UK Weather Forecasts, Reports and Discussion WC 18th October.

So into another week and deeper into the Autumn with Winter showing her hand this week in some areas.

The following is a summary taken from Netweathers home page....

A mixed week on the way, Monday will start on the chilly side and mainly dry but showery rain will spread south during the day with increasingly cool air following in behind it.

By Tuesday that band will have cleared through but showers will readily develop in behind it and as the northerly wind really cuts in and pulls that cold air in, they'll turn wintry from the north. Although it's the high ground of Scotland and Northern England that will see the majority of any snow, lower levels will also see some wintriness at times.

After a widespread frost overnight, Wednesday keeps the cold theme going with those wintry showers continuing especially in coastal parts. There's also the risk of some more persistent sleet and snow moving into Scotland during the day.

Beyond midweek it turns less cold, as some unsettled weather arrives from the Atlantic..


I will attempt to get some detail/data together as far as the winter forecast which is due very soon or may well already be issued.

And at last here we have the Netweather Winter Forecast.
Quite read but well worth taking 10 mins to go through.
Let the discussion begin !

Will it, won’t it ? But the dryness will be the real story

Following back to back cold winters for much of the UK, there is a lot of focus whether this year will follow suit. However, with temperatures forecast to be close to or slightly below average, we believe the most significant aspect of this winter will be the very much below average winter rainfall following on the back of a largely dry summer for parts of the UK and very likely dry spring to follow.

Headline Summary:

•Anomalously cold ocean temperatures in the Tropical Pacific or ‘La Nina’ conditions have become well established. There is a high probability that these conditions will intensify over the coming months and become one of the strongest La Ninas on record.
•With a strong coupling between the atmosphere and ocean signal, global weather patterns are very likely to be ‘forced’ by a strong La Nina with dominant high pressure centres in the northern Pacific and in the North Atlantic.
•La Nina winters have a variable influence on the weather in Europe although we anticipate no sustained extremes of cold and the emphasis on dry, settled weather. Some wintry weather is however expected, particularly during mid to late December an early January.
•Temperatures are likely to be close to or slightly below average with the coldest weather (relative to long term averages) centred over France and Iberia, the south-east of the UK closest to this cold. Compared to many winters of the last two decades, this coming winter would probably be regarded as cold although not of the same degree as last year or 2008/9.
Background to this forecast:

•This forecast is based upon the likely influences of La Nina in the Tropical Pacific, atmospheric signals and air temperatures high up in the atmosphere over the Arctic which are seen as key variables, many of which are dissimilar to last winter.
•However, the last twelve months (probably thirteen months after October’s data) have seen a negative or cold phase of the North Atlantic Oscillation (a key measure of the difference in pressure between Iceland and the Azores). This is unprecedented since the index was first compiled in 1950 and reflects a reversal in the normal pressure patterns which played a significant part in last winter’s weather.
•This forecast based upon an understanding of the dynamical processes involving the world’s oceans and atmosphere, the use of historical-based analogues and Netweather.tv’s customised seasonal predictive model based upon the Climate Forecast System (National Centre for Environmental Prediction).
Record strength La Nina

•Sea temperatures are widely below normal across much of the Tropical Pacific and these colder waters extend to several hundred metres below the surface in the central and eastern Pacific Ocean. This is characteristic of a La Nina event of medium strength magnitude.
•The pattern of surface winds and cloudiness across the Tropics is very typical of La Nina event and model forecasts continue to suggest the sub-surface anomalously cold waters will work their way to the surface over the next 2-3 months further strengthening La Nina to ‘strong’ category event, potentially the strongest La Nina of the last 60 years given the large volume of below average waters with temperatures up to six degrees below normal.
•Since July, global weather patterns have been very consistent with La Nina. The European weather patterns associated with La Nina in winter are somewhat variable. Most were dry and mild although there were some colder events in 1955/56 and 1964/5

Atmospheric indicators fully backing La Nina

•One of the keys to understanding La Ninas and their warm counterpart El Ninos is how the atmospheric variables react to the temperatures of the ocean and whether or not the atmosphere is ‘going along’ with these changes.
•Most atmospheric variables are also exhibiting extreme La Nina like behaviour. Overall levels of storm activity in the Northern Hemisphere is at a 30 year low despite an active Atlantic hurricane season whilst forward intertia in the atmosphere was the third lowest in 60 years during July and August. The pressure differentials measured in the Southern Hemisphere, which usually indicate the future trends of La Nina have been advertising a strong event in the making.
•Of the strong La Nina events, these atmospheric indicators suggest we are historically much further advanced at this time. Given feedback loops, atmosphere reinforcing La Nina, La Nina reinforcing the atmospheric variables, it is very likely that an exceptionally strong La Nina event will take place this winter with a probable peak in December or early January.
Temperatures in the stratosphere

•One of the key elements of last winter’s cold weather was above average temperatures in the upper atmosphere high over the Arctic which promoted ‘blocking’ highs displacing polar air into Europe.
•This year we expect the combination of low solar activity and a westerly wind over the Tropics to be less conducive to blocking highs with colder than normal atmosphere over the Arctic driving polar westerlies which tend to favour blocking highs further south around the UK.
Seasonal Model Guidance (Climate Forecast System)

•Model guidance is for high pressure close to or north and west of the UK for the majority of the winter with a slight tendency to shift further away to the west during February.
•Model sees average or slightly colder than average temperatures for the UK, coldest in the south-east and mildest in the north with central Europe slightly below average.
•Model sees rainfall below average.
•Good consistency between model updates and output appears to be consistent with historical analogue guidance adding confidence to forecast.
Winter Forecast details

December

•High pressure likely to be centred to the north-west of the UK with winds from the north-west with northerly interludes.
•Temperatures likely to be below average, the largest departure of the three months compared to long term averages with the coldest temperatures in the south-east.
•Rainfall likely to be much below average.
January

•Large area of high pressure in the central Atlantic gradually edging towards the UK although an unsettled phase likely with potential for snow, particularly in western areas.
•Likely to be cold to start with fog and frost persistent.
•Rainfall below average.

February

•High pressure centred over the UK with a lot of settled weather.
•Temperatures likely to be slightly above average although surface temperatures may be depressed by fog and cloud.
•Rainfall likely to be much below average.

That seems like a "safe" forecast on the whole! Dare I even say "normal - ish" for our winter??? We will see! If that high pressure remains to our west for most of the time, then probably it will be a settled winter. Hope so....last year was much too cold for my liking...and we were nothing like the UK!! Will have to watch those temperatures over France though but I think we will be OK.

Meant to add......weather here is typically autumn/winter! By that I mean cold, grey and miserable! Horrible easterly winds at the weekend but they seem to be moving round a bit to the south, bringing rain tomorrow. However, temps have settled a bit to around 15 and it's a mixed bag for the rest of the week, until we get to the weekend when it looks to be chucking it down!

And it's 34 in Darwin!!!!! Nice!!!! Wonder if Quantas do major discounts for a mass exodus!!

Lol! All crash Mikes place - i'm sure he'll love that!

Thanks for posting that up Ju. So it looks like La Nina is to blame for the lack of storms then this year, and the unusually calm weather in general. I mean looking at the long range models I can see masses of high pressure, which ties in with La Nina. Nothing of serious low pressure to note of yet.

La Nina = boring weather then!

So with high pressure in charge for most of the winter then, Fog could be an issue. I read somewhere recently that foggy days are forecast, even lingering foggy "days" in December too, but that forecast above is hinting at January for that.

Any other opinions?....

Snow showers are forecast over the northern half of the country tomorrow, getting colder!!!

Wind and temp forecast....

Just to let you know - we reached 0.4'C on the 20th October
Haven't seen any snow yet though - but the charts suggest there will be another chance before November

I must admit, I'm with you on the winter thing, this time of year is my favourite. Darker, colder, longer nights, ice, snow, low pressure systems etc.

0.4 is chilly, my weather station has recorded a low of 1.2 so far.

Currently sat under a real heavy rain belt. Wind is gusty too. I'm awake at this horrid hour because it is making such a racket on my window!

Just noticed a UKASF warning issued for T/Storms in the south with this rain. Nothing showing and the ingredients don't look right. Certainly some heavy stuff mixed in with this lot!

Wazza, i see you posted at 03.36
No thats either great commitment or theres something wrong with you

Few things to say, firstly the Winter Forecast. Having read though it a few times to me its saying that in general its going to be reasonbly settled with nothing of great note. Im certainly not thinking that we are going to see a real cold spell with lots of snow ? And yet having read a few comments from others on FB and Netw forum people are saying we are in for a lot of snow ?
Winter Forecasts/Winter Weather isnt an area where i have much knowledge so not sure what to think on this one. From a personal point of view im hoping for those deep Atlantic Lows to come crashing in so i can get more video and footage from the coast. Winter forecast pointing towards more High Pressure perhaps ? As ever i guess its keep that data up and see what happens.

Onto the UKASF Watch today, ive already been out chasing today and saw some good structure, weak anvils and some superb Mammatus
I have posted images on FB but do still have the issue of posting them here due to the Picture Hosting site i use. Will look at that again in a few minutes.
As far as whats happening out there now, still some heavy showers pushing in from the west, High Res NMM shows CAPE values of up to 350 and LI values of -2 so definately a chance of some of these showers ramping up. Incidentally for all i saw this morning i didnt see/hear any Thunder/Lightning

Wazz, can ya give me a ring re posting images please.
Thought i had sorted it but, well you know me, it didnt work

Thanks mate

Oh stop the fussing i say, heres this mornings pictures

Wo you caught Mammatus!!!!

Great pics there Mate, and real cool effort for getting out. Superb! And Hi Five!!!

After what has been nothing less than an awful year storm wise i have to admit that seeing the Mammatus yesterday was just about the one and only highlight for me. I stood there in awe as it drifted directly over me...what a sight

Being a bit previous here but taken next weeks GFS through on animation for SLP to have a quick look at what may happen and at the moment Friday may be interesting on the S Coast. Showing a deep Low over the country, 988mb, with onshore winds of 30mph+ perhaps
The South coast and most of the East side of the country all show under similar numbers. So may be taking a trip if that holds up, just need to find someone to look after my 3 boys ( half term..arrggh !), any takers

Hey well done on those photos Ups! Brilliant to get those mammatus clouds! Only seen that once and that was in Scotland - seemed as though the sky was falling in!
Nothing quite like that here and no thunder either though I wouldn't have been surprised to hear the odd clap with the extremely heavy rain we've had over the last couple of days - complete white out in showers! Been watching those skies to see if there was anything interesting to see in those clouds as they came across the island but saw nothing. Really windy too!!! Much quieter late this afternoon though and the sun actually came out and gave us a lovely orange sunset!
If you are out and about taking vids of storny weather, I reckon you will need at least 3 bag holders!! Just pack 'em in the car and give them each their task!! Gotta get 'em trained you know for the bigger stuff in the future!