Model Output Discussions 12z 01/09/2016

[Gael_Force]

2 hours ago, Ruben Amsterdam said:

GFS inching closer to a reversal in zonal mean winds at 10hPa? Most interesting chart of the suite I would say. 

I dug out this same chart for last year so as to contrast.

Core of vortex still over the Siberian side but no sign of any wave push to the huge circular vortex that would become a monster by winter.

[bobbydog]

9 minutes ago, Skullzrulerz said:

It's been a very long time since I stepped into this world of model output for nearly 2 years.

First off I seen lately that most of the models support northern blocking until lately which seems to be very slowly just fading away into the sunset with every run which is shame for the cold fans here.

The same can be said with the cooler temperatures until now as it seems it was going to last to maybe late October possibly November as again per the first it seen to be joint in joining the northern blocking as riding off to the sunset.

That's  what I seem to get by according to most of these posts although can differ.

Although fate may have it that I could be wrong or maybe it comes back tomorrow...We shall see.

PS: Just please tell not just me but the other guys what's going on in a neutral respective please

As regards northern blocking, it's unusual to see it at this time of year. It is NOT too early as many seem to think. Yes, these charts would be great in winter but they are equally as good now. Standard autumn weather lets  the vortex form as normal. What we see now means it is dramatically weakened going  into winter. It doesn't mean we won't see any of the usual autumn storms etc, just probably less of them. Dont worry if "the atlantic breaks through" to our little island. it allows the cold pool to form where we need it to. That means that the blocking we are seeing now is killing the vortex and is much more likely to re-appear during the winter months when we have that cold pool in place. Would you rather it stayed cold now and we got a few snow flakes in November or would you rather have autumn play itself out naturally and we get a memorable (even epic!) Winter as a reward? Since my daughter is nearly 5 and has never had the chance to even make a snowball,  I know what I would choose...

[Frosty.]

The Ecm 12z ensemble mean shows no sign of the block crumbling with high pressure persisting to the E / NE and low pressure to the SW. The weather looks benign with sunny spells but for a while the e / se is prone to some showers and nights would be on the chilly side with patchy slight frosts, mist and fog patches.

[Grimers]

The GFS and the ECMWF model show a high over Ireland and W parts of the UK bringing light N winds and cool temperatures tomorrow and a high over Ireland and NW parts of the UK bringing light N winds and cool temperatures on Thursday.

       

[doctor32]

Yet again, high pressure very much the dominant feature for us over the coming weeks, alot of dry weather and only the position of high and associated wind direction determine the temperatures (and of course coastal showers)

Really think it wont be until start of november before we see a real change in the pattern we currently see now.

[Cheshire Freeze]

GFS suggestive of a possible eventual split at the end of the run into November, certainly a lot of pressure being put on the fledgling vortex.

As others have said, very interesting.

Edited October 19, 2016 by CreweCold

[mb018538]

Big differences yet again this morning on the GFS vs UKMO at day 6. For example, UKMO has the UK in between weather systems, pressure around 1015mb. At the same time the GFS goes for high pressure, with a chunk of the north under 1030mb. Let's see what the ECM has to say.

[mb018538]

Also....anyone for a late October BBQ going by the GEM run??

[Mucka]

6 minutes ago, mb018538 said:

Also....anyone for a late October BBQ going by the GEM run??

 

Yes GEM and GFS a little boring with high pressure in control either just tot he South or over the UK throughout but at least they would bring some clement and settled Autumn weather

[mb018538]

ECM also turns things very mild by day 10:



....and dare I say it, patterns starting to revert back to normal??

[fergieweather]

15 minutes ago, mb018538 said:

ECM also turns things very mild by day 10:



....and dare I say it, patterns starting to revert back to normal??

Much as we saw in the period prior to Nicole's extra-tropical transition, we've now entered another phase of model to-and-fro, courtesy of the incipient tropical storm development near Turks & Caicos. NHC gives this an 80% chance of this reaching tropical storm status over next 5 days, running northwards. Given resultant influence on jet strength, this situation has already shown over last 24hrs how models can start to swing towards an earlier return to mobility (versus previous output). In short, we are back in a situation where medium range confidence isn't at all great...! 

[mb018538]

Thanks Ian - many (including myself) switched off to this important development.

http://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=5

Here's a synopsis of said tropical development. I guess the models can't handle this well at all seeing as it is uncertain as to exactly how it will develop - and it will of course interact with the Jetstream as it curves north in in the 10 day period. One to watch over the coming days, and something that could throw a very big spanner in the works!

[Ali1977]

Will another tropical storm not assist with sending WAA into the NH, isn't this what helped create some of this blocking we are getting at the minute?

[Frosty.]

For most of the Ecm 00z it's on the chilly side, especially further north / northeast with a breeze coming out of the East but then much milder air associated with high pressure building in from the s / sw floods across the UK making for a very pleasant end to october with well above average temperatures..not often you see 564 dam thicknesses on the cusp of November!

Edited October 19, 2016 by Frosty.

[Ruben Amsterdam]

Crewcold, I would not call it a split (yet). However, the blue "tail" does show the vortex is not happy as could be

Quote

GFS suggestive of a possible eventual split at the end of the run into November, certainly a lot of pressure being put on the fledgling vortex.

As others have said, very interesting.

 

Edited October 19, 2016 by Ruben Amsterdam

[mb018538]

29 minutes ago, Ali1977 said:

Will another tropical storm not assist with sending WAA into the NH, isn't this what helped create some of this blocking we are getting at the minute?

It can go this way (as has happened this month)....although alternatively it can also fire up the jet W-E and enhance zonal weather. It entirely depends on exactly when and where the energy ends up. All fascinating!

[Seasonality]

2 hours ago, mb018538 said:

ECM also turns things very mild by day 10:



....and dare I say it, patterns starting to revert back to normal??

I'm lucky I split my time between Warsaw and London as that lovely chilly 850hpa air is spilling over Poland, Belarus and the Baltics.

[fergieweather]

2 minutes ago, mb018538 said:

It can go this way (as has happened this month)....although alternatively it can also fire up the jet W-E and enhance zonal weather. It entirely depends on exactly when and where the energy ends up. All fascinating!

The latter scenario is favoured as warmth/copious moisture gets injected into the equation. Tomorrow's EC Monthly might be a bit more instructive (at least of sorts!) as it should have a better capture of the emergent situation in W Atlantic and downstream influences next week.

[Grimers]

The GFS model and the ECMWF model show a high over Ireland and NW parts of the UK bringing light N winds and cool conditions tomorrow and a high over Ireland and all parts of the UK bringing light N winds and cool conditions to all parts of the UK on Friday.

       

Edited October 19, 2016 by Grimers

[terrier]

Looking at the ecm output seems we may be in for a late BBQ session. Nice to see Ian f giving us an insight into the models thankyou for that. Does seem like we may be entering a milder more zonal outlook as we head into November. But as we all know things can change rapidly in model variations at the moment. 

[carinthian]

Well that was a chopping and changing 24 hours with GFS reverting back to a more blocking scenario to the NE and ECM positioning the high to the south with a warmer zonal flow around the British Isles. All in all the Medium forecast 7 to 10 days is not clear with new influences coming into the equation. I suppose it all depends how much more energy can be generated to shift the block and where the high ends up eventually. Nothing linear in the seasonal change as we head towards winter. Have spoken to our Portal Weather Service and their view and probably the thinking of the Offenbach team as well is that a shift pattern to more mobility to a short time across the North Atlantic and weakening after such a long period of high pressure to the NE but the longer term view remains for blocking or some sort to still be the main player possibly more retrogressive in type and opening of Northerlys in  early to mid November.  Just another view but all makes for a interesting period for evolution watching.

Meanwhile here in the Austrian Alps a gradual fall in temps with the German Low formation giving some snow to 1500m over the coming few days but followed with a probable warming for areas further south as the Upper Low loses its influence here. Freezing level now just dropped below 2000m height this morning.

 C

[Essex snowman]

7 minutes ago, terrier said:

Looking at the ecm output seems we may be in for a late BBQ session. Nice to see Ian f giving us an insight into the models thankyou for that. Does seem like we may be entering a milder more zonal outlook as we head into November. But as we all know things can change rapidly in model variations at the moment. 

Seems that way as Ian is so helpful on this site for guys like me who are hopeless at charts etc but everyone on here makes this site what it is the best around weather your a cold lovely or mild hot etc everyone respects each other posts cheers all 

[Ali1977]

1 hour ago, fergieweather said:

The latter scenario is favoured as warmth/copious moisture gets injected into the equation. Tomorrow's EC Monthly might be a bit more instructive (at least of sorts!) as it should have a better capture of the emergent situation in W Atlantic and downstream influences next week.

So a possible move away from what many coldies were hoping for early with regards a cold start to November. It goes to show how hard it is to predict the UK weather beyond even medium range, especially early November when there are still storms and hurricanes developing and effecting weather patterns in the Atlantic.  Hopefully the EC seasonal that was signalling lots of blocking is backed up by the EC monthly you mention above.

 

The NH still looks interesting all the same, no real PV development and some warming in the strat.  All setting up some potentially interesting developments further into the snow season.

Edited October 19, 2016 by Ali1977

[Frosty.]

The Gfs 6z shows a change by early november with very mild and unsettled conditions across the uk as we become a battleground between the atlantic and the stubborn blocking to the east.

The rest of this month looks generally quiet with pleasant autumn weather bringing sunshine but in the next few days, the eastern side of the uk in particular is prone to further occasional showers. Early next week there is intensification to the high centred to the east with a very strong ridge covering most of the uk..so very pleasant by day but with chilly nights and mist / fog with a touch of frost and just the far n / nw exposed to slight atlantic influence until the turn of the month.

Edited October 19, 2016 by Frosty.

[Faronstream]

GFS 06Z is very mild for late October and the start of November, full blown westerlies and precipiation over the normal values. I just hope that it is momentarily and that the first winter month will be brutal cold this year, last time was 2010