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That old boring spring thermal warning plus extra comments

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That old boring spring thermal warning plus extra comments

Postby Dave Thomas » Tue Mar 22, 2022 2:17 pm

The weather continues to give us testing conditions, from the previous very unstable south westerlies and unsettled conditions to the high pressure gusty and turbulent ones right now.

Don’t feel pressured to launch if others are launching/flying but you feel it’s a bit too much for you. Some amazing flights are being flown in these conditions but usually by current and very experienced pilots!

Please fly with extra caution when on a site with rock like Corndon. Rock heats and releases thermals hence the possibility of unpredictable air and is far less forgiving should you fall onto it.

Another warning is mostly related to high presure days when a strong temperature inversion is usually prevelent during the morning and quite often much of the day and can so often catch out pilots who have not experienced this before.
Temperature inversions often result in sharp wind speed and direction changes close to the inversion altitude, as well as a general turbulence due to the forced mixing of air.

Late in the day, these inversions usually are benign, maybe stopping or limiting thermic height gains except for the strongest (hottest) thermals which may punch through and resurge above. However when low down usually just makes for unpleasant soaring conditions, and on accasion dangerous turbulence close to the ground, made worse by any ground effects.
An example of this can be found on the Mynd quite regularly (or the Malverns), where a nice soarable wind speed is measured on the ground, yet in the air it is barely sorable, rough and uninviting. The reason it's most noticable on long ridges, is because the inversion causes a lid on where the air can rise to, and creates a venturi over the top of the hill as the air is forced through a narrow vertical gap and cannot escape around the edge of a hill like Corndon for instance. The venturi wind is strong but mostly horizontal and ground effects create turbulence.

Where possible, the club weather forecasts will indicate conditions that are likely to cause poor flying conditions due to inversions or other limiting factors, These forecasts are mostly aimed at highlighting good ridge soaring conditions, which are in fact the most difficult to forecast.

If you do fly then be doubly prepared– in setting up, during launch, in the air, coming in to land and gaining control of the wing after landing. Expect to encounter turbulence and gusts and rocket thermals at any time.

I did not witness this, but have been told about multiple incidents at the Malverns this last few days with very poor ground handling of pilots who were not current, causing many minor and not so minor problems, ripped wings, pilots being dragged and hurt, low airtimers 'helping' other pilots lay out and causing more problems as not used to steep slopes and a fresh wind.
Dave Thomas
 
Posts: 2449
Joined: Thu May 02, 2013 12:45 pm

Re: That old boring spring thermal warning plus extra commen

Postby Dave Thomas » Tue Mar 22, 2022 2:20 pm

Posted again without so many Typo errors.

The weather continues to give us testing conditions, from the previous very unstable south westerlies and unsettled conditions to the high pressure gusty and turbulent ones right now.

Don’t feel pressured to launch if others are launching/flying but you feel it’s a bit too much for you. Some amazing flights are being flown in these conditions but usually by current and very experienced pilots!

Please fly with extra caution when on a site with rock like Corndon. Rock heats and releases thermals hence the possibility of unpredictable air and is far less forgiving should you fall onto it.

Another warning is mostly related to high pressure days when a strong temperature inversion is usually prevalent during the morning and quite often much of the day and can so often catch out pilots who have not experienced this before.
Temperature inversions often result in sharp wind speed and direction changes close to the inversion altitude, as well as a general turbulence due to the forced mixing of air.

Late in the day, these inversions usually are benign, maybe stopping or limiting thermic height gains except for the strongest (hottest) thermals which may punch through and resurge above. However when low down usually just makes for unpleasant soaring conditions, and on occasion dangerous turbulence close to the ground, made worse by any ground effects.
An example of this can be found on the Mynd quite regularly (or the Malverns), where a nice soarable wind speed is measured on the ground, yet in the air it is barely soarable, rough and uninviting. The reason it's most noticeable on long ridges, is because the inversion causes a lid on where the air can rise to, and creates a venturi over the top of the hill as the air is forced through a narrow vertical gap and cannot escape around the edge of a hill like Corndon for instance. The venturi wind is strong but mostly horizontal and ground effects create turbulence.

Where possible, the club weather forecasts will indicate conditions that are likely to cause poor flying conditions due to inversions or other limiting factors, These forecasts are mostly aimed at highlighting good ridge soaring conditions, which are in fact the most difficult to forecast.

If you do fly then be doubly prepared– in setting up, during launch, in the air, coming in to land and gaining control of the wing after landing. Expect to encounter turbulence and gusts and rocket thermals at any time.

I did not witness this, but have been told about multiple incidents at the Malverns this last few days with very poor ground handling of pilots who were not current, causing many minor and not so minor problems, ripped wings, pilots being dragged and hurt, low airtimers 'helping' other pilots lay out and causing more problems as not used to steep slopes and a fresh wind.
Dave Thomas
 
Posts: 2449
Joined: Thu May 02, 2013 12:45 pm


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