Snowy Hibbo

November 14, 2017

A sub-Seasonal update.... looking at model outlooks.

This is the SubX group of models, with the various models that make it up.

18-24 Nov

The MME mean shows a Greenland high and troughing over the UK and Continental Europe.

25th Nov - Dec 1st

The MME mean shows a similar setup from the previous week. A Greenland high and troughing over U.K and Continental Europe.

2-8 Dec

The MME mean shows a high over Greenland again and troughing over the UK region.

I am adding the CFS Weeklies for the Week 5 & 6 periods.

12-18 Dec

19-25 Dec

Similar setup both weeks, Euro high with UK somewhat in between the euro high and Iceland trough.

And the EC46 model to wrap it up.

14-20 Nov

This week, the model shows a ridge over the Atlantic, going towards the U.K. Troughing in the Scandi region and over Italy.

21-27 Nov

Next week, Greenland ridging comes over the UK. Troughing over Eastern Europe.

28 Nov - 4 Dec

Troughing over Iceland and ridging in the Mediterranean.

5-11 Dec

Troughing south of Greenland, and a Euro ridging pattern is present.

looks interesting....

November 13, 2017

On 12/11/2017 at 08:10, lorenzo said:

Hey, where do you get these plots from? Thanks.

November 12, 2017

1 hour ago, Hocus Pocus said:

ENSO has been poorly modelled fthroughout this year so any such predictions should be taken with a large dose of salt. Most of the climo models appear to be factoring in a moderate Nina hence the less than spectacular long range forecasts

This ^^^

The IRI produce this chart, that shows all the ENSO predictions for the last year or so.

It shows that the models can go off track quite a lot (black line = obs).

Anyway I released a seasonal forecast today. It's for the European Alps, but also has relevance for the UK, as I focus on impacts to the AO. Enjoy....

November 10, 2017

A look at the recent EC Monthly run.

14-20 Nov

Next week looks to feature two troughs, one over Iceland and the other centered over Southern Italy. A ridging pattern occurs in between those two troughs, including the UK. A fairly zonal jet occurs over the UK. Average temperatures across the UK, except for SE England, which is colder than normal. Drier than normal for England, wetter than normal for NW Scotland. Above average snowfall for the Scottish Highlands.

21-27 Nov

Then we start to get a troughing signal centered over France and Iberia. The trough extends over the southern parts of British Isles. A ridge looks to be over Greenland. The jet over the UK looks like it's heading towards the SE. Colder than normal for England, Wales and Ireland, average temps for Scotland. Drier than normal for Wales, the West Scottish Coast and much of Ireland, wetter than normal for the East Coast of Great Britain.

28 Nov - 4 Dec

We get a somewhat similar pattern to the previous week, with a trough signal over France, now heading over Southern Great Britain and across to Germany and Denmark. The Greenland High has moved somewhat to the SE, but is still present between Greenland and Iceland. This creates a ESE-SE direction jet across the U.K. Average temps for the entire UK. Drier than normal for Western Scotland and Ireland, average for the rest of the UK.

5-11 Dec

The only significant anomaly is the still present ridge in the North Atlantic, over Greenland in Week 2, now moving towards Iceland in Week 4. The ridging anomalies are now extending to the Northern UK. Average temps predicted for the U.K. Similar trend to the previous 2 weeks, with a dry Western Scotland, Wales and Ireland. Average precip for the rest of the British Isles.

My European Seasonal Outlook should be out tomorrow. Cheers

November 9, 2017

Firstly the blocking forecast

This is the EPS mean 10 day forecast across the Northern Hemisphere. You can see a clear trend of high latitude blocking,

developing in the D5 to D10 period. This correlates with a -AO. Troughing is also significantly present in the mid latitudes, further showing the -AO pattern across the Northern Hemisphere.

A similar pattern continues in the EPS mean to T+360....

The GEFS forecast for the AO reflects this trend, shown by EPS. Even though I am not lucky enough to have the WxBell EPS AO chart, it's safe to say both models are going for a -AO setup.

CFS also shows a -AO trend from now, into the ensemble's main forecasting period, and beyond that to around Mid December, when CFS thinks that the pattern will change to a more +AO setup, until late January. Very interesting to see a +AO like trend across most of winter, given most of the climate drivers are going for a -AO based winter.

Finally the various CFS forecasts for December in the past 6 days, in this freshly created chart from Ryan Maue.

It gives a great show at what are the trends and what are the distractions, in the various CFS modelling....

This is the CFS forecast for December averaged over the past 7 days (note 3 more runs added to the above chart).

It shows a mostly warm pattern for Europe, including the UK.

Anyway the seasonal models always for some reason seem to contradict the climate signals I see

CFS apparently has a warm bias though....

November 7, 2017

and EC Weeklies....

14-20 Nov

Troughing over Italy and the Balkans, Ridging over the UK and Scandi. Jet mostly Zonal across the Atlantic. Precip forecast for most of the UK is drier than average. Snowfall anomalies are average. England is cooler than normal, Scotland and Ireland is average temperature wise.

21-27 Nov

Troughing over France, Iberia and Southern UK. Strong Greenland/Icelandic High (I believe people have already touched in this). Jetstream heading towards the SE across the U.K. Precip anomalies over Western Great Britain are drier than average and over the Eastern Great Britain, is around average. Snowfall anomalies are average. The entire UK is cooler than normal.

28 Nov- 4 Dec

Troughing over Iberia and France, ridging over Iceland. Similar setup to the previous week with the jet and 500mb anoms in the region. Most of the UK is drier than normal, except the East Coast, which is average. Snowfall is forecast to be below average in the Scottish Highlands. England is cooler than normal, Scotland is average temperature wise

To compare, here is the SubX multi model ensemble forecast. It contains the typical GEFS and GEPS ensembles, and the less well known models, NAVGEM, FIM, NASA GMAO, and CCSM. These are all produced by various American meteorological agencies and research institutes.

11-17 Nov

It shows an Atlantic ridge with a troughing pattern across from Iceland to Italy, including past the Eastern UK.

18-24 Nov

Ridging anomalies from the Atlantic and over Northern Europe, including over the U.K. Troughing over Southern Europe and the Mediterranean.

25 Nov - 1 Dec

A ridge over Scandi into European Russia, with a weak ridging pattern across the U.K.

Anyway that's the sub Seasonal models.....

November 6, 2017

2 hours ago, SLEETY said:

It up to you if you want to believe a computer program will be able to accurately predict the weather seasons in advance.

And you think soon the ec46 will achieve this

Look how much the models struggle after 5 days .Their accuaracy drops off a cliff.

How many times do you see charts in fl verify .Todays gfs06 shows easterly winds with High pressure over Greenland .In the next run it will change again .It always does.

I think he is talking about the future of the EC46. Like 5, 10, 20, 30 years from now. Of course the EC46 will improve.

Back in the 60s and 70s, they could only imagine how far we have come with weather prediction. They probably couldn't predict much, beyond what the sky, clouds and wind told them. But now we can accurately forecast out to 7 days. I think it's pretty incredible. Humanity will obviously work out the puzzle of sub-seasonal forecasting. There's already work to improve it. EC46 is getting improved all the time, and NOAA and it's sister agencies just launched SubX, a sub seasonal forecasting system, that is assessing the work of 6 different models.

October 27, 2017

4 minutes ago, SW1988 said:

I thought the whole idea of computer modelling was to factor in all those different parameters

Impossible to factor them all in. They try their best, but we are still refining it. TBH it is pretty amazing what we have achieved.... accurate 5-7 day outlooks of the weather. We are still working to refine longer range forecasts.

October 27, 2017

continued.....

Week 1 (Next Week)

Next week the fresh EC Weeklies (or EC46) run, shows a ridge to the west of the UK for the week's average. And a trough over most of Eastern Europe, into Russia. Ireland is warmer than average, according to the EC Weeklies model next week, but Great Britain is neutral temperature wise. The UK is forecast to be very dry overall next week.

Week 2 (The week after)

A ridge builds over Scandinavia, moving down to Germany and the UK. This makes a zonal flow across Europe occur in the jetstream (no northerlies, like the week before(next week)). The temperature outlook is neutral. The precipitation outlook is mostly neutral for the UK, except for wetter anomalies in NW Scotland and drier anomalies in Wales and SW England.

Week 3 (14-20 Nov)

A strong Scandi high seems to come this particular week, although the high's strongest point is over Finland and into Russia. This creates a zonal flowing jetstream across the U.K. yet again, though the direction might be slightly ENE. The temperature outlook is once again neutral for the UK. The precipitation outlook is wetter than normal for the majority of the UK, due to what looks to be a strong Atlantic.

Week 4 (Nov 21-27)

Then you get a Euro high, centered on the Baltic Sea. It extends across most of Europe, except the Iberian peninsula. However it extends over the UK, and looks to neutralise our precipitation outlook for most of the UK. However the snowfall anomalies in Scotland are lower than normal.

Very interesting run from the EC Monthly model. Hope it was interesting, SubX should be coming out tomorrow, so I will post that data here.

October 27, 2017

Another sub-seasonal model update....

I was making posts about MJO on Wednesday, talking about the forecast for it. But I have had another look at MJO and all of the equatorial waves.

This MJO forecast shows the current MJO wave is actually associated with a Kelvin wave. Apart from being connected to the QBO, Kelvin waves aren't as important as the MJO though. Very interesting though. More to come.....

October 26, 2017

Now I will show the forecast for some more climate drivers and sub-seasonal forecasts.

The AO is going for a positive phase in the next week. CFS then forecasts a general period of -AO (weaker jetstream, weaker vortex) over the month of November and then a general period of +AO (stronger jetstream, stronger vortex) over the month of December.

The NAO is going for a less well defined outlook, but a general -NAO phase is forecast on CFS from now until about November 24. And then a period of a somewhat +NAO forecast until the end of December, and then a few up and downs into January.

More tomorrow... much better quality post then. Thanks.

October 25, 2017

52 minutes ago, Northern Sky said:

Is there anything in the models to suggest this cold/cool snap will be anything other than a little blip before the PV gets organised and we are back to business as usual?

Very intriguing question.

Firstly I will show the modelling in a different light, compared to the determ models.

This is the NAEFS (North American Ensemble Forecast System) model, which is actually a combo between GEFS and GEPS. Comparing it to EPS, provides a very useful outlook IMO, especially for longer range modelling.

First the next 7 days worth of 500mb anomalies.

Then the first 7 days of November.

Big contrast between the ridge influence in Wk 1 and then the cold snap/trough coming over in Wk 2. Lots of others have pointed this out, but just showing it a little differently.

Now for the question.

The NAO is currently going into a negative phase. Beyond the 2-3rd Nov, it is expected to climb to positive neutral figures. I am not sure whether it is going to continue for a proper +NAO phase.

The MJO is currently entering Phase 7. These phases (6+7) are deemed to the best for a -NAO(+10 days), which is occurring. The relationship with Scandi highs and Atlantic ridges and MJO is poor.

EPS and GEFS (Bias-Corrected) MJO RMM plots above.

The EPS shows a rapid decline to neutral MJO during Phase 7. GEFS shows a slower decline, entering the neutral realm at Phase 1. POAMA and the Canuck models agree with EPS, JMA is in between the main models.

For longer range forecasts, the POAMA model provides a probabilistic (chance of MJO Phase) forecast for the MJO:

For 11-15 Nov, 50-70% Neutral, 10-30% Phase 3.

For 16-20 Nov, 50-70% Neutral, 10-30% Phase 1.

For 21-25 Nov, 50-70% Neutral.

For 26-30 Nov, 50-70% Neutral, 10-30% Phase 2.

Overall this means that MJO will likely remain neutral over November, and if it strengthens later in the month, it is likely to be in Phases 1-4. Which correlates with a +NAO(+10 days).

So in my opinion, we may see a +NAO setup come around in the 2nd or 3rd weeks of November (emphasis on the may). But I haven't looked at the PV, or any other climate driver, except for the MJO and NAO, in proper detail. It's kinda rushed, because it's getting late night here in Aus. I will have a proper longer range look tomorrow, provided the forum doesn't crash .

October 24, 2017

9 hours ago, NorthernRab said:

Oh wow.

Probably the biggest 24 hour increase to date!

Should keep coming down, EC still predicting a push of snow cover to Russia's Western and Southern Borders by the end of the month.

October 24, 2017

13 minutes ago, knocker said:

It must have done it doesn't appear on any site I've looked at although I haven't seen any reason given

Yeah mine is down too. Weird....

October 24, 2017

So the EC Monthly run, Monday edition, has been released (only released on a Monday and Thursday). I posted information about the long range climate drivers two pages ago. Now I am going to have a look at the most reliable (out of a pretty poor bunch) long range model there is.

This week's 500mb anomalies. You can see a fairly strong ridge to the SW, which sets up the jetstream to come across the U.K. and head southeast across Continental Europe. Then it makes way for troughing in Eastern Europe into Russia (which also happens to help Eurasian Snow Cover expansion, which is a important factor in winter).

Week 2 (Next Week) 500mb anomalies. Again a ridge exists near the UK, probably to the west. The UK is on the Eastern edge of this ridge. The trough over Eastern Europe strengthens and moves west, potentially dumping snow across Eastern Europe and the European Alps. EC46 Precipitation anomalies show drier than normal conditions for most of the UK, except North Scotland. The snow anomalies show somewhat higher than normal snowfall in parts of the Scottish Highlands, particularly to the far north. The temperature outlook is mostly neutral for this period.

Week 3 (Week after next week) 500mb anomalies. A ridge is over the Atlantic, near the UK, with the UK being on the ridge's northern boundary. Snow anomalies are neutral, same for temperature anomalies. Precipitation anomalies are wetter than normal in Northern Scotland, but drier than normal for rest of the UK.

Week 4 Ridging anomalies for Southern UK regions. The jetstream seems more going towards the ENE across the U.K, than the other earlier weeks (which were going more to the ESE) IMO. Precipitation anomalies show a wet UK, with most of the region under wetter than normal anomalies. Temperature and Snowfall anomalies are mostly neutral.

That is the EC Weekly model update. Hope you enjoyed that. All detail is IMO.

October 23, 2017

4 hours ago, SteveB said:

Nice dumping for Western Russia, this is exactly were we want to see it & not heading South to Stans & Iran.

Like I said in my previous post, it will be going down to Kazakhstan next. The snow cover will also expand towards Eastern Europe and (non mountain) Scandinavia, as shown by this EC 5 day snow cover forecast.

October 23, 2017

So a little update on the climate drivers.

This community should be aware of the Phase 6 MJO, occurring currently. This is a BOM RMM index.

As some may know, MJO Phase 6 + about 10 days, correlates with a -NAO. So the correlation would expect a -NAO around the 30th of October- 1st of November, based on current forecasts (referencing the EPS RMM forecast below).

Looking at NAO forecasts, GEFS shows the NAO diving, along with the EPO, towards a negative phase in the next day or so. During the MJO analog driven -NAO forecast period (30/10-1/11) occurs, the GEFS NAO forecast shows the negative NAO weakening to neutral, rather than the peak of a -NAO, as the MJO analogs would suggest. Anyway food for thought.....

I tried to get some of my contacts to give me the EPS NAO data, but I couldn't get it unfortunately.

However I do have the CFS long range 90 day forecast for the NAO.

It shows the negative peak of the NAO during the next negative phase to around the 30th of October, in contrast to GEFS which shows it to be the 26th of October. After the negative phase ends, CFS suggests a neutral NAO for the rest of November.

In summary, the NAO is forecast to go negative in the next few days. The peak of the -NAO is forecast to be the 26th of Oct by GEFS and the 30th of Oct by CFS. The MJO favours a -NAO peak between the 29th of October and the 2nd of November. But it looks like the MJO for the most part helps support the incoming -NAO IMO.

A look at the latest EPS Control. A handy reference below.

The EPS Control 5-10 day outlook. Some of the jetstream makes a weird deviation down to that lower height anom, but the main portion of the jetstream comes right over the UK, brings a good first proper 'winter storm' and quite cold weather. You can see a fairly large Atlantic influence, but also an Arctic influence IMO, as the jetstream streams across Greenland and Iceland.

Then you have what looks a bit like a Atlantic Ridge pattern, but what could also be interpreted IMO as a +NAO pattern, with a fairly strong jet. I will have to double check the EPS jetstream zonal wind anomalies tomorrow to confirm that strong jet. Anyway the ridge is over the UK and you can also see Scandinavia troughing. Could be an interesting situation.....

Anyway, hope that was somewhat interesting. Thanks. I will post the EC Weeklies run tomorrow if there is interest.

October 20, 2017

There looks to be some major changes to the Russian landscape, according to EC at least.

Days 1-5: A large low produces a lot of snow in Western Russia, there's also a smaller low north west of Sakhalin generating a lot of snow and snowfall also at Russia's Far Eastern Tip next to the Bering Sea, thanks to the Aleutian Low. The large low weakens and moves towards Kazakhstan at around Day 4. Lows start to develop in Siberia during this period.

Days 6-10: The lows in Siberia bring more snowfall. Central Russia receives snow from the large low, that moves on from Northern Kazakhstan, along the Russia-Mongolia border over this period, bringing snowfall there. Around Day 7-8, a trough develops in Western Russia and by Day 10, it is a strong low dropping lots of snow in European Russia. Also at Day 9-10, the large low, which started in Western Russia, is now strengthening and approaching the Pacific, dumping snow along Russia's Southern Border.

Here is the 500mb anomalies across the Northern Hemisphere, with my annotations pointing out the major lows.

Tomorrow

5 days out

8 days out

Nonetheless, what does this mean?

Well it means a fairly big jump in Siberian Snow Cover extent, towards the West and South.

The SSC goes from this (today's chart) to.....

this. As you can see, the 10 day EC Determ model shows snow cover over most of Russia, extending into Northern Mongolia and Kazakhstan, as well as Eastern Europe. Even though much of this snowfall is forecast at a long range and may change, it looks like we will see lots of snowfall across Russia over the next 10 days.

The GFS 10 day Snow Cover forecast for comparison. Looks similar expansion to EC, except for not as much snowfall in European Russia.

October 20, 2017

Eurasian snow cover data for this year. Currently average in terms of snow extent for Eurasia.

October 19, 2017

12 minutes ago, Staffordshire said:

Is there actually a proven correlation between snow cover and our winters? If so, where could i read about this? Thanks

An expanded Siberian Snow Cover equals a stronger Siberian High which enhances poleward heat flux, which equals a weaker polar vortex which equals a -AO.

This is a typical -AO setup, with a high over the Arctic and a higher chance of winter storms in Europe and the Eastern United States.

This is a infographic that explains it in a little more detail, and explains what happens in years with a less expansive Siberian Snow Cover. However this is no way the only indicator of what is going to happen during winter. It is one of many climate drivers that must be taken into consideration, but the Siberian Snow Cover is an important tool nonetheless. The other guys are correct, noting that Eastern Europe gets colder temperatures during a Strong Siberian Snow Cover event.

For more information on this, look at Judah Cohen's website. He has been studying the correlation between the Siberian Snow Cover and the AO for years.

October 18, 2017

6 hours ago, Summer Sun said:

AccuWeather winter forecast for the UK and Europe

https://www.accuweather.com/en/weather-news/europe-winter-forecast-uk-to-germany-on-alert-for-wind-storms-rain-to-ease-drought-wildfires-in-spain-and-portugal/70003011

They are well known as 'Inaccuweather'. From what I have heard, they base their forecasts off limited guidance.

October 18, 2017

On 15/10/2017 at 17:22, knocker said:

Have I just twigged who the Snowy Hibbo is?

Haha... yeah that's me. Hope you like my tweets . I have heard great things about this forum, so I decided to join and lurk around.

Seems to be a shift in the long range to a potential -NAO in Early November. My special GEFS product is offline, so I can't post the NAO. Hopefully that sticks into winter.

Anyway here's the POAMA DJF MSLP forecast for the European region. Looks +NAO like. Just don't tell the BOM.....

October 18, 2017

2 hours ago, Allseasons-si said:

Also,the MJO working though to phase 8 and quiet amplified too,i seem to recall that this is a good thing,but point me out if i am wrong.

Depends what you want. Phase 6 + 10 days correlates with a -NAO. The current GFS forecast for the NAO is a decreasing of +NAO to neutral conditions. Based on the MJO forecast, there is an increased chance of a -NAO in the first days of November.

CFS seems to agrees with that. Late October and Early November look to feature a -NAO, according to the 4 member CFS ensemble. I'd personally agree with that forecast, based on the connection with the MJO analogs.

October 13, 2017

The JAMSTEC forecast was released yesterday.

It forecasts a Borderline La Niña like many models released this month.

It is one of two models, that consider El Niño Modoki, which is forecast to be neutral.

Another model that doesn't seem to have been mentioned here much is the EC model. It shows a weak-moderate La Niña occurring.

October 11, 2017

On 10/10/2017 at 09:55, Summer Sun said:

NMME is the North American Multi Model Ensemble. It contains various models, including the CFS model, the CanSIPS models, GFDL models, NCAR model, the NASA GMAO model and the IMME model. These models, with the exception of the IMME, CFS, NASA and CanSIPS models, are probably not worth a look alone. But as the NMME contains nearly all of the North American Seasonal models, it tends to be worth a look. But as with all seasonal forecasts, they have their failures.

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