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

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

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

Aphelion 2019: Earth Farthest from Sun Today

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

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

First 90°F Day of the Year for NYC

The heat is on in New York City! The temperature in Central Park soared to 91°F on Saturday, marking the city’s first 90°F day of the year.

While readings in the 90s are not uncommon for the Big Apple during the summer months, they typically premiere earlier in the season. On average, the city usually sees its first 90°F day by the end of May.

According to NWS records, the city’s earliest first 90°F day was April 7, 2010, and its latest was July 26, 1877.

For the season as a whole, NYC typically gets an average of 15 days with temperatures reaching 90°F or higher. By month, that usually breaks down as May (1), June (3), July (6), August (4), and September (1). That said, every year is different. The most 90°F days the city experienced was 37 during the sweltering summer of 2010.

Credit: Melissa Fleming

Summers are Getting Hotter in the US

Summer is the warmest part of the year with high sun angles and long daylight hours. But, as our climate changes, the season is getting even hotter.

Across the contiguous United States, summer temperatures have increased an average of more than 2°F over the past fifty years, according to Climate Central, a non-profit science news organization. The western and southwestern parts of the country have seen the fastest seasonal increase, with places like Boise, ID, Las Vegas, NV, and McAllen, TX each warming more than 5°F since 1970.

Soaring temperatures can pose a risk to human health and cause energy costs to skyrocket as people try to beat the heat.  They can also lead to drought and threaten agricultural production.

Reducing global greenhouse gas emissions, which are causing the atmosphere to warm, can minimize many of these impacts. On a local level, adaptation measures are also important. In urban areas, which tend to heat up quickly, planting more trees can help keep neighborhoods cooler during the increasingly intense heat of the summer months.

Credit: Climate Central

The Science Behind the Summer Solstice

Today is the June Solstice, the first day of summer in the northern hemisphere. The new season officially begins at 15:54 UTC, which is 11:54 AM 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 summer months, the northern half of the Earth is tilted toward the sun. This position allows the northern hemisphere to receive the sun’s energy at a more direct angle and produces our warmest temperatures of the year.

Since the winter solstice in December, the arc of the sun’s daily passage across the sky has been getting higher and daylight hours have been increasing. Today, the sun will be directly overhead at the Tropic of Cancer (23.5°N latitude), its northernmost position, marking the “longest day” of the year. This observable stop in the sun’s apparent annual journey is where today’s event takes its name. Solstice is a word derived from Latin and means “the sun stands still”.

While today brings us the greatest number of daylight hours (15 hours and 5 minutes in NYC), it is not the warmest day of the year.  The hottest part of summer typically lags the solstice by a few weeks. This is because the oceans and continents need time to absorb the sun’s energy and warm up – a phenomenon known as seasonal temperature lag.

Earth’s solstices and equinoxes. Image Credit: NASA

Weather and Health: Hot Cars Can Be Dangerous for Kids

Warm weather can pose a number of health and safety concerns, from poor air quality to being hit by lightning. One of the more deadly risks for children, however, is heatstroke when they are left in a hot car.

Since 1998, according to kidsandcars.org, there has been an average of 38 hot car deaths in the US every year. That is one every nine days. This year, there have already been 11 deaths reported and the official start of summer is still more than a week away.

Credit: USA Today

On a sunny day, the interior temperature of a parked car can increase 19°F in just ten minutes. That means if the outside air temperature is a seemingly comfortable 70°F, the inside of the car can heat up to near 90°F in a very short period. The situation is even worse when the outside temperature is higher and the car sits in the sun longer.

According to the Mayo Clinic, if the human body reaches 104°F, organ damage and death become a real risk. Children are even more vulnerable because their smaller bodies can heat up between three to five times faster than that of an adult. Most hot car victims are under the age of three.

These dangerous situations develop in a number of different ways. Children can sometimes find their own way into a car while playing outside or a guardian leaves them alone in a vehicle for what seems like a quick errand. However, the majority of hot car deaths occur when a parent or caregiver gets distracted or has a change in their daily routine and simply forgets that a child is in the back seat when they park their car.

To avoid a heartbreaking tragedy, remember to Look Before You Lock!

806 children have died in hot cars since 1998 in the US. Year to date for 2019, there have been 11. Credit: NoHeatStroke.org

The 2019 Atlantic Hurricane Season Outlook

The number of hurricanes that develop in the Atlantic basin varies from year to year. For 2019, NOAA’s Climate Prediction Center is forecasting a near average season.

Tropical cyclones, known as hurricanes in the United States, develop around the globe at different times of the year. In this country, we are most impacted by the Atlantic hurricane season, which affects the North Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico. It runs from June 1 through November 30.

Overall, NOAA predicts a 70% likelihood of nine to fifteen named storms forming this season, of which four to eight could become hurricanes, including two to four major hurricanes. An average season produces twelve named storms, including six hurricanes and three that become major hurricanes.

A major hurricane is one that is rated category 3 or higher on the Saffir-Simpson scale.

This year’s outlook, according to NOAA, reflects several competing factors. On one side, there are above average sea surface temperatures in the tropical Atlantic to fuel any storms that develop. Additionally, there is an enhanced west African monsoon in place that can initiate disturbances that turn into storms over the Atlantic. On the other hand, there is an ongoing El Niño event. El Niño conditions in the Pacific tend to cause increased wind shear in the Atlantic, which suppresses tropical development in that basin.

Last year, 2018, saw a very destructive hurricane season in the Atlantic. It produced fifteen named storms, including, Florence and Michael.

Regardless of the number of storms that actually form this year, it is important to remember that it only takes one land-falling system to make it an impactful season.

August 2018: Ninth Warmest August on Record for NYC

August 2018 was a hot month in New York City. It produced two separate heat waves and a total of seven days with readings in the 90s. Overnight lows were also mostly warmer than normal. In the end, the city’s mean temperature for the month was 78.1°F, which is 2.9°F above average. That means August 2018 is now tied with August 1955 as the city’s ninth  warmest August on record.

August was also an over-achiever in terms of precipitation. In all, a whopping 8.59 inches of rain was measured in Central Park. That marks the city’s wettest August in seven years. Of this impressive total, 2.90 inches fell on a single day (August 11), setting a new daily rainfall record for the date. The city, on average, gets 4.44 inches of rain for the entire month.

Credit: The Weather Gamut