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Amie
44183.  Sun Jan 08, 2006 6:05 pm Reply with quote

Quote:
Well, I think this has potential. One more question, addressed to a different kind of special knowledge which we also have on these boards: calling all youngsters (anyone who wasn't born in 1987, say) - does any of this mean anything to you? Are you aware of the 1987 storm at all? Have you heard of Michael Fish? Or is this a topic which will only work for older viewers?


Oh yes, I have heard of him and have seen many clips. I happen to have done Geography at GCSE and it was one of many case studies we had to look at. I learnt someone was crushed by a chimney and a milkman had a narrow escape as his float was crushed by a tree as he had just got out. Oh and he sold the remaining pints the next day..

 
DELETED
222755.  Tue Oct 23, 2007 7:10 am Reply with quote

DELETED

 
Flash
222847.  Tue Oct 23, 2007 9:01 am Reply with quote

You wouldn't have been so damn satisfied if you'd triggered a tsunami and then got hit with a class-action suit by the entire population of eastern America, I'm guessing.

Welcome back, incidentally.

 
Jenny
222993.  Tue Oct 23, 2007 12:06 pm Reply with quote

Yaaay Garrick's back! I am rather enjoying the mental image of you jumping up and down on the fault line.

 
DELETED
223415.  Wed Oct 24, 2007 12:07 pm Reply with quote

DELETED

 
Jenny
223771.  Thu Oct 25, 2007 11:38 am Reply with quote

(((garrick)))

 
Bloggulator
294328.  Wed Mar 12, 2008 12:48 am Reply with quote

Back to that 1987 storm in S. England: This storm was *not* a hurricane: a hurricane is a warm-cored tropical system, without fronts, featuring a calm, often cloudless eye, with the strongest winds circulating around the "eyewall". The strongest winds associated with the 1987 storm were well removed from its center. It was an Atlantic depression which deepened explosively and suddenly, and took an unusual track for such an intense system, from the Bay of Biscay northeastwards into the North Sea.
This storm did have areas of hurricane force winds embedded its south-east quadrant, which affected the English Channel and the southernmost land areas of SE England: But, I repeat, it was not a hurricane!

By the way, the US NOAA/National Hurricane Center's qualification for a tropical system to be named a "hurricane" is for a minimum "sustained" windspeed (not gusts) of least 64 knots or 74mph, over a period of ONE MINUTE. See this link: http://www.aoml.noaa.gov/hrd/tcfaq/D4.html

Quote:
Gusts are a few seconds (3-5 s) wind peak. Typically in a hurricane environment, the value of the maximum 3 second gust over a 1 minute period is on the order of 1.3 times (or 30% higher than) than the 1 min sustained wind.

One complication with the use of the 1 min averaging time for the standard for sustained wind in the Atlantic and Northeast Pacific tropical cyclone basins (where the United States has the official World Meteorological Organization tropical cyclone advisory responsibilities) is that in most of the rest of the world, a 10 min. averaging time is utilized for "sustained wind". While one can utilize a simple ratio to convert from peak 10 min wind to peak 1 min wind (roughly 12% higher for the latter), such systematic differences to make interbasin comparison of tropical cyclones around the world problematic.


When referring to the Great Storm, and whether hurricane force winds occurred, the UK Meteorological Office was quoting mean speeds over a 10 minute period as well as the Beaufort Force 12 definition (64kt or greater) over at least a 10 minute period, commonly one hour: this is a very different standard.

See: http://www.metoffice.gov.uk/education/secondary/students/1987.html

The winds in the 1987 event were not measured according to the tropical cyclone standard: If the 10 minute mean wind speeds were converted using the 12% rule (see above), then "hurricane force" would have been used as widely as the stations reporting "Beaufort Force 11"

Quote:
Winds reached Force 11 (56-63 knots) in many coastal regions of south-east England


Multiply the Force 11 average (59.5kt) by 1.12 = 66.64kts, which places the one minute sustained averages into the "hurricane force" category. Regarding the Royal Sovereign Lightship measurement of 75kts, if taken over a 10 minute period, would indicate a "one minute mean speed" there of over 84kts. But this reading was a *one hour* mean. I do not know what the conversion is from a "one hour mean" to a "10 minute mean" is, but it would be safe to say that it would result in a more conservative figure than a 10 minute mean. Adding another 5% (which also maybe conservative) to 84kt gives 88kt (>100mph). This would be equivalent to a category 2 hurricane in the tropical realm.

In 1987, there were very few observing stations in the English Channel, where the core of strongest winds were. A number of anemometers were destroyed on the South Coast. The strongest gust recorded during the storm was 119kt (137mph) in Brittany. There was an unofficial report of a 145mph gust from a ship.

It appears as if the strength of this storm has been a little underestimated, in comparison to tropical systems.

 

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