27 12 2009
It has often been said that “Weather is not climate”, but ultimately it provides the only meaningful way to verify climate models. Did the climate models predict the cold, snowy weather which has been seen across much of the US?
According to NOAA, October was the third coldest on record in the US, with almost every state showing temperatures from one to ten degrees below normal. Some Parts of Colorado received record snowfall during October, starting the first week of the month.
Image from HPRCC – University of Nebraska at Lincoln
With a few days left, it appears that December is headed for a repeat, with temperatures ranging from one to fifteen degrees below normal. (Note that the color scale is different from October, now the greens show more negative departure, even South Texas is at -6F)
Image from HPRCC – University of Nebraska at Lincoln
Temperatures for the rest of the month are forecast by NCEP to be below normal for almost the entire country, so it is unlikely that the map will change much before New Years Day.
NCEP two week forecast
So let’s compare the complete Autumn temperatures vs. the forecasts from NOAA’s Climate Prediction Center. In August, CPC forecast that most of the US would have above normal temperatures from October through December, and perhaps more importantly did did not predict that any areas would have below normal temperatures.
NOAA CPC Autumn Forecast
As you can see below, their prediction was largely reversed from what has happened. Most of the country has seen below normal temperatures during the same period.
Image from HPRCC – University of Nebraska at Lincoln
So my question is – if the climate models can’t reliably predict the next three months, what basis do they have to claim their ability to forecast 100 years out? It is well known in the weather modeling community that beyond about three days, the models tend to break down due to chaos.
We have all heard lots of predictions of warmer winters, less snow, animal populations moving north, drought, dying ski resorts, etc. But did anyone in the climate modeling community forecast the cold, snowy start to winter which has occurred. If not, it would appear that their models are not mature enough to base policy decisions on.
On the other side of the pond, The Met Office forecast 2010 to be the warmest year ever, as they last did in 2007. On cue, the weather turned bitter cold immediately after the forecast and it appears that the unusally cold weather will continue at least through mid-January. As in 2007, the Met office 2010 forecast is not getting off to a good start:
http://wxmaps.org/pix/temp4.html