Monthly Archives: April 2016

Revised Numbers Show January 2016 Blizzard was a Record Breaker in NYC

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After further review, it turns out that the Blizzard of January 2016 – also known as Winter Storm Jonas – was a record breaker for New York City.

According to the NWS, the storm dumped 27.5 inches of snow in Central Park and not the previously reported 26.8 inches. That makes it the city’s biggest snowstorm on record. The previous reading was a tenth of an inch shy of the now old record that was set in February 2006.

The error was found during an investigation launched in the wake of the historic storm. Snow measurement techniques at eight different sights along the east coast were questioned, as storm totals seemed too high in some places and too low in others. In a statement, NWS Director, Louis Uccellini, said, “Snow measurements are extremely difficult to take because precipitation is inherently variable, a problem compounded by strong winds and compaction during a long duration event.”

In NYC, the mistake stemmed from a communication issue rather than a problem with measurement technique. The Central Park Conservancy, the group responsible for measuring snowfall in Central Park, called their numbers into the NWS office by phone and one of the measurements was written down incorrectly.

In the grand scheme of this massive storm, an extra 0.7 inches of snow may not sound like a lot, but every fraction counts when it comes to records.

Blizzard 2016, NYC. Credit: Melissa Fleming

New Yorkers enjoy the record 27.5 inches of snow dumped on the city by the Blizzard of 2016. Sheep’s Meadow in Central Park, NYC. Credit: Melissa Fleming

How Does Hail Get to be the Size of a Grapefruit?

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Spring is considered severe weather season in the Central US and on Tuesday the power of Mother Nature was on full display across the region. More than 300 severe storm reports were counted and the vast majority included very large hail.

In Kansas and Nebraska, hailstones the size of a grapefruit were reported. Those are balls of ice measuring about four inches in diameter. According to the NWS, once a thunderstorm produces hail with a one inch diameter or more it is considered severe. So, how does hail get that big?

The answer to that question lies with the speed of a storm’s updraft. Basically, the stronger the updraft, the longer the ice remains suspended in the cloud where it can grow larger. Below is a chart that shows approximately how strong an updraft has to be to support different sizes of hail.

The largest hailstone ever recorded fell in Vivian, South Dakota on July 23, 2010 and measured eight inches in diameter – about the size of a volleyball. To support a hailstone that size, the updraft likely exceeded 150mph.

Credit: NWS

Credit: NWS

The Paris Climate Change Agreement is Signed at UN on Earth Day

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On this Earth Day, government officials from around the globe are gathered at the UN headquarters in New York City to sign the historic climate change deal that was hammered out in Paris last December. This signing ceremony is one of several steps needed to put the global accord into effect.

Known as the Paris Agreement, the deal aims to limit global warming to 2°C (3.6°F) above pre-industrial levels. To achieve this goal, countries submitted individual five-year plans called “intended nationally determined contributions” or INDCs. They essentially spell out how much CO2 a country plans to cut based on its own political and economic situation. Under the current collection of national plans, however, the Paris Agreement will only cut greenhouse gas emissions by about half of what is necessary to reach the 2°C (3.6°F) goal. That said, the agreement does legally obligate countries to reconvene every five years to present updated plans detailing how they will deepen their emissions cuts.

The next step in the UN process requires participating countries to formally pledge that they will adopt the agreement within their own legal systems. The final step – known as “entering into force” – will happen when at least 55 countries, which together represent at least 55% of global emissions, adopt the agreement domestically. This last part is likely to take a few years.

A today’s ceremony, 155 countries are expected to sign the agreement.  This will set a new record for the number of signatories on an international accord. The previous record was held by the 1982 Montego Bay Law of the Sea agreement, which had 119 signatories.

Credit: UN

Credit: UN

Earth Day 2016

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Everyday is Earth Day, as the saying goes. But, today marks the official celebration.

The first Earth Day – spearheaded by Senator Gaylord Nelson of Wisconsin – was held on April 22,1970.  An estimated 20 million people attended rallies across the US to protest against rampant industrial pollution and the deterioration of the nation’s natural environment. Raising public awareness and shifting the political tide, these events helped put environmental issues on the national agenda. They led to the creation of the EPA and the passage of the Clean Air Act, Clean Water Act, and the Endangered Species Act.

Forty-six years after the original, Earth Day celebrations are now held in nearly 200 countries. This year, the date is more significant than ever as hundreds of government officials from around the world gathered at the UN to sign the Paris Agreement on Climate Change.

Image Credit: William Anders/NASA

“Earth Rise” from 1968 highlighted how fragile and unique the Earth really is.                              Credit: William Anders/NASA

March 2016: Warmest March on Record for Planet Earth

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Our global temperature continued its upward trend last month with March 2016 marking the warmest March ever recorded on this planet.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for the month – over both land and sea surfaces – was 57.1°F. That is a staggering 2.20°F above the 20th century average and 0.54°F above the former record that was set last year. This temperature was also the highest departure from average for any month on record, surpassing the previous record that was set just last month.  Moreover, March 2016 marked the 11th month in a row to break a monthly global temperature record.

While heat dominated most of the planet, some places were particularly warm, including much of North America and Scandinavia. Here in the contiguous US, it was our 4th warmest March on record.

These soaring temperatures, scientists say, were fueled by a combination of El Niño, which is now fading, and the long-term trend of human-caused climate change. Research by Climate Central’s World Weather Attribution Program shows that while El Niño gives global temperatures a boost, the majority of the temperature increase is due to rising levels of greenhouse gases in the atmosphere. It should also be noted that no other strong El Niño event has produced temperature anomalies as large as the ones seen recently.

Year to date, the first three months of 2016 were the warmest such period on record. Global temperature records date back to 1880.

march 2016 was the 11th consecutive month to break a monthly temperature record. Credit: NOAA

March 2016 was the 11th consecutive month to break a monthly global temperature record.  Credit: NOAA

Historic Flooding in Houston

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Relentless rain unleashed catastrophic flooding across southeast Texas on Monday. Local officials say this was the worst flooding event the region has seen in years.

Rainfall totals across the Houston metro area varied, but some places saw nearly 17 inches in less than 24 hours. The NWS office in Houston reported 9.92 inches of rain at Houston Intercontinental Airport (IAH), making it that city’s second wettest day on record. On average, Houston typically gets 3.46 inches of rain for the entire month of April.

The intense rainfall caused bayous to swell out their banks and flood homes, businesses, and major roadways – effectively paralyzing large parts of this country’s 4th largest city. Rainfall rates reached as high as 3 to 4 inches per hour in some spots, which prompted the NWS to issue a flash flood emergency (the highest level of flood alert) for the area. Local officials say 5 people were killed and more than 100,000 people lost power as a result of the flood.

The primary driver behind this extreme rain event was also main reason why the eastern US has been unseasonably warm and dry recently. The omega block that sat over the country for the past few days basically set up a large ridge of high pressure in the east and blocked an upper-level low from moving past the Four Corners region. Essentially stuck in place, the upper-level low funneled in massive amounts of moisture from the Gulf of Mexico. That moisture was then forced to rise and cool when it interacted with the stationary front in the area. The result was an extended period of thunderstorms and intense rainfall.

Southeast Texas is no stranger to flooding. In fact, this was the fourth major flood to hit the area in the past twelve months. The previous three took place in May, June and October of 2015. But, officials in Houston say Monday’s event was the largest flood the area has seen since Tropical Storm Allison in 2001. That storm dumped more than 35 inches of rain on the Houston metro area over the course of five days and caused $5 billion worth of damage.

The Governor of Texas, Greg Abbot, has declared 9 counties to be disaster areas as a result of Monday’s storm.  More rain, unfortunately, is forecast for the region this week.

View of flooding in downtown Houston, TX. Credit: KHOU

View of flooding in downtown Houston, TX.  Credit: KHOU

First 80° Day of the Year for NYC

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It is only April, but it felt more like mid-June in New York City today.

The temperature in Central Park soared to 82°F, which is a whopping 20°F above average. This was the first 80° reading the city has seen since the end of September last year.

The primary driver of this unseasonable warmth is the omega-blocking pattern centered over the eastern US. A persistent ridge of high pressure over the region is allowing warm air from the south to flow further north than it normally would at this time of year.

While it was unusually warm today, it was not a record for the city. That honor belongs to April 18, 1976 when the mercury hit 96°F.  Nonetheless, after a brisk start to April this year, many New Yorkers were out enjoying the summer-like weather.

Omega Blocking Pattern Brings a Stretch of Warm Weather to Northeast

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After a chilly start to April, warm weather has returned to the northeastern US and it is expected to stick around for the next several days. For this, we can thank an atmospheric phenomenon known as blocking, or more specifically in this case, an omega block.

Atmospheric blocking causes the stagnation of a particular type of weather pattern. In other words, the same type of weather, be it hot, cold, wet or dry, will remain in place over a specific region for an extended period of time.

Flowing from west to east, the jet stream moves weather systems across the country and marks the boundary of cold air to its north and warm air to its south. When flowing in a zonal pattern – a fairly straight line – we generally see seasonal temperatures. But, there are times when it meanders in a more north/south pattern forming large troughs and ridges. When this type of meridional flow develops, warm air can reach farther north than normal and cold air can spill deeper into the south. It also means that weather systems get “blocked” from their typical eastward flow and therefore move more slowly.

The omega block is named after the Greek letter (Ω) that it resembles and is characterized by a high-pressure ridge sandwiched between two low-pressure troughs. Areas under the ridge experience a prolonged period of warm and dry weather, while areas under the troughs see persistent wet and cold conditions.

This current blocking event, centered over the eastern US, is letting the Northeast as well as parts of both the Midwest and West Coast to bask in unseasonable warmth. States in the central plains, on the other hand, are dealing with repetitive rounds of heavy precipitation and the risk of flooding.

Omega Blocking Pattern over US, April 2016. Credit: CBS

Omega Blocking Pattern over US, April 2016. Credit: CBS

Speaking Event: The Art and Science of Climate Change

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Climate change is a complex scientific subject with a plethora of data-rich reports that detail its causation and diverse impacts. But, not everyone responds to facts and figures or charts and graphs. That is why art can help broaden the public conversation and help create new pathways to understanding this critical issue.

On Friday, April 15th, I will be giving a presentation that I developed called The Art and Science of Climate Change at New York University (NYU). Blending my two passions, it introduces the basic science of climate change and explores how artists from around the globe are reacting to its various impacts and possible solutions.

Please contact me to arrange a presentation for your school or organization.

When to Expect the Final Freeze of Spring

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Most people often associate spring with flowers and mild weather. But as a transitional season, it can also produce some serious cold spells. Wearing shorts one day and a parka the next, you start to wonder when the cold will finally fade away.

The answer to that question largely depends on where you live. Below is a map from NOAA that shows the typical final freeze dates across the continental US. While actual weather conditions vary from year to year, the dates shown are based on climatology – a thirty-year average of temperature data.

Here in New York City, our last spring freeze usually comes in mid-April.

Credit: NOAA

Credit: NOAA