Mike's Blog Archive: August 2009

With August winding down and the weather on a rare string of quiet days, the time is finally available to look back and take stock after one of the busiest severe weather seasons in Colorado history.

Tornadoes, hail, heavy rains, high winds... they all played havoc with the city over the last several months. Insurance agencies across the state recorded some of the highest insurance claim totals ever for a single summer.

With all the events, its hard to go back and list them all, but two will stand out for years to come for Denver-area residents.

On the afternoon of Sunday, June 7, several tornadoes touched down across the metro area. The biggest, most notable of them was in southeast Denver and hit the Southlands Mall. This tornado was rated EF-1 from the damage it did around the mall area. The storm responsible for this tornado also spawned several other weaker tornadoes east of town as the storm moved east along an outflow boundary.

Later in the summer, a very significant wind event occured in a rare nighttime storm over western Denver. Just after 10:30pm on July 20, a very strong thunderstorm rapidly developed just north of Arvada and tore south across the western suburbs of Denver doing extensive damage to trees and buildings along and west of Kipling from Arvada south into Lakewood. This storm was responsible for the second highest single storm damage totals in Colorado history. A couple of brief tornadoes were reported in Wheat Ridge, Englewood, and Castle Rock, but the majority of the damage was from straight line winds that likely reached speeds over 90 m.p.h.

Denver wasn't the only location in the state to get hammered this year. Not long after the Wheat Ridge storm, Pueblo took the brunt of a hailstorm that dropped baseball sized hail across the downtown area. Residents all across eastern Colorado had several episodes of heavy hail and tornadoes all throughout the late Spring and early summer.

Severe weather season is on the downhill side, however it is not out of the question to see a couple more events before cooler and quieter weather settles in. Tornadoes have occured in the Denver area as late as October, but the threat will typically subside in early September.

The severe weather of the summer kept our storm chasers very busy all season. Storm Chaser Tony Laubach tallied over 30,000 miles, two-dozen tornadoes, and enough hail to fill an ocean. He has kept a detailed log of his travels on his blog, and includes a very in-depth analysis of the July 20 storm which he chased. You can view his blog here. Storm Chasers Verne Carlson, Roger Hill, and Tim Samaras also kept extremely busy with the record severe weather year. You can check out all their adventures on their blogs linked above.

THERE ARE SEVERAL EVENTS COMING TO THE DENVER AREA THAT YOU SHOULD NOT MISS!

The 2009 Colorado Renewable Energy Conference - August 28-30 at the Colorado School of Mines in Golden - is fast approaching. This conference is open to the public and will include presentations on cleaner energy, sustainability, bio-fuels, photo voltaic and wind energy systems.

The keynote address will be given by Dr. Eric Barron - Director of The National Center for Atmospheric Research (NCAR). I will be the featured dinner speaker for the event.

The Conference web page is www.cres-energy.org/conference - with all of the most up-to-date Conference information.

HERE ARE SOME UPCOMING OPPORTUNITIES TO LEARN MORE ABOUT CLIMATE CHANGE

In preparation for the next UN Climate Change talks (COP15), the Danish Board of Technology and The Danish Cultural Institute are organizing a world-wide public deliberation about climate change and climate change policy. On September 26, 2009 - from sites in over 40 countries on every continent, citizens will deliberate and vote on some of the questions negotiated at COP15.

The idea is that because citizens of the world have to live with global warming and future climate policy, they should be consulted before political decision-makers negotiate at COP15. One of the US sites (there are five) is being sponsored by the Colorado School of Mines in Golden. Sandy Woodson, Division of Liberal Arts and International Studies Undergraduate Advisor and Senior Lecturer, is the Project Manager - according to Woodson, "we need 100 citizens who are demographically representative of the metro area and there is no better way to reach a large number of people than if you would announce this event."

The Danes have named this project "World Wide Views on Global Warming" (see www.wwviews.org), and the intention is to provide COP negotiators with our findings.

If you are interested in participating in this important event, please contact Sandy Woodson at (swoodson@mines.edu).

IMPORTANT UPCOMING EVENTS AT THE DENVER MUSEUM OF NATURE AND SCIENCE!

HERE ARE SOME FUTURE CLIMATE-RELATED EVENTS...

The Denver Museum of Nature & Science hopes to inspire critical thinkers who understand the lessons of the past and act as responsible stewards of the future. In support of this vision, the Museum offers a variety of adult programs that connect credible experts and scientists to popular science topics. The following programs and events relate to the topic of climate change.

GET TO KNOW YOUR ENERGY SOURCES

The average Colorado household uses 600 to 900 kilowatt-hours of electricity each month. This field trip takes participants along the Front Range to explore local sources for this energy. Stops include Cherokee Station in Denver, where low-sulfur coal is turned into energy; the new Vestas plant in Windsor, which manufactures 65-foot blades for wind turbines; Ponnequin Wind Farm in northern Colorado, the state’s first commercial wind factory; and New Belgium Brewery in Fort Collins, a pioneer in sustainability that is 90 percent wind-powered.

Field trip led by geologist Bob Raynolds, PhD, a research associate in the Museum’s Earth Sciences Department 8:30 a.m.–8:30 p.m. on September 9. $75 for members, $105 for nonmembers. Call 303.322.7009 for reservations

KENJI WILLIAMS PRESENTS "BELLA GAIA" (BEAUTIFUL EARTH)

Award-winning director and musician Kenji Williams presents Bella Gaia, a spectacular audio and visual journey around the world. The production is inspired by emotional response of astronauts after seeing the Earth from space. Experience a stunning simulation of the views from space—from fires in the Amazon to time-lapse images of the arctic ice melt—enhanced by Williams’ live classical violin performance.

Live musical performance with stunning visuals 8 p.m. on September 17, 18 and 19 $20 for members, $25 for nonmembers. Call 303.322.7009 for reservations

COLORADO AND CLIMATE CHANGE

This course evaluates global climate change and its impact on Colorado. Participants examine water resources, biodiversity, and the challenges associated with ongoing changes in the landscape.

Course and field trip led by geologist Bob Raynolds, PhD, a research associate in the Museum’s Earth Sciences Department 6:30–8:30 p.m. on Tuesdays and Thursdays, September 29 through October 8; all day on Saturday, October 10 $150 for members, $180 for nonmembers. Call 303.322.7009 for reservations

The Denver Museum of Nature & Science is the Rocky Mountain Region's leading resource for informal science education. A variety of engaging exhibits, discussions and activities help Museum visitors celebrate and understand the natural wonders of Colorado, Earth and the universe. The Museum is located at 2001 Colorado Blvd., Denver, CO, 80205. To learn more about the Museum, check www.dmns.org or call 303-322-7009.

SOME THOUGHTS AND COMMENTS ON OUR RECENT WEATHER AND OUR CHANGING CLIMATE

Many people have asked why we have had such a cool and wet summer and if it has anything to do with climate change. The basic answer is no - the wet summer of 2009 does not negate the long term outlook of hotter and drier weather for the west. The impact of man made climate change is on a very long time scale and cannot be assigned to any particular storm or short term weather event. We are having a wet summer because of the jetstream conditions this year. The winds aloft have been very active and have brought a greater than normal amount of thunderstorm activity to the Rocky Mountain region. Our soils are now full of moisture which lends itself to more evaporation and thus, more thunderstorms. It is a wet cycle, similar to when we get into a periodic drought cycle.

It is worth noting that not all of the western United States has had a cool, wet summer. In fact, the Pacific Northwest has had a very hot and dry summer, with extensive wildfire issues. This problem extends well into western Canada, where hundreds of thousands of acres have burned. Meanwhile, in the southwestern United States, Las Vegas just sweltered through their fourth hottest July on record.

The wet weather in Colorado has help refill our reservoirs and greatly decrease the need for urban irrigation. The cooler weather has also meant less need for air conditioning and thus a lower energy usage - all good news for this season. Over the long term, however, the increase in carbon dioxide and other "greenhouse" gases will mean a gradual warming of the annual temperature for the western United States in particular and the world in general. It is incorrect to try and correlate temperature trends over a matter of months or even a few years with the trends expected over the course of decades.

For more information about climate change and Colorado, please check out a copy of my book - THE COLORADO WEATHER ALMANAC. I cover this topic in much more thorough detail in chapter six of the book. THE COLORADO WEATHER ALMANAC is available at most local bookstores or you can search and order it from Amazon.com.

EL NINO AND LA NINA

One of the additional factors in our wet weather across Colorado and surrounding states has been the shift from a cool La Niña pattern in the Pacific to a warmer El Niño condition.

After three years, a fledgling El Niño has returned and is expected to last through this winter. The last El Niño was back in 2006 and while it brought drenching storms to the West Coast, Colorado didn't feel as many effects as it normally would. This new El Niño is still very weak, but it may still have a fairly profound impact on our weather in the coming months.

The term El Niño became familiar to the public's ear back in the early 1980s when a very strong El Niño event during the winter of 1982-1983 hit California with heavy, wet storms causing flooding and mudslides. El Niño typically occurs every two to five years and usually lasts for 12 months.

El Niño's impacts depend on a variety of factors such as the time of the year and how much the ocean temperature increases. This change in ocean temperature can cause a variety of effects. El Niño can suppress Atlantic hurricane activity, bring much needed winter precipitation to the arid Southwestern states, more mild winters in the North, and can decrease the risk of wildfires in Florida.

In Colorado, we typically see the most significant changes in the Southwest and Central Mountains where they tend to receive increased amounts of winter precipitation. On the Eastern Plains, the winters are usually more mild and the Spring has an increase in precipitation. In late summer, we often see an increase in monsoonal moisture giving us more storms through those dry months. Although in Autumn, El Niño is not usually very noticeable, although the big snowstorm in October of 1997 was during an El Niño year!

In a El Niño diagnostic discussion released recently by the NOAA National Weather Service Climate Prediction Center, scientists noted that eastern equatorial Pacific sea surface temperatures were at least 1.0 degree C above average at the end of June. From this, NOAA expects this El Niño event to continue developing over the next few months, with further strengthening possible.

According to Klaus Wolter of the University of Colorado- CIRES Climate Diagnostics Center NOAA-ESRL Physical Science Division, we have been under weak-to-moderate La Niña conditions since fall of 2008. These conditions continued through the winter keeping Colorado dry and mild. Over the past eight weeks, however, conditions have changed toward an El Niño pattern in the Pacific. The current status of the El Niño / La Niña pattern could be considered "neutral", as the transition takes place. Many Colorado observations from the past few decades indicate that a neutral condition brings more moisture to Colorado.

If you would like to see more information from Klaus Wolter and his Executive Summary check out the Earth System Research Laboratory Web page.

For more information on El Niño, you can check out NOAA's El Niño site at http://www.elnino.noaa.gov

CLIMATE CHANGE - A LESSON IN PHYSICAL AND POLITICAL SCIENCE

The topic of climate change has been given much political attention and in that light, there is a seemingly large controversy about what is happening and to what extent mankind is helping to cause some of the changes.

In the strict world of truly peer reviewed science, the degree of controversy is not as great as some politically driven organizations would have you believe.

There is an often quoted issue of 1997 being the warmest year and that global temperatures have cooled since that time. This information is misleading. In 1997, the world climate was influenced by one of the strongest El Nino events ever recorded. This pool of very warm Pacific Ocean water bumped global temperatures higher. At the present time, the Pacific is just emerging from a La Nina - cooler sea surface temperatures. These periodic warming and cooling episodes need to be taken into consideration in the the overall global temperature trend.

There is much discussion, especially on talk radio about the fact that the sun has by far the largest impact on our climate. The sun has certainly not been overlooked by the many experts worldwide that contributed to the most recent IPCC Assessment on climate. The periodic changes in solar output and the orbital changes are taken into account in the climate studies and modeling.

Another comment often heard is that CO2 is just a tiny fraction of the atmosphere. Just because CO2 is a trace gas does not mean that it is not important in the equation. Small amounts do matter - I weigh 200 pounds, but it certainly does not take 200 pounds of arsenic to kill me.

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.

In the Rocky Mountains, the long term impact of a warming of the climate will likely mean hotter, drier summers and milder, but still perhaps stormy winters. The amount of snowfall may drop on the plains, aside from infrequent major blizzards, while the mountains may see the snow levels and the tree level rise to higher elevations. The biggest worry that climate scientists have is that the weather will become more extreme - more heatwaves, drought, but also more flash floods and severe local storms. These events have always been with us, but the concern is that they will occur with greater regularity.

One of the best lines that I have heard about our climate and it’s unpredictability is that "climate is like an angry bear, we keep prodding and irritating it, and the results will likely be both severe and unpredictable".

Here are a few websites to check out.

www.globalwarming.org

www.epa.gov/globalwarming/

www.realclimate.org

http://www.noaanews.noaa.gov/stories2007/20071213_climateupdate.html

https://www.meted.ucar.edu/loginForm.php?urlPath=broadcastmet/climate&go_back_to=http%253A%252F%252Fwww.meted.ucar.edu%252Fbroadcastmet%252Fclimate%252Findex.htm#

During the course of this very busy storm season, I appreciate the many comments on our rather frequent television program interruptions due to the severe weather. We have had so much thunderstorm, hail and tornado activity lately, that we have had to break into programming much more often than usual and often for extended periods of time.

The storms have been quite severe over Colorado, with numerous reports of hail, lightning and tornadoes. In light of the Windsor Tornado in 2008 and the damaging tornado that touched down in southeast Aurora on June 6th and the major hail and wind storm over the western metro area on July 20th, many local residents, especially children, are very anxious about the weather.

In regard to a decision to cut to local weather coverage, instead of regular programming, we have had a number of viewers write in to express their feeling both ways. In general, when the storms are near that viewer's community, they are very grateful, but if the skies are not threatening overhead, it may seem to that viewer that we are going overboard on the coverage.

During the past several weeks, I have received quite a few e-mails from viewers that have tuned into 7News instead of the other local TV stations because that station was not covering the storm sufficiently. It can be a tough call, but especially after Windsor and the Holly Tornado in 2007, we want to make sure that all of our viewers get the latest information on these powerful and sometimes deadly storms.

The next few days look as though they will stay rather busy, with more thunderstorms likely across the Denver area and the eastern plains through Friday. A weak cold front will slide through the state FRiday night and that should bring in slightly cooler and drier air, lessening the chances for severe storms.

I am looking forward to this weather pattern settling down a bit, so that we can all better enjoy the more pleasant side of Colorado in the summertime as well as enjoy the regular programming on ABC.

After several very cool days, the weather pattern will return to much more typical mid summer form across Colorado. The chilly northwest flow in the upper atmosphere that brought October-like conditions to late July is shifting to a more westerly flow. Warmer air will shift back across the region through the first part of August and temperatures will bounce back to normal.

Drier weather will cover the region for Sunday through Tuesday, but by Wednesday there will be a return to thunderstorms as the "monsoon flow" is expected to develop across the southwestern United States. This should mean more thunderstorms and locally heavy rain in our forecast.

Many people have asked why we have had such a wet summer and if it has anything to do with climate change. The basic answer is no - the wet summer of 2009 does not negate the long term outlook of hotter and drier weather for the west. The impact of man made climate change is on a very long time scale and cannot be assigned to any particular storm or short term weather event. We are having a wet summer because of the jetstream conditions this year. The winds aloft have been very active and have brought a greater than normal amount of thunderstorm activity to the Rocky Mountain region. Our soils are now full of moisture which lends itself to more evaporation and thus, more thunderstorms. It is a wet cycle, similar to when we get into a periodic drought cycle.

The wet weather has help refill our reservoirs and greatly decrease the need for urban irrigation. The cooler weather has also meant less need for air conditioning and thus a lower energy usage - all good news for this season. Over the long term, however, the increase in carbon dioxide and other "greenhouse" gases will mean a gradual warming of the annual temperature for the western United States in particular and the world in general. It is incorrect to try and correlate temperature trends over a matter of months or even a few years with the trends expected over the course of decades.

For more information about climate change and Colorado, please check out a copy of my book - THE COLORADO WEATHER ALMANAC. I cover this topic in much more thorough detail in chapter six of the book. THE COLORADO WEATHER ALMANAC is available at most local bookstores or you can search and order it from Amazon.com.

One of the additional factors in our wet weather across Colorado and surrounding states has been the shift from a cool La Niña pattern in the Pacific to a warmer El Niño condition.

After three years, a fledgling El Niño has returned and is expected to last through this winter. The last El Niño was back in 2006 and while it brought drenching storms to the West Coast, Colorado didn't feel as many effects as it normally would. This new El Niño is still very weak, but it may still have a fairly profound impact on our weather in the coming months.

The next four to six weeks will likely continue to be rather wet across eastern Colorado and New Mexico as the El Niño tends to inspire a stronger flow on monsoon moisture into the southwestern United States. This may bring us heavy showers and thunderstorms through August.

The term El Niño became familiar to the public's ear back in the early 1980s when a very strong El Niño event during the winter of 1982-1983 hit California with heavy, wet storms causing flooding and mudslides. El Niño typically occurs every two to five years and usually lasts for 12 months.

El Niño's impacts depend on a variety of factors such as the time of the year and how much the ocean temperature increases. This change in ocean temperature can cause a variety of effects. El Niño can suppress Atlantic hurricane activity, bring much needed winter precipitation to the arid Southwestern states, more mild winters in the North, and can decrease the risk of wildfires in Florida.

In Colorado, we typically see the most significant changes in the Southwest and Central Mountains where they tend to receive increased amounts of winter precipitation. On the Eastern Plains, the winters are usually more mild and the Spring has an increase in precipitation. In late summer, we often see an increase in monsoonal moisture giving us more storms through those dry months. Although in Autumn, El Niño is not usually very noticeable, although the big snowstorm in October of 1997 was during an El Niño year!

In a El Niño diagnostic discussion released recently by the NOAA National Weather Service Climate Prediction Center, scientists noted that eastern equatorial Pacific sea surface temperatures were at least 1.0 degree C above average at the end of June. From this, NOAA expects this El Niño event to continue developing over the next few months, with further strengthening possible.

According to Klaus Wolter of the University of Colorado- CIRES Climate Diagnostics Center NOAA-ESRL Physical Science Division, we have been under weak-to-moderate La Niña conditions since fall of 2008. These conditions continued through the winter keeping Colorado dry and mild. Over the past eight weeks, however, conditions have changed toward an El Niño pattern in the Pacific. The current status of the El Niño / La Niña pattern could be considered "neutral", as the transition takes place. Many Colorado observations from the past few decades indicate that a neutral condition brings more moisture to Colorado.

If you would like to see more information from Klaus Wolter and his Executive Summary check out the Earth System Research Laboratory Web page.

For more information on El Niño, you can check out NOAA's El Niño site at http://www.elnino.noaa.gov

Print this article Back to Top