Penellype's Weather Channel 2

[Plot70]

I did get a report of heavy rain several miles away but just not locally.

[Mr Bones]

Thanks Pen, that's interesting about rain evaporating on the way down. I had no idea it could happen .. the things you learn on a gardening forum

[Nicos]

We got a few of those massive drops of rain this afternoon. Sploshes the size of a 50p coin!

I got all excited for a moment…who would have thought I’d be excited at the prospect of more rain a few weeks ago!

[Chippy Minton]

most of the small stuff will evaporate on the way down.

That's called virga that is, precipitation that falls but doesn't reach the ground. I believe that is possibly the most useless piece of information that resides in my head but it is the 2nd time I have been able to use it, the first being my daughter's GCSE Geography homework when she had to do a meteorological word for each letter of the alphabet, that was the only 'v' I could think of.....

Could do with a drop of rain and I almost never say that from the north-west. I'm just about through the 1,100 litres of rainwater collected earlier in the year.

[Nicos]

^^^^ interesting!…you learn something every day on here

We didn’t notice any virga ( first time I’ve used that word) but instead a massive thunderstorm with hailstones….fantastically exciting!

And yup , it’s heading North

[Penellype]

That's called virga that is, precipitation that falls but doesn't reach the ground. I believe that is possibly the most useless piece of information that resides in my head but it is the 2nd time I have been able to use it, the first being my daughter's GCSE Geography homework when she had to do a meteorological word for each letter of the alphabet, that was the only 'v' I could think of.....

Could do with a drop of rain and I almost never say that from the north-west. I'm just about through the 1,100 litres of rainwater collected earlier in the year.

Yes, virga, or fallstreaks, are the grey streaks that you sometimes see under clouds but not falling as far as the ground.

More useless information - that smell you get when rain falls on dry ground is called petrichor.

[Penellype]

The met office have released various warnings (yellow and amber) for thunderstorms and heavy rain. These tend to be rather short notice as the situation develops, so it is a good idea to keep an eye on the met office at the moment.

Current amber warnings are for Scotland from today to Thursday, but there is a yellow thunderstorm warning for today and tomorrow covering much of the country from the midlands northwards.

[Penellype]

Met Office amber and yellow wind warnings for parts of the south west over night and into tomorrow from storm Evert. Even outside the warning area it will be a lot more windy than most of us have been used to, so make sure garden furniture, trampolines etc are anchored and plants are well tied in.

[Plot70]

It is getting a bit draughty here in the east midlands.
It has pushed many of three squash leaves over allowing the sun in to ripen the fruits.
It has come at the right time.

[Nicos]

Ok - thanks for the warning Pen.

[quanglewangle]

Wind is getting up here in the far southwest.

My wind guage is broken but I reckon it is currently F7, half gale, maybe 30kts. Just south of west. Luckily we have a hill with a 50m rise 400m in that direction, which takes some of the sting out of it.

Expecting F8, gale later. Should be gone by morning though.

[Nicos]

Wind getting up here

I found this map which shows the eye of the storm almost over your house Q…



Keep those red shoes to hand just in case!

Keep safe everyone - hope there’s not too much damage.

[quanglewangle]

All over by 02:00 here. Not that I got up to look, but the noise stopped.

[sandspider]

Hi Penelope. Hope all is well! Wondering if you have any thoughts on what autumn is likely to be like? The chap at weather without technology thinks it's going to be mainly wet and cold, and the chances are he's right, I fear!

[Penellype]

Hi Penelope. Hope all is well! Wondering if you have any thoughts on what autumn is likely to be like? The chap at weather without technology thinks it's going to be mainly wet and cold, and the chances are he's right, I fear!

Sorry, been really busy with work this last couple of weeks. I've been meaning to post about the impending "heatwave" for the last week of August, that the models have been showing and which has now pretty much completely disappeared. Every single one of the short range models got this wrong, although they were flipping about like a fish out of water at times. The one thing that does seem to have been pointing in the right direction (assuming the heatwave doesn't arrive) is atmospheric angular momentum (AAM), which seems to be linked to something called the MJO (Madden-Julian Oscillation), which is to do with the state of the atmosphere around the equator. I do not pretend to understand the first thing about how this works, and I rely on my information about it from following Matt Hugo on Twitter. Consistently throughout this year, when models have been uncertain the AAM seems to have pointed vaguely in the right direction. The latest I can find from Matt about this is that the AAM remains negative, which does not bode well for late August and early September, and that an extended period of heat is unlikely. High pressure is not to be ruled out at this time of year - one of the difficult things about the MJO is that the same thing results in different weather here depending on the time of year.

Higher pressure does seem to be likely over the next couple of weeks, and as always it is the position of the high that causes all the headaches. Current models have the centre of the high mostly to the west of us, which brings the wind in from a north or north west direction, so in general rather cool. Some of the models have the high moving further north, and this can allow low pressure to develop to the south, which is what has happened a couple of times already this year. This turns the wind into the east, which can be warm or hot, if there is a southerly component (of which there is little sign on the charts I have seen).

One of the big unknowns at this time of year is what happens to ex-hurricanes as they move towards the north pole. After a quiet month or so there are signs of the hurricane season waking up and this can dramatically change the weather pattern for us. There is therefore always more uncertainty at this time of year than in the summer.

Other drivers that are important are the developing, probably weak La Nina, the stage of the solar cycle and the QBO which is now in its easterly phase. The recent weather and these drivers, along with the sea surface temperatures in the Atlantic all bear quite a striking similarity to 2010.

So, the autumn. If pressed, my forecast would be tentatively for higher pressure through September, probably centred somewhere north of us, resulting in mainly dry conditions (particularly the further north you go) but with the potential for more unsettled interludes if an ex-hurricane heads this way. October could also be high pressure dominated, with the possibility of a late burst of warmth (which I seem to remember happened in 2010). I do not expect either September or October to be particularly wet (except possibly in the south) from the charts I have seen. All the while I expect to see high pressure building over the arctic and the effects of this to start to be felt in November. I think November will be cold, potentially with some snow, and I expect that to continue into the first part of the winter at least. ALL of the drivers that I know about are pointing to a cold winter this year.

There, I have stuck my neck out this time. Remember, I have no training at all in meteorology, and therefore at best my forecast is a very slightly educated guess.

I hope I am wrong about winter - I hate cold winters.