Watch out for the F word next week

[Penellype]

This year has been bizarre and autumn appears to have set in a month or so early. After more rain and gales (there is already a warning of wind for northern areas on Sunday), the latest runs of the models are showing some particularly cold temperatures especially on the western side of the country for next Thursday night.
Chart for 6am Friday 22nd August:


Yes, those are small patches of blue in there! This is a long way off and things could change, but it is worth keeping an eye on this page: weather model gfs - united kingdom - temperature low (2m) [base + 6] - zoom - weatheronline

[solway cropper]

I'd be in a permanent state of panic if I took any notice of most weather forecasts. The met office admit that forecasting beyond the next 48 hours is fraught with difficulty. Up here we have a simple technique: if you can see Skiddaw it's going to rain and if you can't see Skiddaw it IS raining!

[Kirk]

Well August has been a lot cooler then one would expect.
My job for the weekend is to add a shelf to the cupboard and sort out the assortment of fleeces I have and get them all on that. Easier to pick one out then, as they will hopefully stay in more or less one place.

[veggiechicken]

I'm like Solway cropper - look out the window and see what the weather is like. Usually, its wet and windy and not too cold. Sunshine is a bonus.

[Greenleaves]

My Sister works for a company that send satellites up, she sends me 48 hour forcasts and these tend to be pretty spot on. Very rare do they agree with any of the other web forcast sites and certainly never with the BBC

[Thelma Sanders]

But the BBC only gets its info from the Met office ....... makes you wonder don't it *shakes head*

[Dorothy rouse]

Only read the 'good weather forecasts' , much better idea, keeps you much more positive.

[Penellype]

Fair enough - I get my forecasts primarily from professional weather forecasters and the forecasting models, mainly the American GFS model, but also the European ECMWF. I pay less attention to the met office and none to the BBC. If the tabloids publish some extreme scare story (we are currently in the middle of a "killer heatwave" apparently!) I tend to assume the opposite.

I agree that often forecasting beyond 48hrs is impossible, but there are some situations when the models are in good agreement and confidence is fairly high. Apart from a slight peak around normal tomorrow, much of next week looks likely to have upper air temperatures around 5-8 degrees below average for the time of year, due to the presence of "northern blocking" (high pressure) developing over Greenland. This effectively sucks the air down from the north pole. I felt it might be a good idea to warn people of the possibility of unusually cold nights for the time of year.

[Kirk]

I agree that often forecasting beyond 48hrs is impossible, but there are some situations when the models are in good agreement and confidence is fairly high. Apart from a slight peak around normal tomorrow, much of next week looks likely to have upper air temperatures around 5-8 degrees below average for the time of year, due to the presence of "northern blocking" (high pressure) developing over Greenland. This effectively sucks the air down from the north pole. I felt it might be a good idea to warn people of the possibility of unusually cold nights for the time of year.

I would disagree a bit, I think the "blocking" pressure system is over Scandanavia and is a low pressure.

The Low over Scandanavia is not moving out and the high cannot get in.
The High rotates clockwise so will pick presently up air from Greenland and rotate it round to us.
The Low rotates anti-clockwise and so is picking up air from the Artic above Scandanavis and rotating that down to us.
We have a funnel effect from both high and low where both are funnelling cold artic air to us.

If the low went off the high would move in and then pick up air from southern Europe to us. So it would I would argue it to be the low blocking the high.

Still going to get cold air however.

One terriable thing about doing astronomy is that you collect a hell of a lot of information about weather and clouds.

[Penellype]

I agree the low over Scandinavia is unusually immobile. Normally it is the highs that stick and the lows move around them. As you say, the net result is the same - its going to get colder.

[Deb P]

I use WeatherSpark's hour by hour guide on my phone to judge a good time to go to the allotment, here in Derbyshire it seems the most accurate, agree BBC weather just too generic to be helpful. The only 'problem' ( if you can call it that) with Weatherspark is that is updated so regularly you can get a different forecast the day before compared to the one on the day: last night It said probable showers today 12-2, so I'm planning to visit late afternoon. This morning it says no rain all day, so I could have gone this morning!

[Penellype]

For very short term will it/won't it rain, you are better off with a rain radar like raintoday.co.uk. There is a mobile version of that site which is useful if you are out and about. It's not perfect, because showers can bubble up out of nowhere, but for a general idea of what is coming in your direction its great.

[skeggijon]

I find looking out of the window quite a good guide lol