sudden jump in wind speed

[Rome]

Hello, Can you solve a puzzle for me. I check the BBC weather forecast for Torbay every day. Have been doing this for years but have just come across something new. Today and a few weeks ago the wind speed indicator changed from white to black and the speed jumped from 25 to 45 for several hours. It did not work up to 45 just instantly changed and instantly changed back to 25.Yet the wind on both occasions seemed no different. Can anyone explain this?

[Stargazer]

Looks like the black arrows indicate expected maximum gusts, and they use these occasionally when gale force gusts are expected.

[Rome]

Thank you for your reply. I began to think that gusts could be a possibility. I do not know why I have never seen this before. I guess Torbay must be just fortunate not to have strong gusts of wind very often. Perhaps as it is a bay it is well sheltered.

Rome