Last September I wrote my first blog entitled "The Climate Dice Are Loaded", which was a piece intended to link the heat of the summer of 2010 with global warming. Over the last three decades there has certainly been a warming trend across the country, but on a seasonal time-frame below normal averages are still occurring. Such has been the case so far in 2011. At the end of the first blog I quipped "Stay tuned to TWC and keep note of averages at your location...and if you like cold temperatures let's see if you get lucky." Well, guess what? Those who like cold, snowy weather east of the Rockies did get lucky. The last two winters have seen a lot of cold, snowy weather in the East. Denialists can always point to each cold wave or snow storm as proof that anthropogenic global warming is not occurring. It's just variable "weather." But can denialists cling to the "It's Just Weather" argument for another decade or two? Ultimately, I know that the future of the planet's temperature trends the next couple of decades will be the key to winning or losing the global warming argument with the general population. Let's look at yet another set of statistics indicating that there is a warming trend.
Instead of looking at complicated graphs and charts of temperature averages and records, a simpler statistical way of looking at overall trends in the lower 48 states comes from The National Climatic Center's Climate at a Glance Site: http://www.ncdc.noaa.gov/oa/climate/research/cag3/cag3.html
Click on the following items once you get in the site in order to get individual monthly and yearly averages:
The site ranks months, seasons and years for the lower 48 states from values of 1 (coldest in recorded history) to 117 (warmest in recorded history). Rankings start with the year 1895. Each ranking is calculated using averages of surface temperature data recorded from approximately 5000 stations across the lower 48 states processed by the National Climatic Data Center. I've plotted the rankings on charts for the last 30 plus years for the purpose of this discussion. To make the charts easier to follow trends, I've color coded the warm months and years in red (those that have rankings above 69) and color coded the cold months and years in blue (those that have rankings below 48). The near average months are shaded in black (+ 10 or -- 10 from the average value of 58.5).
Notice after looking at the Climate at a Glance Site that as the years go by there is a lot more red rankings, particularly from the late 1990's to the present time.
Starting in December 1997 one can see that a vast majority of the months and years in the lower 48 states are red rankings. The last yearly blue ranking was in 1993, and the last black, or near neutral year, was in 1996. That trend has continued into this decade. Notice also that there have only been two instances when there were three consecutive monthly blue rankings since December 1997...from June 2004 through August 2004, which was a cool summer; and the most recent winter of 2010 to 2011.
Also notice that the trend of blue rankings being scattered haphazardly through the months of each year has not changed since the 1980's. There is no evidence, at all, that individual months such as January or August have a better chance of being blue. There is great debate, however, within the climatology community that future winters across North America maybe colder that average due to stronger negative North Atlantic Oscillations with the culprit being global warming given what has happened in the last couple of years. If that's the case, then the climate dice from December through February will be loaded for more blue rankings in the next several years. The climate dice are loaded towards red, overall, but the planet has not warmed enough for ALL of the individual months or seasons to rank above long term averages...at least not yet!
Last month the ranking was 116, meaning that August 2011 was the 2nd hottest August on record since 1895...enough to raise more than a few eyebrows among meteorologists and climatologists. The rankings on the charts are a compilation of the lower 48 individual state rankings and can be found at the following National Climatic Center address: http://www.ncdc.noaa.gov/sotc/national/
For example, the following charts show that the overall ranking of 116 for August 2011 is basically an average of all 48 states. Not all of the states were hot, but there were no states experiencing below average rankings.
So, if one was to do seasonal forecasts for the lower 48 states they MUST keep in mind how the climate has been behaving over the last thirty plus years; otherwise, there will be too much of a cold bias. A seasonal forecast that has a decent chance of verifying well will take into account the fact that temperatures have been above average since the 1970s's as well as a myriad of other factors such as ocean temperatures or the North Atlantic Oscillation.
It will be interesting to see how boreal autumn verifies this year across the continental U.S. If one was to forecast the coldest three months of fall in recorded history for the contiguous U.S. (the lower 48 states) the ranking numbers would be 1/1/1. The warmest three months of fall in recorded history would be 117/117/117. Boreal summer (JUN/JUL/AUG) verified as 92/114/116. The overall ranking for summer 2011 was 116 coming in second to the summer of 1936. The overall ranking for summer is not an average of June, July and August; rather a ranking compared to all other summers. You can follow the progress of each month since the National Climatic Data Center processes and reports the data for the prior month around the 10th at: http://lwf.ncdc.noaa.gov/sotc/national/
By no means am I an expert at seasonal forecasting, but the following are my "quick picks": I'm forecasting rankings of SEP/OCT/NOV of 75/68/32. It appears that September will be above average in the West with below average conditions in the East, while overall being above average. Conditions may cool into October due to some strengthening of a cold vortex which typically resides over Hudson Bay. We could see a cold November since by that point, looking at the charts, the lower 48 states will be "due" for a blue ranking. Monthly "streaks" of red rankings have lasted, on average, five to six months since December 1997. The overall ranking of boreal fall may well be above the average of 58.5. It is becoming increasingly difficult for the climate dice to land in the blue, or below average, level for an entire season across the continental U.S. due to global warming.
Well, I bet you can out-forecast me. If you wish, in the reply section to this blog (you will need to click the comments section highlighted in blue), enter your first name or a made up name, then forecast some "climate lottery picks" for autumn. I'll give everyone until midnight October 15th to make some picks. By that point in time, after following my instructions, you should be able to correctly pick the ranking for September. Also, you'll get up to a 15 day lead on me for the October forecast. I'll try to determine who the winner is by looking at all the posts shortly after December 10th. Shortly after December 15th, I'll give a short meteorological summary for each month explaining why each month of boreal fall verified red, blue or black on the post Climate Dice Three.
Well, continue studying how those climate dice are loaded and good luck making any picks!
Guy
