Penellype's Weather Channel

[Penellype]

Whatever you think best - I'm happy either way.

[Greenleaves]

Whatever you think best - I'm happy either way.

Changed the title to "Penellype's Weather Channel"

[Penellype]

Changed the title to "Penellype's Weather Channel"

That's great, thanks for that.

[1Bee]

We've had light rain but nothing like what we need. I don't think I've ever seen the lakes and rivers so low at this time of year.

[Penellype]

I think we will all see some rain over the next week or so. It may not be enough to return water levels to normal, but it should give some relief from the relentless dry conditions.

[1Bee]

I'm on clay/till and my top soil is blowing away....

[Penellype]

The dry spell has now well and truly broken and most places have had some rain. Things are looking very wet indeed in the midlands southwards tomorrow with over an inch of rain possible.

This is the chart for midnight tonight:



I must confess that to my untrained eye this looks like a straightforward case of a warm and humid southwesterly flow with probably rain in the north west courtesy of the low pressure in the Atlantic. Given this chart alone I would have got the forecast completely and utterly wrong. I can't see it at all, but the "fax" chart (the human interpretation of the models) for the same time shows the reason for the wet weather in the south:



These 2 fronts are not going anywhere fast and what will happen is that a little kink in the front will develop, creating a small but active area of low pressure which will move into the north sea by Thursday:



The associated fronts will then move away slowly.

After this the models show high pressure building over Greenland, Iceland and Scandinavia, with the UK sitting under a trough of low pressure underneath:



The high pressure to the north forces the lows to run underneath it, leaving us in a cool and changeable westerly pattern, so that a week later we still have this:



This is not great news for the bank holiday, which looks like being something of a washout at present.

How long this pattern lasts is anyone's guess, but it looks like a fairly classic blocking pattern to me. From past records of summers following very warm and dry springs there looks to be a high chance that this sort of pattern could continue through the summer. There are exceptions, including notably warm dry summers like 1976, but the fact that the weather has now broken seems to indicate that the wetter option is likely. I could be completely wrong, and I hope I am, but I think we may have seen the best of "summer" already.

[Nicos]

Hopefully for once you are!....

[Penellype]

Watching this evening's charts appear with interest as in the last 24 hours the models have completely changed their minds. Having pointed resolutely to a cool unsettled regime for the rest of May, suddenly we have this for Wednesday next week:



Astonishingly (in view of what has been showing until the last 12 hrs or so), the ECMWF, Met Office and GEM models are in broad agreement, a complete turnaround. Something in the way the latest low pressure system (today's rain) has developed must have caused a change in thinking - I know the models didn't see today's development at all until late on Wednesday.

Taste of summer anyone?

[Thelma Sanders]

Taste of summer anyone?

Oh yes please
We badly needed the rain, but it brought chilly days as well, and I'm fed up with it now

[Greenleaves]

Thanks Penellype, you can ask them to turn the rain off now

[Penellype]

This is the forecast accumulated rainfall from midday today to 6pm Tuesday (the furthest we can go) from the high resolution Arpege model:



There is really very little for most of England and Wales, the bulk of it falling as showers tomorrow (not everywhere will get one). The larger totals over Scotland, N Ireland and the north of England mostly arrive on Monday night.

[Potstubsdustbins]

I think I may even have been able to forecast the change to hot weather myself its always the same that week, by 'that week' I mean the week my son goes.............................on holiday. It is such a regular event that SWMBO and myself have already booked days out for the bank holiday week.

[Penellype]

Here is the mid-day ensemble run for York showing the rise in temperature and (mostly) lack of rainfall for the next week or so:

[Penellype]

Some very heavy showers and a few thunderstorms around today, but there should be far fewer of them tomorrow. Looking increasingly dry and warm with little risk of frost this week after tonight except on Scottish hills. A good opportunity to get plants out I think.

It could all end with an almighty bang sometime around or after the bank holiday...