Model Output Discussion 1st Nov.2013

[Ian Brown]

Maybe im being grump but I see very little away from the higher pennines and Scottish mountains to be excited about.

The Polar profile looks poor going through November and to my eye HLB is progged to be fairly invisible in our locale.

 

Well you usually are HD ! But yes, I see HLB as tough to achieve in the coming weeks and for the winter as a whole.

[Frosty.]

Well you usually are HD ! But yes, I see HLB as tough to achieve in the coming weeks and for the winter as a whole.

Even if it doesn't, we could still get very amplified patterns with potent nw'ly / n'ly blasts, it won't be constant sw'ly mush.

[Mapantz]

Even if it doesn't, we could still get very amplified patterns with potent nw'ly / n'ly blasts, it won't be constant sw'ly mush.

 

I think this is where the IMBY-ism's are starting to apply. I can understand the excitement of some of the potential in the models .. if you live further North.

 

I see nothing exciting from my geographical point of view, just standard colder Autumn weather. The latest model outputs as the days have ticked by, do show a slight watering down compared to what was on offer last week. (I would post charts of comparisons but i can't from a TV)

Edited November 11, 2013 by Mapantz

[Purga]

Definitely a colder and more amplified gfs 06z!!hopefully that continues on the 12z!!things are looking better by the minute peeps!!

Briefly cooler maybe

 

 

then ends up a flat pattern HP south / LP north giving an average to mild setup albeit drier at least.

 

Edited November 11, 2013 by Purga

[Barry12]

 

 

 

then ends up a flat pattern HP south / LP north giving an average to mild setup albeit drier at least.

 

 

The chances of that chart verifying, given it's 15 days away, is slim to say the least. For all we know we could be having a strong North-Easterly flow by then

[nick sussex]

Still a somewhat confused picture with the only bankable synoptics the retrogression of the high and some more amplification upstream in the USA.

 

There isn't any indication of HLB's but this doesn't mean theres no chance of cold, in terms of how east or west the pattern sets up I think we can see that last nights ECM 00hrs operational had  a western bias and if you look the comments from NOAA this morning some standout features that effect Europe as follows:

 

THE END RESULT OF THIS NORTHWESTERLY FLOW PATTERN AND 250-MILLIBARPOLAR JET STREAK...IS TO CARVE A BROAD AND ACTIVE UPPER-LEVELTROUGH INTO THE WESTERN STATES...AND SEND ANOTHER ARCTIC AIRMASSWITH ORIGINS IN NORTHEAST SIBERIA AND NORTHERN ALASKA...TUMBLINGSOUTHEASTWARD INTO THE NORTHWEST QUARTER OF THE NATION NEXTWEEKEND.THE 10/12Z MODEL CYCLE GUIDANCE CONTINUES TO SUPPORT A MID-WINTERWEATHER PATTERN FOR THE LOWER 48...WITH A SERIES OF PROGRESSIVEPACIFIC SYSTEMS CRASHING INLAND ALONG THE WEST COAST OFCANADA...THEN  TRACKING EASTWARD THROUGH SOUTHERN CANADA...THEUPPER GREAT LAKES AND ST LAWRENCE VALLEY. THE SUCCESSION OFCANADIAN FRONTS SPREADS PROGRESSIVELY SOUTHWARD INTO THE LOWER48...AND WITH EACH FRONTAL PASSAGE...A GRADUAL EROSION OF A STABLESURFACE RIDGE PLANTED ACROSS THE EASTERN SEABOARD AND SOUTHEASTERNUS.

 

If there was a flat upstream pattern you wouldn't see that mid winter weather pattern effecting the lower 48, also we want rid of that ridge in the eastern USA, a ridge there acts to help draw the high westwards and in some of the outputs we saw this too far west most notably the ECM last night, preferably we want to see some deep troughing setting up in the eastern USA, the more amplified the pattern there the more north/south the pattern is in western Europe.

 

Because of the lack of a HLB signal any high that builds to the west will topple but its really how far north this initially gets that's key to get some cold into the UK.As you can see from both the ECM and GFS the high topples but allied with the troughing to the east this does funnel down some cold on the eastern flank of the high. And this realistically is the best chance of getting something colder, again though its hard to see anything sustained at the moment.

 

[Frosty.]

I think this is where the IMBY-ism's are starting to apply. I can understand the excitement of some of the potential in the models .. if you live further North.

 

I see nothing exciting from my geographical point of view, just standard colder Autumn weather. The latest model outputs as the days have ticked by, do show a slight watering down compared to what was on offer last week. (I would post charts of comparisons but i can't from a TV)

I was just making the point that even without the northern blocking of the last few years, we will still get spells of cold zonality with snow and ice, it doesn't mean a lack of blocking will stop us having cold spells this winter, i'm just countering the idea that we will have weeks and weeks of sw'ly mush.

[garbagebags]

I think this is where the IMBY-ism's are starting to apply. I can understand the excitement of some of the potential in the models .. if you live further North.

 

I see nothing exciting from my geographical point of view, just standard colder Autumn weather. The latest model outputs as the days have ticked by, do show a slight watering down compared to what was on offer last week. (I would post charts of comparisons but i can't from a TV)

 

At this time of year, yes of course people and georaphically split. People in Aviemore have a good shout with getting snow. People in Cornwall have no chance. So IMBY's are magnified towards the end of Autumn. Try and not think about whether you will get snow or not, and just be happy for the pattern change. Thats why people are excited. Not because of where the -5 line lies. 

[garbagebags]

The chances of that chart verifying, given it's 15 days away, is slim to say the least. For all we know we could be having a strong North-Easterly flow by then

I agree. To get upset at FI is even more bonkers than getting excited by it. People should stick to +192hrs or less. 
(sometimes I actually wish they would bin the FI part of the run. It's really not very helpful.)

Edited November 11, 2013 by garbagebags

[Frosty.]

My understanding of the GEFS 06z mean is we would have a cold nw'ly or n'ly shot early next week, then a cold high with frost and fog followed by another nw'ly / n'ly cold shot, so a reloading cold pattern is possible from early next week onwards with a nw-se aligned jet, an early taste of winter.

[Heisenberg]

Snow, no snow.....it will come at some point this winter, but TBH im thrilled at the prospect of losing the bombardment of rain and mild, even if it is for a short period. Any pattern change to something more seasonal (be it Snow or not) has got to better than what weve had recently....

[garbagebags]

Which is considered the most accurate GFS run, the 00z, the 06z or the 12z ? 

[PolarWarsaw]

The 12z is recognised as the best, but you can split hairs over that and the 0z. The 06z is frequently about as reliable as a minutes silence from David Dickinson.

[shedhead]

Still a somewhat confused picture with the only bankable synoptics the retrogression of the high and some more amplification upstream in the USA.

 

There isn't any indication of HLB's but this doesn't mean theres no chance of cold, in terms of how east or west the pattern sets up I think we can see that last nights ECM 00hrs operational had  a western bias and if you look the comments from NOAA this morning some standout features that effect Europe as follows:

 

THE END RESULT OF THIS NORTHWESTERLY FLOW PATTERN AND 250-MILLIBARPOLAR JET STREAK...IS TO CARVE A BROAD AND ACTIVE UPPER-LEVELTROUGH INTO THE WESTERN STATES...AND SEND ANOTHER ARCTIC AIRMASSWITH ORIGINS IN NORTHEAST SIBERIA AND NORTHERN ALASKA...TUMBLINGSOUTHEASTWARD INTO THE NORTHWEST QUARTER OF THE NATION NEXTWEEKEND.THE 10/12Z MODEL CYCLE GUIDANCE CONTINUES TO SUPPORT A MID-WINTERWEATHER PATTERN FOR THE LOWER 48...WITH A SERIES OF PROGRESSIVEPACIFIC SYSTEMS CRASHING INLAND ALONG THE WEST COAST OFCANADA...THEN  TRACKING EASTWARD THROUGH SOUTHERN CANADA...THEUPPER GREAT LAKES AND ST LAWRENCE VALLEY. THE SUCCESSION OFCANADIAN FRONTS SPREADS PROGRESSIVELY SOUTHWARD INTO THE LOWER48...AND WITH EACH FRONTAL PASSAGE...A GRADUAL EROSION OF A STABLESURFACE RIDGE PLANTED ACROSS THE EASTERN SEABOARD AND SOUTHEASTERNUS.

 

If there was a flat upstream pattern you wouldn't see that mid winter weather pattern effecting the lower 48, also we want rid of that ridge in the eastern USA, a ridge there acts to help draw the high westwards and in some of the outputs we saw this too far west most notably the ECM last night, preferably we want to see some deep troughing setting up in the eastern USA, the more amplified the pattern there the more north/south the pattern is in western Europe.

 

Because of the lack of a HLB signal any high that builds to the west will topple but its really how far north this initially gets that's key to get some cold into the UK.As you can see from both the ECM and GFS the high topples but allied with the troughing to the east this does funnel down some cold on the eastern flank of the high. And this realistically is the best chance of getting something colder, again though its hard to see anything sustained at the moment.

Great post Nick...the last sentance is particularly relevent in the overall context of things, as we've seen very similar patterns being progged time and time again in the 8-10 day range. As the timeframe shortens we often find the models have over cooked the height rises to our northwest and subsequently any cold gets shunted ever eastwards, eventually only affecting parts of Scandi and central/eastern Europe. Not suggesting this is guaranteed to happen again this time, but as has already been said the lack of any HLB potential makes this more likely than not imo.

Edited November 11, 2013 by shedhead

[Frosty.]

When you look through the GEFS 06z perturbations (including the control run) you can see what I mean on my last post when I mentioned reloads of very cold n'ly weather, there are some peachy cold charts here in different timeframes, most of them would bring snow to all levels and widespread sharp frosts, even a few severe cold options...like I said yesterday, we will be very unlucky not to have our first cold blast during the next two or three weeks..and then the fun really begins with winter less than 3 weeks away. 

[Yarmy]

The 12z is recognised as the best, but you can split hairs over that and the 0z. The 06z is frequently about as reliable as a minutes silence from David Dickinson.

 

This has been done about a million times, but there is hardly any difference in terms of verification stats between all 4 runs of the GFS. In fact, the 06z was a smidgen better than the 0z in the short term (up to T96).

[Nick L]

This has been done about a million times, but there is hardly any difference in terms of verification stats between all 4 runs of the GFS. In fact, the 06z was a smidgen better than the 0z in the short term (up to T96).

 

This! Someone posted the verification chart last night, there really is very little between the 4. It tends to be the "best" one is whatever is showing the coldest/snowiest option

[shedhead]

This! Someone posted the verification chart last night, there really is very little between the 4. It tends to be the "best" one is whatever is showing the coldest/snowiest option

And that's just in summer.....

[garbagebags]

So, even the "pub run" is as reliable as the other 3? I was led to believe it used less data?

[Nick L]

So, even the "pub run" is as reliable as the other 3? I was led to believe it used less data?

 

A lot of data collection is automated so I would be very surprised if this was the case. 

[Chris K]

So, even the "pub run" is as reliable as the other 3? I was led to believe it used less data?

 

To be honest, people can discuss the verification stats, but really it's about learning to get to know the models and patterns they show on a day to day basis, rather than taking only one run at a time into account.

 

Eventually you start noticing certain things that might be out of kilter with other runs from the same day. Just one example is that certain pressure patterns might suddenly get shunted off too progressively in the models, but actually take longer to establish/change than what is shown.

 

That is why reading posts from many different people in here has helped me learn to look out for these various factors.

[summer blizzard]

ECWMF day 9 is interesting, that's a marginal snow event.

 

GFS really cranks up the surface cold though in a week or so, we'd be looking at some pretty low minima in the Glens.

 

 

I frickin love inversions.

[Snowman.]

 

The chances of that chart verifying, given it's 15 days away, is slim to say the least. For all we know we could be having a strong North-Easterly flow by then

I agree. To get upset at FI is even more bonkers than getting excited by it. People should stick to +192hrs or less. 

(sometimes I actually wish they would bin the FI part of the run. It's really not very helpful.)

 

FI part of the run is the most valuable part when it showing a change in pattern as its the first to usually pick it up.

 

This all came from FI and stayed in there until Hi res caught hold of it then the spanner was thrown.

[radiohead]

The colder air arrives a little earlier on the 12Z GFS.

 

[nick sussex]

More amplified upstream here on the GFS 12hrs run and its toned down those low heights to the ne, the phasing upstream of that shortwave with the main trough is certainly something to keep an eye on!

 

Note the shortwave to the south of Greenland, that needs to head se, overall its a bit messy but certainly interesting.

Edited November 11, 2013 by nick sussex