Model Output Discussions 06z 04/11/16

[gottolovethisweather]

5 hours ago, gottolovethisweather said:

No further comments necessary as it appears I was on the ball. Here's hoping the 0z is the new trendsetter. If this is the new evolution (difficult to judge on simply one run in isolation as this doesn't tell the full story), if you're looking for the white stuff, it'll be ice rather than snow for a while yet.  Longer spells of HP dominance as I've said several times before should be welcomed by coldies as they are often precursors to something special down the road. I'll vouch for a CET well below normal this December now even at this stage, game on!

 

 

1

First of all, apologies for bumping the above post from earlier yet, "all right stop, collaborate and listen" I think the ECM has latched onto something here and it doesn't want to let go of this emerging trend. For fans of active Atlantic weather, I guess you take a few days leave of watching the models. For fans of settled weather, enjoy and those into Vanilla Ice go check the daily forecasts. "Ice ice baby, Ice ice baby" is going to be the main weather headline as we move into the first month of Meteorological Winter. 

Edited November 26, 2016 by gottolovethisweather

[IDO]

1 minute ago, Captain Shortwave said:

The problem with saying that there is good model agreement at day 8 onwards is quite simply this.

This was the output for day 6 yesterday

      

Now 24 hours later we have decent agreement for this...

      

Looking at this, the ECM seems to be ahead of the game as the chart 24 hours ago wasn't too far off, the only difference was a secondary low which ran north east and flattened the UK ridge (base of the Atlantic trough). The other two have now come around to the same broad longwave solution now.

Now the GEFs at around day 8 allow the Azores high to ridge north east and cut off the low heights to our south west and hence send the jet over the top, hence the mild mean solution. What if this situation does not occur as seen by the transformation over the past 24 hours? Whilst the GEFs show reasonable longer range consistency, I would treat this with caution given the chance that the upstream jet could again split against heights near the UK.

I agree, as the models sharpen up the flow there will be subtle changes, but to the extent where they make any difference to the UK for snow/cold? Well I just cannot see it. And of course they could just as well change for the worse (GEM for instance)? 

The ECM is showing that the 0z was indeed an outlier (uppers), as it moves the pattern further east, closer to the GFS take.

D7 charts for comparison: 

Subtle differences as you would expect but the pattern looks to be firming up. A cool period coming up but we are not Southern softies and no way is this a cold flow (gottolovethisweather??), the 2m temps barely touch 0c mins in London:

[gottolovethisweather]

13 minutes ago, IDO said:

Subtle differences as you would expect but the pattern looks to be firming up. A cool period coming up but we are not Southern softies and no way is this a cold flow (gottolovethisweather??), the 2m temps barely touch 0c mins in London:

 

 

1

Fair dos, I'm Dreaming Of, please take heed of my subsequent edit in red text in the original reply. Different ensembles are chucking up differing options right now, none of which show SW'rlies or rainbands hence my predictions of much frost and fog by night as and when cloud cover permits. Regarding surface cold, I think it will trend colder by the day for several days yet.

Edited November 26, 2016 by gottolovethisweather

[Frosty.]

Well the Ecm 12z is high pressure all the way, nothing like the Gem which brings in mild mushy southwesterlies. Last night's Ecm was much closer to what the Gem 12z is currently showing but now even by T+240 hours the Ecm is still rock solid anticyclonic with power to add.

Edited November 26, 2016 by Frosty.

[karlos1983]

5 minutes ago, Frosty. said:

well the Ecm 12z is high pressure all the way, nothing like the Gem which brought in mild mushy southwesterlies.

Nice dry and cold soil for when the real deal  arrives Karl 

Edited November 26, 2016 by karlos1983

[Snowman.]

Pretty good NH pattern on the ECM far from the circle and more of a H 

[SMU]

So from nothing today - a comparison of March 13 in the afternoon 4pm post-

now we have the JMA-

march 13 first -

 

very very similar with plenty of wiggle room!!

[Orpingtoniceagedec10]

With the persistent easterlies over the south east, when can we start thinking about lake effect snow ? I seem to remember this was how December 2010 started.

[BLAST FROM THE PAST]

If you use the JH method of run for run e.g. 12z for following 12z etc then ECM remains a good move forward. Looking at how changes have happened model wise you cannot contemplate beyond t120 with any form of confidence in accepting any run

 

BFTP

[January Snowstorm]

I might be alone in this but I hate high pressure dominant weather in winter. Frosts and fog at best. It might aswell be mild and comfortable.

Surely the dream is to get snow and because of that we need cold. Cold on its own just delivers hardship and higher heating costs. I don't see much of interst in next 10 days tbh.

[Banbury]

1 minute ago, January Snowstorm said:

I might be alone in this but I hate high pressure dominant weather in winter. Frosts and fog at best. It might aswell be mild and comfortable.

Surely the dream is to get snow and because of that we need cold. Cold on its own just delivers hardship and higher heating costs. I don't see much of interst in next 10 days tbh.

Very rare you get mild and comfortable in Winter , normally milder weather in the form of SWlies brings , floods misery and insurance claims

 

Frost and Fog belong in Winter, its quite welcome IMBY

[Orpingtoniceagedec10]

If the low to the west of Portugal can somehow limo with the low over Poland, surely that would bring lake effect snow ?

[Frosty.]

5 minutes ago, karlos1983 said:

Nice dry and cold soil for when the real deal  arrives Karl 

Agreed, no lack of frosts for the next week or so at least.

[karlos1983]

2 minutes ago, Orpingtoniceagedec10 said:

If the low to the west of Portugal can somehow limo with the low over Poland, surely that would bring lake effect snow ?

Which lake 

sure if we can get a decent cold pool and a keen breeze with some disruption in the flow, its game on at this time of year for big showers, but I'm not seeing that in the output at the moment. 

Edited November 26, 2016 by karlos1983

[Captain Shortwave]

21 minutes ago, IDO said:

I agree, as the models sharpen up the flow there will be subtle changes, but to the extent where they make any difference to the UK for snow/cold? Well I just cannot see it. And of course they could just as well change for the worse (GEM for instance)? 

The ECM is showing that the 0z was indeed an outlier (uppers), as it moves the pattern further east, closer to the GFS take.

D7 charts for comparison: 

Subtle differences as you would expect but the pattern looks to be firming up. A cool period coming up but we are not Southern softies and no way is this a cold flow (gottolovethisweather??), the 2m temps barely touch 0c mins in London:

I think the question is in terms of 2M temperatures, how good are the models at predicting inversions?

The GFS seems to be skewed even at the earlier timeframes with air frosts predicted even in central London during the first half of the coming week so either the GFS or human forecasters are wrong there. I suspect that surface temperatures will remain suppressed, especially further south though a brief milder interlude looks possible around mid/late this coming week before the high regains full control over the UK.

At this point it is worth stressing that even the ECM 00z doesn't bring widespread or even localised significant snow, but does allow cold upper air to cut back into the UK to increase the surface chill, that seemed a little extreme but no signs of a proper Euro high developing either (whilst 850s do trend above 0C the temperatures at the surface will remain chilly or indeed cold in areas prone to fog). Needless to say the general trend tonight is for the current holding pattern to hold in an event that seems rarer these days than a cold blocking scenario, a true prolonged UK high. 

Overall this is absolutely fine for me, the background signals as we push further into December look good and the evolution to retrograde heights from the UK towards our north west is a text book one, so I suspect a strong signal to develop in the mid to later range in the near future. Indeed the March 2013 spell did exactly that....

         

The key is to a proper Euro ridge developing, even though the surface high drifts away there is never a strong ridge there to block the cold air moving in towards Scandinavia and then the rest of Europe. The same applies here as whilst we see surface heights remain high over or near the UK, we never see that strong warm ridge develop.

 

 

Edited November 26, 2016 by Captain Shortwave

[Orpingtoniceagedec10]

Which lake " the English Channel and Thames estuary" 

[knocker]

The ecm is not a million miles from the GFS with the much amplified  strong Aleutian ridge into the Arctic and upper low  Western N. America. Thus a very strong jet winging out of the southern States and much energy transfer to the active trough in the western Atlantic which keeps the Azores HP honest and stops it ridging north west and has it gently ridging adjacent to the UK. So some quite pleasant and dry weather to end the run with temps perhaps a little below average in the south but above in Scotland.

[igloo]

2 minutes ago, Frosty. said:

Agreed, no lack of frosts for the next week or so at least.

that will depend on cloud cover something you can only forecast 2 days invance  will it be cloudy and raw with no frost or sunny and hard frosts and feel pleasant in the sun during the day im not sure anybody can tell 

[Radiating Dendrite]

2 minutes ago, Orpingtoniceagedec10 said:

Which lake " the English Channel and Thames estuary" 

These are not the right synoptics. You need a keen NE / E wind and a deep cold pool with low heights. Hopefully we may get that in the long term but there are many hurdles to overcome.

 

[ArHu3]

2 minutes ago, knocker said:

The ecm is not a million miles from the GFS with the much amplified  strong Aleutian ridge into the Arctic and upper low  Western N. America. Thus a very strong jet winging out of the southern States and much energy transfer to the active trough in the western Atlantic which keeps the Azores HP honest and stops it ridging north west and has it gently ridging adjacent to the UK. So some quite pleasant and dry weather to end the run with temps perhaps a little below average in the south but above in Scotland.

Bizar how again the cold seems to stop at the dutch border!

[Ventnor Viking]

2 hours ago, IDO said:

Not really seeing anything unusually cold in the next 7 days. The trend looks to push the cold upper flow too far east for snow (nominal chance now) and still a small chance of a dry northerly. The high has been consistently modelled to sink SE and in this run it does. That high is not going to just sit there IMO as the models are not even entertaining that. The Azores then pushes in bringing milder air from around D9.

I see no upstream amplification to stop the mobility of the flow and there is absolutely no WAA worth its salt other than transient topplers. Very little potential showing up in the runs and unless the models flip soon its wait it out till mid-Dec.

At around D9 on the GEM and GEFS: 

Mild more likely in the mid term with 14c after D10 possible with that Azores push.

We have a PV in disarray and there is just no forcing to take advantage of this, even if its just Rossby wave action to kick the strat PV; really a missed opportunity despite the potential further down the line. Thankfully the trop PV still showing no trend to regroup so maybe in a couple of weeks we will get some forcing but certainly zero consistent cold runs coming from the GFS and that is not good when so much is in our favour.

 

I agree, I think frost at night and if fog lingers during the day then it could minimise temps during the day but its surface cold which as I mentioned earlier isn't a reflection on the true atmospheric pattern as wind and orientation of the HP can dictate who sees the colder conditions.  

[Frosty.]

4 minutes ago, igloo said:

that will depend on cloud cover something you can only forecast 2 days in advance  will it be cloudy and raw with no frost or sunny and hard frosts and feel pleasant in the sun during the day im not sure anybody can tell 

Absolutely correct, potential for frosts I should have said..and fog. 

Edited November 26, 2016 by Frosty.

[Orpingtoniceagedec10]

2 minutes ago, Radiating Dendrite said:

These are not the right synoptics. You need a keen NE / E wind and a deep cold pool with low heights. Hopefully we may get that in the long term but there are many hurdles to overcome.

 

Thanks for that, I'm still a newbie and learning. Wishful thinking! 

[Ventnor Viking]

7 minutes ago, Orpingtoniceagedec10 said:

Which lake " the English Channel and Thames estuary" 

Not the right set up unfortunately. There needs to be a deep cold pool moving from the east and a low pressure to unstable the atmosphere. very rare we get these types of set ups.

[mulzy]

I know it's the CFS but this is how things could pan out as Steve M eluded to earlier.  We need things to go our way of course but certainly not impossible.