Model output discussion - 5th December 2016 - Into Winter we go

[nick sussex]

We really are stuck in a rut for the next ten days  with the only real uncertainty seeing where the high might end up.

In an effort to find something interesting to say about the outputs that's hard going! But there are two points of interest and I use the term interest with much artistic licence.

Looking at the ECM spreads its likely some ensembles cut a shortwave south towards Poland, whether that can get corrected further west , also we still see the ridge extension from the Siberian high which might give the Euro high a nudge further nw.

The suggestion from the ECM and some of the more B list models is to dig troughing to the west of the UK, unfortunately at the moment the PV seems far too strong for any interest but its whether we can see the Euro high get far enough nw to force some trough disruption.

 

Edited December 12, 2016 by nick sussex

[mb018538]

Would things not initially be cloudy and around average as the high is building in from the west? Perhaps then breaking somewhat as some drier air comes in off the continent. I understand it's fairly non-descript and not what many want....but when you compare it to 12 months ago when thousands of peoples lives were ruined with the incessant wind, rain and flooding, I think we all know what the better outcome is.

[nick sussex]

Just now, mb018538 said:

Would things not initially be cloudy and around average as the high is building in from the west? Perhaps then breaking somewhat as some drier air comes in off the continent. I understand it's fairly non-descript and not what many want....but when you compare it to 12 months ago when thousands of peoples lives were ruined with the incessant wind, rain and flooding, I think we all know what the better outcome is.

Yes of course its much better to see these drier conditions than another ruined Christmas for people who suffered terribly with last years floods. The GFS 06hrs run does actually look quite cold at the surface from day 6 to day 10.

[knocker]

Although the upstream pattern change has occurred by this period still looking at a strong Canadian vortex, a flat flow across the States and a weaker Atlantic trough. The HP still hanging around adjacent to the UK warding off all comers, apart from those that sneak around to the north. The surface high probably around to the SE. This would mean light zephyrs for most of England under the influence of the high with Scotland maybe not so lucky. Thus the temps will vary with a slight nip to the south (the SW excepted) and rising as you move north.

Now where did I put those blasted nuts

Edited December 12, 2016 by knocker

[No Balls Like Snow Balls]

Probability maps updated today from METEO.

Covers Jan/Feb/Mar

 

 

[bluearmy]

pretty unhelpful over a three month period but we know from ian that the model has shifted somewhat

[danm]

7 minutes ago, No Balls Like Snow Balls said:

Probability maps updated today from METEO.

Covers Jan/Feb/Mar

 

 

So we've gone for a colder than average first half of winter to a colder than average second half? 

[Nouska]

1 hour ago, Tamara said:

Indecision related to tropical convection persists related to "destructive" signal of further cyclone activity in the I/O - which continues to interfere with the low frequency (amplification) signal over Indonesia. Additionally there is now a watch in place for significant tropical cyclonic activity in the Western Pacific (a good thing)

Good summary.

One of the other useful functions of the site that gives the UKMO 168 chart is the ability to 'quick look' at tropical cyclone genesis forecasts in the other basins.

http://ruc.noaa.gov/hfip/tcgen/

In this case, option NIO (northern Indian Ocean) and use the loop function to compare all the listed models day 1-7.

It looks to me that the MJO forecast from some models is following the projected path of Vardah - being it is the strongest signal at present but if something else develops further east who knows. Perhaps ECM is correct in not being misled by a short lifespan cyclone?

    

 

[karlos1983]

So in order of likelihood (according to MetO) 

1.above normal 

2.near normal

3.below normal

60-80% means they must be pretty certain. If it's not relevant why publish it today? 

[karlos1983]

4 minutes ago, danm said:

So we've gone for a colder than average first half of winter to a colder than average second half? 

None of those images suggest cold. Quite the opposite unfortunately 

Edited December 12, 2016 by karlos1983

[Singularity]

For what it's worth, the  06z GFS raw numbers, following on from a Hadley CET estimate corrected slightly downwards (as provisional numbers are nearly always above the final ones), fully neutralises the positive CET anomaly as of 27th Dec.

You'd then need a CET mean of about 0.2*C to produce a below average month overall. That'd be achievable under a slack ridge or indeed in a cold easterly regime. A northerly would have to be pretty potent to do the job.

So this could well be strong case of a month for which the overall mean hides some notable extremes of weekly/multi-day mean temperature.

[ArHu3]

5 minutes ago, danm said:

So we've gone for a colder than average first half of winter to a colder than average second half? 

No 60-80% chance above normal,  0-20% below normal 

[Penrith Snow]

Dear me,

Those probability maps from the MetO are terrible! 80% chance of mild and 20% chance of cold, it doesn't get much worse than that.

Its almost a winter is over scenario.

If Glosea5 hadn't mad such a hash of the early winter I would be throwing in the towel but even allowing for its recent unreliability the prospects going forward are not good.

Andy

[nick sussex]

12 minutes ago, Penrith Snow said:

Dear me,

Those probability maps from the MetO are terrible! 80% chance of mild and 20% chance of cold, it doesn't get much worse than that.

Its almost a winter is over scenario.

If Glosea5 hadn't mad such a hash of the early winter I would be throwing in the towel but even allowing for its recent unreliability the prospects going forward are not good.

Andy

The problem with those UKMO maps is that you can conceivably end up above normal but still have seen some decent snow and cold. For example if the winter was dry and cold with little snow coldies in here would think it was a bit naff. If we saw a month with wild swings between very mild and very cold with snow the view would be very much different. Unfortunately in recent winters its just been rubbish from beginning to end.Thankfully I have little faith in either Glosea or the ECM longer range so won't be losing any sleep over what either say. Science does need to test the boundaries but whereas in medical science you can to a degree remove many variables the weather is far more complicated IMO.

I think a good example that highlights the problems with longer range forecasting is the current MJO, there has been conflicting signals because of cyclone activity, would any longer range forecast have included that variable? I'm a firm believer in the butterfly effect and nothing I've seen over recent years in terms of forecasting accuracy has altered that view.

Edited December 12, 2016 by nick sussex

[Dennis]

well we see a very blocked pattern this week

[Summer Sun]

Mean maps show above average 2m temps for Jan to March

Same for 850's

Pressure higher than average

Rain nothing worse than average

[Ravelin]

11 minutes ago, Penrith Snow said:

Those probability maps from the MetO are terrible! 80% chance of mild and 20% chance of cold, it doesn't get much worse than that.

Whoah, slow down, "above Average" does not necessarily mean "mild". It could be <0.5C above average, which in Jan or Feb especially does not necessarily mean warmth. Also, it's an average over a 3mth period, which can hide a lot of variation.

 

[Abyss]

2 minutes ago, nick sussex said:

The problem with those UKMO maps is that you can conceivably end up above normal but still have seen some decent snow and cold. For example if the winter was dry and cold with little snow coldies in here would think it was a bit naff. If we saw a month with wild swings between very mild and very cold with snow the view would be very much different. Unfortunately in recent winters its just been rubbish from beginning to end.Thankfully I have little faith in either Glosea or the ECM longer range so won't be losing any sleep over what either say. Science does need to test the boundaries but whereas in medical science you can to a degree remove many variables the weather is far more complicated IMO.

Exactly. This Winter is testament to that. No point getting hung up on what LRF show but many do and its rinse repeat each time.

[Summer Sun]

Looking into spring and the high is still shown to be close by to the UK right through to the 3 month period covering March to May

[chrisbell-nottheweatherman]

2 minutes ago, Summer Sun said:

Looking into spring and the high is still shown to be close by to the UK right through to the 3 month period covering March to May

Which model is that?  I wonder whether mean anomalies that far out are much more accurate than pure chance, though I stand to be corrected, of course.

Edited December 12, 2016 by chrisbell-nottheweatherman

[karlos1983]

Anyone hoping to find salvation in the CFS, don't bother. I found a toppler in 3 weeks time, but that's about your lot.

That felt slightly desperate, and for nothing 

 

[Summer Sun]

2 minutes ago, chrisbell-nottheweatherman said:

Which model is that?  I wonder whether mean anomalies that far out are much more accurate than pure chance, though I stand to be corrected, of course.

GloSea5?

Other than that not sure

[chrisbell-nottheweatherman]

Just now, Summer Sun said:

GloSea5?

Other than that not sure

Thanks.  I was mainly wondering what the source was for that output.

[karlos1983]

7 minutes ago, Summer Sun said:

Looking into spring and the high is still shown to be close by to the UK right through to the 3 month period covering March to May

I'm somewhat reluctant to take those charts with any seriousness whatsoever... call me a cynic . .... 

Edited December 12, 2016 by karlos1983

[frosty ground]

 

Euro high anyone?