Weather charts to make you weak at the knees

From NOAA’s Storm Prediction Center


The black line is the cumulative average from 2005-2010. The red line shows the cumulative numbers from this year. See just how far out of normal this year is.  April was probably the most brutal month on record, taking 2011 from a relatively normal year to something out of bounds.

Here is another look at some tornado data. What it attempts to due is to remove some of the bias from tornado reporting – 50 years ago a lot of tornadoes occurred where no one was around to see them. Now, not so much. So they use some mathematical approaches to normalize all the years to a single year (2007), comparing each year’s difference from that reference year. This then allows them to create a chart where they can now show where the 75% and 25% curves are. That means 75% of the tornado counts in those years were less than the top line (yellow) and 25% were more than the bottom line (blue).

They also graphed the most extreme years high (red line) and low (pink). Now look at the result, with this year in black:

tornado 2

This year  started out as a normal year, right on the 50% line. But, since the end of March, it has moved off the trend line to become the most extreme year so far. For this year to return to normal, there would have to essentially be no more tornadoes the rest of the year. But even the weakest previous years had about 5-700 more tornadoes between now and December, so it seem very unlikely that this year will return to ‘normal’ at all. In fact, if it follows previous years, we are only about halfway through the total count.

2011 could become the most extreme year for next year’s charts.