defined as having at least one inch of snow on the ground on December 25th. In the US, the climatological probability of having snow for Christmas is greatest across the northern tier of the country. Moving south, average temperatures increase and the odds for snow steadily decrease.

Here in New York City, the historical chance of having a White Christmas is 11%. This low probability is largely due to the city’s proximity to the Atlantic Ocean and its moderating influence on the temperature.

The snowiest Christmas on record for the Big Apple, according to the NWS, took place in 1909 when seven inches of snow was reported in Central Park.

This year, with temperatures forecast to be in the mid-40s on the big day, the city’s already minimal chance for snow has largely melted away.

Snow or no snow, The Weather Gamut wishes you a very Happy Holiday Season!

Source: NOAA

The Science Behind the Winter Solstice

Today is the December solstice, the first day of winter in the northern hemisphere. The new season officially begins at 11:19 PM EST.

The astronomical seasons, which are different than meteorological seasons, are produced by the tilt of the Earth’s axis – a 23.5° angle – and the movement of the planet around the sun. During the winter months, the northern half of the Earth is tilted away from the sun. This position means the northern hemisphere receives the sun’s energy at a less direct angle and brings us our coolest temperatures of the year.

Since the summer solstice in June, the arc of the sun’s apparent daily passage across the sky has been dropping southward and daylight hours have been decreasing. Today, it will reach its southernmost position at the Tropic of Capricorn (23.5° south latitude), marking the shortest day of the year. This observable stop is where today’s event takes its name. Solstice is derived from the Latin words “sol” for sun and “sisto” for stop.

Soon, the sun will appear to move northward again and daylight hours will slowly start to increase. Marking this transition from darkness to light, the winter solstice has long been a cause for celebration across many cultures throughout human history.

Earth’s solstices and equinoxes. Image Credit: NASA

Weather and Health: SAD

Autumn and winter, with their crisp temperatures, are favorite seasons for many. But for others, the decreasing daylight hours can bring on a condition known as Seasonal Affective Disorder (SAD).

According to the Mayo Clinic, SAD is a “subtype of depression that comes and goes with the seasons” and is most common in fall and winter. Its exact cause is not fully understood, but researchers say a reduction of sunlight can disrupt the production of serotonin and melatonin – chemicals in the brain that regulate mood and sleep patterns. SAD symptoms include low spirits, lack of energy, difficulty concentrating, and changes in both sleep and eating patterns.

SAD is typically found in places that are far from the equator where daylight is at a minimum in the winter months. A report by the American Academy of Family Physicians says about 6% of the US population suffers from some degree of SAD, with most cases occurring in Alaska.

The most common treatment for SAD is light therapy. This involves sitting in front of a special lamp that gives off a light that is similar to natural sunshine. It has been shown to trigger the brain chemicals that regulate mood. The more serious cases of SAD could require advanced talk-therapy or even medication.

While everyone can feel a little “blue” once in a while, SAD is characterized by a prolonged feeling of depression. It can be a serious condition and should be diagnosed by a medical professional.

Weather affects mood. Credit: hercampus

First Snowfall of the Season for NYC

New York City saw its first snowfall of the 2019-2020 winter season on Monday.

According to the NWS, 1.5 inches of snow was measured in Central Park. While not a blockbuster event, it was exciting to see the flakes fill the air. With all the holiday lights and decorations on display, the snow also added to the city’s festive atmosphere.

The timing of this first snowfall was about normal for the Big Apple. On average, the first flakes of the season are seen in early to mid-December. Our earliest first snow event on record was on October 21, 1952, and our latest was January 29,1973. New York City typically gets 4.8 inches of snow in December and  25.8 inches for the entire winter season.

Credit: Melissa Fleming

From Snow to Freezing Rain: Why Winter Precipitation Can Take Several Forms

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 supercooled 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

A Spring Preview Melts March Snow in NYC

The calendar says March, but it felt more like May in New York City on Friday.

The temperature soared to 75°F in Central Park, missing the record high by just 2°F. But, with the mercury only dropping to 49°F at night, it did tie the record warm low temperature for the date that was set in 1913.

The normal high and low temperatures for this time of year in NYC are 49°F and 35°F, respectively.

With below normal temperatures dominating the beginning of March, this sudden warm up felt like weather whiplash. Just a week earlier, there was snow on the ground with snowmen dotting the landscape in parks across the city.

But, as with most things that go up, they must also come back down. Cooler conditions are expected to return over the weekend.

What a difference a week can bring: the same snowman in Central Park one week apart. Credit: Melissa Fleming

 

Flashback Facts: NYC’s Great Blizzard of 1888

On this day in 1888, one of the worst snowstorms on record hit New York City. Here is a look back at some of the facts from that historic storm.

Snow fills the street and sidewalk on Park Place in Brooklyn, after the Blizzard of 1888. Credit: NOAA.

  • 21 inches of snow was measured in Central Park, the 4th largest snowstorm on record for the city
  • Wind gusts reached 80mph, causing blizzard conditions
  • Snowdrifts reached as high as 30 feet in parts of the city.
  • The storm shut down transportation systems and left people confined to their homes for days.
  • It took NYC 14 days to fully recover from the storm.
  • As result of the paralyzing impacts of this blizzard, the city moved all overhead wires underground.

Source: NOAA