Beaufort Wind scale displaying wrongly

richard_newberry · Post by **richard_newberry** » Thu 07 Jan 2016 11:49 am

The beaufort doesnt correspond with the wind speed. I have gentle breeze at F3 when getting wind speed over 12mph

Beaufort F3 is between wind speed 8-12mph, mines 15-19mph

Should be saying Beaufort F4.

Or does the Beaufort scale use wind avg then current wind speed?

i.e. http://www.statman.info/conversions/wind_force.html

Post by **steve** » Thu 07 Jan 2016 11:51 am

Your average wind speed is currently 13.6 mph, and Cumulus is showing F4. That's correct.

Post by **steve** » Thu 07 Jan 2016 11:53 am

And now it's 6.9 with F2. Also correct.

richard_newberry · Post by **richard_newberry** » Thu 07 Jan 2016 11:53 am

steve wrote:Your average wind speed is currently 13.6 mph, and Cumulus is showing F4. That's correct.

Should it be going with speed rather then wind avg?

Post by **steve** » Thu 07 Jan 2016 11:54 am

And now it's 7.6 with F3. Still correct.

Post by **steve** » Thu 07 Jan 2016 11:54 am

richard_newberry wrote:Should it be going with speed rather then wind avg?

No. And the figure you are displaying as 'current wind speed' on your web site looks like the station's 'gust' value to me, which is definitely the wrong thing to determine Bft from. The wind speed figures supplied by Cumulus are defined in the FAQ.

logjam · Post by **logjam** » Thu 07 Jan 2016 4:59 pm

The beaufort scale is really a measure of the wind speed regards the overall effect of the wind. A single gust figure is interesting but wouldn't be an indicator of what the wind was actually doing generally to the environment. A measure of sustained force is required. The average wind speed is a better indicator of that.

Having said that, 'frequent gusts' can occasionally do more damage than an average speed might indicate. In that case a 'warning' for that beaufort descriptor is sometimes given even if the average is less than the usual figures. For instance a 'Storm Force Warning' might be given even if the average is expected to be less than 55mph, but the wind speed is expected to frequently gust around 68mph, or more. That is used for warning predictions though. AFAIK it isn't used for current or historic weather descriptions.

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