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Observations and thoughts on all things weather and climate

First Day of Spring 2018

Today is the Vernal Equinox, the first day of spring in the northern hemisphere. The new season officially begins at 16:15 UTC, which is 12:15 PM Eastern Daylight Time.

Our astronomical seasons are a product of the tilt of the Earth’s axis – a 23.5° angle – and the movement of the planet around the sun. During the spring months, the Earth’s axis is tilted neither toward nor away from the sun. This position distributes the sun’s energy equally between the northern and southern hemispheres.

Since the winter solstice in December, the arc of the sun’s apparent daily passage across the sky has been getting higher and daylight hours have been increasing. Today, the sun appears directly overhead at the equator and we have approximately equal hours of day and night. The word “equinox” is derived from Latin and means “equal night”.

As a transitional season, spring is a time when the chill of winter fades away and the warmth of summer gradually returns. The most noticeable increases in average daily temperature, however, usually lag the equinox by a few weeks.

Earth’s solstices and equinoxes. Image Credit: NASA

“Anthropocene”: A Look at Climate Change Through the Arts

Art and science are coming together at the Ann Street Gallery in Newburgh, NY to expand the public conversation on climate change. In a group exhibition called Anthropocene, artworks of various mediums explore the diverse impacts of this pressing issue.

In choosing Anthropocene as a title, the show highlights the fact that humans are the major cause of the Earth’s current transformation. The word, modeled on the names of geologic epochs, is widely used to describe the age we live in today where human activity is the dominant influence on the environment.

Curated by Virginia Walsh, the show features the work of: Darcie Abbatiello, Michael Asbill, Brigitte Amarger, Caitlin Cass, Reenie Charriere, Mariah Conner, Michael Fishcherkeller, Susan Fishman, Melissa Fleming, Stephanie Garon, Helen Glazer, Eloisa Guanlao, Colleen Keough, Dakotah Konicek, Rena Leinberger, Jonathan Barry Marquis, Gregory Martin, Daniel W. Miller, Sarah Misra, Itty Neuhaus, Maye Osborne, Elaine Quave, Jamie Rodriguez, John Shlichta, Gianna Stewart, and Uros Weinberger.

Anthropocene is on view from February 24 through April 7. The Ann Street Gallery is located at 104 Ann Street, Newburgh, NY. Gallery hours:
Wednesday – Thursday: 9 AM to 12:30 PM and 1:30 PM to 4 PM
Friday – Saturday: 11 AM to 5 PM

The opening reception is scheduled for Saturday, February 24th from 6:30 to 8:30 PM.

“Energy: 300 Million Years” by Melissa Fleming is one of the pieces in the show. Credit: Melissa Fleming

 

Weather Lingo: January Thaw

January is usually the coldest month of the year – the so-called dead of winter. There are times during the month, however, when temperatures soar well above average. This is known as a “January Thaw”.

This type of weather phenomenon typically occurs after an extended cold blast and is marked by temperatures at least 10°F above normal for few days. It does not necessarily occur every year, but when it does, it is usually in mid to late January, hence the name.

Credit: Melissa Fleming

What the Winter Solstice Means

Today is the December solstice, the first day of winter in the northern hemisphere. The new season officially begins at 16:28 UTC, which is 11:28 AM EST.

The astronomical seasons, which are different than meteorological 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 southernmost 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.

Soon, 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.

Solstices and Equinoxes. Credit: NASA 

Weather Lingo: ACE

There are a number of different ways to gauge a hurricane season. One of these is the Accumulated Cyclone Energy index, which is widely referred to as ACE.

It expresses the combined intensity and duration of individual cyclones and provides a measure of activity for an entire hurricane season. For a single storm, it is calculated by summing the squares of the maximum sustained wind speeds measured every six hours while they are at least tropical storm strength. This number is then divided by 10,000 to make it more user-friendly. Overall, the stronger and longer-lived a storm is, the higher its ACE value.

The ACE for a season is the sum of the ACE values from individual storms that occurred that year. NOAA considers a season with an ACE of 111 or higher to be above average, while an ACE of 66 or lower is regarded as below average.

The Atlantic hurricane season runs from June 1 through November 30.

Source: CSU

(Note: Year to date the Atlantic Basin has had 13 storms with a combined ACE of 202 and there are still two months left in the 2017 hurricane season.)

Today is the Autumnal Equinox – Here’s What That Means

Today is the Autumnal Equinox, the first day of fall in the northern hemisphere. The new season officially begins at 20:02 UTC, which is 4:02 PM Eastern Daylight Time.

The astronomical seasons, as opposed to the meteorological seasons,  are a product of Earth’s axial tilt – a 23.5° angle – and the movement of the planet around the sun. During the autumn months, the Earth’s axis is tilted neither toward nor away from the sun. This position distributes the sun’s energy equally between the northern and southern hemispheres.

Since the summer solstice in June, the arc of the sun’s apparent daily passage across the sky has been moving southward and daylight hours have been decreasing. Today, the sun appears directly overhead at the equator and we have approximately equal hours of day and night. The word “equinox” is derived from Latin and means “equal night”.

With the sun sitting lower in the sky and daylight hours continuing to shorten, autumn is a season of falling temperatures. According to NOAA, the average high temperature in most US cities drops about 10°F between September and October.

Earth’s solstices and equinoxes. Image Credit: NASA

Climate Week NYC 2017

Climate Week NYC begins on Monday.

This annual global summit takes place alongside the UN General Assembly and brings together leaders from a variety of sectors, including business, government, and civil society, to discuss climate change. Organized by The Climate Group since 2009, the goal of the conference and its affiliate events is to raise awareness and keeping climate action at the top of the global agenda. This year’s event will focus on the implementation of the Paris Climate Agreement and UN sustainable development goals.

Public events in support of the summit’s mission are scheduled all week around the city, from September 18-24. They range in style from panel discussions and seminars to concerts and exhibitions. For the full program of events, go to the Climate Week website.

Credit: The Climate Group

The Great American Solar Eclipse of 2017

The Great American Solar Eclipse will take place on Monday, August 21. It will be the first time that a total solar eclipse has been visible anywhere in the contiguous US since 1979 and the first event of its kind to travel across the entire continent since 1918.

A solar eclipse occurs when the moon passes between the Earth and the Sun, casting a shadow on the planet’s surface. Communities that are located in the large, but lighter penumbral shadow will see a partial eclipse. Those in the smaller, but darker umbral shadow will experience a total solar eclipse. Moving across the Earth, the umbral shadow creates what is known as a path of totality.

Credit: NASA

On Monday, this path will cross through fourteen states, from Oregon to South Carolina. However, every state in the Lower 48, as well as parts of Mexico and Canada, will see some degree of a partial eclipse.

This celestial event is also expected to affect the weather across the country. As the moon briefly obscures the Sun, temperatures are forecast to drop a few degrees. This, in turn, will also cause the winds to slacken.

When viewing this historic event, do not look directly at the Sun. Doing so will cause serious eye damage. Use special eclipse viewing glasses or a method of indirect viewing, such as a pinhole projector.

Path of Totality for Solar Eclipse 2017. Credit: GreatAmericanEclipse

Weather History: Ten Year Anniversary of NYC’s Strongest Tornado

Ten years ago today, an EF2 tornado roared through New York City. It was the strongest twister on record to hit the Big Apple.

NYC Tornado of 2007. Credit: NYT

With winds measured up to 135 mph, it left a trail of destruction nine miles long from Staten Island to Brooklyn with the hardest hit neighborhoods being Bay Ridge and Sunset Park. The storm toppled trees and knocked out power to more than 4,000 customers. It damaged hundreds of cars and dozens of homes, including five that had their roofs ripped off. The storm also dumped 1.91 inches of rain in just one hour, which caused flash floods and the temporary suspension of subway service during the morning commute.

Historically, tornadoes have been rare events in NYC. In recent years, however, they have been happening more frequently. Of the eleven twisters that have touched down in the city since 1950, seven have occurred since 2003.

Note: Tornado ratings moved from the Fujita Scale (F) to the Enhanced Fujita Scale (EF) in 2007.

What are the Dog Days of Summer?

The “Dog Days” of summer have arrived. This popular saying refers to what are traditionally the hottest and most oppressive days of the season.

Rooted in astronomy, the phrase is linked to Sirius, the brightest star seen from Earth. As part of the constellation Canis Major, it is known as the Dog Star.  During most of July and August, Sirius rises and sets with our Sun. Ancient Greeks and Romans believed it acted like a second Sun, adding extra heat to summer days. Today, we know that light from this distant star does not affect our weather, but the name has endured.

Varying by latitude around the globe, the so-called “Dog Days” of summer typically run from July 3 to August 11 in the United States.

Sirius, the “Dog Star”.  Credit: EarthSky/Tom Wildoner