Our global temperature continued its upward trend last month with October 2015 marking the warmest October ever recorded for the entire 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 58.86°F, which is a whopping 1.76°F above the 20th century average. It surpassed the previous record set in October 2014 by 0.36°F. It also marked the highest departure from average for any month on record, eclipsing the previous record set just last month. October was also the sixth consecutive month this year to break a monthly temperature record.
Although strong El Niño conditions – a natural climate phenomena that boosts oceanic and atmospheric temperatures – helped fuel October’s record warmth, it does not tell the whole story. The long-term trend of human-caused climate change was also a key factor. NOAA reports that fourteen of the fifteen warmest years on record have occurred since 2000 and they were not all El Niño years.
While heat dominated most of the planet last month, some places were particularly warm, including most of Australia and North America. Here in the contiguous United States, with an average temperature of 57.4°F, it was our fourth warmest October on record and the warmest since 1963.
Year to date, the first ten months of 2015 were the warmest of any year on record. This strengthens the likelihood that 2015 will surpass 2014 as the Earth’s warmest year ever recorded. Global temperature records date back to 1880.
On Thursday, I was asked to appear on the Weather Channel’s new show, Weather Underground TV (WUTV). As a personal weather station owner, we discussed the recent dramatic temperature fluctuations in the northeast, thoughts about the upcoming winter season, and even touched on climate. It went very quickly, but it was a great experience!
The show, co-hosted by Mike Bettes and Sarah Dillingham, covers breaking weather news, but also dives into the science behind the weather and the challenges of forecasting. With a bevy of experts from both the Weather Channel and Weather Underground on tap to discuss the topics of the day, the two-hour program is always interesting. Simply put, it is must see TV for anyone interested in the “why’s” and “’how’s” of weather.
Weather Gamut writer, Melissa Fleming, talks with Sarah Dillingham on WUTV, October 29, 2015
Bouncing between the extremes of drought and flood, the weather whiplash in Texas continued this weekend. For the second time this year, torrential rain caused widespread flooding across the Lone Star State.
The city of Corsicana, south of Dallas, saw more than 18 inches of rain between Friday and Saturday. Flash floods caused extensive damage and even derailed a Union Pacific freight train. In Houston, where they received 8 inches of rain on Saturday and Sunday, bayous swelled out of their banks and flooded roadways. Local officials say Buffalo Bayou near the downtown area rose 20 feet in just 12 hours.
The cause of this prolonged rain event involved the interaction of a few key atmospheric players. First, an area of high pressure over the east coast – with a clockwise circulation – pushed tropical moisture across the Gulf of Mexico and into Texas. Then, there was a strong upper level low – with a counter clockwise circulation – over the southwest and a cold front moving southeast. These added lift to the atmosphere. When the warm saturated air was forced to rise, it cooled. Since cool air holds less moisture than warm air, the moisture was wrung out of the atmosphere in the form of intense rain. Then, on the heels of all that, remnants of Hurricane Patricia from the Pacific Ocean traveled across Mexico and into Texas. It brought even more tropical moisture into the mix.
Ironically, much of Texas was in a drought just last week. It was considered a “flash drought” as it developed very quickly this summer after intense rains and catastrophic flooding in May brought the previous drought to an abrupt end. From drought to flood to drought and back to flood, Texas certainly has had a wild ride with weather this year.
Freight train derailed by flood waters near Corsicana, TX. Credit: NBC News
This autumn season has been marked by a number of intense rain and flooding events across the US, from South Carolina to California. Drought, however, continues to plague large sections of this country.
According to the latest report from the US Drought monitor, 58.96% of the nation is in some form of drought. Many areas in the mid-west and the northeast are listed as abnormally dry or experiencing moderate drought. But, it is the western and southern states that have been particularly dry.
In California, despite some unusually heavy rain recently, the long-term drought continues. In fact, 99.86% of the state is experiencing conditions of moderate drought or worse, with 46% in exceptional drought – the worst possible category. These extremely parched conditions have helped fuel an explosive wildfire season across the Golden State.
As discussed in an earlier post, the multi-year drought in Texas came to an abrupt end this past spring with intense rainfall and catastrophic flooding across the region. Over the summer, however, drought conditions returned. Developing fairly quickly, this is known as a flash drought. As of this week, 65.25% of the massive Lone Star State is in some form of drought and 21.40% is in extreme drought. That is serious weather whiplash!
The Drought Monitor is a weekly publication produced by a partnership of government agencies, including the National Drought Mitigation Center, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration.
Our global temperature continued its upward trend last month with September 2015 marking the warmest September ever recorded for the entire planet.
According to a report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for the month – over both land and sea surfaces – was 60.62°F, which is 1.62°F above the 20th century average. It surpassed the previous record set just last year by 0.19°F and marked the highest departure from average for any month on record. September was also the fifth consecutive month this year to break a monthly temperature record.
Although strong El Niño conditions – a natural climate phenomena that boosts oceanic and atmospheric temperatures – helped fuel September’s record warmth, it does not tell the whole story. The long-term trend of human-caused climate change was also a key factor. NOAA reports that fourteen of the fifteen warmest years on record have occurred since 2000 and they were not all El Niño years. This September, the globally averaged sea surface temperature was 1.46°F above the 20th century average of 61.1°F. That is the highest temperature departure for any September on record. And, as NOAA points out, “This departure from average is also 0.45°F higher than the global ocean temperature for September 1997, when the last strong El Niño occurred.”
While heat dominated most of the planet last month, some places were particularly warm, including most of North America. Here in the contiguous United States, it was our second warmest September on record. With a monthly temperature of 68.5°F, which is 3.7°F above the long-term norm, only September 1998 was warmer. In fact, most of the lower forty-eight states experienced exceptionally warm conditions and nine – Connecticut, Colorado, Maine, Michigan, Minnesota, New Mexico, Rhode Island, Utah, and Wisconsin – were record warm.
Year to date, the first nine months of 2015 were the warmest of any year on record. That puts 2015 well on track to becoming Earth’s warmest year ever recorded. Global temperature records date back to 1880.
Powerful, but slow moving, thunderstorms brought heavy rain to the mountainous region of northern Los Angeles County, California on Thursday afternoon. With the soil hardened from years of drought, the water ran off downhill and unleashed flashfloods and mudslides across the area.
Local officials say the mud – up to 5 feet deep in some spots – trapped hundreds of motorists in their vehicles on Interstate-5 and Route 58. Homes in the Elizabeth Lake area were also surrounded by mud and debris flows. Luckily, no fatalities have been reported.
According to the NWS, Antelope Valley, which sits between I-5 and Rt. 58, received 1.81 inches of rain in 30 minutes. They have described that as a “1,000 year rain event”, which means there is a 1-in-1,000 (0.1%) chance of this type of event happening in any given year. It is interesting to note that this is the second “1,000 year rain event” to happen in the US this month. The other was the historic flooding in South Carolina.
The intensity of this California deluge had two main drivers. The first was a cut-off low-pressure system over the area that provided lift. The second involved the warmer than normal sea surface temperatures in the Pacific Ocean, which allow for increased amounts of evaporation and higher levels of humidity. Combined, these two factors were able to generate enough instability in the atmosphere to produce heavy thunderstorms.
While experts say this storm was not related to El Niño, it does offer a glimpse of what may be in store for the Southwest over the next few months. The impacts of El Niño are typically strongest during the winter season.
Vehicles stuck in the mud along California’s Rt. 58. Credit: Caltrans/EPA
Relentless rain unleashed catastrophic flooding across South Carolina this past weekend. Officials say it was one of the worst disasters in the state’s history.
According to the NWS, an estimated 5.8 trillion gallons of water fell in the Palmetto state in just four days with some communities receiving more than 20 inches of rain. This storm total exceeds that of any tropical cyclone on record that has impacted South Carolina.
Receiving this massive amount of precipitation in such a short period of time overwhelmed rivers and streams, and even caused a number of dams to breach. The floodwaters inundated homes, businesses, and shut down major roadways, including parts of Interstate-95. Local officials say the storm also caused water mains to break, leaving more than 40,000 people without drinkable water. To date, seventeen weather-related deaths have been reported across the state.
This type of rainfall is considered a one in thousand year event in South Carolina. That does not mean it can only happen once every thousand years. It refers to the recurrence interval – a statistical calculation that means an event has a one in one thousand chance (0.1%) of happening in any given year in a given location.
The cause of this widespread and destructive flooding was the unique convergence of three different weather systems that essentially set up an atmospheric river – a fire hose of moisture – aimed directly at South Carolina. The first was Hurricane Joaquin, which sat over the Bahamas for days and pumped huge amounts of moisture into the atmosphere. The second was an upper level low-pressure area over the southeastern US and Gulf of Mexico. It helped pull some of Joaquin’s moisture westward toward the US coastline. And lastly, there was a stalled frontal boundary along the coast. When the warm saturated air encountered the cooler air along the front, it was forced to rise and cool. Since cool air holds less moisture than warm air, the moisture was wrung out of the atmosphere in the form of intense rain over the same area for days.
Although the rain has now cleared, South Carolina is not out of the woods just yet. As swollen rivers make their way to the Atlantic, more flooding is expected in the state’s coastal low country.
Many things in nature are adapted to certain climate conditions. That said, some are choosier than others. Giant Sequoia trees, the largest living organisms on the planet, need a “Goldilocks” type of environment to grow and reproduce. Visiting Sequoia National Park recently, I had the opportunity to learn more about the climate requirements of these amazing trees.
Needing conditions that are not too hot and not too cold, as well as not too wet and not too dry, Giant Sequoias grow naturally in only one place on Earth. That unique place is a narrow band about 70-miles long on the western slopes of California’s Sierra Nevada Mountains known as the Sequoia Belt. According to the National Park Service (NPS), these trees only grow at elevations between 5,000 and 7,500 feet. Temperatures above 7,500 feet are usually too cold and conditions below 5,000 feet are too dry. Within this limited range, about 75 groves reveal where conditions for the massive trees are just right.
These ideal conditions are produced by a combination of weather and topography. When moisture-laden air from the Pacific runs into the Sierras, it rises and cools. On average, it cools about 3.6°F for every 1000 feet it rises. Since cooler air holds less moisture than warm air, the moisture is dropped as rain and snow over the mountains with precipitation amounts generally increasing with elevation. While California is in the midst of a multi-year drought, the NPS says the area around Giant Forest (elevation 6400 feet) usually gets an average of 44 inches of precipitation a year. It also typically sees only one day a year with temperatures below 10°F.
Compared to other sites within a five mile radius, the average conditions in Giant Forest are perfect for the giant sequoias. Upslope, Emerald Lake (elevation 9200 feet) gets 59 inches in average annual precipitation and sees around ten days a year with temperatures below 10°F. Downslope, Ash Mountain (elevation 1700 feet), only sees about 26 inches of precipitation a year and the temperature reportedly never falls below 10°F.
Given the narrow natural range in which these giant trees are able to thrive, they face serious challenges from climate change. As temperatures increase, more precipitation is coming down in the form of rain instead of snow. This reduces the snowpack and the subsequent spring and summer melt water available to the trees during the region’s dry season. While the resilient mature sequoias – some are over 3000 years old – are not in immediate danger, researchers say these big trees were not made to withstand decades of drought. The younger trees – seedlings and saplings – on the other hand, face a more difficult struggle for survival. The drier conditions make it harder for them to develop robust root systems and also leave them more susceptible to wildfires, which are projected to increase.
Given the impressive age of some of these trees, they must have endured natural climate fluctuations in the past. This time, however, the human caused change is happening very quickly and is forecast to produce conditions unfamiliar to even these ancient giants. According to the US National Climate Assessment, the southwest – which includes California – is normally the hottest and driest part of the country, but climate change is making it even more so. The report shows that 2001 through 2010 was the region’s warmest decade on record with temperatures almost 2°F above historic averages. Looking ahead, it projects continued increases in average annual temperature and a decrease in precipitation. In the meantime, scientists continue to monitor and research the giant sequoias to better understand how they will react to our changing climate and to offer informed recommendations to evolving conservation strategies.
Below is a short video by The Redwoods and Climate Change Initiative (RCCI) on the impact of extended drought on Giant Sequoias. Oh, and in case you were wondering, Giant Sequoias (sequoiadendron giganteum) and Coastal Redwoods (sequoia sempervirens) are closely related, but are two different species.
Situated high is California’s Sierra Nevada Mountains, Sequoia National Park protects the only place on Earth where giant sequoias – the world’s largest trees by volume – grow naturally. Air pollution, however, does not recognize the boundaries set up by the National Park Service (NPS). While hiking there recently, I learned more about the air quality issues facing this national natural treasure.
According to a recent report by the National Parks Conservation Association, Sequoia National Park received an “F” for air quality. While other parks in the NPS system also have air quality concerns, Sequoia NP was rated the worst in the nation. In 2014, its Ash Mountain monitoring station recorded 56 days where the level of ozone was above federal health standards.
In most parts of the country, air quality issues are often connected to emissions from coal-fired power plants, but in California there are a few other factors at play. While the region’s notorious wildfires do create some air quality problems, the NPS says the vast majority of the pollution in the park comes from human activities outside its borders. With a prevailing westerly wind in the region during the summer months, emissions from large-scale industrial and agricultural activities as well as massive amounts of vehicle exhaust are swept eastward from San Francisco and across the San Joaquin Valley. Trapped by the topography of the valley, the polluted air is heated and forced to rise up to the elevation of the park. Pollutants found in the air include nitrogen oxides, ground level ozone, fine particulate matter, and traces of pesticides.
Of these pollutants, ground level ozone, which forms when nitrogen oxides react with heat and U.V. light, poses the most serious threat to human health. It is known to cause a variety of repository problems and is often the reason given for air quality alerts. It is also harmful to plants and trees – the organisms that are supposed to be protected by the park.
While ozone does not seem to be impacting mature sequoias, the NPS says experiments have shown that it is stunting the growth of sequoia seedlings. That said, other trees in the park, such as Ponderosa and Jeffrey Pines are feeling its full effect. Damaging their stomata – tiny pores on their needles that usually absorb carbon dioxide -the pollutant reduces a tree’s ability to perform photosynthesis and therefore its ability to produce and store food. As a result, they are weakened and more susceptible to disease and insects. The telltale sign of ozone damage is the yellowing and thinning of a conifer’s needles.
Air pollution is also responsible for the smog that obscures views in the park. On a clear day, according the NPS, the view from Beetle Rock – which is about 6,200 feet above sea level – extends for more than 100 miles. In summer, when the smog is worst, that view is often significantly reduced.
The good news is that air quality issues in the park – like much of the rest of the country – have improved in recent years as a result of measures associated with the Clean Air Act. The bad news is that it still remains a serious problem. Seeing that our actions can make a difference, we can continue to reduce air pollution by conserving energy and reducing emissions – a similar strategy to reducing the impacts of climate change.
A view looking southwest from the edge of Giant Forest in Sequoia National Park. Credit: NPS
For the continental U.S. as a whole, the hottest part of summer arrives in mid to late July. On the regional level, however, there are significant differences in the timing of the hottest part of the season.
Based on historical averages, NOAA’s National Centers for Environmental Information (NCEI) produced a map showing how the warmest days of summer vary across the country. The desert southwest, for example, is an early bloomer in terms of heat. It’s warmest days typically arrive in June. By early July, the North American Monsoon – a seasonal shift in wind direction – kicks in and helps keep the region relatively cool and rainy through September.
In parts of the south central states, a persistent area of high pressure typically builds over the region in August. This limits cloud formation and dries out the soil, which helps to send temperatures skyrocketing.
On the other far end of the spectrum, temperatures along the west coast do not peak until September. This lag is the result of hot air rising over interior deserts and cool Pacific air flowing in-land. By September, this upper-level wind pattern usually weakens and allows warm air to flow toward the coast.
While the NCEI map is derived from long-term climate averages, it is important to note that short-term variability can cause the date of peak temperatures to vary in any given year.
