force X gusting Y.. aghhhhhhhhhhhhhhhhhhhh

captainslarty

captainslarty

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I wish people would stop using the misleading line "It was force 6 gusting 7" or similar... it CANT gust to a scale above.. and is extremely misleading for most.. it also brings about a false sense of security to some sailors who THINK they have been in the higher scale condition..
This is becoming more and more noticable in yottie mags from our humble ipc...
rant over /forums/images/graemlins/ooo.gif
 
I know of them saying similar to "sw 7 possibly 8 later" or similar... even with no timescale they are forecasting a 7 or an 8.. thats ok.. its the "gusting' that is just plain silly and misleading.
Just like the boat tests on the solent with a force x wind and no real sea due to the lack of fetch... the boats are often quoted as standing up well to a force 7 for instance, but they have never been near one.

Nurese ?? me steady pills please.....
 
[ QUOTE ]
The Met offce say it all the time.

[/ QUOTE ]Sure about that? Can't say I've ever noticed. We have a separate VHF logbook for relevant radio transmissions and inshore waters forecasts, and don't racall that. In fact I've just had a quick look at the radio log, about sixty or seventy days from April to October last year, and it doesn't appear. Some other source perhaps?
 
So if the wind is blowing say, 18 knots, and you get some gust up to, say, 20-25% increase in wind speed, say thats 22-23 knots.....That would be what force 5 gusting to force 6?

And why is that not possible?
 
If you're out in a 6 then it is reasonable to expects gust of perhaps an additional 15 kts, quite easily gusting up to the mid (if not high) 30s. That's not unusual and as far as I am aware should be built into the expectations of a F6. Gusts into mid 30s don't make it a 7 or an 8. It's still just a 6, and, as far as I know is consistent with how the Met Office reports their forecast.

The issue concerning the Beaufort scale is surely about sustained wind, and not gusts?
 
The velocity equivalents given in the table are based on the empirical relationship between estimated number and measured velocity, V = 1.87 Ö B3, where V is in miles per hour, and B is the corresponding Beaufort number. The pressure equivalents are derived from the relationship p = 0.003V2, where p is in pounds per square foot and V is in miles per hour [Meteorological Office, 1963].

The gust speeds in the table above have been estimated by multiplying wind speeds by 1.25; i.e. it is assumed that the Beaufort wind speed are sustained 1-minute wind speeds. The multiplication factor is from Lander and Guard [1991].

The mean wind speeds given here are the same as those in Munich Re (1988, p53) though the latter are stated to be for a height of 10m above the surface. The wind speeds given in UNDRO (1991, p47) are lower then the mean wind speeds given here, but the Specifications are the same!
 
[ QUOTE ]
Wind Southerly 5 to 7, perhaps gale 8 at times.

[/ QUOTE ]That's absolutely standard Met Office parlance, and means exactly what it says. It is sustained wind "for a time", not gusts. During a sustained blow at F8 (which AFAIR I've managed to avoid sailing in), it would be reasonable to expect gusts beyond the standard F8 windspeeds.
 
No, its not the same.
If you are in a 5, its a 5, a 7 is a 7.. 2 different animals.. just because a gust of wind occurs and a wind speed indicator reads a certain figure as peak does NOT mean that the person encountered, or experienced such a wind force on the beaufort scale.
Thats the issue.. people who quote the scale based on gust, not sustained winds and the seas that that can bring.

Your quote forecast could indeed bring gusts of 58 mph !!.. and it is STILL an 8
A dangerous situation.
 
Here's a possible explanation of the term "force X gusting Y". In Met Office parlance, wind forces can be measured either by the sustained wind speed or by gust strength. For example F8 is either 34-40kts sustained, or gusts of 43-51kts.
Now if the sustained speed was between 34-40kts, but the gusts corresponded to F10, 61-68kts, couldn't this be described as "F8 gusting F10"?

Actually I think not. That's simply a F10. So try this instead. Gusts are temporary phenomena, for example the US Office of Meterology describes them as lasting no more than 20 seconds. But it is often the case that gusts are followed by periods (10 minutes or more) of increased wind strength. For example, the wind is blowing between 34-40kts, there is a gust, after which the wind blows at 48-55kts for a while before subsiding again .Would it not be reasonable to describe this situation as "force 8 gusting 10". This tells us nothing about the strength of the gusts.
 
Well I certainly see were you are coming from, however I am uncertain that the practice of describing the potential gust speeds in terms of "Force" is such a bad thing.....

The Beufort scale is a rather broad brush, in theory 4 can be anything from 20-35 knots of wind speed (in the gusts) ... and whilst I am sure most people would be perfectly happy sailing in 20 knots, a lot of people would be put off if they were going to potentially encounter wind speeds gusting to 35...... This may be more important in inshore waters were you will naturally tend to have more people in small boats with less experience....

So, while I perfectly understand that describing gusts in terms of force's ( even though these are within the defined gust range of a particular force) is a departure from the strict definition of the scale, Given the ability to more accuratly predict actual wind speeds, including gust strengths, surely adding more data in regards to the conditions that a individual may encounter, including using effectivley a rough short hand (Ie "Force") to describe the wind speed is actually a good thing?

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Edited to remove the repetition of several better refutations of Flipper_K6354's statement

While I'm happy to take the odd gust of 22 knots while sailing in a F4 with all sail set, I would put in a couple of reefs to sail in a F6. That's not just because I sail better with two reefs in 22-27 knots, but also because I don't fancy having full sail set in a gust of 34 knots.
 
Quote
I know of them saying similar to "sw 7 possibly 8 later" or similar... even with no timescale they are forecasting a 7 or an 8..
.................................................................................
Soon, and later are specific time scale definitions when used in this context.
Imminent within six hours of the time of forecast
Soon between six and twelve and
Later after 12 hours.
Winds of at least Beaufort force 8 (34-40 knots) or gusts reaching 43-51 knots is an 8.



i
for those who want more.
 
Actually Andrew, no I disagree, it wouldnt be a 10. It would be an 8 with bloody high gusts !! /forums/images/graemlins/ooo.gif

The fact that the gusts are such, and not sustained and tend to be infrequent at that level. does not make it a 10.
Beaufort is trying more to describe potential SEASTATE as a byproduct of the wind. The wind wont kill ya, but the sea will. Seastate depends on many factors, but the most influential one offshore is fetch and sustained windspeed over a time period.
 
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