Winter 2017-18: Discussion

First time this season ( that I know of ) that wintry ppn showing up on radar. However with current temp/dps I think its just picking up hail. Still good to see though.

Well made point.

I wouldn't entirely agree, I think there are some general weather factors that can help us understand weather in the future to a degree, however they aren't suitable for saying with any definite degree that you'll get xxx weather. However, organisations like Met Eireann are forecasting what the weather will most likely be like, they're not in the game of giving uncertain probabilities outside the reliable range.

Nobody will be ever able to say "this winter will be very snowy" or "this winter will have no snow whatsoever", as they are very specific, but general terms like MT thinking this winter will be slightly cooler than average are possibly in my opinion.

nagdefy wrote: »

All opinions are not equal...

I have the utmost respect for MT and the work he does on the weather fora. Also others like sryan who attempt to make long range predictions based on science.

I'd argue though that Evelyn Cusack and Met Eireann's opinions on Long Range Forecasting are as equal and valid as anyone on this site though.

I'd agree with those opinions expressed at 1min 16sec in from 3 years ago. See below.

Though her last quote from Sagon is a little pop at religion i feel, which is out of order for a weather forecast. I feel she's bringing her own personal beliefs into a weather forecast.

Thanks. I try to keep my forecasting as accurate as possible with the methodology I use.

I acted like a dick before saying I know what’s going to happen for absolute certain - me being one of the posters I think HighLine was getting at in his above comment.

He is right. Long range forecasting is impossible and is highly experimental. You’re either right through science/complete random guesses or not. No certainty whatsoever.

I have respect for people like MT because he actually tries to put work into making these predictions unlike somebody like let’s say James Madden, Nathan Rao etc. But even that isn’t any different at the end of the day as it’s still experimental and a complete guess. You will always find odd ones out with the methodology we use to predict our weather. Our atmosphere is always willing to give us some surprises.

Hi everybody.
I watch the weather forum a lot. Especially after Halloween! I have great admiration for those of you who can gather and interpret data, and then go on to make educated 'guesses' as to how the weather will behave in the future. We all know they're not guesses at all, but I don't say prediction because to me that suggests certainty, and with this stuff how could anyone be CERTAIN.

My opinion on weather is that its like getting a pot of hot water, stirring it gently, then adding various amounts of warmed dyed water in different parts, then predicting how that will affect a very specific location in the pot. Of course, with absolutely mad levels of data collection, over many cycles, and a super-duper computer , it might be possible to make a prediction on the next attempt.

As you can tell from my hamfisted previous paragraph, I know sod all about meteorology, but I think I can appreciate the difficult science required. (I actually thought of this one evening while pouring milk into my tea!:D

Keep it up guys, like most people on here, I admire and appreciate your efforts.

sryanbruen wrote: »

let’s say James Madden, Nathan Rao etc.

NickNickleby wrote: »

My opinion on weather is that its like getting a pot of hot water, stirring it gently, then adding various amounts of warmed dyed water in different parts, then predicting how that will affect a very specific location in the pot. Of course, with absolutely mad levels of data collection, over many cycles, and a super-duper computer , it might be possible to make a prediction on the next attempt.

As you can tell from my hamfisted previous paragraph, I know sod all about meteorology, but I think I can appreciate the difficult science required. (I actually thought of this one evening while pouring milk into my tea!:D

That's not a bad analogy at all.

You reminded me of this great little paragraph:

Imagine a rotating sphere that is 12,800 kilometers (8000 miles) in diameter, has a bumpy surface, is surrounded by a 40-kilometer-deep mixture of different gases whose concentrations vary both spatially and over time, and is heated, along with its surrounding gases, by a nuclear reactor 150 million kilometers (93 million miles) away. Imagine also that this sphere is revolving around the nuclear reactor and that some locations are heated more during one part of the revolution and other locations are heated during another part of the revolution. And imagine that this mixture of gases continually receives inputs from the surface below, generally calmly but sometimes through violent and highly localized injections. Then, imagine that after watching the gaseous mixture, you are expected to predict its state at one location on the sphere one, two, or more days into the future. This is essentially the task encountered day by day by a weather forecaster (Ryan, Bulletin of the American Meteorological Society,1982).

The main point of disagreement I would have with the critical comments is that when I describe a mix of weather types during the winter, this is

(a) normally what happens, and

(b) in my forecast, is tied to fairly specific periods so that actually it is not an effort to muddy the waters by saying everything might happen, but an attempt to say when the various components will happen.

Also I attempt to give some idea of the relative frequency of the different types compared to normal. This winter, I think very mild weather might be less frequent than it has been in several recent winters, and colder than average temperatures might be more frequent. That is fairly specific, then I go into some details about when I foresee these trends.

As several have noted, the pursuit of long-range forecasting is a science under development, and nobody seriously involved in it would argue that it is a developed science (the way astronomy is a developed science, I went to Baker City Oregon last August 21st expecting to see a total eclipse of the Sun at 10:22 a.m. and one thought that crossed my mind when it actually happened was, what are we doing wrong in our science?)

On the other hand, the general state of long-range forecasting in North America seems to be a bit further advanced, perhaps because we have a more variable climate so that different regimes show their hand a bit earlier? It seems to me that most of the errors in LRF here are matters of degree or exact boundaries between regimes, and quite often the large scale picture is what many forecasters have said they expect. This is especially true when there's an El Nino. For Europe, I suspect it is more difficult because variations are smaller and everything depends on blocking or no blocking, we can get our cold weather more directly with a continent between us and source regions for arctic air.

So none of this has changed much since I got involved in the subject over ten years ago, and it probably doesn't help that in the background of the science (but in the foreground of public perception) we have these same few people making exactly the same forecast (worst winter ever) time after time. I think that is skewing perception because serious students of this difficult (and admittedly rudimentary) science would not expect the same thing to happen every winter.

I found the pressure analysis above to be interesting, I suspect it may have to do with background pressure variations in the atmosphere caused by interactions between the Sun and sources of gravitational energy. Although the curves look quite pronounced, Oneiric would probably agree that differences of 5 to 10 mb are not a large component of the overall variability (which is closer to 50-100 mb). So if this were the only factor at work, we would just see a slight uptick in storminess around those times of lower pressures.

I analyzed some pressure stats for Malin Head over a roughly similar period and found significant troughs (10-15 mb) around the times of new and full moons in December and January. This tendency fades out in February and March. Some time I might start a thread about some research I've done into the dynamics that might be causing those oscillations, but even 10-15 mb, while it may sound significant, is a rather small portion of the overall variability.

I have come to less dramatic conclusions than Ken Ring about lunar effects, but I think the Moon does have some influence on atmospheric variations, however, it is not a strong enough signal to dominate so it has to work with larger scale variations that are caused by independent factors. My research shows that you can get some fairly large signals if you divide the data into groups of similar weather patterns, as opposed to trying to find the signals in all the data. However, I might have to live about five centuries to get anywhere near the end of the trail in this research so as that's not too likely I am hoping to get it at least adequately described before I pass, then somebody else can have the fun I've had trying to decode all of this.

Danno wrote: »

Exactly, it's very condescending and has no place in a publicly funded broadcast from a publicly funded organisation.

While I don't disagree with the point, I'd like to point out that before the news starts, what do we have? The Angeles.

Danno wrote: »

We have a strong sense of history in this island, and this ought to be preserved outright, regardless of who it offends. If it offends anyone, there is Rosslare and they do sell one-way tickets without quibble.

But you just said "Exactly, it's very condescending and has no place in a publicly funded broadcast from a publicly funded organisation"

Double standards?

So anyway, yeah, I reckon on average, this winter will be markedly colder than both last summer and next.

Long range weather forecasting is a bit like trying to predict which sports team will win your competition of choice at the start of a long season

You can look at the team sheets and compare the players and managers against each other and think that the better team on paper will win more games on average than the team of young try hards

But then the matches are played and there are lucky goals, red cards, injuries, managers get sacked and teams get into a bad run of form, referees make mistakes, players score own goals, keepers drop the ball, playmakers hit a bad run of form, dressing room spats happen to disrupt the teams performance...

And all of a sudden you have Leicester City or Connacht coming from nowhere and winning the league.

All the experts who made their predictions at the start of the season all had good and justifiable reasons backed up with analysis and statistics, but sports, as well as weather are chaotic and predictions cannot account for the seemingly random events that can change the course of history.

nagdefy wrote: »

I think it was on the TV3 night show that she was giggling away at Danny Healy Rae's climate views. We all know Danny HR doesn't have the most enlightened views on Climate Change and wouldn't be one for a scientific approach. Yet she came across as a rude know it all..

I wager though, that Danny Healy Rae has a far more enlightened view on the intricacies of people and society in general than Evelyn would have; after all, that is why he is doing what he is doing. I think when push comes to shove, he probably has done more to help out ordinary, everyday people who have to deal with real world problems than she ever has.

M.T. Cranium wrote: »

I would agree, there's a definite lack of major storms (in western Europe) in the first half of December compared to the second half and then the first half of January.

It's not an absolute lack, however, there was a very severe storm around 8-9 Dec of 1886, and if the calendar had changed before 1752, the Daniel Defoe storm (1703) would also have fallen on the 8th of December (it was recorded on the 27th of November because Britain was still using the Julian calendar).

These are not excluded times in other climate regions in the mid-latitudes so it would seem to be a function of the Atlantic circulation. Really cold air masses seem rare across far eastern Canada until well into December so that's probably the main reason why the jet stream remains rather bland, while December is too late in the season to get much stimulation from tropical remnants (some think the Defoe storm might have been a late season tropical remnant, all we know with any certainty about it was that it tracked roughly WSW-ENE across south Wales and central England -- it probably had a nasty backlash effect in Ireland but there are no records that I know of concerning its effects in Ireland).

The pressure pattern that Oneiric3 shows for the recent past could be studied over a hundred and fifty years (almost) by using the wetterzentrale archives. Probably just one pressure reading taken at one location would be sufficient, so I might see if we could form a research communal effort, pick the location and have several people note down daily pressure readings from the maps for that location (Dec/Jan.Feb) then collate it into a study. It sounds daunting but you could probably do one winter in less than an hour.

If I don't manage to get that going, I will see if I have some time this winter to do the data entry from 1871 when the maps begin, to whenever Oneiric's study began, think that was 1981. Then we can see if this effect is permanent or if it shows any tendency to shift with time over 150 years.

If ten people were willing to take ten years and send me the data, we could get this done fairly fast. I could check the work at random to make sure no systematic errors were creeping in.

The data I used was extracted (about 5 years ago) from the ECMWF reanalysis project via grib extraction (ERA 40 + ERA Interim) and from 5 grid points located at the 5 various locations used in the original 'IMT' series.

http://apps.ecmwf.int/datasets/

The data goes back to 1957 only, and though the ERA - 20 does go back to January 1900, I can't seem extract data from them as I can the other two.


What I will do later, if it is any use, is include all the data from 1957 up to 2010 and average it out as opposed to using just the latest 1981-2010 average.