Monthly Archives: January 2015

First Major Winter Storm of 2015 in NYC

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A major winter storm blasted a large area of the eastern U.S. on Monday and Tuesday. Heavy snow and high winds impacted states from the Mid-Atlantic to New England.

Here in New York City, the storm dumped 9.8 inches of snow in Central Park. While that is a substantial amount, it is a far cry from the record-breaking numbers and blizzard conditions that were forecast. In response to this forecast bust, the NWS said, “The science of forecasting storms, while continually improving, still can be subject to error, especially if we’re on the edge of the heavy precipitation shield. Efforts, including research, are already underway to more easily communicate that forecast uncertainty.”

Starting out as a weak area of low pressure, this storm quickly intensified when it interacted with the jet stream and transformed into a massive nor’easter. It tracked further east than expected and that change in distance to the coast made a big difference in where the heaviest snow fell. On Long Island, only a few miles east of NYC, communities dealt with blizzard conditions and over 20 inches of snow.

While not one for the record books in the Big Apple, this storm ended the so-called snow drought in the northeast and brought enough snow for a fun day of sledding in parks across the city.

Weather History: NYC’s Biggest Snowstorms

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A blizzard warning is currently in effect for New York City. The storm is expected to be our biggest snowmaker of the season to date. It could also possibly be one for the record books.

Here is a look at the top ten snowstorms in New York City history.

Source: NOAA

All measurements are from Central Park in NYC. Source: NWS.

What is a Blizzard?

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A blizzard is expected to blast the northeastern United States over the next two days. Different than a typical winter storm, a blizzard is characterized more by its winds than the amount of snow it produces.

According to the National Weather Service, a blizzard means the following conditions prevail for three hours or longer:

  • Sustained winds or frequent gusts of 35mph or higher, and
  • Considerable falling and/or blowing snow that frequently reduces visibility to ¼ mile or less.

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

Climate Change in Saguaro National Park

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The saguaro – the classic symbol of the American southwest – is the largest cactus species in the United States and only grows in the Sonoran Desert. Straddling the city of Tucson, AZ, Saguaro National Park protects over 90,000 acres of its namesake cactus. While visiting there recently, I learned how this unique environment is being impacted by climate change.

The Southwest is the hottest and driest part of this country and climate change is making it even more so.  According to the US National Climate Assessment, 2001 through 2010 was the region’s warmest decade on record with temperatures almost 2°F above historic averages. Looking ahead, the report projects continued increases in average annual temperature and a decrease in precipitation, especially in the southernmost part of the region. In a National Park Service (NPS) report on arid lands, the agency says it has already observed a widespread winter and spring warming trend and a lengthening of the frost-free season in the Sonoran Desert.

These warmer conditions are causing a variety of environmental changes in Saguaro National Park. While fewer cacti are dying from severe freeze events, evaporation rates are increasing, making an already parched area even drier. “Arid ecosystems,” the NPS says, “are particularly sensitive to climate change and climate variability because organisms in these regions live near their physiological limits for water and temperature stress.” Even slight changes in the environment can dramatically alter the distribution and abundance of many desert species. On average, the region currently receives less than 12 inches of rain per year.

The phenology, or the timing of natural events, is also being thrown out of sync as the climate changes. The vital rains of the region’s monsoon season traditionally begin in early July, but are projected to arrive later and later in the coming years. This can be a problem for the saguaros, because they have evolved to produce fruit in the beginning of July. While adapted for the dry desert environment, the cacti still depend on adequate rain during the summer growing season for both their own survival and the establishment of seedlings.

Another serious climate change challenge for the Sonoran Desert is the spread of non-native plant species. Buffelgrass, a native of Africa, was introduced to Arizona in the 1940’s for cattle forage. Thriving in the heat, this invasive species is crowding out the native plants (including the cacti), changing the look of the landscape, and increasing the risk of wildfires.

The Sonoran Desert did not evolve with fire as an ecological factor. Lush with vegetation by desert standards, the region usually had large gaps between groups of plants. This helped keep any wildfires small. Now, as the buffelgrass fills in those open spaces, fires can burn hotter and spread much more easily. Adding insult to injury, the buffelgrass grows back after a fire has killed the native plants.

The changing environment is also problematic for the animals that depend on the saguaros for food and shelter. These include a wide array of species, ranging from woodpeckers to coyotes.

Scientists are continuing to monitor and research how additional changes in temperature and precipitation will affect this beautiful and unique place.

Saguaro National Park, Arizona. Photo Credit: The Weather Gamut

Saguaro National Park, Arizona.  Photo Credit: The Weather Gamut

2014: Warmest Year on Record for Planet Earth

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Its official!  2014 was the warmest year ever recorded on planet Earth.

According to a report released today by NOAA’s National Climatic Data Center, Earth’s combined average temperature for the year – over both land and sea surfaces – was 58.33°F.  That is 1.33°F above the 20th century average. It surpassed the previous annual record held by both 2005 and 2010 by 0.07°F.  2014 also marked the 38th consecutive year that our global temperature was above its long-term norm.

Rising ocean temperatures, according to NOAA, helped fuel this record warmth. The globally averaged sea surface temperature for 2014 was 1.03°F above the 20th century average of 60.9°F.  That is the highest on record, breaking the former record set in 1998 and tied in 2003 by 0.09°F.

It is interesting to note that ENSO-neutral conditions were present during all of 2014. That means El Niño, the warm phase of ENSO (El Niño-Southern Oscillation) did not influence this record warm year. Scientists, while acknowledging the decrease in the rate of warming over the past decade, say this fact undeniably confirms the continuation of global warming.

While heat dominated most of the planet in 2014, including parts of Alaska and the western United States, the eastern two-thirds of this country was one of the few cold pockets. Overall, the contiguous US experienced its 34th warmest year on record. This highlights the fact that climate change is a complex global phenomenon that involves much more than what is happening in our own backyards.

With records going back to 1880, nine of this planet’s top ten warmest years on record have all occurred since 2000. The only exception was 1998. As greenhouse gases – which drive our global temperature upward – are continuously emitted into the atmosphere, scientists say we can expect global temperatures to continue to rise and more warm records to be broken.

Credit: NOAA

Credit: NOAA

Credit: NOAA

Credit: NOAA

Warmest December on Record for Planet Earth

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Like most of the US, including here in NYC, temperatures across the globe soared last month.  In fact, December 2014 was Earth’s warmest December on record.

According to the latest report from NOAA’s National Climatic Data Center, the planet’s combined average temperature for the month – over both land and sea surfaces – was 55.39°F.  That is 1.39°F above the 20th century average. December 2014 also marked the 6th month this year to break a global temperature record.

The calendar year of 2014 (January – December), is now ranked as the warmest year on record for planet Earth. Global temperature records date back to 1880.

201412

Credit: NOAA

Weather and Art: Vortex

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The word vortex – popularized last winter by extended arctic outbreaks related to a wobbly polar vortex – can sound rather ominous. A vortex, however, is simply a whirling mass of air or water.  Its spiral pattern is found throughout nature.

In the weather world, vortices form for a variety and combination of reasons, including differences in atmospheric pressure, wind shear, and centrifugal force. Tornadoes, waterspouts, and hurricanes, are all examples. They, unlike the polar vortex, are visible because of the water vapor and debris that gets sucked into them.

The spiral shape of a vortex is also represented in art in various sizes and materials. One of the largest is Richard Serra’s massive (67’x21’x20’) cor-ten steel sculpture, “Vortex” (2002), at the Modern Art Museum of Fort Worth in Texas. One of my more recent sightings, however, was on a much smaller scale. Also simply titled “Vortex” (1932), this was a small (11×14”) gelatin silver photographic print by Edward W. Quigley at the Museum of Modern Art in NYC. As someone who is fascinated by the intersection of art and science, this image really stood out to me at MOMA’s current photography exhibition, “Modern Photographs: The Thomas Walther Collection, 1909-1949”. It is on view through April 19, 2015.

Credit: Edward W. Quigley and MOMA

“Vortex”, 1932.  Credit: Edward W. Quigley and MOMA

Credit: Richard Serra and

“Vortex”, 2002.  Credit: Richard Serra and Modern Art Museum of Fort Worth 

The Dead of Winter: Coldest Part of the Season

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The “Dead of Winter” is an old saying that refers to the coldest part of the winter season. This annual chilly period, statistically, begins today.

While actual daily weather varies, historical average temperatures in most of North America reach their lowest point of the year between January 10th and February 10th.  This 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 heat 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 cold weeks are the climatological opposite of the “Dog Days of Summer.”

Arctic Air Brings Brutally Cold Temperatures to NYC

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A massive arctic outbreak has sent most of the U.S. into a deep freeze.  From the Mid-West to the Eastern Seaboard and down to the Gulf Coast, many cities are dealing with the coldest temperatures they have seen this season.

Here in New York City, the mercury fell to 8°F in Central Park this morning. Factoring in the wind chill, it felt like -8°F. Our normal low temperature for this time of year is 27°F.

As cold as it was today, it was not the coldest day the Big Apple has ever experienced. That dubious honor, according to the NWS, belongs to February 9, 1934, when the low temperature was a brutal -15°F.

Produced by a deep dip in the jet stream, our current frigid conditions are expected to stick around through the weekend. Bundle up!

Earth’s Perihelion 2015

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The Earth reached its Perihelion today at 6:36 UTC, which is 1:36 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 about 146 million kilometers away from the Sun. That is approximately 5 million kilometers (3 million miles) closer than 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”.

Image Credit: mydarksky.org

Image Credit: mydarksky.org