Monthly Archives: January 2016

2015: The 7th Warmest Year on Record for NYC

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New York City experienced some noteworthy weather in 2015, especially swinging between the extremes of record cold and record warmth. In the end, though, the warmth won out. The city’s average annual temperature in Central Park was 56.7°F, which is 1.7°F above normal. That means 2015 tied 2010 as NYC’s 7th warmest year on record!

Starting off brutally cold, the winter of 2015 brought the city a number of extended arctic outbreaks and the term polar vortex seemed to be on everyone’s lips. The coldest day of the year came on February 20th when the temperature dropped to 2°F – a new record low for the date. Visible signs of the prolonged cold conditions were seen all over the city, from frozen fountains to ice filling both the Hudson and East Rivers. In the end, February 2015 ranked as our 3rd coldest February on record.

When the summer finally arrived, there were a number of very warm and humid days, but the first official heat wave – 3 consecutive days with readings of 90°F or higher – did not develop until August. The city typically sees 15 days per year with temperatures in the 90s, but 2015 produced a sweltering 20 – mostly in August and September. The hottest day did not arrive until September 8th when the mercury soared to 97°F in Central Park. After August 2015 became the city’s third warmest August on record, the heat just kept coming. September, November, and December were all record warm.

Precipitation was also erratic in NYC during 2015. While we had a number of heavy rain events, including some that broke daily rainfall records, such as the 2.10 inches that came down on January 18th, the city was mostly dry. Overall, we received 40.97 inches of rain in Central Park for the entire year. That is 8.97 inches below normal. This dearth of rain caused a moderate drought during the last few moths of the year. Snowfall, however, was abundant. March 2015 was our 6th snowiest March on record with 18.6 inches measured in Central Park. January and February also delivered above average snow totals with 16.9 inches and 13.6 inches, respectively. For the calendar year as a whole, the city accumulated 49.1 inches of snow, which is an astounding 23.3 inches above average.

Given that El Niño conditions developed and strengthened in 2015 and are forecast to last through the winter months of the new year, it will be interesting to see what type of weather events 2016 will bring.

2015Temps

Temperatures went from significantly below average to significantly above average in NYC during 2015. Credit: The Weather Gamut.

2015-rain

Rainfall was mostly below average in NYC during 2015. Credit: The Weather Gamut.

Earth’s Perihelion 2016

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The Earth will reach its Perihelion today at 22:49 UTC, which is 5:49 PM 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/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

Earth’s Perihelion and Aphelion. Credit: TimeandDate.com

NYC Monthly Summary: December 2015

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It was down right balmy in New York City this December! With an average temperature of 50.8°F in Central Park, which is a staggering 13.3°F above average, it was the city’s warmest December on record. The previous record of 44.1°F was set in 2001.

Overall, we had thirty out of thirty-one days with high temperatures above average. Five of those days tied or broke daily high temperature records, including Christmas Eve when the mercury soared to a spring-like 72°F in Central Park. Overnight lows were also above average throughout the month. In fact, this was the first December on record that overnight temperatures did not fall below freezing at least once.

While a few warm days in December is not that uncommon, this extended pattern of sustained warmth was very unusual. Driven primarily by El Niño, a persistent ridge in the jet stream over the eastern US allowed warm southern air to flow further north than it normally would at this time of year.

Given this unseasonable warmth, it is not surprising that only a trace of snow was measured in Central Park this December. On average, NYC usually receives 4.8 inches of snow for the month.  Rain, on the other hand, was plentiful.  In fact, December marked the first time since June that we saw above average rainfall. In all, the city received 4.72 inches of rain, which is 0.72 inches above normal. The majority of this total fell during two separate heavy rain events, which seem to be getting more common. Nonetheless, according to the latest report (12/29) from the US Drought Monitor, the city remains in a moderate drought.

DecTemps

Credit: The Weather Gamut

DecRainfall

Credit: The Weather Gamut