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Model Output Discussions 06z 04/11/16

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7 minutes ago, KasimWeatherQuarnford said:

Excuse me if I'm wrong but isn't that char showing surface -mslp over greenland with a resultant SW'rly flow over the UK ?

 

My Icelandic isn't great, but it's showing mean (surface?) pressure anomalies for a 7-day period (I think). Positive over Greenland/Iceland/Scandinavia, negative over Iberia.

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29 minutes ago, ajpoolshark said:

in reply to the posts about tweets, let's not dwell too much on isolated tweets and instead comment on the models.....moving on 

Correct, there is a blocking/ mute option which people can use if you disagree with people's comments! Far less clutter for us all to scroll through then 

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3 minutes ago, bluearmy said:

Yep strider - about 12c below average - I checked the facts before posting !

IMG_4678.PNG

IMG_4679.PNG

suspect this his will be the last post on this!

worth watching the NH profile fi on the 06z and the retrogressive nature of the Atlantic ridge over three waves. Even with an apparent zonal appearance to the run, there is a retrogressive background 

Good illustration of how the Alps pop up into the milder upper air and therefore have positive anomalies.

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No real changes in the outputs with the GFS still showing the threat ofmild SWlies and the models in general showing a high pressure dominated outlook.

Really uncertain on just how much cloud there will be though, suspect we need the high to drift towards the east and we pick up a SE'ly flow before any cloud shifts so frosts could actually become rather patchy than a widespread event.

Still no signs the high will retrogress though and if anything it does seem a case of when rather than IF the high sinks but obviously nothing can't be ruled out yet but there just seems to be a constant stream of shortwaves riding over the top of the high which is a little frustrating too see.

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7 minutes ago, bluearmy said:

Yep strider - about 12c below average - I checked the facts before posting !

IMG_4678.PNG

IMG_4679.PNG

suspect this his will be the last post on this!

worth watching the NH profile fi on the 06z and the retrogressive nature of the Atlantic ridge over three waves. Even with an apparent zonal appearance to the run, there is a retrogressive background 

 

Scale is in Fahrenheit, but your point is still valid of course.  Very impressive inversion: frozen canals in Holland?

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Todays outputs all point to the same trend in terms of some increase in amplification upstream and more digging south of troughing in the Atlantic but early differences mean the weather for the UK could be either a spell of milder sw'erlies or staying cold.

We're left chasing shortwaves again and in this instance we see the big impact these have on the forward evolution. Looking at the UKMO and the expected upstream pattern after T168hrs its hard to see that becoming milder because the trough energy is splitting to the west of the UK. I've done my best guess looking at the Atlantic UKMO set up at T168hrs. This is the overall European picture at T168hrs:

UN144-21.gif

Looking at the ECM trend and if we project that onto the UKMO, the high is likely to be pulled further to the nw and shortwave energy is likely to head se from the main troughing to the west. I can't see the UKMO sinking the high and at this point those early differences between T96 and T144hrs look like being pivotal in terms of the medium term.

In a nutshell phasing of shortwave energy given the sensitive set up will send us more likely into the sinking high scenario and a spell of milder conditions and then we wait to see whether we get the PV split and and more amplification.

If the UKMO is correct the high will remain and retrogress further to the nw, our quickest route to more interesting conditions is through the UKMO. The ECM is just about passable going forward. The GFS 00hrs and 06hrs are not good and we want nothing to do with them!

 

Edited by nick sussex

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8 minutes ago, nick sussex said:

Todays outputs all point to the same trend in terms of some increase in amplification upstream and more digging south of troughing in the Atlantic but early differences mean the weather for the UK could be either a spell of milder sw'erlies or staying cold.

We're left chasing shortwaves again and in this instance we see the big impact these have on the forward evolution. Looking at the UKMO and the expected upstream pattern after T168hrs its hard to see that becoming milder because the trough energy is splitting to the west of the UK. I've done my best guess looking at the Atlantic UKMO set up at T168hrs. This is the overall European picture at T168hrs:

UN144-21.gif

Looking at the ECM trend and if we project that onto the UKMO, the high is likely to be pulled further to the nw and shortwave energy is likely to head se from the main troughing to the west. I can't see the UKMO sinking the high and at this point those early differences between T96 and T144hrs look like being pivotal in terms of the medium term.

In a nutshell phasing of shortwave energy given the sensitive set up will send us more likely into the sinking high scenario and a spell of milder conditions and then we wait to see whether we get the PV split and and more amplification.

If the UKMO is correct the high will remain and retrogress further to the nw, our quickest route to more interesting conditions is through the UKMO. The ECM is just about passable going forward. The GFS 00hrs and 06hrs are not good and we want nothing to do with them!

 

To be fair nick the 06z gets closer to the ukmo output between 120 and 144 hours compared to the 00z by shoving the high more over the uk!but goes default and push everything eastwards after that!!12z will continue the improvements i feel!!

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Here's Gibby's summary of the 00z outputs - please ignore the text below the charts as explained before they auto update and thus might not represent the text below

Quote

 

Another day but the message remains the same with High pressure looking like staying in control of the UK weather for a good while yet. Rather than repeat yesterdays text I will just note some fundamental differences today in that the models from the American side of the Atlantic show a trend towards milder SW winds next week with some rain at times whereas the UKMO and ECM models from this side of the pond are more resilient to letting our High pressure slip away which would mean a longer period of fine and settled weather as a result with just chasing cloud amounts and clear skies the forecasting headaches.

So in a nutshell despite the current very sharp frosts this is not the start of a sustained freeze up that some newspaper outlets would have you believe and while frosts and freezing fog patches remain a possibility over the next week or so the frosts will become less widespread and severe after tonight as more in the way of cloud moves in by Thursday.

Then fairly benign conditions prevail with temperatures in the range average to just below with the chance that things might become altogether milder for a time later next week.

 

2

http://www.norton-radstockweather.co.uk/latest-model-analysis

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This is what we want to see in the Med term. then goes onto this

 

gensnh-8-1-180.png

gensnh-8-1-240.png

gensnh-8-1-384.png

Edited by booferking

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GEFS FI starting to smell the coffee, fair few showing some form of northern blocking. 

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11 minutes ago, Ali1977 said:

GEFS FI starting to smell the coffee, fair few showing some form of northern blocking. 

Fits with what Matt Hugo was saying.

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Trends. Only a few members showing anything significant in FI but the spread is growing in the charts now, as mid December comes into range. My view would be to expect several days of model volatility, followed by some super charts, followed by a gradual emergence of consensus into the end of next week and next weekend. Whether that consensus shows raging easterlies, a U.K. Block, or a more progressive pattern however, remains to be seen. Here, I bow down to the pros who appear to have an inclination...

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Hopefully the GEFS will start to pick up the Northerly blocking signal in the far reaches of FI soon, bare in mind we are talking three weeks away, there is no chance of complete agreement at that range.

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1 minute ago, mountain shadow said:

Hopefully the GEFS will start to pick up the Northerly blocking signal in the far reaches of FI soon, bare in mind we are talking three weeks away, there is no chance of complete agreement at that range.

They have already :)

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1 minute ago, Seasonality said:

They have already :)

Is the mean looking more pronounced than yesterdays? I seem to recall Bluearmy posting a mean chart with increased height anomalies to the North West. What we need are some black hole anomalies, then I get excited.

Edited by mountain shadow

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1 minute ago, mountain shadow said:

Is the mean looking more pronounced than yesterdays? I seem recall Bluearmy posting a mean charts with increased height anomalies to the North West. What we need are some black hole anomalies, then I get excited.

Not sure, maybe someone else can answer?

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2 minutes ago, Seasonality said:

Not sure, maybe someone else can answer?

Maybe interesting for some.

Screen Shot 2016-11-29 at 14.20.05.png

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11 minutes ago, mountain shadow said:

Hopefully the GEFS will start to pick up the Northerly blocking signal in the far reaches of FI soon, bare in mind we are talking three weeks away, there is no chance of complete agreement at that range.

The good news is that Euro heights are sparse on the GEFS 06Z, with only 2 or 3 out of 21 members having a serious go at keeping them by T360. Lots more distribution of heights around the Atlantic and slightly to our north - but no overwhelming signal for significant northern blocking just yet from the GEFS. All I gather from this is that the envelope for UK cold gets a little narrower between D8-D12, and then a little wider after D13. So, so far off though.

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41 minutes ago, Yarmy said:

My Icelandic isn't great, but it's showing mean (surface?) pressure anomalies for a 7-day period (I think). Positive over Greenland/Iceland/Scandinavia, negative over Iberia.

Yes I think that's along the right lines. To quote MH

Quote

Ignoring the MSLP isobars, for now, note the signal for higher than average pressure anoms to the north of the UK on the below chart for week 4, this is, essentially the EC monthly for 19th to the 25th Dec with also a signal for -ve MSLP anoms over Iberia which, in theory, would equate to a potential E or NE'ly flow.

Assuming it's surface pressure then the highest anomaly is over the Norwegian coast. This in itself doesn't directly translate into surface chart but I'm assuming that Matt is indicating that this where the high cell resides and thus you have the NE/E flow over the UK. I actually think it is a little confusing.

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The Gfs 6z becomes very mild for the second half of next week with southwesterly winds and quite spring like temps reaching 14/16c 59f and it also looks unsettled with bands of rain sweeping through interspersed with sunshine and showers. The charts later next week have a positive NAO look to them with strengthening Azores high and Icelandic low influence, eventually with a Euro high.

hgt500-1000.png

ukmaxtemp.png

hgt500-1000 (1).png

ukprec.png

hgt500-1000 (2).png

ukmaxtemp (1).png

ukmaxtemp (2).png

hgt500-1000 (3).png

h500slp.png

ukmaxtemp (3).png

Edited by Frosty.

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Going back to the mean slp and anomoly chart for week 4, one should always ignore the mean slp charts as they will nearly always revert to climatology once you get towards 14 days. The anomolys show where the favoured position is for pressure change away from the norm. 

it is tough to make too many deductions from output at this range and the anomolys  charts are often far easier to read without having slp present to distract! 

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18 hours ago, SN0WM4N said:

gensnh-21-5-384.png 

 

Now we need to see if it lasts. 

How does today's compare Snowman? Is the signal stronger, weaker or much the same?

 

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What if the GEFS(?) isn't merely 'smelling' the coffee? What if it's planting the seeds, nurturing the plants and grinding the beans as well? Just a thought, and hopefully one that's well off-beam...:D

Honestly, I'm not Scrooge - I promise - but the Ghost of Christmas Past has just paid me a wee visit.:good:

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2 minutes ago, Ed Stone said:

What if the GEFS(?) isn't merely 'smelling' the coffee? What if it's planting the seeds, nurturing the plants and grinding the beans as well? Just a thought, and hopefully one that's well off-beam...:D

Honestly, I'm not Scrooge - I promise - but the Ghost of Christmas Past has just paid me a wee visit.:good:

Perhaps the bossoms are beginning to ascend.

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