Beaufort Scale

nking · Post by **nking** » Mon 01 Mar 2010 5:50 pm

I have just noticed that both the latest and average wind speed were < 1 mph yet Cumulus was still showing F1, is there a time delay before Cumulus will report Calm?

Post by **steve** » Mon 01 Mar 2010 6:17 pm

It updates the Bft value at the same time as the average speed. Bft 0 is below 0.3 m/s, i.e. below 0.67 mph. What was your actual indicated average speed?

nking · Post by **nking** » Mon 01 Mar 2010 6:36 pm

It was .8 mph so based upon your calculation then Cumulus is correct. I had just looked at the Beaufort Scale and taken it as < 1 mph hence my question. I guess where you live it is never Calm!!

Now why didn't you choose < 1 kts for Cumulus

Post by **steve** » Mon 01 Mar 2010 6:42 pm

I had to choose one set of values (they're all rounded differently, so they're not quite the same), so I used the m/s values from here: http://www.metoffice.gov.uk/weather/mar ... scale.html

My understanding is that while Beaufort was originally a visual scale, these days it is defined by a formula that uses m/s.

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