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Are Tropical Cyclone Rainfall Rates Increasing?

March 23, 2018

By Paul Homewood

 

There is no evidence that tropical cyclones are getting more frequent or more intense, but are they getting wetter?

This is a common suggestion, and is something that is predicted by climate models.

One of the problems with measuring past trends is the patchy nature of recorded data. Whereas we now have much more complete data, and an abundance of measuring sites, in the past this was not always the case.

This is a critical issue, because extremes in rainfall are, by nature, usually very localised. If you don’t have a rain gauge at that precise location, you will end up underestimating the amount of rain.

 

Walsh et al published a very detailed and up to date assessment of the state of tropical cyclone science, “Tropical Cyclones and Climate Science”, in 2015. It had this to say about rainfall:

 

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Walsh et al

 

In reality, it will be decades before we can start to get meaningful trends, but this will not stop alarmists jumping up and down every time a TC brings bad floods.

 

As the Miami Herald reminded us last year, Harvey may have been terrible, but it was a long way from being the worst:

 

image

Hurricane Harvey might have beget rain in biblical volume and billions in flood damage when it stalled over Houston, but it’s not the wettest storm delivered by the Atlantic.

Not by far.

Cuba got hammered by more than 100 inches of rain when Hurricane Flora sat over the island for four days in 1963. And even earlier, in 1909 before hurricanes were named, a storm dropped more than 96 inches of rain on Jamaica. In more recent history, Wilma dumped more than 62 inches of rain on Mexico in 2005 and Hurricane Mitch, blamed for killing more than 11,000 in Central America in 1998, soaked Nicaragua with more than 62 inches, according to records compiled by National Oceanic and Atmospheric Administration forecaster David Roth.

As Texas digs its way out of what’s likely to be the state’s worst natural disaster in history, the widespread flooding that submerged whole towns and sent 30,000 people to shelters serves as a sobering reminder that hurricanes may be defined by wind. But their most lethal weapon is usually water.

http://www.miamiherald.com/news/weather/hurricane/article170512137.html

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6 Comments
  1. March 23, 2018 7:18 pm

    Reblogged this on Climate Collections.

  2. March 23, 2018 8:33 pm

    “Are Tropical Cyclone Rainfall Rates Increasing?”

    I suspect that when attempting to find the answer to that, one would probably only be looking at a period since perhaps the late 1970’s. Well, that seems to be the period that most references to increasing trends are connected to. But – that is a known GW period (be it AGW, or simply GW).

    ‘Did tropical cyclone rainfall rates decrease between 1910 and the 1970’s – during a global cooling period?

    • dave permalink
      March 23, 2018 8:48 pm

      “Did..?”

      Well, now you are asking proper scientific questions. And that is absolutely forbidden in our “brave new world.”

      • dave permalink
        March 23, 2018 8:53 pm

        By “our” I mean “their” of course!

  3. March 23, 2018 11:42 pm

    This year off the Kimberley, Broome, by the end of February, broke the previous annual rainfall record set in 1896. This was a result of three weak cyclones affecting the Kimberley coast. We have had no rain since, despite a Category 5 cyclone passing by 300km to the north. Strong cyclones often produce more damage, but less rainfall, but it all depends on the speed. A slow moving storm can result in devastating rainfall events, and happens somewhere in our region every 20 or 30 years.
    I have seen 4 of these events in the Broome region since 1970.

  4. Phoenix44 permalink
    March 24, 2018 10:04 am

    I don’t believe the question makes sense. The only temperature that is at a record is the global average temperature.The average makes little or no difference to what is happening locally. If the area where a cyclone forms is colder than its local average, it will not be wetter just because the Arctic, and thus the global average temperature is somehow warmer. The cyclone cannot know that.

    For cyclones to be wetter, you have to show that the area where they from, each time they form, is warmer. But warmer than what? Only record warmth can create record wettness, and I have not seen seen any evidence that each time a cyclone forms it is in an area of record warmth.

    Perhaps on average cyclones are wetter, but there seems to be little evidence of that either. This seem to fall into the fallacy of applying an average across the entire area, when the variability within the area is what drives the thing you are looking at. Lots of the claims about plants make the same error.

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