Autumn is Heating Up Across the US

Autumn is a transitional season. It is generally a time when the heat of summer fades away and the chill of winter gradually returns. But, as our climate changes, the season is heating up.

Across the contiguous United States, autumn temperatures have increased an average of 2.5°F over the past fifty years, according to Climate Central. The western part of the country has seen the fastest seasonal increase, with Reno, NV warming 7.7°F.  Las Vegas, NV, and El Paso, TX have each seen a rise of more than 5°F since 1970.

These warmer temperatures may feel like a summer bonus for some, but they also bring a number of negative impacts. Less frost-free days means the allergy season is extended and disease-carrying pests like mosquitos and ticks are able to live and thrive longer. Warmer temperatures also drive up energy bills, as people with air conditioning units use them longer into the season. This in turn, if they are powered by fossil fuels, adds even more heat-trapping greenhouse gases to the atmosphere.

Wildlife is also feeling the effects of a warming fall. The timing of when fruits ripen, for example, is being skewed from its “normal schedule”. In turn, this is impacting the once well-synced patterns of animal behaviors such as bird migration and hibernation.

Looking ahead, as greenhouse gas emissions continue to increase, so too will the temperature and its associated impacts.

Credit: Climate Central

Summer Nights are Getting Warmer Across the US

Summer is the time of year when warm temperatures are expected. As our climate changes, however, the season is getting even hotter, especially at night.

Since 2010, according to NOAA, there have been 34% more record-warm low temperatures set than record-warm high temperatures. Nationally, summertime lows have increased an average of 1.8°F since 1895, according to an analysis by Climate Central, a nonprofit science news organization. The southwestern part of the country has seen the greatest warming, with Reno and Las Vegas, Nevada showing an increase of 16.9°F and 9.1°F respectively. Not far behind are El Paso, Texas at 7.7°F and Salt Lake City, Utah at 6.6°F.

In addition to climate change, land use issues also play a role in our warming nights. Paved surfaces hold more heat than vegetated ones, so cities tend to be hotter than rural areas, particularly during the overnight hours. This is known as the urban heat island effect.

When temperatures do not significantly cool off at night, people do not get a chance to recover from the heat of the day. This can cause serious health concerns, especially for young children, the sick, and the elderly. Warmer nights also drive up energy bills, as people with air conditioning units use them more. This in turn, if they are powered by fossil fuels, adds even more greenhouse gases to the atmosphere.

Credit: Climate Central

Hurricane Barry Makes Landfall in Louisiana, Soaking Gulf Coast

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

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

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

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

May 2019: Second Wettest Month on Record for US

When it rains, it pours! This old adage was proven to be true last month. With national weather data dating back to 1895, May 2019 was the second wettest month ever recorded in the contiguous United States. Only May 2015 was wetter.

According to NOAA, an average of 4.41 inches of rain fell across the lower 48 states, which is 1.50 inches above average. Heavy precipitation was reported from the West Coast through the Mid-West, and into parts of the Northeast. Kansas, Nebraska, and Missouri each experienced their wettest May on record.

This relentless rain caused deadly and destructive flooding in several states along the Arkansas, Missouri, and Mississippi Rivers.

While there were a number of factors that contributed to May’s excessive rainfall, including El Nino, climate change also likely played a part.  As the National Climate Assessment points out, heavy precipitation events are increasing in both frequency and intensity across the United States as the atmosphere warms.

As greenhouse gases heat the atmosphere, the air is able to hold more water vapor. More specifically, according to the Clausius–Clapeyron relation, for every increase of 1°F, the saturation level of the atmosphere increases by about 4%. In other words, warmer temperatures lead to more evaporation from oceans, rivers, and lakes, and therefore more water vapor is available to condense and fall as precipitation.

Sadly, with our global temperature continuing to rise, experts say we should expect to see more extreme rain and flooding events in the future.

Credit: NOAA

Names for the 2019 Atlantic Hurricane Season

Today is the first day of the 2019 Atlantic Hurricane Season. Although one named storm, Andrea, already formed, the season officially runs from June 1 to November 30.

Since 1950, each tropical storm or hurricane to form in the Atlantic has been given a unique name. They come from a set of six rotating lists produced by the World Meteorological Organization. A name is retired only when a storm was particularly noteworthy – causing a large number of fatalities or an extraordinary amount of damage.

Some notable retired names include:  Harvey, Irma, Katrina, Maria, Michael, and Sandy. The names for this year’s storms are listed below.

Credit: NOAA

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.

Spring is Heating Up

Spring is a transitional season. It is a time when the chill of winter fades away and the warmth of summer gradually returns. But, as our climate changes, the season is heating up.

Across the contiguous United States, spring temperatures have increased an average of more than 2°F over the past fifty years, according to Climate Central. The southwest part of the country has seen the fastest seasonal increase, with Las Vegas, NV and Tucson, AZ warming more than 6°F since 1970.

Warming temperatures mean more frost-free days. While this may lengthen the growing season for some crops, it also extends the allergy season and allows pests like mosquitos and ticks to live and thrive longer.

Looking ahead, if greenhouse gas emissions continue to rise, scientists say spring could arrive at least two weeks earlier by 2050 compared to recent years.

After Review Hurricane Michael Upgraded to Rare Category-5 Status

Hurricane Michael, which pummeled the Florida panhandle in October, has been upgraded from a category-4 to a category-5 storm, the strongest on the Saffir-Simpson scale.

According to a report by the National Hurricane Center, the storm’s winds reached 160mph when it made landfall near Mexico Beach, FL. That is a 5mph increase from the estimate used last autumn. The agency says the uptick was the result of a re-analysis of reams of data, including aircraft winds, surface winds, surface pressures, satellite intensity estimates, and Doppler radar velocities.  The review also took into account data that was not available in real time.

In the grand scheme of things, an increase of 5mph may not sounds like a lot, but it puts Michael in rare company. It now ranks as the fourth category-5 storm on record to make landfall in the US. The other three were the Labor Day Hurricane of 1935, Hurricane Camille in 1969, and Hurricane Andrew in 1992. Michael is also the third cat-5 storm to hit the Sunshine state.

Regardless of the technical upgrade and historic statistics, Hurricane Michael was a devastating storm that will be long remembered by those it affected. The storm claimed the lives of 16 people and caused an estimated $25 billion in damage. More than six months after coming ashore, much of the area is still recovering.

Hurricane Michael making landfall as a Category 5 storm along the Florida Panhandle on October 10, 2018. Credit: NOAA