Monthly Archives: July 2019

First Heatwave of 2019 Brings Extreme Temperatures to NYC

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A heatwave gripped a large swath of the eastern United States this weekend. For many areas, the temperatures were extreme.

The threshold for what constitutes a heatwave varies by region, but here in the northeast, it is defined as three consecutive days with temperatures reaching 90°F or higher. In New York City, the official temperature in Central Park reached 91°F on Friday, and 95°F on both Saturday and Sunday. Overnight lows were also well above average. In fact, on Saturday, the temperature only cooled down to 82°F, tying the record warm low termperature for the date that was set in 2015.

When the humidity was factored in, it felt even hotter. The heat index ranged from 105°F-110°F.

The city’s airports, LGA and JFK, both in the borough of Queens, posted record high temperatures over the weekend, according to the National Weather Service. JFK hit 99°F on Saturday, breaking the previous record of 96°F that was set in 2013. On Sunday, LGA reached the century mark (100°F), tying the high-temperature record for the date at the site that was set in 1991.

The cause of this exceptional heat was two-fold. First, a large area of high pressure sitting over the central US was pumping hot air from the southwest toward the northeast. At the same time, a strong Bermuda High off the east coast was pumping warm, moist air from the Gulf of Mexico into the region. Together, they made it dangerously hot, which is why the NWS issued an excessive heat warning for the city. It is also why several outdoor events around the Big Apple were canceled, including the NYC Triathlon.

The hottest day ever recorded in New York City occurred on July 9, 1936, when the air temperature hit 106°F in the shade. The city’s normal high temperature this time of year is 84°F.

A Tale of Two Highs: The Science Behind the Excessive Heat in the Northeast

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Summer is the season for warm weather and even the occasional heatwave. But, the excessive heat that is gripping the eastern United States this weekend is exceptional. Its source is essentially a tale of highs – two areas of high pressure, that is.

The first is a Bermuda High. This is a large, semi-permanent, area of high pressure situated off the east coast. Spinning clockwise, it is strongest in the summer months and often steers hot, humid air from the Gulf of Mexico toward the northeast. It is usually the main cause of heatwaves in the region.

This current heatwave, however, is getting an extra boost from a second area of high pressure that is sitting over the central US. Also spinning clockwise, it is funneling hot air aloft from the southwest toward the northeast. Traveling eastward, this hot air must pass over the Appalachian Mountains, which run parallel to the eastern seaboard from Georgia to Maine. Following the topography downslope on the lee side of the mountains, the air compresses and warms even further. This is producing the exceptionally high air temperatures, such as the upper 90s and triple digits reported in cites across the region.

Combining this excessively hot air with the humidity being pumped into the area by the Bermuda High, the heat index or real feel temperatures are well above 100°F in many places.

This type of weather is more than just uncomfortable, it is dangerous. To avoid health complications, the American Red Cross recommends avoiding strenuous outdoor activity, drinking plenty of fluids, and cooling off in air-conditioned spaces when possible.

Credit: NOAA/NWS

Extreme Heat Can Pose a Danger to Your Health

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A heat emergency has been issued for New York City.  As temperatures soar, it is important to remember that intense heat can cause serious health problems.

According to the CDC, extreme heat – temperatures that are significantly hotter than the average local summertime high – is one of the leading causes of weather-related deaths in this country. Claiming hundreds of lives every year, excessive heat kills more people across the U.S. than hurricanes and tornadoes combined.

Extreme heat is deadly because it forces the human body beyond its capacity to cool itself. Linked to overheating and dehydration, heat-related illnesses can range in severity from mild to life-threatening.  Symptoms for each stage include:

Heat Cramps:  Painful muscle spasms in the legs and/or abdomen

Heat Exhaustion:  fatigue, weakness, clammy skin, and nausea

Heat Stroke:  rapid pulse, hot and dry skin, no sweating. This is a medical emergency

To beat the heat, the American Red Cross suggests:

  • Avoid strenuous activity
  • Dress lightly
  • Eat lightly
  • Drink plenty of water
  • Replenish salts and minerals lost through perspiration with sport-drinks
  • Limit caffeine and alcohol
  • Stay out of the sun
  • Cool off in an air-conditioned building, when possible

Credit: NWS/WRN

June 2019: Warmest June on Record for Planet Earth

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Our global temperature continued its upward trend last month with June 2019 marking the warmest June 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 61.61°F. That is a staggering 1.71°F above the 20th-century average and 0.04°F above the previous record that was set in 2016.

June 2019 also marked the 414th consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below-average reading was December 1984. Furthermore, nine of the ten warmest Junes have occurred since 2010. June 1998 is the only year from the last century on the top ten list and currently ranks eighth.

While heat dominated most of the planet this June, some places were particularly warm, including Europe, parts Russia and South America, as well as Alaska. In fact, Europe posted its warmest June on record and Alaska had its second warmest June since statewide record-keeping began there in 1925.

For the contiguous US as a whole, this June was close to average and ranked in the middle third of the national record. To put this disparity into context, consider that the United States constitutes less than 2% of the total surface of the Earth. This detail also highlights the fact that climate change is a complex global phenomenon that involves long-term trends more than the short-term weather conditions that are happening in any one part of the world.

Year to date, the first six months of 2019 tied with the first half of 2017 as the second warmest such period of any year on record. At this point, it is very likely that 2019 will finish among the top five warmest years on record. Global temperature records date back to 1880.

June 2019: Earth’s Warmest June on Record. Credit: NOAA

Swamped by Barry, Arkansas Sets New State Tropical Rainfall Record

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Hurricane Barry made headlines for making landfall in Louisiana over the weekend, but its torrential rain made history Arkansas this week.

According to the NWS, the remnants of the moisture-laden storm dumped 16.59 inches of rain in Dierks, Arkansas, setting a new tropical rainfall record for the state. The previous record of 13.91 was set in Portland, AR during Tropical Storm Allison in 1989.

Arkansas is the fifth state to set a new tropical rainfall record in the last two years. The other four include Texas, Hawaii, North Carolina, and South Carolina.

These types of extreme rain events have been happening more frequently in recent years and most experts see a link to climate change. As the atmosphere and oceans warm, storms are able to carry more moisture, and therefore drop more rain.

Credit: The Weather Gamut

Hurricane Barry Makes Landfall in Louisiana, Soaking Gulf Coast

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Hurricane Barry made landfall at Intracoastal City, Louisiana on Saturday. It was the second named storm and first hurricane of the 2019 Atlantic season.

Coming ashore with winds measured up to 75 mph, Barry was classified as a category one hurricane. But, it was rain rather than the wind that had the biggest impact on the area. Moving slowly at about 7mph, the storm dumped heavy precipitation across the region, causing widespread flooding.  Some parishes even saw the water overtop levees in spots. The highest rainfall total of 23.58 inches was reported near Ragley, LA.  

Extensive power outages were also reported across Louisiana. According to state energy officials, more than 120,000 customers were in the dark in the wake of the storm.

While downgraded to a tropical storm after landfall, Barry is still laden with moisture. It is expected to bring heavy rain and flooding to regions further inland as it travels north into Arkansas.

Hurricane Barry. Credit: NOAA

“Warming Stripes”: The Colors of Climate Change

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Sometimes a picture is worth a thousand words. That is the case with “Warming Stripes”, a creative visualization of climate data by Ed Hawkins, a scientist at the UK’s National Centre for Atmospheric Science.

Painting a picture of our changing climate, each stripe represents a single year from 1850 through the present. With an aesthetic similar to color field paintings by artists such as Barnett Newman or Mark Rothko, the images use only color to communicate meaning. Simplifying a complex issue for maximum impact with the general public, they avoid distracting details and focus on the big picture.

In “Warming Stripes for the Globe” (see below), it is plain to see the shift from blue (cooler) on the left to red (warmer) on the right. While there were a few warm years here and there in the past, the overall trend clearly shows temperatures are getting warmer. It is also important to note that the red has been getting darker (hotter) in recent years.

To see how the warming trend is playing out on a more regional or local level in different parts of the world, visit www.showyourstripes.info

“Warming Stripes for Globe, 1850-2018”. Credit: Ed Hawkins

Weather History: Thomas Jefferson and the Temperature on July 4, 1776

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As the main author of the Declaration of Independence and the third President of the United States, Thomas Jefferson is regarded as one of this country’s Founding Fathers. He was also an astute and systematic weather observer.

Portrait of Thomas Jefferson by Rembrandt Peale, 1805. Credit: NYHS

In the summer of 1776, Jefferson was in Philadelphia, PA attending the Second Continental Congress, which adopted the Declaration of Independence.  While there, he purchased a thermometer and a barometer – new and expensive weather equipment at that time. On July 4, Jefferson noted that the weather conditions in Philadelphia were cloudy with a high temperature of 76°F.

For the next 50 years, he kept a meticulous weather journal.  He recorded daily temperature data wherever he was – at home in Virginia or while traveling.

In an effort to understand the bigger picture of climate in America, Jefferson established a small network of fellow observers around Virginia as well as contacts in a few other states. According to records at Monticello, his estate in Virginia, he hoped to establish a national network for weather observations. While this plan did not come to fruition during his lifetime, today’s National Weather Service considers him the “father of weather observers.”

Happy Independence Day!

An excerpt from Thomas Jefferson’s Weather Journal, July 1776. Credit: NCDC

Aphelion 2019: Earth Farthest from Sun Today

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The Earth will reach its farthest point from the Sun today – an event known as the aphelion. It will officially take place at 22:10 UTC, which is 6:10 PM Eastern Daylight Time.

This annual event is a result of the elliptical shape of the Earth’s orbit and the slightly off-centered position of the Sun inside that path. The exact date of the Aphelion differs from year to year, but it’s usually in early July – summer in the northern hemisphere.

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, Earth is about 152 million kilometers (94 million miles) away from the Sun. That is approximately 5 million kilometers (3 million miles) further than during the perihelion in early January. That means the planet will move more slowly along its orbital path than at any other time of the year. As a result, summer is elongated by a few days in the northern hemisphere.

The word, aphelion, is Greek for “away from the sun”.

Earth’s Perihelion and Aphelion. Credit: Time and Date.com

June 2019: A Soggy Start to Summer in NYC

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June 2019 was another month of wild temperature swings in New York City. Highs ranged from an unseasonably cool 65°F to a balmy 91°F. In the end, however, the cold and warmth balanced each other out. The city’s mean temperature for the month was 71.7°F, which is only 0.3°F above average.

In terms of precipitation, the city was unusually wet. Overall, 13 out 30 days posted measurable rainfall that added up to 5.46 inches for the month. While that is a soggy statistic, it was not the wettest June the city has seen. That dubious honor belongs to June 2003 when 10.26 inches of rain was measured in Central Park. The city, on average, gets 4.41 inches for the month.

Credit: The Weather Gamut