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The Met Office’s Obsession With Gusts

October 20, 2017
tags: , ,

By Paul Homewood

 

 

image

https://uk.news.yahoo.com/storm-brian-apos-weather-bomb-082924683.html

 

There was a discussion about the merits of using sustained wind speeds rather than gusts on the Ophelia thread the other day.

Doug Holman gave this particularly relevant comment:

 

Some people measure speed (velocity for the purists) in mph while others use kph or knots. What matters is that comparisons are made using the same units. We would rightly object if we were caught doing 48 in a 30 limit and it turned out that the speed camera had been inadvertently set to kilometres instead of miles.

Conventionally, we measure wind in terms of a mean speed but “warmunists” (a term borrowed from Ian Magness, above) seem to think that they can win their battle against capitalism by replacing mean with maximum gust speeds. A gust is (by definition) at least 10 knots (11 mph) more than the mean speed but a maximum gust could be much higher, and depends on numerous factors, such as the local topography and wind direction. That’s why mean speeds are used in overall risk assessment, such as in the shipping forecast.

If we stick to the Beaufort scale, we know that there’s risk of trees falling when the mean speed reaches between 55 and 63 mph, or “force 10”. Of course, the gusts will be higher. But which would you consider more dangerous: a “force 8” gale (between 39 and 46 mph) with a single freak gust of 80mph or a proper “force 10” storm with widespread gusts of the same speed?

Frankly, I blame the car manufacturers for replacing “air conditioning” with “climate control.” It led some of our “professional” politicians to imagine that this could work for the entire world. If their understanding of meteorology is this risible, are we not entitled to know what, if anything, we can safely entrust them to do?

https://notalotofpeopleknowthat.wordpress.com/2017/10/17/ex-hurricane-ophelia/#comment-102231

 

This has been a particular bugbear of mine for some time, and, with Storm Brian heading our way, it is a good time to revisit it.

The real problem that I find is that the UK Met Office rarely seems to offer any assessment of mean wind speeds, either on their forecast or after the event. Instead they concentrate on gusts, as their latest missive above about Brian highlights.

A good example of this came in their news release about Ophelia on Tuesday, which stated:

Ex-Hurricane Ophelia has moved out over the North Sea after bringing gusts of over 90mph to parts of the UK.

There have been widespread impacts across Northern Ireland, western Wales, north west England and south west Scotland. Travel disruption, fallen trees and power cuts have all been reported with many properties already having had power restored.

The strongest wind gusts were recorded on the southern edge of the low pressure through the afternoon on Monday (16 October). The tables below outline the top wind gusts recorded in the UK and the Republic of Ireland.

 

image

https://www.metoffice.gov.uk/news/releases/2017/ex-hurricane-ophelia-passes-after-90mph-winds

 

Nowhere in their report was there the slightest mention of sustained or mean wind speeds, although they certainly keep such data.

But matters are even worse because all of the UK sites mentioned are extremely exposed sites, and clearly not representative of most of the country.

For instance, Capel Curig is high up in the wilds of Snowdonia, at an altitude of 216 m.

Aberdaron is not only at the tip of the Llyn Peninsula in N. Wales, but the weather is at the top of the cliffs at a height of 95 m.

Places like Mumbles Head also appear regularly near the top of the wind charts for similar reasons.

 

Not to be outdone, the BBC now use black logos (denoting gust speeds) at times of windy conditions, rather than the usual grey ones for mean speeds:

image

http://www.bbc.co.uk/weather/2638077?day=1

 

This is done supposedly to warn people, but I suspect most would be totally confused.

 

I suspect the real purpose of all of this is to overhype storms and make them appear much worse then they really are.

 

What makes this all so unforgiveable is that there is already a well established system for forecasting and reporting winds, the Beaufort Scale.

The fact that this is still used for serious purposes, such as the Shipping Forecasts, suggests that the Met Office’s preoccupation with gusts on exposed headlands is nothing more than a PR exercise, concerned with generating headlines.

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37 Comments
  1. October 20, 2017 3:53 pm

    Reblogged this on Climate Collections.

  2. Ian permalink
    October 20, 2017 4:32 pm

    Surely they’re still suffering from Michael-Fish-itis (evident from the number of his appearances) and are just playing it safe.

    • October 20, 2017 6:05 pm

      I agree. Ever since Michael Fish they have erred on the cautious (or alarmist) side with all their forecasts. Consequently the actual weather is invariably better than the forecast weather.

  3. A C Osborn permalink
    October 20, 2017 5:08 pm

    Paul, “suggests that the Met Office’s preoccupation with gusts on exposed headlands is nothing more than a PR exercise, concerned with generating headlines.” is spot on.
    Sound Bites and Newspaper Headlines.

  4. mwhite permalink
    October 20, 2017 6:45 pm

    Why didn’t they rename Ophelia?

    • October 20, 2017 7:04 pm

      They stick with the original name, only naming new ones

    • It doesn't add up... permalink
      October 22, 2017 12:18 am

      Because Rosencrantz and Guildenstern are dead?

  5. TinyCO2 permalink
    October 20, 2017 8:08 pm

    It’s crying wolf and has the same effect. Eventually people automatically subtract a hype factor from anything the MetOffice says. I was at an outdoor meeting at the height of the storm and eveyone was muttering about the lack of accuracy in the forecasts. We were sure that people had been put off coming.

  6. Martyn Farmer permalink
    October 20, 2017 8:41 pm

    A lovely observational piece by Emma Duncan in todays (Oct: 20th) ‘The Times’ Comments Notebook?

    Surfers 1, BBC 0
    When Ophelia bore down on the British Isles, I was in an old house in a wood on the west coast of Ireland, precisely where the BBC assured us the hurricane would pass through. The surfers’ favourite website, windguru.cz, disagreed, maintaining that the hurricane would go far to the east of us. We put our faith in the BBC and, concerned that we would be trapped by falling trees, battened down the hatches. In the event, there was a light breeze and the worst we had to contend with was a flock of sheep on the lawn. Surfers 1, BBC 0. The fact that the website is domiciled in the landlocked Czech Republic somehow made that particularly satisfying.

  7. Curious George permalink
    October 21, 2017 12:08 am

    I am not sure what determines whether a tree stands or snaps, whether a roof stands or is carried away? Would it be a wind gust or a sustained wind speed? Is a tornado a wind gust?

    • John F. Hultquist permalink
      October 21, 2017 3:58 am

      Seems to be complicated, doesn’t it?
      Here’s a go at it:
      https://www.scientificamerican.com/article/do-all-trees-snap-at-about-94-mph/

    • dave permalink
      October 21, 2017 8:33 am

      A local airstrip does not have a “wind-sock;” instead, it has a “wind-rock.” The sign built into the ground next to it has instructions for interpreting the conditions. “Rock turned over!” means Hurricane; “Rock gone!” means Tornado.

      For anybody who thinks (nobody here, I am sure) that weather was invented recently:

      “And then came that extraordinary Monday (August 30, 1658) which lovers of coincidence* have taken care to remember as the day of most tremendous hurricane that ever blew over London and England. From morning to night the wind raged and howled, emptying the streets, unroofing houses, tearing up trees in the parks, foundering ships at sea, and taking even Flanders and the coasts of France within its furious whirl. The storm was felt within England as far as Lincolnshire, where in the vicinity of an old manor house, a boy of fifteen
      years of age, named Isaac Newton, was taking it to account, as he afterwards remembered, by jumping first with the wind, and then against it, and computing its force by the difference of the distances…” (David Masson, The Life of Milton, vol v , p 358).

      Every man his own anemometer!

      La Nina continues to establish itself:

      A (modest) drop in Global Brightness Temperature Anomalies usually follows about three months later.

      *Cromwell was dying.

  8. John F. Hultquist permalink
    October 21, 2017 4:25 am

    Paul mentions “headlands” — that is, geography.
    There are other land surface features that concentrate air flow that really have little to do with the magnitude of a storm. For example, if a good blow starts up a valley that narrows with elevation, the shape — a funnel? — induces increasing velocity. Trees will break given enough wind speed, structural faults in the tree, and sometimes with “snap-back” when the wind abruptly stops. Pushing trees with shallow roots over in wet ground is a different matter.

    We live east of the Cascade Crest. Storms off the Pacific Ocean bring winds up and over that roughly 6,000 ft. ridge line. The air is compressed against the tropopause (or something) and can, with the right circumstances, bring extra strong winds and gusts on us, say, and not other parts of the area, 20 miles north or south of us.
    It is foolish under such circumstances to equate the strength of the storm with the wind or gusts at these isolated locations.
    It is not that these situations are not interesting — they are. Sort of like a novelty chocolate bar.

    • RAH permalink
      October 21, 2017 4:06 pm

      This truck driver knows that when the wind direction is correct relative to the direction of travel the embankments for overpasses become wind hazard zones. On a windy day driving on interstates with vast stretches of open farm lands or water (such as I-90 along lake Erie in NY) up wind it can be very interesting. White knuckles when one passes under every overpass. A good thing for you drivers to remember when passing big trucks on the downwind side on windy days.

  9. October 21, 2017 5:46 am

    Storm Brian is all gusts and more gusts according to the BBC and the Met Office.
    http://www.bbc.co.uk/news/uk-41704779

    • Tom O permalink
      October 23, 2017 1:40 pm

      I suppose it is just me, but naming every damn storm sounds totally anal. Yes, winter storms can be destructive, but the old tradition of naming hurricanes – not tropical storms – and only hurricanes differentiates between truly destructive storms and “other storms.” Might as well stat naming Tornadoes, too. Of course you would have to add a few designators, such as F1Abby25 or F3Bertrum4 as you cycled through the letters and strengths.

  10. Malcolm Bell permalink
    October 21, 2017 6:53 am

    Exactly right.

  11. dearieme permalink
    October 21, 2017 9:15 am

    “speed (velocity for the purists)”: good Lord, he imagines that velocity is just a posh word for speed. Where on earth did he go to school?

  12. mikewaite permalink
    October 21, 2017 10:07 am

    “O wild west wind , thou breath of Autumn’s being—“.
    “Ring out wild bells to the wild sky—”
    There was a time when people enjoyed and were exhilarated by the gusts of March and Autumn and to both Shelley and Tennyson the winds, at the years end, heralded not disaster but a new beginning , blowing out the old , bringing in the new.
    Was it the BBC , for reasons of its own , that started to foster this fear and hatred of the great outdoors?

    • dave permalink
      October 21, 2017 11:44 am

      I think it was Ellsworth Huntington who established that productivity in factories ROSE in the days following high winds. He mentions one occasion in his own University, when the students worked as volunteers, clearing up after a huge storm, and took a standard exam immediately afterwards, despite being exhausted. Their marks were the highest ever recorded.

  13. auralay permalink
    October 21, 2017 11:43 am

    The forecaster on BBC 6o’clock news actually said that Brian was (from memory) “Just a normal seasonal storm”. I don’t expect to see him again until after a lengthy reeducation program!

    • October 22, 2017 12:04 pm

      I heard someone from the Met Office being interviewed on the radio who said it was normal for this time of year. He clearly needs a stint of re-education to get with the programme.

  14. Bloke down the pub permalink
    October 21, 2017 1:17 pm

    It’a a while since I listened to the shipping forecast but don’t they include gusts in their predictions?
    The sad truth is that the Met Office relies on public funding, so it is in their interests to make a mountain out of a molehill to make any threat sound more terrifying and their prognostications commensurately more vital.

    • October 21, 2017 1:41 pm

      From memory they’d say something like:

      “Gale Force 6, gusting to 8”

      • Nigel S permalink
        October 22, 2017 9:58 am

        Not sure about ‘Gusting to 8’, I don’t recall hearing that. The modified Beaufort scale used by the Met Office includes gusts. ‘Gale: Winds of at least Beaufort force 8 (34-40 knots) or gusts reaching 43-51 knots’. The 27% (average) increase in gust speed represents a 61% increase in wind load (square of speed). This glossary explains the precise meaning of the carefully chosen script.

        https://www.metoffice.gov.uk/guide/weather/marine/glossary

        Force 6 is a ‘Yachtsman’s gale’ (somewhat like a fisherman’s tale).

      • October 22, 2017 12:01 pm

        Yes, the shipping forecast used to include that phraseology. I guess the Beaufort scale is old imperial and will soon be a distant, melodic memory for us.

      • Gerry, England permalink
        October 23, 2017 12:39 pm

        From my memory banks I think what they would say is ‘force 6, rising occasionally to force 8’ or ‘varying locally force 8’. I don’t think I had ever heard gusting used.

      • October 23, 2017 1:19 pm

        You’re probably right!

  15. auralay permalink
    October 21, 2017 1:44 pm

    Brian is not a super storm; he is a very naughty wind. Well, someone had to say it!

  16. Dermot Flaherty permalink
    October 21, 2017 6:08 pm

    According to the Beaufort scale, if 1987 is to be remembered as the year of the Great Storm) then 2017 is shaping up to be the year of the Great Breeze.

    • Nigel S permalink
      October 22, 2017 4:40 am

      Great Wheeze (at least in the Met Office’s opinion).

  17. Gerry, England permalink
    October 21, 2017 9:22 pm

    Perhaps what is missing is the frequency of the occurrence of gusts. Something may be able to withstand a mean windspeed but a sudden gust can be what causes something to break or give way. A big factor in the 1987 storm was the heavy rain that had come before to soften the ground allied to the trees still being in leaf.

  18. Nigel S permalink
    October 22, 2017 11:12 am

    It’s part of the plan along with naming the storms. 70mph sounds close to a hurricane and a 61knot gust would certainly be bad news on a small boat in the Irish Sea but it’s only just a Storm according to the Met Office shipping forecast glossary (Storm: Winds of force 10 (48-55 knots) or gusts reaching 61-68 knots).

  19. October 22, 2017 11:58 am

    Everything is so bloody dramatic these days. We used to be allowed to get on with our lives, take what was thrown at us and move on. Now the authorities try to scare us about future events in the most ridiculous of manners. It’s either because younger generations brought up on a diet of computer games and safe spaces are unable to cope with the real world or because said authorities want us to live in fear of our lives. It’s risible.

    • Gerry, England permalink
      October 23, 2017 12:43 pm

      You can’t help but be cynical and think it is part of a plan to try to convince us that there is more extreme weather due to climate change, especially as they are struggling with global warming only being revived by a known natural phenomenon. In one report I even read a so called expert saying that this was the first time the wind had been this strong since 18 or 19 whatever and so is unprecedented, obviously not knowing the meaning of the word.

  20. jimcooling permalink
    October 23, 2017 5:51 pm

    Just a pedantic technical point: speed and velocity are not the same.

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