I was watching NBC Dateline's Path of Destruction tonight, a program on the current outbreak of tornadoes with Brian Williams in Alabama. He was discussing the power of tornadoes with Jim Cantore of the Weather Channel. Williams ask Cantore, why are we seeing such powerful storm like we have never seen in a life time, we must be doing something to cause this. Cantore said that is getting warmer and the warming is juicing up the jet-stream, which is producing the stronger tornadoes.
What? I used to admire Jim Cantore, but once NBC bought the Weather Channel I began to question the accuracy of his analysis. He should know that it is the clash of cold air with the warm air coming from the Gulf of Mexico that causes tornado activity. Cold air is an essential element for the creation of tornadoes.
Here is what Dr Roy Spence had to say about this clash of air masses.
MORE Tornadoes from Global Warming? That’s a Joke, Right?
by Roy W. Spencer, Ph. D.
If there is one weather phenomenon global warming theory does NOT predict more of, it would be severe thunderstorms and tornadoes.Tornadic thunderstorms do not require tropical-type warmth. In fact, tornadoes are almost unheard of in the tropics, despite frequent thunderstorm activity.
Instead, tornadoes require strong wind shear (wind speed and direction changing rapidly with height in the lower atmosphere), the kind which develops when cold and warm air masses “collide”. Of course, other elements must be present, such as an unstable airmass and sufficient low-level humidity, but wind shear is the key. Strong warm advection (warm air riding up and over the cooler air mass, which is also what causes the strong wind shear) in advance of a low pressure area riding along the boundary between the two air masses is where these storms form.
But contrasting air mass temperatures is the key. Active tornado seasons in the U.S. are almost always due to unusually COOL air persisting over the Midwest and Ohio Valley longer than it normally does as we transition into spring.
For example, the poster child for active tornado seasons was the Superoutbreak of 1974, which was during globally cool conditions. This year, we are seeing much cooler than normal conditions through the corn belt, even delaying the planting schedule. Cool La Nina years seem to favor more tornadoes, and we are now coming out of a persistent La Nina. The global-average temperature has plummeted by about 1 deg. F in just one year.
It is well known that strong to violent tornado activity in the U.S. has decreased markedly since statistics began in the 1950s, which has also been a period of average warming. So, if anything, global warming causes FEWER tornado outbreaks…not more. In other words, more violent tornadoes would, if anything, be a sign of “global cooling”, not “global warming”.Anyone who claims more tornadoes are caused by global warming is either misinformed, pandering, or delusional.
As for Brian Williams claim of the strongest in a life time, here is a historical listing to violent tornadoe outbreaks from Watt Up With That:
Historically, there have been many tornado outbreaks that occurred well before climate change was on anyone’s radar. Here’s a few:
1908 Southeast tornado outbreak 324 fatalities, ≥1,720 injuries
1920 Palm Sunday tornado outbreak ≥380 fatalities, ≥1215 injuries
1925 Tri-State tornado ≥747 fatalities, ≥2298 injuries
1932 Deep South tornado outbreak ≥330 fatalities, 2145 injuries
1952 Arkansas-Tennessee tornado outbreak 208 fatalities
1965 Palm Sunday tornado outbreak 256 fatalities
April 3-4 1974 Super Outbreak 315 fatalities
You would think that professional meteorologist Jim Cantore would know about this historic tornado activity and set Brian Williams straight. Or, maybe that would not have fit the NBC global warming template.
Update (05-01-11, 11:45) NBC’s Brian Williams tries to tie recent tornadoes to global warming … again
The Daily Caller has video evidence that Brian Williams has tried several times to tie recent tornadoes to global warming. Details here. The Caller also notes:
Although that seems like a harmless-enough question, late last year it was reported General Electric (GE), a stakeholder in Williams’ parent company NBC Universal, received $24.9 million in grants, much of it tied to so-called green energy technology, from the $800-billion stimulus President Barack Obama signed into law in 2009. Therefore, establishing such a link could serve in in GE’s interest some argue.