Penellype's Weather Channel

[1Bee]

We're getting some, but just enough to wet the leaves for blight, not enough to soak the ground... Grr. Our soil, which is too wet to work for 6 months of the year, is dry as dust, inches down.

No doubt i'll be complaining about the rain soon enough...

[Penellype]

A yellow warning of rain has been issued for the north west and parts of Scotland today where there may be slow moving thundery showers, see - https://www.metoffice.gov.uk/public/weather/warnings for details.

The general weather pattern of slack high pressure to the north and east with low to the south has not changed much for some time now. Ths has resulted in some warm and sunny weather for some places, thunderstorms for others and a generally cool and cloudy situation for the east. Next week looks set to produce something of a change, but maybe not the one that was expected.

Until yesterday all the models appeared in agreement that we were due for a more unsettled period next week with low pressure moving in from the atlantic. Recent runs have changed this, with a ridge forming in the atlantic which is forecast to topple over us during the week, pushing the low currently over Spain away to the east. This means more warm and dry weather for the south and east, with more in the way of sunshine likely in eastern areas. The north and west are likely to be wetter and possibly windy for a while.

It is possible that the models may revert to their original idea and bring the lows (and the jet stream) further south, giving a more unsettled picture everywhere - when they change suddenly like this it can simply reflect uncertainty in the general position. Hopefully though we will get rid of the humidity, which has returned with the thunderstorms, for a while.

[1Bee]

Pene, do you know where I can find out how much rain we've had locally over the last weeks? I had a Google but couldn't find what I was looking for. Thanks.

[Penellype]

Hmm, I think your best bet is to find the nearest weather station on Wunderground, for example this one in Carlisle https://www.wunderground.com/persona...RLISL2#history. You can step back by a day, week, month or year at a time and look at the totals. Some weather stations don't measure precipitation so you may need to find one that does, and the ones with the gold medal by the name (as this one has) are the most reliable.

The Wunderground site can be very slow, and is rather slow this evening.

[1Bee]

Thanks Pene. I've had a good furtle around there, but I can't find exactly what I'm looking for. I suspect there aren't stations close enough in an area that has very localised weather. I've lost count of the times I've drive through rain on the way home from work to find the plot still bone dry....

[Penellype]

The current showery weather is often very localised - one day recently it rained hard at the stables (3 miles away) but was almost dry here.

[Penellype]

More yellow warnings of rain today in the north east and south west - see https://www.metoffice.gov.uk/public/weather/warnings for details. It certainly looks very showery here, and with little wind the showers are not moving much.

The models are now firming up on a change to more unsettled weather, with a vigorous low pressure system moving through on Thursday. This will bring some rain and strong winds for a time in northern and western areas - make sure things are fastened down well as there could be some hefty gusts and we haven't had much in the way of wind recently.

The weekend looks likely to be cool and unsettled, after that there is a lot of uncertainty.

[Penellype]

More yellow warnings, this time for wind Wednesday night into Thursday. The warnings are for the north, with gusts upto 70mph for coasts and hills but it will be windy everywhere.

[Potstubsdustbins]

That will be the hanging baskets into shelter then..

Thanks Pen

[Chippy Minton]

........ after that there is a lot of uncertainty.

Not according to the Daily Moan:

"forecasters predict three MORE months of heatwaves with temperatures rocketing to 85F until August"

Note "more" in capitals, therefore it must be extra true....

"Britain could be gearing up for a three-month heatwave in which temperatures skyrocket to 85F (29C) by the first week of July, according to forecasters. "

Now pulling it back to "could be", but using Fahrenheit and skyrockets (not sure where else a rocket would go) to make it sound more dramatic.

You're not allowed to lie in the papers so...... (and it's "according to forecasters" so must be true, like according to scientists...) Apparently Thirlmere's looking a bit low.

Will carry on following your forecasts P, they're much more accurate, if less dramatic

[Penellype]

Not according to the Daily Moan:

"forecasters predict three MORE months of heatwaves with temperatures rocketing to 85F until August"

Note "more" in capitals, therefore it must be extra true....

"Britain could be gearing up for a three-month heatwave in which temperatures skyrocket to 85F (29C) by the first week of July, according to forecasters. "

Now pulling it back to "could be", but using Fahrenheit and skyrockets (not sure where else a rocket would go) to make it sound more dramatic.

You're not allowed to lie in the papers so...... (and it's "according to forecasters" so must be true, like according to scientists...) Apparently Thirlmere's looking a bit low.

Will carry on following your forecasts P, they're much more accurate, if less dramatic

The models have only got to hint at a probability of something slightly above/below average and we get this hyperbole. All of the longer range models are climate models (rather than weather models) and the climate is in general warmer than it was in the 1960-80 average period that is generally used for comparison, particularly by the Met Office, so there is a tendency for the forecasts to predict warmer than average. In addition some of the long range models (including the Met Office) use probability rather than specific forecasts. So when the Met Office released their 3 month contingency planners guidelines they said that a warm and dry summer was more likely than a cold and wet one. They produced a set of charts and graphs illustrating this, and as with all statistical probabilities there is a spread of possible outcomes with the high point of the graph being the most likely. The newspapers read two words - warmer, drier, and go off and forecast a record heatwave.

There are of course other long range models - about 12 that I know of. The forecasts that they produce vary from day to day and the papers can pick and choose the ones they like the look of. If you choose carefully amongst these you can usually predict anything you want to see, because long range forecasting is experimental and often little better than guesswork.

To return to a more sensible view of this summer, it seems to me that the weather has been in a particular pattern for quite a while now, with high pressure over northern Europe and also ridging up from the Azores. This pattern gave us the Beast from the East in early spring and it has been responsible for the unusually dry and sunny weather experienced by parts of the country especially the north and west, in May. This pattern is currently being broken down as the jet stream strengthens (possibly caused by a warm mid atlantic) and a noticeable change starts from the west today. This is not unusual as the jet stream does tend to strengthen a bit in June - May is its quietest month.

There are 2 possible outcomes from this (effectively stating the obvious). Either the breakdown will be temporary and the pattern will return, in which case a heatwave is a possibility depending on the precise position of high pressure. Or a fundamental change will take place in the pattern and something else will take over. The models are split over which of these is the most likely, with some of the long range ones going for a return to what we had before, and it is these that the papers will be noticing.

My guess, for what it is worth, is that the pattern of high pressure is fairly strongly entrenched, possibly due to the current easterly QBO, which suppresses the jet stream somewhat. I therefore expect the basic pattern to remain, but as many places have seen over the past few weeks, high pressure does not always mean fine and sunny. The position is crucial - it can be cool if you are on the wrong side of the high, it can be cloudy or humid and thundery or it can be hot and sunny. What it is unlikely to be is repeatedly wet and windy as that is low pressure weather - and that is what we are getting next.

Today's GFS charts (for York) show the low pressure that is coming well:





The first chart shows the warm spike associated with the warm sector of the low, and the associated rain at the bottom - there will be more rain the further north and west you are, very little in the south and east. For the eastern side of the country at least, there is very little in the way of rain on the chart throughout the forecast period. The 2nd chart shows the corresponding surface temperatures (top) and pressure (bottom). The saw tooth appearance of the temperature line is due to the day and night fluctuations. Note the sudden dip in pressure as the low passes. The cooler air mass introduced by the change to more atlantic driven weather results in a drop in surface temperatures, although nothing particularly drastic. These then recover into next week as pressure rises again. Beyond that the pressure predictions are all over the shop, with some ensemble members forecasting steady high pressure and others a considerable drop, illustrating the uncertainty at this range. Bear in mind that although the 5 day prediction is reasonably accurate much of the time from these short term models and the next 5 days is a fair shot at the likely outcome some of the time, anything beyond 10 days is very tentative and can't be relied on.

[1Bee]

So, Thursday's storm and Saturday's forecast rain notwithstanding, should I buy a hosepipe....? Beginning to think this sort of dry weather is not going to be the exception any more, and my shoulders are seriously protesting the water portage...

[Penellype]

So, Thursday's storm and Saturday's forecast rain notwithstanding, should I buy a hosepipe....? Beginning to think this sort of dry weather is not going to be the exception any more, and my shoulders are seriously protesting the water portage...

The north west is always going to be wetter than here in York, simply because of its position next to the atlantic. The corresponding chart for Carlisle, which is more in your direction, is this:



Even then the rainfall spikes are small.

Whether you buy a hosepipe or not is up to you. I don't think you can say that the dry weather is a long term trend, its more likely to be a blip. We do get dry summers - I still remember 1976 when the ground was baked hard with huge cracks in it, everywhere was brown and there was a shortage of water through the whole country. That drought started in the summer of 1975 and lasted over a year, but we haven't seen anything comparable since, although one year in the 90s, possibly 1996, was pretty dry.

[Penellype]

The Met Office have upgraded the warning for wind to amber for parts of Northern Ireland. Met Eirann, The Irish Met Office, have named the storm Hector.

[Chippy Minton]

So, Thursday's storm and Saturday's forecast rain notwithstanding, should I buy a hosepipe....?

Our problem in the north-west (and we're only just in), is that we generally use a hosepipe, if we have such a thing, to pump water out rather than bring it in! Reversing the flow takes time