Joseph D’Aleo, CCM
This time of the year it has become traditional for practicing meteorologists to do attribution analysis for their clients regarding the outlook for surface temperatures, droughts, floods, hurricanes, tornadoes and wildfires. Most climate modelers attempt to try and connect these events with changes in CO2. Their climate models have failed and successful vulnerable industries have learned to trust forecasters that understand the true natural factors that actually impact the weather.
Nevertheless, you can expect that when major weather events do occur and most summers will see such events, the media and the climate alarmists will be quick to blame selected industries and fossil fuel production/use. From the information below it will be clear that rising Atmospheric CO2 levels are really irrelevant to the expected weather parameter outlooks.
SUMMER HEAT
Heat records have declined since the 1930s, which holds 22 of the state/territory hottest ever temperature records. There have been more record all-time lows than highs since the 1940s.
Here in the United States, the number of 100F, 95F and 90F days per year has been steadily declining since the 1930s. The Environmental Protection Agency Heat Wave Index confirms the 1930s as the hottest decade.
Source: EPA Heat Wave Index (Kunkel 2016)
James Hansen while at NASA in 1999 said about the U.S. temperature record “In the U.S. the warmest decade was the 1930s and the warmest year was 1934”. That is clearly evident here.
Despite year-to-year variability, trends show a downward trend for excessive daytime heat though nighttime temperatures have increased due to urbanization. Heat is enhanced during dry eras as we found in the dust bowl of the 1930s and the dry early 1950s.
Ocean temperatures affect where the summer warmth is usually focused. This year is a developing La Nina year. La Ninas tend to see warmth in the north central increase. This would suggest as the La Nina strengthens, the warmth would be greater late in the season.
Forecasters are watching warm water north of the cold La Nina tropical water, warm water may shift the normal La Nina warmth further west from the canonical La Nina locations as the latest European model shows.
Wherever dryness dominates (now in the southern high plains), the heat would be enhanced as we see most summers. It is clear that extremes of temperatures are related to natural factors.
HURRICANES
The 2010’s was the second quietest decade for landfalling hurricanes and major hurricanes since 1850.
Tropical storms develop in the subtropical Atlantic. When the ocean water there is warmer than normal, the chances that more of the disturbances moving west will develop into tropical storms or hurricanes are greater.
This year though colder water has developed to the north, it is warmer in the ‘Main Development Region’ (10-20N, 20-80W) and an active season is expected.
Hurricane experts like the late Dr. William Gray found that the Atlantic ocean temperatures which oscillate on a multi-decadal scale drive the warming and cooling in the subtropics and the activity of the hurricane seasons. The warm period 1950 to 1969 was compared to the cold period 1970 to 1987 for major hurricanes below.
See the long term cycle in in the unadjusted ocean data and how it relates to the number of storms and major storms that made landfall on the east coast.
Also as noted, a La Nina is developing and they tend to produce less eastern Pacific storms and less downstream high atmospheric wind shear in the Atlantic Basin that disrupts storms.
Based on these factors, Weatherbell Analytics believes we have an active season and an enhanced risk of a landfall on the Gulf and east coasts,
TORNADOES
This past decade was the quietest decade for tornadoes since tracking began in the 1950s.
It is now near the average of recent years after a burst of tornadoes in April.
La Ninas increase the contrast in temperatures and favor active seasons. This La Nina is coming on late however and a normal season in the end is the most likely outcome.
FLOODS AND DROUGHTS
NOAA has found no evidence of increased frequency of floods and droughts (the spring of 2019 had the smallest % of US in drought on record). After a very wet year for all but a small part of the northwest, the La Nina developing in 2020, tends to produce developing dryness in the central states and excessive rains in the southeast and east.
WILDFIRES
Wildfires cause havoc but were far more prevalent before the forest management, fire suppression and grazing of the 1900s. They are problems now because more have left the failing cities to move out of state or to the beauty of the foothills. The power lines to service them can spark new fires when the cold air rushes through the mountain passes this time of years downing trees onto the power lines.
In the modern era since 1996, the number of wildfires has decreased though the acres burned have increased slightly.
This La Nina year looks a lot like 2017.
2017 was an active fire season in the U.S. but by no means a record. The U.S. had 71,499 fires, the 12th most in 24 years and the most since 2012. The 10,026, 086 acres burned was the 2th most behind the drought year of 2015. The fires burned in the Northwest including Montana with a very dry summer then the action shifted south seasonally with the seasonal start of the wind events like Diablo in northern California and Santa Ana to the south.
Fires spread to northern California in October with an episode of the dry Diablo wind that blows from the east and then in December as strong and persistent Santa Ana winds and dry air triggered a round of large fires in Ventura County. According to the California Department of Forestry and Fire Protection the 2017 California wildfire season was the most destructive one on record with a total of 8,987 fires that burned 1,241,158 acres. It included five of the 20 most destructive wildland-urban interface fires in the state’s history.
90% of the fires are caused by humans though natural seasonal weather variations create conditions that are conducive to fires and the rapid spread of these fires west to increasingly populated areas. Human-caused fires result from campfires left unattended, the burning of debris, downed power lines, negligently discarded cigarettes and intentional acts of arson.
In the past, lightning and campfires caused most forest fires; today most are the result of power lines igniting trees. The power lines have increased proportionately with the population, so it can be reasoned that most of the damage from large wildfires in California is partially a result of increased population not Global Warming. The increased danger is also greatly aggravated by poor government forest management choices.
“In the United States, wildfires are also due in part to a failure to thin forests or remove dead and diseased trees”. In 2014, forestry professor David B. South of Auburn University testified to the U.S. Senate Environment and Public Works Committee that “data suggest that extremely large megafires were four-times more common before 1940,” adding that “we cannot reasonably say that anthropogenic global warming causes extremely large wildfires.” As he explained, “To attribute this human-caused increase in fire risk to carbon dioxide emissions is simply unscientific.”
Tropical Hot Spot Research 