Tag Archives: winter

NYC Monthly Summary: January 2016

Posted on by

January is usually the coldest month on the calendar for New York City, but this year it felt like a weather rollercoaster. We had highs that ranged from an unseasonably balmy 59°F to a frosty 27°F. In the end though, with 19 out of 31 days posting above average readings, the warmth won out. These multiple extended warm spells helped push the city’s mean temperature for the month up to 34.5°F, which is 1.9°F above normal.

On the precipitation side of things, snowfall was abundant. In all 27.2 inches was measured in Central Park this January. Most of this impressive total fell during a single storm – The Blizzard of 2016. This classic nor’easter moved up the coast during one the city’s cold snaps and brought us 26.8 inches of snow – the second largest snowfall total from a single storm on record. On average, the city normally sees 7 inches of snow during the month of January and 25.8 inches for the entire winter season.

Rainfall was also plentiful during the first month of the year. The city received 4.41 inches, which is 0.76 inches above normal. Again, most of this came down during a few heavy precipitation events, including January 10th when 1.8 inches was measured in Central Park setting a new daily rainfall record for the date. As a result of all this precipitation, the city is no longer listed in any category on the US drought monitor.

Temperatures in NYC this January felt like they were on a rollercoaster. Credit: The Weather Gamut

Temperatures in NYC this January felt like they were on a rollercoaster. Credit: The Weather Gamut

Blizzard of 2016: Fourth Most Powerful Snowstorm on Record in Northeast

Posted on by

The blizzard that slammed a large section of the northeastern US, including NYC, last weekend was one of the most powerful winter storms to hit the region in decades.

According to NOAA, the storm was given a value of 7.66 on the Northeast Snowfall Impact Scale (NESIS). That is considered a category 4 or “crippling” snow event.  It was also the 4th most powerful winter storm to impact the northeast since 1950.

Covering 434,000 square miles across 26 states, the storm impacted more than 102 million people. Of those, approximately 24 million people saw more than 20 inches of snow.

The region’s strongest storm on record was the so called “Super-Storm” of March 1993.

Source: NCEI

Source: NCEI

Source: NOAA

Source: NOAA

The Northeast Snowfall Impact Scale

Posted on by

Similar to the national Saffiir-Simpson Scale for hurricanes and the Enhanced Fujita Scale for tornadoes, major winter storms that occur in the northeastern US have a special rating system. It is called the North East Snowfall Impact Scale or NESIS.

Developed in 2004 by Paul Kocin and Dr. Louis Uccellini of the National Weather Service, the scale is used to rank and compare storms in the region. It classifies large snow events into one of five categories based on the size of the area covered, number of people affected, and snowfall totals. The higher the NESIS value, the more impactful the storm.

Source: NCEI

Source: NCEI

Blizzard of 2016: The Second Biggest Snowstorm on Record for NYC

Posted on by

A massive winter storm slammed the eastern United States this weekend. With some areas getting more than two feet of snow, records fell across the region.

Here in New York City, a whopping 26.8 inches of snow was measured in Central Park – the city’s second highest storm total since record keeping began in 1869. This storm, according to the NWS, was only one-tenth of an inch shy of tying the city’s all time record of 26.9 inches set in February 2006.

To put this event into perspective, consider that, on average, NYC normally sees 7 inches of snow during the month of January and 25.8 inches for the entire winter season.

The cause of this historic event involved a few key players.  First, an area of low pressure moved up the east coast funneling in relatively warm and humid air from the southeast. At the same time, an area of high pressure to the north pushed cold air south. When the two air masses met, the warmer air was forced to rise and cool. Since cool air holds less moisture than warm air, the moisture was wrung out of the atmosphere as precipitation – snow, in this case. While developing as a classic nor’easter, this storm gained an extra boost of both energy and moisture from a warmer than normal Atlantic Ocean. Sea surface temperatures off the coast have been running about 5°F to 6°F above average for this time of year.

The pressure differences between the low and high also produced powerful winds. In Central Park, wind gusts peaked at 42 mph.

Dramatically ending the region’s so-called snow drought and impacting tens of millions of people, this storm garnered a great deal of media attention. Known by a few different names – The Blizzard of 2016, Winter Storm Jonas, and Snowzilla – this storm will not be forgotten anytime soon, regardless of its moniker.

Credit: NWS/NOAA

Three of the city’s top five snow producing storms have occurred in the past ten years. Credit: NWS/NOAA

What is a Blizzard?

Posted on by

A blizzard is expected to blast a large part of the northeastern United States, including NYC, this weekend. Different than a typical winter storm, a blizzard is characterized more by its winds than the amount of snow it produces.

According to the NWS,  the three key factors in a blizzard are wind, visibility, and time. More specifically, they are:

  • Wind – Sustained winds or frequent gusts of 35mph or higher.
  • Visibility – Falling and/or blowing snow that reduces visibility to ¼ mile or less.
  • Time – Wind and reduced visibility conditions must prevail for at least 3 hours.

These conditions heighten the risk for power outages and often produce whiteout conditions on roadways, making travel extremely dangerous.  Stay Safe!

First Snowfall of the Season for NYC

Posted on by

The first measurable snowfall of the 2015-2016 winter season has finally arrived in New York City!

According to the NWS, 0.4 inches fell in Central Park on Sunday. With the snow sticking only to grassy areas and parked cars, it was not a blockbuster event by any stretch of the imagination.  But, after this winter’s mild start, it was exciting to see flakes fill the air.

This first snowfall arrived rather late by local standards, but it was not the latest. That record belongs to January 29, 1973. On average, the city should have already seen about 9 inches of snow at this point in the season.

First Snowfall of the season in NYC

First snowfall of the season in NYC.  Credit: The Weather Gamut.

Hurricane Alex: A Rare January Storm in the Atlantic

Posted on by

January, a winter month in the northern hemisphere, is a time when we are usually talking about snowstorms. Nevertheless, Hurricane Alex, the first named storm of the 2016 Atlantic Hurricane season has officially formed.

According to the National Hurricane Center, Alex is the first Atlantic hurricane to form in January since 1938. With sustained winds of 85 mph, it is the second strongest January hurricane on record. Hurricane Alice, which formed at the end December 1954 and lasted through early January 1955, had winds that peaked at 90 mph.

Alex transitioned from a sub-tropical storm – a storm that has both tropical and non-tropical characteristics – into a fully tropical system on Wednesday and then strengthened into a category-one hurricane on Thursday morning.  This type of rapid intensification is usually associated with the storm moving over very warm ocean waters. In this case, however, the sea surface temperatures in the area were above average, but just barely warm enough to support tropical development. So, according to NOAA, Alex likely got an extra boost from an unstable atmosphere. The wide temperature spread between the warm surface air and a pocket of unusually cold air aloft encouraged convection and helped strengthen the warm core of this off-season storm.

Alex is currently located 490 miles south of the Azores and moving north-northeast at about 20 mph. It is expected to bring strong winds, heavy rain, and storm surge flooding to that archipelago over the next 24 hours.

The Atlantic hurricane season traditionally runs from June 1 to November 30th.

Hurricane Alex's forecast track. Credit: NOAA/NHC

The forecast track for Hurricane Alex. Credit: NOAA/NHC

First Arctic Blast of the Season for NYC

Posted on by

After a delayed start, winter is off and running in the northeastern US. An arctic outbreak has sent the region into a deep freeze with many cities dealing with the coldest temperatures they have seen all season.

Here in New York City, the mercury fell to 11°F in Central Park this morning – the coldest reading the city has seen since February of last year. The high only made it to 29°F.  While this type of cold pattern is not that uncommon in January, it feels rather jarring after a record warm December. 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. But, after a brief warm-up, another shot of arctic air is forecast to hit the city next week. Keep those coats and gloves handy!

Winter Solstice 2015

Posted on by

The December solstice – the first day of winter in the northern hemisphere – is upon us. The new season officially begins at 04:48 UTC on December 22nd, which is 11:48 PM EST tonight.

The astronomical 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 toward the southern horizon and daylight hours have been decreasing. Today, it will reach its southern most 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.

Starting tomorrow, 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

Earth’s solstices and equinoxes. Image Credit: NASA

Mandatory Water Restrictions Issued for Drought-Stricken California

Posted on by

In response to the multi-year drought that has been plaguing California, Governor Jerry Brown issued an executive order on Wednesday that requires water usage across the state to be reduced by 25%. This is the first time statewide mandatory water restrictions have been enacted in California.

Standing on a dry patch of land in the Sierra Nevada Mountains that is normally covered with five feet of snow at this time of year, the governor said, “We are in a historic drought and that demands unprecedented action.” Last year, the state declared a drought emergency and asked residents to voluntarily reduce their water usage by 20%. This year, the reductions are compulsory and will be enforced with hefty fines for those who do not comply.

Statewide, according to the California Cooperative Snow Survey Program, the Sierra Snowpack is about 5% of normal for the date. Acting like a savings account, the snowpack is a critical part of the state’s water supply. They store water from the wet winter  season and slowly release it to rivers and reservoirs as they melt in the spring and summer.

The current California drought – now in its fourth year – is considered the worst drought on record in the state since 1895. Scientists who study historical climate proxies, such as tree-rings, say this drought is possibly the worst the region has seen in 1000 years.

California is no stranger to drought, but experts say warming conditions related to climate change are making this event worse than it would be otherwise. Once drought takes hold of a region, it tends to feed on itself in a vicious cycle. To start, high temperatures increase evaporation rates causing the soil to dry out.  Without plentiful rain to replace the moisture, the sun’s energy heats the ground and the air even further making the affected area even drier.   California, according to NOAA, just had its warmest winter on record. The previous record was set only last year.

Local water agencies across the state will be responsible for implementing the cutbacks required by the governor’s executive order and for monitoring compliance.

20150331_CA_trd