Saturday
Back | HomeInterestingly there was indeed wave today - as forecast back on Thursday - which was used to prolong flights at flat land sites, if not actually for climbing. No doubt it was stronger upstream towards Wales - but it was probably too cloudy to use effectively. Notable today was the strong horizontal wind shear: in an atmosphere with high static stability the air will stratify nicely and you will easily see discrete steps of another 10 knots of wind speed across 100’ vertically. Hard to wave off in time if you’re on a winch launch.
Looking at tomorrow (Sunday) the wind will be around 10 knots from the northwest. I’d be surprised if that’s enough from that direction for the South Downs to work but Booker’s ridge (“Stokenchurch”? I forget) should be working - if someone can tell me after tomorrow I’d be much obliged. Back across towards Wales I think the temperature and wind profile is conduicive to wave though it’ll likely be weak at the lowest levels - again, feed back on what actually happens would be much apprectiated (e.g. flights on ladder, comments, or e-mails to address on right). Weather-wise it will be bright and sunny in most areas, perhaps a bit cloudier in the north Wales/Cheshire area, so if there is wave it will be possible to take the climbs to a decent height. (Edit: this little finger of cloud actually extends down past Brum. What’s remarkable is that it’s on the GFS, the UK meso, RASP and Meteoblue in almost identical form. I’ve never seen a mesoscale feature so small replicated across three totally different and two related models before so closely. Will be interesting to see if they’re right.)
Quick look at Monday - it always gets left out - mostly cloudy, some rain around, hardly any wind. Not very exciting.
At Shobdon today the wind was as forecast by the Met Office F214 at lower levels - 320/330 degrees, about 30 kts at 4 - 5000 ft. The cloud amounts were very variable, base mostly 4500 ft amsl. We were unable to use the primary wave in the lee of Radnor Forest because although there were gaps from time to time they were not large enough or open for long enough. A pity because there was quite strong lift - 4 kts at 3500 - 4000’. Cloud amounts a bit further downwind were not so much. There was very weak lift on what was probably the tertiary wave and Peter Reading contacted at 2800, and eventually reached 10,000’. The Shobdon ridges worked although they would normally need a more northerly wind. This was perhaps because the wave was synchronised with the ridges. Unfortunately the highest we could get on the wave-enhanced ridge was 2000’ and so it was not possible to make the transition into the wave itself.
Air locally around Booker was lively today (Sunday) to say the least. On tow it went v. smooth at about 1800’….. but no sign of any significant wave lift. Another pilot reported 0 sink at 4000’ off tow for a short while. Booker/Stokenchurch ridge was working. One ASW27 was having oodles of fun at around 1200’, reporting wind as onto the ridge (so I guess NW’ly at 23-25kts). We didn’t use the ridge field as it was expected to be quite soggy. A ground inspection later in the day proved this to be incorrect and it was in fact quite useable…oh well!
Wind on the ground at Booker this Sunday was just 10 - 12Kts NWl’y which is usually regarded as the right direction but too little for the ridge. I went anyway! As we climbed out towards Chinnor the wind increased to about 22kts at 1000ft AGL. On the ridge itself I was consistently seeing 310 / 23Kts which is perfect for the bit from the M40 to Bledlow. I guess the stronger upper winds help the lift below.
Crossing NE to Whiteleaf was easy (cost 300ft) but the ridges from there to Wendover were less good. I suspect they work best when the wind is a bit more Wl’y. Coming back I left Whiteleaf Cross at 1100ft AMSL and arrived on the ridge at Bledlow at about 800ft AMSL just below ridge height.
Played on the ridge at Chinnor for a while and then home when the wind dropped to 20Kts. Left the ridge at 1300ft and arrived at Booker at 700ft after 1Hr 40Mins of fun.
Jim
> Booker’s ridge (”Stokenchurch”? I forget)
The bit from the M40 up to Princes Risborough is often called Chinnor Ridge.