Roger Smith's Winter 2011-12 Forecast

[Roger J Smith]

Winter Forecast for 2011-12

Methodology

My forecast continues to use natural variations as the main foundation, but this season I have brought daily CET data on stream replacing monthly data for the first time. I am hoping this will lead to an increase in accuracy and fine-tuning of the forecast. Essentially, the forecast is generated by isolating several dozen cycles of various lengths, all of rather small amplitude when considered in isolation. These also have directional parameters -- some of the variables are retrograde, helping to set a pattern for the forecast in terms of blocking and air mass origins to complement the basic numerical output. The technique has given mixed results but has in the past three winters identified most of the colder periods with considerable accuracy. The most recent summer forecast, while somewhat off the mark in calling for slightly warmer than average, was closer than many other approaches. Last winter there was a generally good review for the forecast to late January but we expected the cold to return in February which it failed to do. When I say "we" the reference is to my long-time collaborator in long-range forecasting and research, "Blast from the Past." Fred has reviewed this forecast and gives it a general endorsement, but would like to confine his forecasting to 4-6 weeks this winter season due to heavy workload. He will drop into the thread and give some updates from time to time.

Returning to methodology, the numerical output includes some variables based on lunar orbital cycles (although this is about 20-30 per cent of the variability in the research model) and this input assists in timing various events or spells of weather. Other input tends to establish longer-term pressure signals and flow patterns. The blend gives us numerical output that could be used to create even daily-scale model maps but at the current level of validation, I prefer to use this blend to give just an indication of the sort of rhythm of weather events at different stages of the winter season. In any case, a long-range forecast is mostly useful for establishing tendencies and ranges of possible impact and not in nailing down events that can be refined closer to time anyway.

General Forecast Statement

The winter season appears likely to be cold again, at least on balance, but unlike last year, January may be the most wintry month of the three. The very basic overview is for a rather cold November, a variable December near average overall, a cold and potentially snowy January, and a mild February, followed by a "backward" March that has a return to rather wintry weather later in the month. For reference, CET monthly temperatures are predicted at 5.8 for November, 4.5 for December, 1.5 for January, 6.2 for February, and 6.5 for March. Precipitation is expected to be generally 25-50 per cent above normal except for pockets near normal in the south and east. Snowfall is expected to be above normal almost everywhere with several wintry periods expected.

The detailed outlook

From what will evidently be a cold period in late October, expect a recovery to mild weather for a while in early NOVEMBER, but progressively colder weather mid to late month with some early signs of winter in northerly and easterly outbreaks. Some frost days may occur in central and northern regions but unlike last year, this late November cold is not expected to dig in and produce a lengthy cold spell.

DECEMBER may be a roller coaster of mild and cold spells. The coldest part of the month is likely to come around the 15th to 20th. Before that, the first two weeks may include some strong winds from deep Atlantic lows, heavy rainfalls, brief intervals of hail or snow, but eventually, arctic air should develop and there could be snow on the ground at times just before Christmas. Then the Christmas holiday period is expected to turn milder with fog and rain especially around the 27th when it could once again become rather stormy. By New Years Eve it may be turning a lot colder.

JANUARY may be "the" month for this coming winter, and there may be several occasions with snow although the first week to ten days may start with more of a northwest flow that would restrict snow to western and northern regions. This could be a windy period in general before deeper cold arrives probably from a Scandinavian high. This should direct the winds more easterly and give the higher snowfall potential in central and eastern counties. Severe frost may develop and the CET estimate (1.5) is conservative depending on snow cover feedback, but frost days seem very likely around mid-January. There may be further snowfalls later in the month as the storm track tries to push back north.

FEBRUARY could start out cold and snowy but the model output shows a strong warming early in the month and a peak of very mild conditions in mid to late February. This suggests that southerly flow may predominate and reverse the cold pattern to mild or even very mild. It may be rather dry in this pattern for the south and east, trending to wet in western Scotland and Northern Ireland.

MARCH is expected to start out mild but become a "backward" sort of early spring month with returns to wintry patterns later on. The below normal trend may deepen into early April. The warmth of April 2011 may be in contrast to a cold April in 2012 with May the warm month this time.

I will of course update this forecast if different indications are given from more reliable time scales, but this is what the numerical output shows at present. You could think of this method as being similar in concept to the CFS system although using (presumably) different input. As always, we hope for the best and consider "success" to be fairly loosely defined in terms of being more often right than wrong, or on the right side of normal two-thirds of the time.

A Few Other Notes

This winter, the lunar perigee falls about halfway from full moon to new moon or during the descending phase of lunar declination. This has in past analogues been associated with temperature reversals from mild to cold as the southward pull of the Moon towards southern max (at winter new moon) is enhanced. This is one reason why a lot of the colder intervals in the forecast are essentially lined up around mid-month although this period is only 28 days. The energy levels this winter will vary from an active phase lasting 5-6 days to a low-energy phase lasting 8-10 days. This may show up in a modulation of stormy weeks followed by blocked or inactive weeks. It's one reason why I suspect the main theme of the winter before any severe cold in January may be "from one extreme to the other." We may be reading a lot of comments in discussions about how the season cannot "make up its mind" and settle into one pattern. For those who like their winters active, this should be a good thing. For those who like cold and/or snow, patience may be necessary but January should deliver this time.

I think that in such an active pattern, a major windstorm seems a fairly good bet. While not wishing to be too specific, periods around the December and January full moons are favoured for strong westerly winds.

My advice to people in weather-sensitive areas of the economy would be to plan for a severe winter or at least a more severe winter than average, but not to expect it to be non-stop, there will be relaxed spells between wintry blasts. Some of the more extreme conditions in January may be harsh in isolated higher regions of the country. Livestock may need to be indoors or provided with extra feed at times. Road travel may be disrupted about 5 to 10 per cent of the time outside the more temperate south. There is a good chance of seeing four or five significant snowfall events and one or two major events possibly blizzards in some cases.

So now we wait ... and watch.

[kold weather]

Very interesting Roger, my personal feeling is actually fairly close to that pattern and type of winter you've just described, though I'm for now leaning milder then you are it seems.

Your December reminds me alot of December 2009 actually, with a fairly stormy first 10-14 days followed by that cold shot that really dragged the CET down. Sortas like 2009-2010 winter then with several nasty cold bursts but other spells that aren't as cold thrown in, but enough cold spells to keep a decently cold winter overall.

[ForeverPomeroysnow]

Thanks RJS, reading between the lines it looks good for a varied winter

Is it your feeling then that the more west based areas (Ireland, West Scotland, Wales, West England) will have a somewhat drier winter as opposed to the east.

The one thing I have noticed for my area (Co.Tyrone) is that the last three winters/springs have been rather dry and the summers/autumns overly wet. Its like a switch flips from us and Eastern Britian as to has the dry and wet and in what seasons.

Thanks again for putting your thoughts out there and good luck with it!!

[ISAAC]

Thanks for sharing, very nice read.

[Staffordshire]

My forecast is very similar to this I'm expecting a stormy December also... if you look on the autumn thread you can see it on 5th September.

[Backtrack]

A top quality, well thought out forecast. I have given you a +1. The amount of work you have put into that deserves some kind of recognition.

Thank you.

[johnholmes]

thanks Roger

As usual from you a well thought out explanation of what you use to arrive at your forecast. No gimmicks just as you see it.

As with any winter forecast the proof will be evident on 1 March. To all those who may comment perhaps the key bits are to compare Rogers' CET predictions with what the actual shows on 1 March and also compare his 'general' idea of the weather type and the periods.

thanks again Roger.

[summer blizzard]

Very interesting forecast.

Vaguely similar to what i am leaning toward in the November-January period (December a lot more settled). I fully agree in regards to March-April, La Nina rarely produces the warm springs we saw last year.

[syed2878]

A verry well thot out forecast nice1 man. Just hope we get a good dumping of snow in brum.

[Mike Storm]

Yes thankyou for your forecast... all i need now is to buy that Davis Vantage Vue Ive had my eye on

[Norway Nut]

Thanks for the very interesting forecast but .....

Living at 40m asl here in the coastal fringes of Western Norway ( 50 km south of Bergen) can I interpret your forecast as if I was in the Shetlands or am I too far east and on the wrong side of the North Sea?

Again many thanks for the forecast

[Gavin P]

Thanks very much Roger.

Sounds like a very interesting winter with something for everybody. January obviously being the highlight for cold/snow lovers.

[BLAST FROM THE PAST]

Good Luck Roger. Not that you needed it but to confirm that I concur with the rhythm of your winter LRF.

I wish to say that last year I had a pretty prepared laid out pattern prepared but this year at this stage I only have a overview ready and I was/still am in no position to grace any detailed addition at this stage to RJS' LRF and won't have for some time.

Hence the clear decision to let Roger's work speak for itself at this very impressively early stage.

For clarity on a point mentioned elsewhere, a CET proposed by RJS of 1.5c comes under my parameter of an 'extreme' month....its all relevant as we are talking about UK standards here.

Very interesting proposal of synoptic pattern for January by Roger...

BFTP

[Met4Cast]

Good forecast

http://www.irishweatheronline.com/forecast/winter-2011-2012-forecast-for-uk/42008.html

Is the above website yours?

[ForeverPomeroysnow]

Good forecast

http://www.irishweat...r-uk/42008.html

Is the above website yours?

RJS also forecasts for Irishweatheronline under a different username, a fact I only learnt myself a few days ago!!

[BlueHedgehog074]

A really, really great forcast dude, and I found the reasons you gave very amusing and informative. Looks like we could be in for a rather interesting Winter ahead. Wind, heavy rain, snow, hail, frost, sunshine, showers... ahhhhhhh, love Winter.

[Guest]

It all looks highly likely - I think I will make plans to get back to France from late Feb onwards - although I love the snow at the proper time in winter I also love warm springs.

As a further note, I don't know if it is my imagination but often there appears to be a change in weather set up about the full moon. Is there any basis in this?

[Roger J Smith]

I'll wait a couple of days and post some general responses to "popular questions" but as to Norway being like the Shetlands, maybe yes for temperature trend but of course not so much for precip. The milder February regime might play out as continued dry cold there also.

This is the earliest I can remember making a winter forecast, but I suppose if winter is going to be N-D-J instead of D-J-F, this is what must happen.

To answer the question about the Irish website, (Irish Weather Online) -- my forecasts are used there, but all the website development and news gathering work is done by some Irish weather enthusiasts. When I take time off they also cover the forecasting. The internet creates a lot of interesting situations, can't say that I would have imagined doing daily or long-range forecasts in Ireland or the U.K. back in the 1980s or 1990s from my home office here but it becomes possible, whether totally rational or not. Sometimes I wander out for a walk here and wonder (briefly) why the weather suddenly changed.

[Liam J]

If only we could bank that forecast Roger!! An action packed winter of weather would suit me just fine. I couldn't face another boring spell like the one that we had to endure during Jan/Feb 2011.

Thank you for that detailed analysis, I hope it proves true to some extent!! We will only know in 4-5months time what the end result shall be, but hopefully we'll see some apsects come to fruitition long before.

[BLAST FROM THE PAST]

For some reason I cannot edit my comment....so 'relevant' should have read 'relative'.

[Snowmadsam]

really interesting read thank you, hope for a snowy end to december and a cold januray would be nice

[ZONE 51]

Excellent work! we look foward to an interesting winter ahead, i have confidence that your forecast will go as you expect it RJS, its very difficult to get the timing correct so i do not expect pure accuracy on that, what i have more confidence in is what you see evolve, to happen, with the patterns and setups, its very interesting on what methods you use to predict and make a forecast.

Edited October 17, 2011 by ElectricSnowStorm

[The watcher]

Fairly similar to mine, with February being my choice of the warmest of the Winter months. I'm feeling though that both December and January will be colder. I will not be posting my forecast as early as this, mid-late November will be my calling.

[Partholon]

So reading between the lines; colder overall this winter, but at no point will we experience sustained and severe cold like we had last year. I'm not surprised given last December was the coldest in 100 years in many areas.

It now seems James Madden is the only well-known LRF forecaster going for similar conditions to last year to reoccur. I wonder how he'll be viewed come the first of March?

[sblog]

Would prefer a snow early - mid December or 2nd week in Jan - got the kids over new Year and I know I'll get caravaned at by the ex if I didn't them have back on time - of course it'll be my fault!!!!

Anyway, nice forecast....let's see what happens this yr - and early next