By Paul Homewood
While Hurricane Maria continues this year’s run of hurricanes, it is worth reading this Telegraph article from Sep 8th. It certainly makes a refreshing change from the wearying drivel written by Jillian Ambrose and co:
The destruction left by hurricanes Irma and Harvey has left many wondering why this year has been particularly bad for disastrous weather.
Harvey pummeled Texas, while Irma has been barrelling through the Carribbean and Bahamas, hurtling towards Florida.
Many thousands of homes have been destroyed and lives have been lost after the worst hurricanes seen for some years came in from the Atlantic Ocean.
The US expects hurricanes – they have a season of them every year – but not of this magnitude.
So why is it so bad? And can we expect more in the future? We asked scientists and other experts to explain.
What is causing these large hurricanes?
Julian Heming, the Met Office’s tropical prediction scientist, told The Telegraph about the reasons Irma is such a large hurricane.
"Irma is a powerful hurricane because all the characteristics required to produce an intense hurricane in the Atlantic are coinciding:
- Sea surface temperatures under Irma are 1 to 1.5°C higher than the average for this time of year providing abundant moisture and warmth.
- The wind shear (change in wind with height) is low, meaning air can flow in up and out of the hurricane very efficiently, thus promoting intensification.
- There are no drying influences at present, such as pockets of Saharan dust which sometimes drift out over the Atlantic.
- Irma is moving fast enough to prevent cool water up-welled under the hurricane from having any impact on the continued feed of warm, moist air into the hurricane.
- Up until now there has been no interaction with large land masses that might disrupt intensification due to cutting off the moisture supply."
The Met Office said that this is not totally unexpected and we have seen hurricanes of this magnitude in the past.
Mr Heming said: "It is worth pointing out that it is the peak of the hurricane season, so having hurricanes in this region now is not unexpected.
"Having three simultaneous hurricanes in the Atlantic region does not happen every year, but has been recorded several times before in the last 50 years: 1967, 1980, 1995, 1998, 2010.
"The North Atlantic hurricane season runs from June-November, with peak activity during August-October. During peak season around 96% of all Atlantic major hurricanes (categories 3, 4 and 5 on the Saffir-Simpson Hurricane wind scale) occur."
Unfortunately they then go on to spoilt it quoting the usual crooks.
They might instead have quoted some of the ample evidence that hurricanes are not becoming bigger or more powerful, despite the theories.
For instance, NOAA’s own data from their Hurricane Research Division:
Atlantic basin cyclone intensity by Accumulated cyclone energy, timeseries 1895-2014
Contrary to popular myth, the season with the highest ACE was not 2005, but 1933.
And as NOAA’s Chris Landsea explains, data prior to 1966 almost certainly underestimates ACE.
via NOT A LOT OF PEOPLE KNOW THAT
September 19, 2017 at 11:03AM
Iowa Climate Science Education 