Penellype's Weather Channel

[Penellype]

Thanks Penellype - really interesting read.

What does the seaweed say?

Not sure about the seaweed, but I do like this:
John

[emarisa28]

Looks like the cold snap could be starting next week
https://uk.yahoo.com/news/brrr-winte...409520182.html

Will this help kill the bugs in my soil?

[Penellype]

I wouldn't expect it to be cold enough to kill bugs at this time of year. The sort of cold that does that would be where the soil freezes solid and stays that way for a few days. The current forecast for early November is for night frosts but not staying below freezing all day.

[veggiechicken]

Looks like the cold snap could be starting next week
https://uk.yahoo.com/news/brrr-winte...409520182.html

Will this help kill the bugs in my soil?

I'm not going to panic having read that article!

"Describing the drop, Met Office forecaster Nicky Maxey warned that temperatures could be about to fall into single figures.

‘We could be looking at one or two degrees below what we’d expect at that time of year’, she said."

Doubt that I'll notice one or two degrees difference. Never mind, the snow picture was pretty

[Cadalot]

Just read the thread and even the well constructed thoughts of Panllype have a lot of IF's in the reasoning.

As my old Dad use to say IF is a very small word with a very large meaning, IF your Auntie had balls she would be your Uncle!

I'm happy to wait for the weather to unfold and react to it as it happens

[Bigmallly]

I think it is just preparatory info Cad. We either take note or we don't.

[Thelma Sanders]

I think it is just preparatory info Cad. We either take note or we don't.

IMO it's always better to be prepared, just in case, rather than just hope for the best.

Like when the MetO gives storm warnings, you batten down the hatches but no storm arrives. We moan, but how bad could things have been if the storm had hit us without the warning?

[Cadalot]

Since Michael Fish screwed up bigtime they give warnings about everything, and now nobody really takes any notice.

[vixylix]

Thanks P - very good for a layman to understand!

I hate Winter, but I'm very much hoping for a 'normal' cold winter, and hopefully a 'normal' spring to give mother nature a helping hand

[Penellype]

Just read the thread and even the well constructed thoughts of Panllype have a lot of IF's in the reasoning.

As my old Dad use to say IF is a very small word with a very large meaning, IF your Auntie had balls she would be your Uncle!

I'm happy to wait for the weather to unfold and react to it as it happens

Anyone who produces a forecast beyond the next 3-5 days without qualifying it with ifs and buts is either deluded or doesn't understand the subject. It is simply impossible to forecast long range with any accuracy. All you can do is look at the most likely scenarios.

The reason for starting this thread is that I know that people on here are perhaps experimenting with growing things out of season, and it can be helpful to have things like fleece or bubble wrap to hand rather than having to try to find something suitable at the last minute.

[vixylix]

*EDIT* and kill off all the whitefly

[sparrow100]

Thanks penellype for going to the trouble of typing all this out. It's a fascinating read. Am heeding the warnings personally and hoping for a decent winter.

[Greenleaves]

I agree with Sparrow, it does help in the planning...better to be prepared than caught lacking. Penellype clearly states it is not a forecast but an indication based on current weather paterns/data.

[Penellype]

As we start November the first signs of colder weather are beginning to show up on the models. This is what we are seeing at the moment, with an (I hope) comprehensible explanation. Charts are from TheWeatherOutlook - latest UK weather forecasts, reports and news and are from the American GFS model which is used by many weather apps and forecasting sites.

Today



High pressure and warm air are over the country, creating a lot of cloud, but generally mainly dry and mild.

Tuesday night



A cold front has moved down over the country introducing colder air - note that the high pressure is to the west and low to the east, resulting in a northerly wind. The green and blue colours are just grazing the east coast. Likely to be much less cloudy and with a cooler air mass, frost at night almost anywhere. Keep an eye on forecasts. This is within the "reliable" timeframe of the models now, and there is good agreement - see below.

During the remainder of the week things warm up slightly as the wind swings round to the west, but this does not last long...

Saturday morning (a week today)



Once again the high pressure is moving towards Greenland and this time the colder air is over the country, especially the east. A low pressure system is not far away and if this were to happen there could easily be snow showers in the east. This is NOT within the reliable timeframe of the model yet - see below.

Once again the cold doesn't last that long, although the temperature does not rise as far as it did before.

2 weeks away (Sat 12th November)



This shows another hit of cold weather as the pattern re-estabishes itself. Notice that each time this happens more of the country is covered in blue. This would be cold enough for snow in many places given the required cloud and precipitation. This is in fantasy land at the moment, but has consistently appeared in the last few runs of the GFS model.

So, how do we interpret this lot?



This is the "ensemble" graph of the upper air temperatures (for York) from http://www.wetterzentrale.de/. There are 20 model runs starting from very slightly different conditions (within experimental error). Each is shown in a different colour. The red line is the 30 year average for the time of year and the white line is the average of all of the runs. Tuesday night's drop in temperature shows up very clearly on every single one of the 20 lines. This makes it extremely likely (and there is also agreement from other models such as the Met Office and European ECMWF).

After Tuesday the graph tells us to be more cautious, particularly about the charts posted above. The thick green line is the "operational" run, the one that the charts are made up from. This is the highest resolution run, and in theory the most accurate. However, looking at this graph you can clearly see that between 3rd and 9th November and again from 11th to the end of the graph, the thick green line is one of the coldest runs. Even by bonfire night there is quite a big spread, and many of the lines don't see the 2 cold spells at all at this stage. The white average line is nowhere near the -5C upper air temperature required for snow.

So, what do we make of this? I think it is clear that it is going to get much colder after Monday with a very real threat of night frosts. The current warmth is unlikely to reappear - none of the lines take us back to where we are now. Weather will be more "seasonal" - this is not a big freeze, although the tabloids may say otherwise!

Beyond Tuesday, be aware that the threat exists of short and possibly increasingly cold snaps maybe with the threat of snow in places At the moment this is only a possibility, not a probability, and things will become clearer nearer the time.

[SusieG]

^^^^^^^ phew..!!! Thanks Pen..! ^^^^^^^