February 2017: Second Warmest February on Record for US

February 2017 was the second-warmest February ever recorded in the continental US.

The average temperature of the lower 48 states, according to NOAA’s National Centers of Environmental Information, was 41.2°F. That is a whopping 7.3°F above the 20th-century average and only 0.2°F shy of the record that was set in 1954.

From the Rocky Mountains to the East Coast, thirty-nine states were warmer than normal and sixteen were record warm. Cooler conditions prevailed in the west, but no state in the region was record cold.

Across the country, a substantial number of local temperature records were challenged during the month. In all, 11,743 daily warm records were tied or broken compared to only 418 cold records. Experts say if the weather pattern was “normal”, records events would be unlikely. If it were volatile but balanced, a similar number of record highs and lows would be expected. However, February’s pattern was extremely lopsided.

On a day-to-day basis, these remarkable conditions were driven by a persistent ridge in the jet stream over the eastern US and a trough in the west. That said, the bigger picture of global warming cannot be discounted. According to World Weather Attribution, a partnership of international scientists, “the chances of seeing a February as warm as the one experienced across the Lower 48 has increased more than threefold because of human-caused climate change.”

February also closed out the country’s sixth warmest meteorological winter. Weather records for the contiguous United States date back to 1895.

February 2017 was the second warmest February on record for the US. Credit: NOAA

NYC Posts 6th Warmest Winter on Record

The spring equinox is still a few weeks away, but meteorological winter (December, January, and February) has officially ended and it was the sixth warmest on record in New York City.

The season, with daily highs ranging from 23°F to 70°F, felt like a temperature roller coaster. But in the end, the warmth came out on top. The city’s average temperature for the season, according to the NWS, was 39.3°F. That is an incredible 4.2°F above normal.

In all, fifty-three days posted above average readings and every month was warmer than its long-term norm. In fact, February 2017 was the city’s warmest February on record.

In terms of snowfall, the city received 20.5 inches in Central Park, which is only 0.5 inches below average. Of this total, 9.4 inches fell during February’s single, quick hitting nor’easter when conditions were briefly cold enough to support snow.

This winter’s pattern of prolonged warm spells separated by a few short-lived blasts of cold air was largely driven by the North Atlantic Oscillation’s positive phase occurring more often and lasting longer than its negative phase.

The city’s warmest winter on record was the 2001-2002 season when the average temperature soared to 41.5°F.  Central Park weather records date back to 1869.

February 2017: NYC’s Warmest February on Record and 20th Consecutive Month with an Above Average Temperature

February 2017 was New York City’s warmest February on record. Its mean temperature of 41.6°F was a staggering 6.3°F above the long-term norm. Moreover, February was the city’s 20th consecutive month with an above-average temperature.

Overall, we had nineteen out of twenty-eight days that were warmer than normal. Seven of those produced readings in the 60s and one even hit 70°F, marking the first time the city has seen that type of heat in February in twenty years. Two record warm minimum temperatures were also set during the month. On February 19th and 24th, the Big Apple only cooled down to 53°F and 58°F respectively. The average low for those dates is 30°F.

While a few warm days in February are not uncommon, this extended pattern of sustained warmth was very unusual. Driven largely by a persistent positive phase of the North Atlantic Oscillation, warm southern air was funneled northward almost continuously throughout the month.

February is usually the city’s snowiest month on the calendar, and this year, despite the unseasonable warmth, it did not disappoint. Central Park received 9.4 inches of snow, which is 0.2 inches above average. All of it fell during a single, quick hitting nor’easter when the air was briefly cold enough to support frozen precipitation.

Rainfall, on the other hand, was not as abundant. Only 2.48 inches was reported, which is 0.61 inches below normal. The city, according to the latest report from the US drought monitor (2/23) remains abnormally dry.

New York City weather records date back to 1869.

Feb 2017 was NYC’s warmest Feb on record and 20th straight month with an above average temperature. Credit: The Weather Gamut.

Why This Winter Has Been So Warm in the Eastern US

The weather usually associated with winter in the eastern United States has not really taken hold this year. One of the reasons for this involves something called the North Atlantic Oscillation (NAO).

This is a natural phenomenon that affects the position of the jet stream and weather patterns thousands of miles away. Based in the North Atlantic Ocean, it 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 systems and a robust jet stream that keeps cold air bottled up in the northern latitudes.

Fluctuating between positive and negative, the strength and duration of these phases vary. This winter, however, the positive phase has been occurring more often and lasting longer than the negative phase. That is why the eastern US has been experiencing prolonged warm spells separated by a few brief blasts of cold air.

Unsurprisingly, this season’s soaring temperatures have sparked many important conversations about global warming. But as weather is extremely variable, no single warm day or week can be linked (at this time) to our changing climate. That said, anomalously warm events are happening more often, which is consistent with the long-term trend of human-caused climate change.  2016, for example, was this planet’s third consecutive warmest year on record.

Typical impacts associated with the positive phase of NAO. Credit: NOAA/NCDC

NAO observations, Nov 2016 to date. Credit: NOAA/CPC

NYC Hits 70° in February for the First Time in Twenty Years

It is only February, but it felt more like May in New York City on Friday. The temperature in Central Park soared to 70°F, which is a whopping 26°F above average.

According to the NWS, this was the first time in twenty years that the city had a reading in the 70s during the month of February. However, it was not a record breaker. That honor belongs to February 24, 1985 when the mercury hit 75°F.

The primary driver of these balmy conditions is a strong Bermuda High off the east coast of the US that is funneling warm southern air into the region.

Many New Yorkers got out to enjoy this early spring preview and described it as “amazing” or “unbelievable”. Personally, it felt a little surreal to see rowboats out in Central Park during a month when sledding and ice-skating are usually the norm.

That said, a chilly change will be in the air later this weekend when temperatures are expected to return to more seasonable levels.

Rowboats on The Lake in Central Park on Feb 24, 2017 when the temperature hit 70°F in NYC. Credit: Melissa Fleming

A Spring-like February Weekend in NYC

Between picnics in the park and overflowing crowds at local ice cream shops, it felt more like late April than mid-February in New York City this holiday weekend.

The temperature in Central Park soared to 63°F on Saturday and 65°F on Sunday. Both days missed setting a new record high by only a few degrees. Overnight lows were also unusually mild. According to the NWS, a new record warm minimum temperature was set on Sunday with a reading of 53°F. The previous record of 49°F was established in 1997.

The city’s normal high for this time of year is 43°F.  Its normal low is 30°F.

Any snow that was left over from the storm earlier this month was no match for these spring-like temperatures.  More abnormally warm conditions are expected later this week, so keep that frisbee handy.

Not much snow left in NYC after a weekend with temperatures in the 60s. Credit: Melissa Fleming

NYC Monthly Summary: March 2016

March 2016 was more like a lamb than a lion in New York City this year. With an average temperature of 48.9°F in Central Park, which is a staggering 6.4°F above average, it was the city’s 4th warmest March on record.

Overall, we had 23 out of 31 days with above average temperatures. Five of those days posted readings in the 70s and two set new daily high temperature records. Historically, our average temperature for the month is 42.5°F.

While a few warm days in March is not that uncommon, this extended pattern of sustained warmth was 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 0.9 inches of snow was measured in Central Park this March. On average, NYC usually receives 3.90 inches of snow for the month.  Rainfall was also scarce.  In all, the city received a mere 1.17 inches of rain. That is 3.19 inches below normal.

March_Temps

23 out of 31 days posted above average temperatures this March in NYC. Credit: The Weather Gamut

NYC Seasonal Summary: Winter 2015-16

The spring equinox is still a few weeks away, but meteorological winter (December, January, and February) has officially come to a close and it was the second warmest on record in New York City.

According to the NWS, the city’s average temperature for the season was 40.98°F. That is a staggering 5.9°F above normal. Only the winter of 2001-2002, with an average temperature of 41.5°F, was warmer.

Even though most of the winter felt like we were riding a temperature rollercoaster – from a record warm Christmas to a record cold Valentine’s Day – the warmth won out in the end. We had 40 days where the temperature reached 50°F or higher and every month of the season posted an above average reading. In fact, December 2015 was a staggering 13.3°F above normal and was the city’s warmest December on record.

In terms of snowfall, the city measured 31.2 inches in Central Park, which is 10.2 inches above average. Of this impressive total, 26.8 inches fell during the Blizzard of 2016 at the end of January. Without that storm, the city would have only had 4.4 inches of snow for the entire season.

For the past two winters, multiple extended artic outbreaks courtesy of the polar vortex kept the region colder than average. This year, a strong El Niño in the Pacific helped warmer than normal conditions dominate most of the season in the northeast.

National Weather Service records for Central Park date back to 1873.

Winter of 2015-16 brought NYC a rollercoaster of temperatures, but the warmth won out. It was the city's 2nd warmest winter on record. Credit: The Weather Gamut

Winter of 2015-16 brought NYC a rollercoaster of temperatures, but the warmth won out. It was the city’s 2nd warmest winter on record. Credit: The Weather Gamut

NYC Monthly Weather Summary: February 2016

February 2016 felt like a weather rollercoaster in New York City. The month brought us both a record low of -1°F on Valentine’s Day and our first 60°F temperature of the year. But, in the end, with 14 out of 29 days posting above average readings, the warmth won out. The city’s mean temperature for the month was 37.7°F, which is 2.4°F above normal.

February is usually the snowiest month on the calendar for NYC, producing 9.2 inches of snow on average. But with mild conditions dominating the month this year, only 4 inches were measured in Central Park.

Rainfall, on the other hand, was abundant. The city received 4.4 inches, which is 1.31 inches above average. The majority of this total fell during a few separate heavy rain events, which seem to be getting more common in our region.

NYC saw a rollercoaster of temperatures this February. Credit: The Weather Gamut.

NYC saw a rollercoaster of temperatures this February. Credit: The Weather Gamut.

Record Warm Weekend for NYC

What a difference a week can make!  Last weekend, New York City received five inches of snow.  This weekend, as winter officially arrived, the Big Apple experienced record-breaking warmth.

On Saturday, according to the NWS, the temperature in Central Park reached 65°F – a new record high for the date.  The previous record of 62°F was set in 1923 and tied in 2011.  On Sunday, the mercury continued to soar and the city’s temperature reached a balmy 71°F.  This shattered the old record of 63°F set in 1998. The average high for this time of year in NYC is 41°F.

These unseasonably high temperatures were the result of warm winds moving into the area from the south as the jet stream retreated to the north. The mild weather is not expected to last much longer, though. Colder – even below average – conditions are expected to return tomorrow as a cold front moves into the region.