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The Seasonal Forecast Thread


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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

Fred PLEASE would you write in complete sentences? I find it hard to follow your points as you currently write in this fashion. Are you repeating something you said 21/12/12 or quoting someone else?

thanks

John

My quote John, I am remaining confident of the outlook as set out and today's models solidify that viewpoint. Sorry I had done an 18hr day after a 5 hr quick changeover between shifts so I was a tad tired.

regards

BFTP

Edited by BLAST FROM THE PAST
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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl

Noting that a lot of cold air is leaking south into various parts of Asia this past week, about a week from now much colder air builds up over northwest Canada and a retrograde period begins around 20 Jan -- all of this suggests to me the best signal we could hope to see in the 2-3 week time frame (unless we get the whole Siberian moving west then) would be an elongated north-south ridge over east-central Atlantic that might even raise temperatures briefly above normal but then in larger retrograde to follow, the pattern would be ideal for stronger high pressure to build up over northern Europe. So for me it's a continued patient watch for severe cold to develop near end of month into February. Deepest portion of cold from my research is indicated to be 10-15 Feb.

Great. 10 - 15 February is exactly the week I am out of the UK, my only trip away all winter. If the south of england is buried while I am away I will spit with fury!

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Posted
  • Location: Irlam
  • Location: Irlam

January will be much drier and anticyclonic with a cold snowy easterly brought by an intense Scandi high around mid to late month. A lot of snow in the east. As a consequence, it will be a cold month, close to January 2010 in terms of coldness, maybe colder.

I think my Scandi high prediction might go bust. Probably not as cold as I was suggesting.

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Posted
  • Location: Slovenia, Central Europe 1050m ASL
  • Location: Slovenia, Central Europe 1050m ASL

December is over, and it is time I present my January and February analog seasonal forecasts. I made these composites back in October, and first published them on Nov. 1st, on a weather forum here in my country. HERE is the link to that topic, with some extra analogs.

I will also make some CFSv2 comparisons with my "forecast composites".

Posted ImagePosted Image

And my analogs. The only thing that is not really logical, is that tongue of cold, extending out from E Greenland. But hey, these are composites, so I got the picture that I got.

Posted ImagePosted Image

And CFSv2 forecasts one month ago.

Posted Image

Precipitation:

Posted Image

My analogs:

Posted ImagePosted Image

CFS forecast one month ago:

Posted Image

Pattern. The funny thing about January, is that the CFS was more easterly with the entire pattern. It has the ridge axis over USA E. coast, while my analog has it over CONUS. But given the patterns so far, it doesn't really look like the monthly reanalysis is going to verify. Posted ImagePosted Image But there seem to be signals in favour of this analog in the future.

Posted Image

Posted ImagePosted Image

February. Kinda grabbing onto something here, but i am not sure if having the CFSv2 backing you up is a good thing or not, given its reputation. Posted Image

Posted ImagePosted Image

CFS forecasts one month ago:

Posted Image

Basically my first year of "analog forecasting". Regardless of the final verification, I think it is my obligation to share these analogs here. Posted Image And keep in mind that these analogs or composites must be interpreted the same way as ensemble means.

Best regards.

Edited by Recretos
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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire

Wow, we are seeing some fairly significant cold even without the full synoptics in place, if my idea about February being core of the cold signal is still valid, we may be entering into a 6-7 week period of intense cold with possibly just one brief reversal before deeper cold sets in. That brief reversal seems most likely to happen near end of January. Looking at the current synoptics, strong high pressure north of eastern Siberia could be nudged westward by effects of rising heights over western North America. There has been a deep (930s to 940s) low nibbling away at the base of this Siberian-arctic high for several days now, and in my research, a stronger retrograde signal develops in February.

There is tremendous potential in the current situation for an epic cold (and therefore probably snowy as well) period lasting from this spell to first week or ten days of March. If we start to see any signs in 10-15 day output of building high pressure in northwest Russia or Finland then I would say look out for record cold to move west. Looking at the way these rather weak synoptics have maxed out for snow and cold, can you imagine if we get -10 uppers moving across the North Sea later this winter?

GFS of course seems to be lukewarm to idea of further cold this month and that could prove true, it matches my research output closer than the current ECM or GEM, but at this point for me it's all about February's potential and how that actually plays out. I am of curious now to see whether this is a case of cold coming early or just a huge signal starting to appear. If it's the latter then even 1947 could find itself with a rival, certainly 1895 and 1855 may have to move over a space.

Pretty mouth watering stuff RJS! Interesting that you feel that a less cold period would most likely be towards the end of Jan as today's Metoffice 6-15 Day outlook also points towards this scenario. Interesting times that's for sure.....

Edited by Don
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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

Well the Atlantic is by no means down for the count, it has been pushed back to the Irish Sea but it remains somewhat milder in Ireland and southwest England, so it seems logical to assume that if pressures eventually build over Russia there would be a time where this frontal boundary would re-establish closer to the North Sea with perhaps one strong low making it over the top of the building block, then if a block swells up it could overwhelm the weak Atlantic remnant and we would get into something much more definitively cold. Most of the major cold spells in February have built up in stages from about the same point as this one, back some distance in this thread I posted results of a study of winter CET daily temps in the 20 coldest February cases and the slide down through January was fairly steady with 23 Jan onward being subzero in the averages of those winters (the February average was about -0.2, actually the end of February was milder than the end of January on average even in cases of coldest Feb so that's interesting, hard for February to hog all the cold air of any given winter). Only 1969 seems to be a major exception to that rule.

Something worth noting -- of the big three cold Febs 1855, 1895 and 1947, the first two had similar record cold in the Great Lakes region in early Feb, but 1947 saw mild east winds across eastern Canada with a very large positive anomaly in Labrador trending to about a +1 anomaly in Toronto. That winter was very cold in western Canada with blizzards stranding livestock in the prairies and plains states, and set a record low of -63 C in the Yukon (on Feb 3rd). So there are two evidently different patterns that can produce a record cold February, one being hemispheric blocking and an easterly jet sort of set-up, and the other apparently being more of an omega block over the western Atlantic with retrograde tendencies. I think this year may provide a third example, omega blocking over the eastern Atlantic slowly retrograde but with central North America under a mild to warm ridge, because my output also shows a very mild February for the eastern part of North America while it's near-record cold in Europe.

Edited by Roger J Smith
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Posted
  • Location: Selly Oak, Birmingham or Thanet, East Kent
  • Location: Selly Oak, Birmingham or Thanet, East Kent

Well, interesting what Matt Hugo said in the Strat thread, about the EC 32 dayer being very bullish about height rises to the North and NEly winds in Feb. If that happens, then surely, the RJS model would attract a lot of interest. Interesting times ahead.

Edited by lce Blast
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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Feb Forecast

The first half of the month will feature high pressure retrogressing from Scandinavia to Greenland with repeated northerly and easterly outbreaks producing well below average temperatures and precipitation around average. The second half of the month will feature a much weaker -AO pattern leading to high pressure being dominant over the UK, temperatures will be slightly below average and precipitation well below average.

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Posted
  • Location: Selly Oak, Birmingham or Thanet, East Kent
  • Location: Selly Oak, Birmingham or Thanet, East Kent

I was just looking at the forecast from October from the Glosea model, and I must say, for the period of Nov-Jan, I am amazed at how accurate it's been with the geopotential heights. It got many details spot on, including the low heights over/south of the UK, and the strongish heights near the aleutians. In fact, pretty much every detail in the Northen Hemisphere matches very well with what actually happened.

Posted Image

Posted Image

Impressive.

Edited by lce Blast
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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

By the way summer blizzard, what are the strongest analogue matches for the summer? I think so far 2008 is in there and maybe 1999 as well so far. What I mean by this is strongest analogues my friend.

2008 is certainly a probable QBO match however so are many others that were warmer, i shall have a look through the data.

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

By the way summer blizzard, what are the strongest analogue matches for the summer? I think so far 2008 is in there and maybe 1999 as well so far. What I mean by this is strongest analogues my friend.

Okay so we don't really know what the ENSO will do this summer but based on increasingly westerlies and warm sub-surface temperatures to the west i think we will see an ENSO neutral-weak El Nino type setup along with a positive QBO so taking the summer season with years matching these we get...

qbo

1980

1985

1990

1995

1997

1999

2002

2004

2006

2008

MEI

1951

1953

1958

1969

1976

1977

1979

1980

1986

1990

1994

2002

2003

2004

2005

2006

2009

2012

A mixed bag but we know that 1990 and 2006 were notable in July and with 1976, 2003 and 1995 as weaker analogues that certainly springs my ears up, though there are probably some horror shows in there too.

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Posted
  • Location: Bearsden, East Dunbartonshire
  • Location: Bearsden, East Dunbartonshire

FEBRUARY - DETAILED FORECAST

First week: Starting cold and bright followed by a brief interlude of milder, wetter conditions before a return to cold, showery conditions with snow in the N and W

Second week: Cold and settled to begin with then a mild wetter interlude before a return to cold and settled conditions.

Third week: Largely cold with settled conditions in the north and at times unsettled in south, highest risk of snow in eastern areas

Final week: Starting cold before unsettled conditions brings a breakdown with a change to temperatures closer to average and changeable weather conditions.

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

It really doesn't surprise me (my being sceptical of non-computer-based LRFing, in general) that RJS's effort might go a similar way to everyone-else's...And that's not meant to suggest that certain folks don't understand their weather; but, that the scale of the calculations required to make reliably accurate predictions, three months' ahead of time, is currently impossible to master...

Edited by Rybris Ponce
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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

No comment except that the above makes an easily disproven statement of fact concerning "non-use of computers" if I am reading it accurately. Perhaps it means something other than what it says literally, but taken literally, it is simply 100% opposite from reality, in fact, I spend many hours a day doing research on a computer using data files that could not possibly be managed by paper-and-pencil type methods (maybe a group of a hundred medieval monks could do it, I sure don't have the time to crunch one or two extensive data files a week by hand).

However, I think the statements above are just an annual ritual of some kind and unrelated to either what I actually do, or what the weather is now actually doing (turning a lot colder).

So I have to admit that I am both confused and annoyed, I suppose there's nothing new there.

Edited by Roger J Smith
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Posted
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Weather Preferences: Sunshine and 15-25c
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)

because my output also shows a very mild February for the eastern part of North America while it's near-record cold in Europe.

i think the early part Feb 1991 was similar..almost record warmth across eastern and North eastern America...and bitter cold across Europe...however i am struggling to see how this pattern is going to evolve?
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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

What do you make of the current ECM run? Or are you just commenting on the North American part of that pattern? I think it will warm up in about ten days across the eastern half of North America (actually it has only been cold for about half of the past two weeks otherwise a rather mild January).

The only mild weather I see coming towards the UK is a brief shot on Sunday then the roof is going to cave in and by about day 8 to 10 on the ECM, the pattern looks glacial with -12 uppers close to eastern England and a growing connection to Siberian air moving west. So I have been confused reading this thread today, not sure what these comments are aimed at, the very mild spell end of January was actually something we were talking about extensively in relation to the 1969 analogue and also the idea that it might resemble 1947 with a slight time delay (it was very mild in mid-January of 1947 before that pattern changed dramatically).

The earlier comments seem to be hinting at some notion that February is not going to be a cold month and yet the ECM has about a 5-7 C negative anomaly from Tuesday to mid-month. The GFS may be what you're basing this on, but even that has some signs of a much colder pattern, and I am not sure the GFS will be right as odd man out twice in succession.

Anyway, I don't honestly know what's intended but to suggest that I am not using computers is just plain wrong, whether it's intentional or otherwise.

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Posted
  • Location: Glasgow, Scotland (Charing Cross, 40m asl)
  • Weather Preferences: cold and snowy in winter, a good mix of weather the rest of the time
  • Location: Glasgow, Scotland (Charing Cross, 40m asl)

What do you make of the current ECM run? Or are you just commenting on the North American part of that pattern? I think it will warm up in about ten days across the eastern half of North America (actually it has only been cold for about half of the past two weeks otherwise a rather mild January).

The only mild weather I see coming towards the UK is a brief shot on Sunday then the roof is going to cave in and by about day 8 to 10 on the ECM, the pattern looks glacial with -12 uppers close to eastern England and a growing connection to Siberian air moving west. So I have been confused reading this thread today, not sure what these comments are aimed at, the very mild spell end of January was actually something we were talking about extensively in relation to the 1969 analogue and also the idea that it might resemble 1947 with a slight time delay (it was very mild in mid-January of 1947 before that pattern changed dramatically).

The earlier comments seem to be hinting at some notion that February is not going to be a cold month and yet the ECM has about a 5-7 C negative anomaly from Tuesday to mid-month. The GFS may be what you're basing this on, but even that has some signs of a much colder pattern, and I am not sure the GFS will be right as odd man out twice in succession.

Anyway, I don't honestly know what's intended but to suggest that I am not using computers is just plain wrong, whether it's intentional or otherwise.

I think people were jumping the gun with regards to the ensembles at the 8-10 day range this morning. Certainly the cold looks like remaining up to around D7/D8 but after this we're once again looking at a setup which could go either way but as you say there is some real wintry potential there, with a northerly toppler this evening followed by an impressive looking northwesterly turning northerly into the middle of next week and with the cold trough over Europe remaining a key player in the output.
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Posted
  • Location: Selly Oak, Birmingham or Thanet, East Kent
  • Location: Selly Oak, Birmingham or Thanet, East Kent

Can say that I have been checking all my index values and looking at one new one that I developed which really puts a strong emphasis on this late winter cold spell in my outlook. Almost all the record cold values for February fall into the roughly one-sixth of all cases that are picked up in my various index values, so I remain optimistic that the severe cold will come after a long, slow and perhaps stalled for weeks retrogression of the obvious source, to be delivered in February. I am not even that confident of an arrival by 31 Jan looking at all data I would say it may be just creeping in about then but the core of the cold will be around middle of February lasting well into March with a sudden thaw and reversal at that point.

I just wanted to highlight this post that Roger made in December. He clearly states the cold only creeping in around 31st Jan (which it is), and the main cold coming in mid February (as the ECM is now hinting at with the building of a Scandi High towards mid Feb). The forecast has not gone wrong yet, lets just wait and see what happens mid month.

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Posted
  • Location: st albans
  • Location: st albans

Roger - nothing other than a comment based upon the general 00z ens and todays meto update which doesnt sound particularly cold out to mid month. That gave me an insight that mogreps wasnt supportive of the ecm op .

The 12z ecm may provide a backtrack, given the improved gefs 12z suite wrt cold. Up till today, i had been convinced that the pattern now shown by the op ecm runs was coming. I'll withdraw my comment above until later in the weekend to see if the cold can indeed intnsify beyond the euro trough next week.

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Anyway, I don't honestly know what's intended but to suggest that I am not using computers is just plain wrong, whether it's intentional or otherwise.

No, Roger; I was not suggesting that at all, or anything like it...I was merely referring to the amount of number-crunching required in numerical forecasting...

I mean no dis-respect to anyone, when I say that I am sceptical; ditto, when I say that, as yet, I've never seen any seasonal forecast (including those done by the world's most-powerful supercomputers) that I'd plan my future itinerary on...

Sceptical does not (at least in this case) imply dismissive...Posted Image

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Posted
  • Location: Stoke Gifford, nr Bristol, SGlos
  • Location: Stoke Gifford, nr Bristol, SGlos

Roger's main emphasis on cold has been February - his forecast was made a couple of months ago.

As it's currently 1st February how anyone can judge the success or otherwise of Roger's forecast today for Winter is beyond me.

Judge it in early March

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Posted
  • Location: HANDSWORTH BIRMINGHAM B21. 130MASL. 427FT.
  • Weather Preferences: WINTERS WITH HEAVY DISRUPTIVE SNOWFALL AVRAGE SPRING HOT SUMMERS.
  • Location: HANDSWORTH BIRMINGHAM B21. 130MASL. 427FT.

i agree with that statement brisel boy. I will say this so far rjs's forecast kept on track where as some of the pro forecasters on here there forecasts has not gon to plan, how ever respect to all who do the lrf's.

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