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GliderPilot · 09-24-2007, 03:22 PM

So, what weather do I ideally look for to fly cross country? Well the best conditions are usually after a cold front has passed in spring or autumn and then the sun starts shining and the temperatures rise. We start to notice small fluffy white “cotton wool” like clouds called “cumulus”. These cumulus form at the top of a thermal and “mark” the thermal out to glider pilots. Pilots will look for the clouds to see where the lift they need may be. Ideally for me, winds will be light in the region of 5-10 knots so that the wind doesn’t affect the thermal as it rises. For a 500km day, the lift should start developing early in the day at about 1100 hours, and build in strength and remaining till about 1800 hours. This gives 7 hours of hopefully good soaring conditions. This doesn’t happed that often here in the UK, but occurs a lot more regularly in warmer places such as Spain, South Africa and Australia. Cloud bases, and therefore thermal and climb heights, should be about 4500 feet to 5500 feet. Some pilots will enter cloud to climb higher. I don’t like flying in cloud, you never know who or what else may be in them. Cloud flying is illegal for gliders in some countries such as Germany. Themals are not always marked by cloud. If the air is too hot or too dry, thermals will be present, but no cloud. These days are called “blue” days. Gliders will still go cross country, but we look for ground features we know should produce lift, or hope to blunder into good lift as we stumble along.

There are other types of lift that we may use such as hill/ridge lift, wave lift or convergences of air masses, but that’s a different topic.

09-24-2007, 03:22 PM	#8
GliderPilot Collector Join Date: Dec 2006 Location: ENGLAND Posts: 481	Re: Dedicated to gliding and gliders So, what weather do I ideally look for to fly cross country? Well the best conditions are usually after a cold front has passed in spring or autumn and then the sun starts shining and the temperatures rise. We start to notice small fluffy white “cotton wool” like clouds called “cumulus”. These cumulus form at the top of a thermal and “mark” the thermal out to glider pilots. Pilots will look for the clouds to see where the lift they need may be. Ideally for me, winds will be light in the region of 5-10 knots so that the wind doesn’t affect the thermal as it rises. For a 500km day, the lift should start developing early in the day at about 1100 hours, and build in strength and remaining till about 1800 hours. This gives 7 hours of hopefully good soaring conditions. This doesn’t happed that often here in the UK, but occurs a lot more regularly in warmer places such as Spain, South Africa and Australia. Cloud bases, and therefore thermal and climb heights, should be about 4500 feet to 5500 feet. Some pilots will enter cloud to climb higher. I don’t like flying in cloud, you never know who or what else may be in them. Cloud flying is illegal for gliders in some countries such as Germany. Themals are not always marked by cloud. If the air is too hot or too dry, thermals will be present, but no cloud. These days are called “blue” days. Gliders will still go cross country, but we look for ground features we know should produce lift, or hope to blunder into good lift as we stumble along. There are other types of lift that we may use such as hill/ridge lift, wave lift or convergences of air masses, but that’s a different topic. Last edited by GliderPilot; 09-24-2007 at 03:25 PM.