Glidemet

May as well get it out of the way quickly.

This bank holiday weekend it will be mostly raining. Yes, I know what I said in previous forecasts, but it happens. Whereas before it looked like high pressure kept incoming Atlantic fronts just at bay, now they don’t. Low pressure dominates.

So tomorrow (Wednesday) East Anglia should be good for a few hours for 3,500—4,000 ft, but cloudy elsewhere. Thursday looks rather good in the southwest and south Wales. Friday could be pretty useful in most places.

Then the rain comes.

Monday sees a weak northerly flow set up as the high that has dominated our weather for the last few days looses its identity (low fill, highs… deflate?). As such it’s quite hard to pin down where will be good and where will be bad. The northeast will probably be a bit damp with a low spreading cloudbase. The Pennines will likely prevent that air affecting the northwest too much, so I suspect we’ll see cloud bases to 4,000 ft without too much spreadout.

Through the midlands, making slow progress southwards, a weak and shallow cold front marks the boundary of the cooler damper northern air meeting the still-warm south, and so will likely be just spreadout stratocumulus. Just to the south though, roughly south Wales to Suffolk at noon, fair conditions with bases to over 4,000 ft in Wales, but down to 3,000 ft in the east. This zone slowly moves south through the day but the associated cloud bases rise—-6,000 ft is not out of the question in south Wales, while 4,500 ft should be seen around the Dunstable area.

South of this area and down into Kent will be blue until early afternoon when quite high cumulus will appear and go to nigh 5,000 ft as far south as Lasham. Beyond there lower/bluer. Generally blue in the southwest but still thermic.

I don’t think one day has ever taken so long to describe. It’ll probably all turn out to be toss anyway.

Tuesday, generally cloudy with only Kent having a bit of a chance. I haven’t really been monitoring the charts as far ahead as Wednesday but right now they show something of a showery low in the Channel with just cloud to the north. The details of the low will probably change but I doubt the general story will much. Thursday looks positively wet on the rear flank of that low with only the southwest peeking out in sunshine, but confidence is marginal. Friday—-hints of ridging with a bit of a northerly (sounds like Monday!). Weekend (have been monitoring, fair consistency on this) looks reasonably settled, again under a weakly ridged mainly northerly flow.

Tomorrow (Saturday) unfortunately now looks to be blue for much of the south. Given the expected surface temperatures thermals will reach an inversion at about 4,000 ft, but as gliders can’t climb to the very top of thermals due to their inherent sink rate, climbs will generally feel like they’re topping out at around 3-3,5,000 ft. Cirrus cover will be much less tomorrow so that will at least help boost climb strengths compared to today. Sea breezes will get a long way into East Anglia and some way into the north east coast, but the influx of moister air will help provide moisture for cumulus, although the climbs they mark probably won’t work too well. Should also be some sea breeze lines along the south coast, and near western coasts too.

The north and Wales should see much more cumulus with bases to about 4,000 ft, with a fair chance of going up to 5,000 ft in the afternoon—-probably the best areas in the country.

Winds will be light westerlies in the north, slack in the midlands, and about ten knots from the east in the south (the result of having high pressure smack over the country).

Sunday again looks best over Wales and the West Midlands (basically Shobdon/Mynd territory), and not bad in the north either although some showers may kick off on the eastern slopes of the Pennines. The south looks “low and blue” (how I hate typing that). Probably the hottest day of the day so far.

Monday looks a right mixed bag, rather cloudy in the north but possibly quite good from North Wales to London and southwestwards, possibly booming along the sea breeze on the south coast. Tuesday a bit cloudy and touch damp for most.

I have to say that when I briefly looked at the ladder on Tuesday evening I was worried that I’d over-egged the day. Since then though lots of flights have been added, including several crackers from Sutton Bank to Scotland and back. I was really hoping to see that. (Yeah, and the 13 syndicate did 99% of Dunstable—Scotland—Dunstable. FAIL!  )

Tomorrow (Thursday) sees the remains of the warm front fading out and hence although it will be convective it will generally tend to early and extensive spreadout pretty much everywhere apart from the eastern Highlands!

Friday is when things improve with the damp air continuing to ease away eastwards. The west is where the good air will be with Cumbria—Wales—SW peninsula all looking good for about 4,000 ft but not too much spreadout. A hint of an easterly flow will retard in the inland penetration of the sea breeze in these areas, keeping the good area larger for longer. The east of the country probably still too claggy for anything good.

Saturday is looking a rather fine day. The residual moisture has been off-set by subsidence warming the airmass through compression reducing the relative humidity. Upshot is a fairly low inversion, about 4-5,000 ft, but a low risk of spreadout, so good cumulus over most of the country south of about Leeds; remains a bit damp further north. However an easterly flow of about 10 knots at height will encourage strong sea breeze penetration a long way inland all down the east coast, so careful task setting will be required. A good day though.

Sunday looks similar, with less wind but cumulus bases a bit lower with a risk of spreadout due to moisture advected in from the North Sea over night. Of course we’re talking about five days ahead so detail like that is subject to change.

A rough-and-ready outlook is for something of a northerly flow to return early next—-chilly! And with a long sea track, probably rather cloudy. We’ll see.

And who are also checking here (why?? )—-did you get tonight’s (“Monday”) forecast twice? Might be a wee bug in the system. (This post is in the “information” category, so should not be emailed out, unless you actively chose to subscribe to it.)

Flight of the day belongs to… well, yeah, it’s the 13 syndicate again. But this time only because:

1. They flew over where I’m currently working (in Oxfordshire)
2. They flew over my house in Exeter (well, close to it, certainly within sight)
3. They then flew over where I was working. Again. I could have seen them over DID had I looked up at the right moment.

Considering that the same journey by car would have taken the same six hours that the pilots took to fly the task, that’s… quite cool.

Tomorrow (Tuesday), despite the cirrus lurking about the south of England at the moment, doesn’t look that bad. Said cirrus moves off to the south overnight, while most of England and Wales stays in thermic air. The north of England will be the best area, with good bases to over 4,000 ft by mid-morning continuing up to 6,000 ft in places in the afternoon in a large area from Nottingham to southern Scotland. Further south bases will be a little lower and a tiny bit more prone to spreadout, but really quite a good day there too, though a few light showers are likely in central southern England. Very light westerly winds at height. Far west might be afflicted by top cover.

Wednesday looks weakly useable in the east, but top/medium cover will likely spoil the west. Thursday sees high pressure becoming established over us but it looks a tad damp. Definitely soarable though. The high remains in place through Friday and the weekend, drying out with time with Saturday looking excellent, but Sunday sees a bit of cloud coming in from the east on current runs, so not so good.