Ninman
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Posts posted by Ninman
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Metcheck very confusing. So February is wet and mild with significant cold spells???
February 2013
Slightly wetter than average. Slightly Milder than average across all areas with significant cold spells expected.
So the only way that would work is if the cold spells were a few days long and then immediately jumped to well above average (say to 15-20c) to bring the CET value up. Considering Feb is the shortage month of the year, the temps will need to see-saw wildly and quickly!
I don't put much faith in this happening!
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There's a ground frost here too. Looks like it could be widespread this morning.
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I would like to defend James Madden, his winter forecast for winter 2009 and 10 were correct, so where his forecast for Summer 2012
His forecast for summer did seem to be largely correct, however his winter forecast last year was wrong. It doesnt matter if he gets it wrong, but not admitting so, and then trying to find any shred of evidence to prove he was right, really annoys me.
Vogan's ideas are good, and I am supportive of the effort he's going to, but I am dissapointed he's now charging £33 a year to view his website, especially, when last year he kept calling for a brutal winter, and even believed a week before xmas that it could snow on xmas eve (when all forecasts/mdels were pointing to mild/wet/windy)! He then kept changing his mind about when we would see snow, and kept calling it every 2 weeks until it finally did in February. Unfortunaly I cant provide a link to this as I refuse to pay that much to access inaccurate LRFs or shortrange forecasts I can view on the MO website for free.
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Put it on for half hour last night after getting home and it just took the chill off (raising it from about 16c to 18c).
This morning it fell to 15.2c but the sun is out and directly falling on the both of us as we have breakfast so it isn't on at the moment despite it only being 16.5c.
We call these the 'golden hours' from about 9am till 11am where sunlight actually penetrates into the house and warms it. Struggling to see the screen & budgies are going crazy (they love it!) but refuse to block any of the precious radiation out as this is 'free' heating!
I like 'free heating'! I have a conservatory connecting to the lounge - it usually gets up to about 23c this time of the year if its a sunny day, so I unleash the warmth in to the rest of the house before sunset. I think housing companies should start building glass houses
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The GFS has gone mental! I bet it will be the opposite on the next run
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My heating is on now, but thats at the wife's request....I suggested putting on a thicker jumper but she wasn't having any of it!
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I'm only an amateur snow enthusiast (just made this term up lol) and I find it very hard to believe it is possible to predict what Winter will be like from 2-3 months away.
This is the beauty of it. Currently its not possible to predict exactly what the weather willbe like in 3 months time; and this is the golden nuggat that people are trying to reach. From what I can see, there are so many variables/factors that can dictate the weather and this is the challenge that people are tying to overcome.
By trying to understand, we make mistakes, and from these mistakes we learn, which enhances our understanding and allows further development to take place in trying to predict future weather.
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The leaves on the trees are starting to turn a deep red/yellow where I am. I love the colours that autumn brings. I think they are looking more vivid than last year. Lets hope we get a few fine, cold crisp mornings in October (It is looking like we will, last Autumn was rubbish). I like the feeling of crunching leaves underfoot and kicking them up in the air as I walk!
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As I mentioned at the end of last weekend, I started doing some correlations and stuff between some of the different teleconnections (MEI, PDO, etc), things like sea ice, sunspot numbers and of course, with the winter CET (Dec-Feb). I’ve gotten through quite a bit of it now, and thought I’d post up some results. So today will be a look at the PDO.
I’ll start off by saying that these are all very simple analysis, from someone who’s just learning the stuff, so don’t take it all too seriously and feel free to point out any mistakes I’ve made!
Anyway, the first things I looked at in detail were correlations between the PDO (Pacific Decadal Oscillation) and the Winter CET.
The PDO is defined by principal component analysis, and is recognised by a reverse "C" shape of -ve sea surface temperature anomalies in the north Pacific stretching from the Bering sea, down the US west coast and into the tropics when the PDO index is -ve, with the opposite occuring when the PDO index is +ve. Each phase appears to last several decades at a time, though going back before 1900, things are a little less clear.
http://jisao.washington.edu/pdo/
Data for the PDO can be found here http://jisao.washing.../pdo/PDO.latest
Annual PDO
The correlations I looked at were for PDO annual values and CET winter values from 1900-2011.
What is clear is that individual annual PDO values have little to no relevance when it comes to winters here. There is hardly any correlation at all, whether it be lagged, averaged over a few years, or whether the CET is de-trended or not. None of the correlations were significant.
Where the PDO does appear have an effect though is when you view it on a cyclic scale (in this case, as 30 year mean). There is then a clear relationship between a –ve phase of the PDO and an increased likelihood of colder than average winters. How one would wish to factor that into a long range forecast is up to them, but it would seem as though using the strength of the PDO at any given time is pointless, only the longer term phase that we’re currently in matters.
1 Year PDO & Winter CET ....................... 10 Year PDO & Winter CET ..................... 30 Year PDO & WInter CET
The reasons for this relationship? Well, plotting the winters following the lowest PDO value years, shows a reduction in upper zonal winds across the British Isles, as well as a tendency for stronger heights to the west and north of the UK, with very low heights across mainland Europe and into the Iberian Peninsula.
500hPa Heights, -ve PDO Years ........................... 300hPa Zonal Winds
This basically indicates a slightly southerly tracking jet with an increased likelihood of northern blocking, which is what you want for cold spells. While other factors will be at play to cause these patterns, I think it's safe to assume that the -ve PDO phase will also contribute to them. The fact that there is no correlation on a year to year basis suggests that PDO's influence in the North Atlantic is easily over-ridden by other factors, and that it's influence can only be discerned by looking at the longer term anomalies.
So, the PDO, in my opinion, not much good for short range forecasts, but handy for working out decadal trends! So considering we're currently 5 years into a -ve PDO phase, it's likely a good sign for cooler winters!
Tomorrow, if time permits, I may have a look at the relationship of ENSO and our winters, by using MEI values.
Good stuff!! I didn't really understand this before but you have put it in a clear and easy to understand way
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One thing I have noticed on the CFS is that it is consistantly showing for the last week upper 850 values of -8 to -12 at the end of January/early feb. Obviously it's months away so I won't read too much in to it, but it looks promising for cold weather. I wouldn't be dissapointed if it didnt snow, so long as it is cold......It would be nice to have a season that reflects its typical self! 16c in December 2011 and 13c in Summer 2012 just feels wrong!
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No
I saw a brief patch of grass frost this morning! I think last year I didn't see any frost until December.
On a seperate note, have you seen the GFS run this morning? Beginning of Oct is indicating snow for Scotland and a northerly airflow as the jetstream pushes south, bringing the colder air south also (increasing the risk of frost). With the stormy weather we will get in the next few days, it looks like Autumn could be quite erratic - quite different to last Autumn!
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I'll take an interest in this thread (and others I've heard about, such as the winter stratospheric thread) just to see how forecasts turn out and the reasoning behind them and why things do or don't happen. I'm sure it'll be a good learning experience.
In terms of what I think will happen, I can't really add anything of value at the moment. I'll leave that to more learned people this year. I don't even have a gut feel.Same here! I keep reading articles/posts on various websites about the reasoning behind why this winter is supposed to be cold/snowy but then others counter argument this, and then models show something different!. An interest in the weather is fairly new to me, so this is a good learning curve no matter how winter turns out and whichever LRF is right.wrong
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GFS models are forecasting a possible cold incursion for early next week. I posted some images on the models discussion thread. Could bring in some cold uppers (0 degrees - perhaps less?) and some decent snow for the mountains. So I will be watching to see if the GFS firms up on this as we get closer to the weekend.
I'm heading up to the Scottish borders next week and it looks like there could be another cold night Monday night according to the GFS :
In terms of what I think will happen, I can't really add anything of value at the moment. I'll leave that to more learned people this year.
Upcoming Cold (Chilly?) Snap
in Spring Weather Discussion
Posted
I woke up this morning and saw the car iced over with a light dusting of snow. I don't think i've ever seen snow this early here....beats having to wait until Feb like last year!