Originally Posted by
AnthonyGA
The question that I find myself asking is: How abrupt are the transitions between these wind speeds? A 200-knot wind at 30,000 feet should be harmless enough in itself (albeit frustrating if you're trying to fly against it), but an abrupt transition between a layer at 200 kts and one at 180 kts could be pretty scary. A change in direction would be equally unsettling.
So ... how abrupt are the transitions at high altitudes? Can you feel it (I've been a passenger in airliners and felt turbulence, but of course I had no way of knowing wind speeds at the time)? I seem to recall reading that the transitions were a significant source of CAT.
It varies. If you look in the Met Office site, they have an aviation briefing service available. It's free, you have to register but I've never had any spam from them. Form F214 gives wind strenght & direction details at a number of locations across the UK, along with temperature. Each box contains a altitude in thousands of feet AMSL followed wind direction, wind speed (knots) and temperature in degrees C for that altitude.
http://secure.metoffice.gov.uk/aviation/index.jsp