Penellype's Weather Channel

[Potstubsdustbins]

Last night was exactly as you said Pen, very windy and minus 1.7C.

You should get a job with the Beeb....................

[Jay22]

Very windy here too and we had snow and sun at the same time!

[1Bee]

-1.5 at the plot last night... hail and rain, but no snow yet.

[treepixie]

It's very cold here and windy, everything covered or fleeced

[Penellype]

Really really difficult conditions for gardeners to manage at the moment.

Sleet, snow and hail here this afternoon and some vicious gusts of wind. Attempts at putting nets and plastic covers over some of the leafy veg to protect them from hail had me running round the garden chasing low flying objects. Then 10 minutes later I was removing the plastic covers from the pak choi and namenia for fear of them getting too hot in the sun, which might make them bolt...

More of the same tonight and tomorrow. Tomorrow night sees lighter winds but still a frost risk - this continues into Saturday as things warm up only slowly. The bank holiday is looking very mixed with the potential for quite a bit of rain but there is a great deal of uncertainty at the moment about what happens next.

[Greenleaves]

I'll take rain

[bramble]

Fleeced and covered all I could yesterday evening.
I had three chilli peppers in the greenhouse grown from seed this year so still fairly small.
So I decided to bring them into the house in case the cold killed them.
On the way back to the house I got side tracked and put them down out of my hand.
When I went out this morning they were sitting where I left them and they were fine.
So much for worrying.

[burnie]

Not that cold up here today, plus 2 in the greenhouse overnight and 9 degrees outside and a bit of sun, but a bitter cold wind. Was over at my daughters in Perth and the hills were mostly white with snow, but none lower down, saw lots of wildlife driving to and fro, swallows and house martins around and 2 brown hares near our village on the return journey, must get over with the camera and big lens.

[Penellype]

The worst of the cold this time seems to have been in the south and west. Showers coming in off the north sea have decayed to cloud for more northern and eastern areas, protecting us from the worst of the cold.

[Penellype]

The cold spell is coming to an end now as the wind backs round to the west. The next couple of days should be reasonable, although the temperatures will be nothing to get excited about and there remains a slight frost risk at night.

Tomorrow's chart looks like this:



Low pressure is in the atlantic with the high building over Scandinavia. This is going to prevent the low from taking its usual track and it will extend southwards instead. This is always tricky to forecast, with the exact track of the low, and therefore the position of any associated fronts and rain, subject to considerable uncertainty. Currently Sunday's chart looks like this:



The wind is now coming up from the south east so it will be warmer, but with the low in this position it is likely to be wet, particularly in the south and west. Notice the next low waiting to the south of Greenland, and the high curving back towards Greenland - this is the start of northern blocking and will fix the weather pattern for at least the next month or so. The lows are becoming stuck in the atlantic, and the low south of Greenland is about to suck warm air north to join the developing high. As this happens the winds will swing round to the east. This is the position forecast for Thursday:



In winter this is a classic cold setup - it would be frosty or snowy and bitterly cold. Thankfully in May it isn't so bad, but the air is still coming from the Baltic so it is not going to be a heatwave. However it would be mostly dry, except perhaps for the south east corner of the country.

The important aspect of this setup is the track of the low pressure systems which are starting to move underneath the blocking high. If they stay to the south of us it should be mostly dry and average to cool. If they establish a track further north we could be in for a cool and wet month or two. Currently the GFS model appears to be favouring the 2nd of these, but this is not the only possible solution from this position.

This chart, for 9th May, would be cool and pretty wet, especially in the south:



The ensemble chart for York shows that earlier predictions of a possible heatwave for next week are unlikely to happen, and that the current GFS operational run (thick green line), from which the above charts were taken, is one of the colder ones:



Note that the rainfall spikes at the bottom have generally increased in size since the last time I posted one of these.

[Ms-T]

Happy to have more rain in the south east we need it badly .

[Penellype]

No rain here today, having had it forecast for much of the past week. It fizzled out around Leeds.

The models are sticking to the idea of the high pressure building to the north and moving across towards Greenland (retrogressing), but it is slightly further south than in my last post, which reduces the rain risk. However, a worrying development over the past day or so is that around 9th May most of the runs are forecasting another cold snap:



Some of these runs are pretty cold, quite cold enough for night time frosts and wintery showers. The trouble with this sort of pattern is that it rather easily puts us into a northerly wind:



This isn't quite as directly from the north as last time (the thick green line is not one of the coldest), but its coming from a pretty cold part of the world and it wouldn't take much of an adjustment to put us directly in the firing line.

Don't put the fleece away just yet!

[Penellype]

Everything has been progressing very much as expected, with most places away from the far south west staying dry and the wind coming from the east or north east. Western areas have had plenty of warm sunshine but colder nights, while eastern areas have been cooler and cloudier but with warmer nights. It has felt very chilly at times in the fairly stiff breeze.

Things remain much the same for the next few days, but the high pressure is gradually slipping away westwards and this will eventually lead to a change in wind direction and possibly some much needed rain as low pressure moves in:



By Friday the low is bringing up warmer air from the south west, but there would be fronts associated with this bringing rain. Quite how much rain is open to question. After this we have disagreement between the models, with the GFS wanting to keep us wet and possibly fairly windy for a week:



while the ECMWF brings back the high pressure:



Therefore, although the ensemble chart looks quite wet after the end of next week, I wouldn't bank on this actually happening:



For the next week or so keep an eye on the forecasts because where skies are clear and winds fall light there is still the possibility of ground frost in vulnerable areas.

[Penellype]

So, the forecast rain has arrived, at least if you live in the western half of the country. We've had light intermittent drizzle here but no measurable rain

The low pressure that is bringing the rain is moving up from the south, bringing a showery airstream which will persist over the weekend. The showers are likely to be heaviest in the north with hail possible. The low pressure sticks around to the north west of Scotland, with more fronts moving across the country on Monday and Tuesday. There will be drier interludes and the flow is from the south west so it will be warm and probably muggy. The warm spell doesn't last and by Friday temperatures will be nearer average for the time of year.

Beyond that there is more uncertainty, with this morning's GFS operational run (thick green line) going quite cold, but with little support from other ensemble runs:



The rainfall spikes along the bottom show the increased risk of rain for the next week or so, after which it seems to mostly fizzle out. Some of this, particularly around 17th-19th could well be in the form of thunderstorms as a cold front moves into very warm air.

Note how unlevel the red 30 year average line is, illustrating the vast range of temperatures possible at this time of year.

[Greenleaves]

Penellype, shall we edit the thread title to Spring/Summer or would you like a new sticky thread for that?