Penellype's Weather Channel

[Bacchus]

Thanks for the winderfinder site link - It took me few moments to work out you need to click on the small arrow on the box that pops up from the nearest station - which takes you to a new page that lists all the temperatures - great! The BBC site is always a good backup but the windfinder seems to be slightly more local for me by a happy coincidence.

[Penellype]

After a couple of drier days (away from the far west) rain is expected to move in from the south west tonight and move north through the day. Sunday is likely to be showery before another band of rain moves in on Monday. Overall it looks like a wet week, but at least it will be reasonably mild with little risk of frost away from high ground.

During the week high pressure will build over Scandinavia, bringing the wind back round to the east, but this time the origin of the air is the south east rather than northern Russia, so it will not be cold and snowy. With a bit of luck we will be on the edge of the high and the weather may become a little drier, although probably not completely dry.

At the end of the ensemble run several of the members (including the higher resolution operational run) go really quite cold again. This is a long way off and is in the unreliable time frame, but if this did happen it would be cold enough for frost at night and perhaps snow. It is not too late for snow at the end of April, so it wants watching.



This is the ensemble chart for York showing above average upper air temperatures for the next week to 10 days, with some big rainfall spikes next week. About half the lines take a dive to much colder than average around 20th April.

[Penellype]

Some interesting developments...

The weather for this week is still dominated by low pressure, with bands of rain (one heavy one coming tonight into tomorrow) and easterly winds, although not cold. There are some yellow warnings of rain in places metoffice.gov.uk/public/weather/warnings.

Both the ECMWF and the GFS models are now seeing high pressure building from the south around day 10 (19th April). This is predicted to position itself slightly to our east, which would draw up warm air from the south or south east, possibly giving us a taste of summer with temperatures in the low 20s and little if any rain . However on the GFS model (the ECM stops at day 10) it doesn't last long and is replaced by a northerly wind and low pressure, with much cooler temperatures again within a few days.

There is plenty of time for this to change, but I do find today's ensemble chart interesting if compared with the one I posted on 6th April:



Apart from slightly higher temperatures around the 10 day mark, these 2 charts look very, very similar. In particular, the change to colder conditions hasn't got any nearer - it is now showing around 23rd April. It will be interesting to see how this develops over the next few days.

[Penellype]

Time for an update.

The cold, grey and damp weather that plagued the country courtesy of an easterly wind has now loosened its grip. This was caused by abnormally low sea temperatures in the north sea (left over from the very cold weather earlier in the year) and illustrates just how hard it is for amateurs like me to predict what is going to happen from the models and charts. We "should" have been seeing temperatures in the mid teens during the week from the upper air temperatures and wind direction, but because the surface air was cooled by the sea and picked up moisture, all we got was cloud and drizzle which was too thick for the sun to clear away.

The pattern is now changing significantly. This is today's chart:



Here we have a deep low pressure forming in the atlantic and high pressure to the east, pulling up the wind from the south. We have lost the influence of the cold north sea, and therefore everywhere is warmer. The area of low pressure just to the west of Ireland will bring some rain today, heaviest in the west, but unlike recent lows, this one is not diving to the south of us. It will move in a much more normal northeast direction, because that is where the jet stream (roughly in the position of the thick black line between green and yellow) is going.

The bigger low could have brought us a nasty storm, but because of the high to the east it is going to stay mostly to the west (blocked by the high) as it winds itself up and moves north. It will bring a wet day mainly to the west on Tuesday, when everywhere will be windy.

However, this particular lump of cloud has a definite silver lining. Because of the strength of the low and the position of the high, it is going to suck up very warm air from the south, so by the 2nd half of the week we will have temperatures into the high teens or 20s pretty much through the whole country (as long as you are not on a mountain). There will be plenty of sunshine too, so a real taste of summer.



There is a lot of uncertainty about how long this will last - my guess is 2-3 days of warm/hot weather followed by something of a cool down with the possibility of thunder storms encroaching from the south. However, the cooler weather should still be very pleasant with temperatures in the mid teens although some rain may creep back in particularly towards the north and west as low pressure from the atlantic moves closer.

This is the ensemble chart for York:



There is a dip in the temperature as today's low moves through, with some rain associated with that, and a sharp rise (indicating wind) into Tuesday again with a little rain. Western areas will have bigger rainfall spikes than York. The continued rise in temperature during the week is clear, but the uncertainties then start to creep in, with some members keeping the high pressure longer than others. In the longer range things cool down but the upper air temperature remains generally above average. There is more in the way of rain on the chart towards the end of April with more influence from low pressure.

A lot will depend on where high pressure develops, and this is what is causing the uncertainties. Some runs of the model have high pressure building over Greenland, which is not great, whereas others have a much more normal high to the south with low pressure moving in at times but on a normal south west to north east track. This would be changeable but not cold. As everything has been so abnormal for so long, I hesitate to make any sort of prediction beyond a week or so, but I've noticed years in the past where by the end of the summer I've looked back and thought that the most summery weather was in April. The long range forecasts I have seen (very unreliable) all forecast a bad summer this year. It is therefore possible that the coming week could be the best weather of the year. I hope not.

[Penellype]

The hot weather will start to break down today as lower pressure moves in from the south west. This will create heavy showers and possibly some quite violent thunderstorms, which will move north and east through the afternoon and evening. As always with showers and storms, not everywhere will get one. At the same time a stronger low is moving in from the west and the associated fronts will bring rain to the north and west. Behind the front is much cooler air, which will bring a change to more normal temperatures for the time of year. This will move across the country during Sunday.

After that we go into a much more normal changeable westerly regime, with low pressure moving in from time to time from the west. For the next week or so these are not particularly deep lows, so we are not looking at strong winds and heavy rain but there will be rain about at times.

Towards 26-28 April there has been a consistent signal for a couple of colder nights. There has been a frost here on the night of 26th April for the last 2 years, which is interesting, so this is worth keeping an eye on if you are thinking of planting out vulnerable plants or summer bedding.

Beyond that there are huge discrepancies in the models, with this morning's GFS run going quite cold towards the end, but that is too far ahead to worry about.

This is the GFS ensemble for York:



The cooling temperature trend is clear, although in the short term it never goes far below average. There are plenty of rainfall spikes - expect these to be bigger if you are in the western half of the country.

[Nicos]

Thanks for the warning Pen...

[Penellype]

WARNING

It is now much cooler, and below average for the time of year. For at least the next week the night time temperatures are forecast to fall to between 2 and 4C here, with tomorrow night currently the coldest.

Check the forecast in your area and be prepared to bring in any tender plants and cover things like potatoes and fruit blossom.

[Small pumpkin]

Highlands & islands weather is also giving a frost warning for the weekend. I have fleece at the ready.

[Thelma Sanders]

Depressing isn't it - I've just been looking at the forecasts, as well

Started last night here, with the temperature in the greenhouse actually 4' lower than forecast, good job I thought it 'felt' cold in the evening and brought the peppers and chillis indoors.

Not really unusual for this time of year though, is it?

[Penellype]

Not unusual at all - what is unusual is the heat we had last week.

Last year the coldest night of the winter here was 26th April (-2C).

[bikermike]

It was forecast to be down to 1-2C in Barnet, but it's picked up now.

In Hay it's currently forecast to be 1C on Sat am...

Brrrr...

[1Bee]

Thanks Penellype.

I *think* everything I have out is either hardy or protected, but I guess we'll soon find out!

[Penellype]

Time for a "proper" update.

The bizarre weather this spring continues. It has now turned much colder and wetter again, especially wet over parts of England today. The main area of rain has moved away into the north sea now leaving behind some showers. Tonight could be quite cold where skies clear as winds are light.

With low pressure still in control there is likely to be showers or rain in places as associated fronts move across the country over the weekend. Sunday may be the better day of the 2. The chilly weather is once again due to the jet stream diving south - this is the position on Sunday:



Notice the low pressure forming over France - this spells trouble. This low will deepen as it drifts north and the result will be torrential rain and north easterly gales on Monday, particularly but not exclusively for the south and east. On the northern and eastern side of the low it will be cold enough for snow on hills and possibly to lower levels, although at this time of year it is unlikely to settle except on high ground. It will be a cold, raw and thoroughly unpleasant day. Over an inch of rain is possible in places as this low is not moving very fast and heavy rain could fall all day:



Once this system is out of the way the wind returns to the west and the jet stream gradually moves north so that after a few more chilly nights and possibly damp days we might see an improvement towards the bank holiday. This is getting beyond the reliable timeframe, but next Saturday's chart looks like this:



This is much better, warmer and drier (at least away from the north west) so let's hope it is right.

The ensemble chart for York shows the current colder than average conditions and the rain today and Monday. The warming trend later next week still contains a good deal of scatter, so it can't altogether be relied on:



Apologies that the screenshots come up rather small when you click on them. My new computer is HD and my screenshot software doesn't work on it, so I am trying something else, but its not great. I'll attempt to find something more satisfactory soon.

[geepee]

Time for a "proper" update.

The bizarre weather this spring continues. It has now turned much colder and wetter again, especially wet over parts of England today. The main area of rain has moved away into the north sea now leaving behind some showers. Tonight could be quite cold where skies clear as winds are light.

With low pressure still in control there is likely to be showers or rain in places as associated fronts move across the country over the weekend. Sunday may be the better day of the 2. The chilly weather is once again due to the jet stream diving south - this is the position on Sunday:

[ATTACH=CONFIG]79879[/ATTACH]

Notice the low pressure forming over France - this spells trouble. This low will deepen as it drifts north and the result will be torrential rain and north easterly gales on Monday, particularly but not exclusively for the south and east. On the northern and eastern side of the low it will be cold enough for snow on hills and possibly to lower levels, although at this time of year it is unlikely to settle except on high ground. It will be a cold, raw and thoroughly unpleasant day. Over an inch of rain is possible in places as this low is not moving very fast and heavy rain could fall all day:

[ATTACH=CONFIG]79880[/ATTACH]

Once this system is out of the way the wind returns to the west and the jet stream gradually moves north so that after a few more chilly nights and possibly damp days we might see an improvement towards the bank holiday. This is getting beyond the reliable timeframe, but next Saturday's chart looks like this:

[ATTACH=CONFIG]79881[/ATTACH]

This is much better, warmer and drier (at least away from the north west) so let's hope it is right.

The ensemble chart for York shows the current colder than average conditions and the rain today and Monday. The warming trend later next week still contains a good deal of scatter, so it can't altogether be relied on:

[ATTACH=CONFIG]79883[/ATTACH]

Apologies that the screenshots come up rather small when you click on them. My new computer is HD and my screenshot software doesn't work on it, so I am trying something else, but its not great. I'll attempt to find something more satisfactory soon.

Size doesnt matter.....its the thought and feeling/content behind it that counts.
Very informative ,as always.

[Chippy Minton]

So, I was reading a fine quality online version of a daily tabloid (therefore it must be right as you're not allowed to lie in the press )) There was a discussion of the "beauty from the east". Apparently a low forming somewhere which will pull warm weather up from the continent early/mid May. Anything showing yet on your charts Penellype?

Only really picked it up at it had some sort of meteorological reasoning behind it as opposed to the normal drivel....