Mike's Weather Blog Archive: September 2010

The recent hot and dry weather created severe fire danger conditions over Colorado, with two damaging fires along the Front Range. Are we looking at more severe wildfire seasons in the future in Colorado? In the short term, there is little moisture in the forecast for Colorado. The summer monsoon was cut off in late July as the sea surface temperatures cooled in the Equatorial Pacific. This cooling is the result of the developing La Nina pattern in the Pacific. La Nina tends to weaken the monsoon flow of moisture in the late summer and may well lead to a rather windy and dry winter along the Front Range of Colorado. Here is a great link for more information about La Nina.

Monday September 27th, join me at the downtown Denver REI store for a very informative seminar about Climate Change and Colorado. The event is being hosted by Colorado State University and will feature several excellent speakers. Click here to learn more about the event and to sign up as space is limited.

There is a great deal of concern about our changing climate in Colorado, but the concern is high around the world. Here is a link to a recent article in the New York Times about the changing ocean temperatures and how they are impacting coral reefs.

The majority of climate scientists are in agreement that the overall warming of the planet (about 1.4 degrees Farhenheit since 1900), has been caused in part by mankind. This warming is due to the increase of so called "greenhouse gases" - such as CO2, methane and CFCs (chloro-fluorocarbons). These gases absorb outgoing heat from our planet and "reflect" it back to Earth. When this happens, energy from the Sun is trapped in our atmosphere and warms our climate.

As often noted, the Greenhouse Effect is normal and natural, in fact if not for this effect, the Earth would be about 60 degrees Farenheit colder - a lifeless ice planet. The problem we face is that the delicate balance of temperature may be upset by a change in atmospheric chemistry. In the past 200 years (since the Industrial Revolution) the increased burning of fossil fuels has released vast amounts of carbon dioxide into the atmosphere. The concentration of CO2 has risen about 25% in the past two centuries from 280 parts per million to over 385 parts per million. Human activity releases about seven billion metric tons of carbon dioxide into the air every year - adding to the 750 billion metric tons that are already there. Of the 7 billion tons, only about three billion tons stays in the atmosphere; the rest is absorbed by plants and the oceans. This "carbon sink" capacity complicates the issue of global warming, because the oceans have had a vast holding capacity for CO2. The oceans are becoming more acidic, however, and there is concern that this carbon sink capacity may reach a limit.

Some scientists feel that the increase in atmospheric CO2 will be offset by the ability of plants and the oceans to absorb this gas. In fact, some experts believe that the increase in CO2 will be a good thing - improving crop yields and making more parts of the world able to support crops. At the same time, others worry that warming will cause more severe droughts in key agricultural areas. In addition, which plants will benefit most - will it be useful crops, or weeds!

The issue is not a simple one because we must use computer models to predict future climate. These models are very complicated and must be run on a supercomputer. Even with today's technology, we cannot perfectly model something as complex as our atmosphere, so the models are simplified and do have errors. One of the undisputable facts is "we cannot even predict tomorrow's weather with 100% accuracy, how can we expect to predict the weather for the next 100 years! Of course, we are not attempting to forecast day to day weather that far in advance, just trends. There is no way to run an actual atmospheric simulation of the changes to come as we only have this one Earth - there isn't another similar planet nearby to run actual experiments.

My opinion is that we are indeed having an impact on the warming our climate, and this effect is riding along side of a naturally occurring warm period. It is very important that we study this topic with even greater effort in order to be able to take action for the future. This action may well be to use technology to bring ever increasing efficiencies to our society. Through a more efficient use of our fuels, we will be able to limit the amount of greenhouse gases released, while still enabling our complex technological society to function and thrive.

We will need every bit of cooperation from all sides to truly solve the energy/environment issues that face us in the coming decades. I doubt that we will come to terms with reducing carbon emissions, the population growth alone will preclude that. In addition, the growing 3rd world does not want to live in a hut with one light bulb, they want the same things we enjoy.

Where will we get the energy? Fossil fuels are amazing, but the demand will only soar. We are tranferring so much wealth to other countries and there is no way that we could ever domestically replace what we must import. From a national economic and security point alone, we have to widen our energy portfolio. Wouldn't it be great to be able to tell OPEC, Russia, Venezuela that "we really don't need your oil".

Granted, we get much of our oil from Canada and some other "friendlier" nations, but it is a fungible commodity - that world oil price is still enriching the Middle East and that puts the U.S. in a position of weakness.

I am not opposed to coal - but we must burn it better, nuclear, natural gas, wind, solar. We need it all and we need to invest in a smarter grid.

I hate for America to not be at the energy forefront in the 21st Century. We can lead the world with better and cleaner ways to make power, we have done it before with major endevours. The Transcontinental Railroad in the 1880s, the Manhatten Project, The Interstate Highways, The Space Program, the Computer Revolution.

Instead of bowing down to special interests, we must, for our heirs, do the right things. To paraphrase JFK, "not because they are easy, but because they are hard."

Early Autumn is normally a dry period for Colorado, and it does not appear as though we will see very much rain or snow in our forecast for the next few weeks. Click here for more information about our extended outlook.

Here is a link to our average Autumn weather in the Denver area:

Denver Climate Page

To see our average annual weather information in the Denver area, click this link: Climate Information for Denver

La Nina is defined as cooler than normal sea-surface temperatures in the central and eastern tropical Pacific ocean. This change in temperature can impact global weather patterns as it changes the energy budget in the tropical atmosphere. La Niña conditions recur every few years and can persist for as long as two years

The end of the recent El Nino in the Pacific early this summer was expected as the warmer than normal sea surface conditions during last winter and spring had been weakening during the past few months. This may have resulted in a slightly drier monsoon season over Colorado this summer, although El Nino is more of a climate forcing mechanism in the cold season than during the summer months. To learn much more about various forcing mechanisms in our climate, try this new website!

Climate Information From NOAA

La Nina tends to favor more tropical storm activity in the Atlantic, the Caribbean and the eastern Pacific, but there are many other factors involved. El Nino conditions tend to supress tropical development due to increased windspeeds in the subtropical jetstream. This tends to shear off the tops of developing hurricanes. For more information on tropical storms, here is the link to the National Hurricane Center

El Nino conditions tend to increase the jet stream energy from southwest to northeast - this tends to block really cold air into Canada, so our cold season temperatures often average a little milder than normal over the course of an El Nino winter. La Nina tends to increase the jetstream flow from the Pacific Northwest to the Southern Plains. During a La Nina fall and winter, Colorado trends toward windy conditions, with outbreaks of very strong winds along the Front Range. Because the average jet stream direction tends to come out of the northwest, some strong surges of cold air can be expected from time to time.

La Nina winter usually feature more storms moving in from the northwest, bringing heavy rain and snow to the Pacific Northwest, good snows on the Wasatch Mountains in Utah and some heavy snow from Steamboat into Summit County. La Nina winters tend to favor our northern and central mountain resorts with the heaviest snows - at the expense of the San Juans.

If you are an avid fan of our southwestern ski resorts, remember the Pacific Ocean is a huge place and the location of the cool pool of water can shift east and west by hundreds of miles. A shift in the location of the cool water has an impact on the jet stream patterns that eventually move over the United States. Each El Nino or La Nina seems to have it's own personality, so a shift in the location of the coolest water may have a big impact on the storm track over Colorado.

A good source for additional weather information is the National Weather Service page on El Nino and La Nina. You may also wish to check out the homepages for the Denver National Weather Service, the Colorado Climate Center and the Climate Predicition Center. The various addresses are listed as follows...

El Nino & La Nina

Denver National Weather Service

Colorado Climate Center

Climate Prediction Center