Model output discussions pm 31/12/15

[IDO]

2 minutes ago, johnholmes said:

The question to ask Nick is, how likely at that time scale is this to actually happen? Will it be there at T198h, moved on of course from the actual position shown at 222h. At 240h even at 500mb any model is rarely more than 70% correct. At the surface then it is much less for such detail.

Not only the margin of error that FI gives but it's the 06z and taking that seriously after D7 is going to lead to a lot of disappointments! Anyway both the op and control have little support from the GEFS and are technical outliers after D10:

      

Added to that both the hi res runs have the perfect setup^^^ with an upper low setting up just west of the Azores aiding two wave WAA towards Greenland. This feature has maybe one other ensemble member support and the rest of the members are rather poor in comparison:

Mean:   

The main clusters at D15 are 40% Atlantic and 30% UK high. The GFS is probably too early with the amplification re GP's lag of three weeks, but we would accept it if the hi-res have spotted an early bonus!

[nick sussex]

1 minute ago, *Sub*Zero* said:

Just had a look at the 00z ECM control and at day 10 the UK is in a northerly air flow with a ridge out west up to Iceland so frost and snow (for favoured locations in a northerly) all of the UK in -5c or below 850's and the 522 dam to the south coast. Thereafter the ridge gets toppled and we eventually end up with with heights centred over Spain/SW France leaving the UK in W/SW flow with depressions tracking close to Iceland. Would be drier than recently especially over England and Wales, rain at times for the NW of the UK.

I like the beginning bit but not the second part! Hopefully we get the toppling ridge towards Scandi.

[Cloud 10]

16 minutes ago, Glacier Point said:

Torpedo away !

These westerly winds, induced by the MJO will be fluxed poleward over time (takes around 21 days). On everything we've seen this winter, poleward fluxing has occurred. As soon as those westerlies strike the sub-tropical Atlantic belt, the NAO will flip negative.  The AO being negative should also allow for the MJO to remain highly active, so we may see a further pulses of westerly winds being fluxed poleward after passage of the MJO through the Indian Ocean late January.

 

Another way to look at the GWO which is going off the scale again much as it did last July which Tamara has often commented on.

 

[Essex winter]

Sorry guys what does gwo stand for and what effects will this have on our shores?

[bobbydog]

41 minutes ago, Glacier Point said:

Torpedo away !

These westerly winds, induced by the MJO will be fluxed poleward over time (takes around 21 days). On everything we've seen this winter, poleward fluxing has occurred. As soon as those westerlies strike the sub-tropical Atlantic belt, the NAO will flip negative.  The AO being negative should also allow for the MJO to remain highly active, so we may see a further pulses of westerly winds being fluxed poleward after passage of the MJO through the Indian Ocean late January.

is there any way to watch the progress of the "torpedo"?

basically so we can 'up periscope' and see it hit its target!

 

 

[nick sussex]

8 minutes ago, IDO said:

Not only the margin of error that FI gives but it's the 06z and taking that seriously after D7 is going to lead to a lot of disappointments! Anyway both the op and control have little support from the GEFS and are technical outliers after D10:

      

Added to that both the hi res runs have the perfect setup^^^ with an upper low setting up just west of the Azores aiding two wave WAA towards Greenland. This feature has maybe one other ensemble member support and the rest of the members are rather poor in comparison:

Mean:  

The main clusters at D15 are 40% Atlantic and 30% UK high. The GFS is probably too early with the amplification re GP's lag of three weeks, but we would accept it if the hi-res have spotted an early bonus!

IDO the 850's don't always give a correct picture. We want to see what the pattern looks like at T240hrs, like where is the PV, has it split over Greenland and how many tweeks are needed to get it to support the GFS operational and control runs. The issue seems to be shortwave attachment to the UK troughing but even with that I count around 8 which look promising. Bear in mind that its the upstream pattern between T144 and T168hrs which allows the progression to what the GFS and control run deliver.

If the ensembles have got that wrong then the rest is likely to be wrong. I think we need to wait and see what happens with those shortwaves to the sw, I'm more worried about those and that's why I'm being cautious.

[Liam J]

17 minutes ago, nick sussex said:

I like the beginning bit but not the second part! Hopefully we get the toppling ridge towards Scandi.

I don't like the second part either! A bit of deja vu for a moment but there was no blow torch mild air as we saw last month! The very last frame 360hrs temps are approaching double figures with the 546 dam approaching, but very much FI by this stage! 

[West is Best]

2 hours ago, cyclonic happiness said:

I don't know if that's any better. If it's gonna be extremely wet and windy, I'd rather it be mild.

This really is turning into Japanese water torture isn't it?   

It'll be good for the Scottish ski resorts though. Sometimes these cold meridional setups when we nudge north of the PFJ are the best conditions for them.

For the rest it could be grim and I agree with you. If you're going to have lashing rain it's probably better it's mild than cold.

We do indeed need to look for those Greenland height rises with this kind of pattern.

Edited January 3, 2016 by West is Best

[Sideways Snow]

1 hour ago, bobbydog said:

is there any way to watch the progress of the "torpedo"?

basically so we can 'up periscope' and see it hit its target!

 

 

Apologies for my ignorance but what is the 'Torpedo'?

[IDO]

3 minutes ago, Sideways Snow said:

Apologies for my ignorance but what is the 'Torpedo'?

I am assuming it is a metaphor for that AAM spike!

[kev f]

1 hour ago, IDO said:

Not only the margin of error that FI gives but it's the 06z and taking that seriously after D7 is going to lead to a lot of disappointments! Anyway both the op and control have little support from the GEFS and are technical outliers after D10:

      

Added to that both the hi res runs have the perfect setup^^^ with an upper low setting up just west of the Azores aiding two wave WAA towards Greenland. This feature has maybe one other ensemble member support and the rest of the members are rather poor in comparison:

Mean:   

The main clusters at D15 are 40% Atlantic and 30% UK high. The GFS is probably too early with the amplification re GP's lag of three weeks, but we would accept it if the hi-res have spotted an early bonus!

long time lurker so go easy!! am i right in assuming that upper low west of the azores is a consequence of what GP is referring to when he says as soon as the westerlies hit the sub-tropical Atlantic that will flip the NAO negative? ie low presure in the sub tropical atlantic aiding WAA north and setting up a High pressure in our locale thus the NAO flipping negative...??

[Polar Maritime]

Here you go E.W :  Global Wind Oscillation

 http://www.esrl.noaa.gov/psd/map/clim/gwo_maproom_new.htm

 http://www.esrl.noaa.gov/psd/map/clim/wb08_revised_final.pdf

Edited January 3, 2016 by Polar Maritime

[Sideways Snow]

11 minutes ago, IDO said:

I am assuming it is a metaphor for that AAM spike!

Thanks IDO

[bluearmy]

People - Stewart has posted about something which he believes will have an effect in approx three weeks time. One would expect it to begin to show in the evolution of deep fi in some of the fi gfs op runs in 7/0 days from now. to ask now what consequences it would have for our little bit of nw Europe is hopeful in the extreme.  I know it's been a frustrating winter for coldies thus far - if I were you, I would be looking at the amplification out west in about 8/10 days time and wondering if that might deliver either a cold northerly or potentially an undercutting of the Atlantic rather than potential three weeks away. 

[IDO]

1 hour ago, nick sussex said:

IDO the 850's don't always give a correct picture. We want to see what the pattern looks like at T240hrs, like where is the PV, has it split over Greenland and how many tweeks are needed to get it to support the GFS operational and control runs. The issue seems to be shortwave attachment to the UK troughing but even with that I count around 8 which look promising. Bear in mind that its the upstream pattern between T144 and T168hrs which allows the progression to what the GFS and control run deliver.

If the ensembles have got that wrong then the rest is likely to be wrong. I think we need to wait and see what happens with those shortwaves to the sw, I'm more worried about those and that's why I'm being cautious.

Sorry Nick, I was coming from a purely statistical point of view. The T850's are outside the margins of error and therefore the chances of them happening statistically are low compared to the dataset, though with weather the confidence in that conclusion is maybe less certain, as of course the ensembles may be having a bad day.

As you say in a fluid situation with maybe the Weather Gods onside for the UK what we see is quite feasible, but I do like a bit more support before I will tell family and friends (once bitten...). As I have said in previous posts I think GFS sporadic cold charts are just jumping the gun with reference to background signals. The last week of Jan looks like where we may get some Rossby wave action and even then the UK maybe on the wrong side of any block

[IDO]

7 minutes ago, kev f said:

long time lurker so go easy!! am i right in assuming that upper low west of the azores is a consequence of what GP is referring to when he says as soon as the westerlies hit the sub-tropical Atlantic that will flip the NAO negative? ie low presure in the sub tropical atlantic aiding WAA north and setting up a High pressure in our locale thus the NAO flipping negative...??

No. See Bluearmy's post, too early. That cut off upper low is an aid to supporting any HP cell (stops it sinking as quick) so is helful to get some WAA up north. Getting a feature like that right at this range would be a rare feat from GFS so I wouldn't get too hopeful yet of that being the final solution.

Just keep watching and there may be some promising charts showing up around next weekend onwards...

[Essex winter]

19 minutes ago, Polar Maritime said:

Here you go E.W :  Global Wind Oscillation

 http://www.esrl.noaa.gov/psd/map/clim/gwo_maproom_new.htm

 http://www.esrl.noaa.gov/psd/map/clim/wb08_revised_final.pdf

Thanks PM.mUch appreciated.EW

[Polar Maritime]

Models please, There is a banter thread open. Thanks.

[Tamara]

5 hours ago, Cloud 10 said:

 

Another way to look at the GWO which is going off the scale again much as it did last July which Tamara has often commented on.

 

Yes indeed.

Going a stage further than that, we can see a complete 12 month cycle picture regarding the sum total of tropical and extra tropical forcing on the atmospheric circulation since exactly this time last winter.

 

I won't apologise for yet further references to the past year in the context of the remarkable flux of atmospheric state and associated synoptic weather patterns we have witnessed, because the passage of time is continuing to illustrate more and more clearly the cyclical relevance of how the lagged effects of sub seasonal and intra seasonal phenomenon play such a large part in forecasting diagnostics.

We can look at the graph representation and transpose a dateline representation of the main synoptic patterns as they have evolved through the year and see how the massive AAM surges, by no coincidence, continue to correspond with the highest impact weather events globally at the surface. The UK (and the rest NW Europe as a whole)  has been at the heart of just some of these, there is no doubt.

First of all, we remember the atmospheric un-co-operation we frustratingly faced last January, with GLAMM tending negative too often and acting destructively in something of an ocean/atmosphere disconnect under a weak but trending upward ENSO signal. This therefore, in the consequential absence of poleward AAM, not assisting what was technically a potentially vulnerable and 'there for the taking' polar stratosphere.

Engagement of atmosphere/ocean began properly in the summer, as the graph clearly represents - with global atmospheric angular momentum sustaining almost complete positive territory since.

I think we could consider the July massive AAM spike and strong Pacific convective flare-up as Torpedo No 1. 

It was followed by a strong -AO kick to the atmosphere, through July, as the lag effects of MJO induced forcing at the dateline further kicked the atmospheric pattern

It was illustration No 1 in 2015 exactly how potent amplitude AAM phases, in conjunction with ocean/atmosphere forcing, can translate into noteworthy changes and effects on the atmospheric circulation weather patterns.

Its worth also noting on the graph the brief GLAMM departure dip in November, associated with transitory Indian Ocean tropical interference to the base state Nino pattern, at the beginning of the current tropical convection cycle.

The possible July > Jan link-up +AAM surge I have been mentioning since November, and which might give us the tropical > extra tropical kick to the atmosphere to properly change the Annular Modes from +ve to -ve,  as it did through July, is now verifying fully evident in real time data,

To the present. In the meantime and before those envisaged changes, the cocktail of high express train strong Nino Jetstream and hostile w/QBo vortex has, and still is providing, as VI (vortex intensification) begins its demise, a fair amount of high impact weather of its own downstream where sit at the end of the barrage.

But here we are with what I consider Torpedo No 2 under the on-going ENSO/GLAMM regime. 

This year, unlike last January, we have as just implied above, a much less co-operative stratosphere than last winter (at least potentially at face value!) was. So we have a good litmus test to come which will ultimately demonstrate the potency of this lagged ocean/atmosphere coupled depth charge later this month.

Much has already been expertly said about the potential implications in our parish from this. So with the fuse lit,  its a case of sitting back now and watching for the winter prototype to detonate  - and see if it can catapult us into something much more appealing than the appalling fare we continue to suffer in the meantime.

Hopefully this illustration summary is enough to demonstrate exactly why watching the long term teleconnections and GSDM tools are a very useful addition to longer range and seasonal forecasting - and when interpreted sensibly into context of numerical NWP model output, not a meteorological version of Mystic Meg sooth-saying.

Edited: To clarify we might be an Island, but are still a member country of Europe

Edited January 3, 2016 by Tamara

[Cloud 10]

36 minutes ago, Polar Maritime said:

Here you go E.W :  Global Wind Oscillation

 http://www.esrl.noaa.gov/psd/map/clim/gwo_maproom_new.htm

 http://www.esrl.noaa.gov/psd/map/clim/wb08_revised_final.pdf

 

Some good discussions about the GWO (Global Wind Oscillation) here on Netweather from a few years back as well.

Gwo And Global Angular Momentum - The netweather guides... - Netweather Community Forums

 

[recklessabandon]

A question for the more experienced perhaps? Currently sea surface temperatures are approximately 2 - 4 C above average (anyone who lives near the coast will notice this) with the current sea surface temperatures here on the Northumberland coast at 11.5 C! (anomolies chart below). Have we ever been in such a scenario in January?

So lets say such a scenario plays out where a prolonged northerly / north easterly occurs as is now being discussed as potential - my thoughts are that this in the short term is more likely to lead to increased convection, but significant modification delivering cold rain and sleet to many low lying / coastal locations rather than snow, and given the elevated SSTs - the most likely scenario is that the Scottish Highlands and other upland areas of the UK (NYM, Cheviots, Pennines etc) will get a pasting with the rest of the UK left cold and soggy.

[phil nw.]

A ramping post and replies have been moved here https://forum.netweather.tv/topic/84481-winters-moans-ramps-chat-and-banter/

where they are better suited.

We welcome any punts for the longer range as long as they are shown to have some model or similar data to support them.

Edited January 3, 2016 by phil nw.

[nick sussex]

The dynamical model forecasts for the MJO haven't been updated for a few days so looking at the smoothed out version which reduces ENSO and Kelvin wave interference this still looks good:

The MJO composite chart for high amplitude phase 7 and positive ENSO is here:

Note the similarities with the chart that Greenland 1080 just posted! Interesting, if only things were that simple! Because of the very strong ENSO this will have some moderation of the MJO signal but nice to see regardless.

 

Edited January 3, 2016 by nick sussex

[Cloud 10]

06z GFS parallel run agrees with the "normal" GFS regarding the possible mid-month cold shot.

 

[knocker]

16 minutes ago, recklessabandon said:

A question for the more experienced perhaps? Currently sea surface temperatures are approximately 2 - 4 C above average (anyone who lives near the coast will notice this) with the current sea surface temperatures here on the Northumberland coast at 11.5 C! (anomolies chart below). Have we ever been in such a scenario in January?

So lets say such a scenario plays out where a prolonged northerly / north easterly occurs as is now being discussed as potential - my thoughts are that this in the short term is more likely to lead to increased convection, but significant modification delivering cold rain and sleet to many low lying / coastal locations rather than snow, and given the elevated SSTs - the most likely scenario is that the Scottish Highlands and other upland areas of the UK (NYM, Cheviots, Pennines etc) will get a pasting with the rest of the UK left cold and soggy.

I have to say I find that anomaly surprisingly high. This was the chart week ending the 27th