Windy weather app: tides & currents

Places, technique, kayaks, safety, the sea...
Post Reply
Chris Bolton
Posts: 3997
Joined: Sun Aug 22, 2004 11:33 pm
Location: NW England
Has thanked: 97 times
Been thanked: 271 times

Windy weather app: tides & currents

Post by Chris Bolton »

I use Windy quite a bit for understanding weather trends, either the App or the web page. It now includes the option to view Currents, or Tidal Currents. Posting about it here as I find it interesting but odd and wonder what anyone else thinks.

First thing to say is that they are on a coarse grid, so there's no detail on anything smaller than (at a guess) 10 miles. No Corrievreckan or Penrhyn Mawr, but the general flow around the British Isles is interesting. The Currents map seems to include both tide and ocean currents such as the Gulf Stream, but there seems to be a lot more ocean current than I expected, and it wiggles a lot. The data comes from the Copernicus project, which is based on satellite observation, so maybe they are able to measure things for which there's been no datum previously.
User avatar
P4ddy
Posts: 266
Joined: Tue Jul 07, 2020 9:27 pm
Location: Southampton
Has thanked: 96 times
Been thanked: 16 times
Contact:

Re: Windy weather app: tides & currents

Post by P4ddy »

Looks like an interesting paddle off dungeness. Would that be a bit of a confused tidal stream?


Just looked on the laptop instead of my phone & its much more detailed, Its more off Deal but looks half way to Calais what I was looking at.
Chris Bolton
Posts: 3997
Joined: Sun Aug 22, 2004 11:33 pm
Location: NW England
Has thanked: 97 times
Been thanked: 271 times

Re: Windy weather app: tides & currents

Post by Chris Bolton »

Just looked on the laptop instead of my phone & its much more detailed
It's not really more detailed, it's just at a bigger scale, if you follow the difference. Like a map of Britain that only shows motorways, where you could zoom in but the A roads won't appear, there's no detail of the tidal flow around individual features. If you look at North Wales, it shows the strongest tides along the North coast of Anglesey, but as those who paddle there know, the strongest tide races are actually off Holyhead - the flow appears to go right through Holy Island as if it wasn't there, so it doesn't show up as a tide race.

As I understand it, they have a crude model of the sea bed and satellite measurements of the surface level of the sea. The computer works backwards from that data to calculate the current flow that would be needed to move the water around as the surface levels change. To get the tidal predictions they must tie the results in to the position of the moon and sun and then extrapolate that forwards. They may echo the traditional tidal prediction methods based on measuring the level at a points on the coast and calculating the multiple resonance patterns necessary to fit the data, except that they have many more data points to work from. So the total tidal flow through the Channel between Dover and Calais may be more accurate than traditional tide tables, but where that flow is, in detail, won't be at all accurate.
User avatar
Robert Craig
Posts: 842
Joined: Tue Aug 23, 2005 8:55 pm
Location: Glasgow
Has thanked: 57 times
Been thanked: 21 times

Re: Windy weather app: tides & currents

Post by Robert Craig »

Now, that's nice!
Post Reply

Return to “Sea Kayaking”