by Robert W. Endlich, December 18, 2018 in CAtmSciForum
In describing the errors in the Fourth National Climate Assessment, ‘NCA4’, I’ll use the words from the Executive Summary which purport to link climate changes in the USA to global climate change.
The first claim, “The last few years have also seen record-breaking, climate-related weather extremes,“ is shown to be false, simply by examining climate records, some from the National Climate Data Center.
Tornadoes have been decreasing over the past six decades as temperatures moderate from the significant cooling of the 1940s to 1970s. As a basic knowledge of meteorology teaches, it is the pole to equator temperature difference that drives the intensity of cold season storms and especially the spring-season storms which bring the extremely strong tornado outbreaks.
Figure 1. Annual count of strong to violent tornadoes from 1954-2014, showing a significant decrease of tornado activity the past 60 years, based on data from NOAAs Storm Prediction Center. [Note: This graphic replaces the original graphic that showed all tornadoes EF1 and stronger. Correction made 1/25/2019].
by Charles the moderator, May 29, 2019 in WUWT
By Roy Spencer | Fox News
Progressive politicians like Al Gore, Sen. Bernie Sanders, I-Vt., and Rep. Alexandria Ocasio-Cortez, D.N.Y., don’t hesitate to blame any kind of severe weather – even if it is decreasing over time – on global warming.
With the devastating Dayton, Ohio tornadoes fresh on our minds, it is useful to examine exactly why (modest) global warming has produced fewer – not more – of such events.
The simple answer is that tornado formation requires unusually cool air.
Very few thunderstorms produce tornadoes. In the hot and humid tropics, they are virtually unheard of. The reason why is that (unlike hurricanes) tornadoes require strong wind shear, which means wind speed increasing and changing direction with height in the lower atmosphere.
These conditions exist only when a cool air mass collides with a warm air mass. And the perfect conditions for this have existed this year as winter has refused to lose its grip on the western United States. So far for the month of May 2019, the average temperature across the U.S. is close to 2 degrees Fahrenheit below normal.
by Charles the moderator, December 27 2018 in WUWT
From LMT Online
In the whirlwind that is 2018, there has been a notable lack of high-end twisters.
We’re now days away from this becoming the first year in the modern record with no violent tornadoes touching down in the United States. Violent tornadoes are the strongest on a 0 to 5 scale, or those ranked EF4 or EF5.
It was a quiet year for tornadoes overall, with below normal numbers most months. Unless you’re a storm chaser, this is not bad news. The low tornado count is undoubtedly a big part of the reason the 10 tornado deaths in 2018 is also vying to be a record low.
While we still have several days to go in 2018, and some severe weather is likely across the South to close it out, odds favor the country making it the rest of the way without a violent tornado.
If and when that happens, it will be the first time since the modern record began in 1950.