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Model Output Discussion - Into Autumn 2020.


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1 hour ago, northwestsnow said:

Glosea throwing some very +NAO projections for Winter, connected to its idea of a strong La Nina,all eyes on the Eastern Pacific over the coming weeks.(Coldies would want weak to moderate i guess).

Indeed, nothing more than a moderate La Nina.  Hopefully Gosea is overdoing the La Nina!

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Fitting macro scale ENSO patterns, (or any other macro scale drivers) to idealistic synoptic patterns is inevitably set to lead to departure in reality from such expectations.   The macro scale wind-f

ECM indicating a return to some settled weather end of next week however a few showers & the flow becoming Northerly so the potential for some frost developing- Nice & seasonal.

Well the AO off the scale is an interesting sight !

Posted Images

Notable Northerly again on the GFS bringing the -5c line into the UK around 25-26th Sept.

Chance of Snow over the hills 4-500M in Western Scotland ....

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Edited by Steve Murr
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16 minutes ago, Steve Murr said:

Notable Northerly again on the GFS bringing the -5c line into the UK around 25-26th Sept.

Chance of Snow over the hills 4-500M in Western Scotland ....

B8B82362-4747-4A53-B6C2-15D28966760E.thumb.jpeg.da69063724a73551a254aba02b18b016.jpeg

Indeed very normal  (from observing for decades) after the first equinoxial gales would often see the first snow on the mountains of the coming winter .

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Again the Gfs, this time the 6z indicates a risk of September snaw..Shirley worth a BOOM..528 dam in sept is nothing to be sniffed at!!!!!!!😁:shok::cold::bomb::drunk:😜❄️️ 
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Edited by Jon Snow
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There’s actually reasonable support for a polar / arctic maritime NW’ly / N’ly shot according to the GEFS 6z mean!..MOOB indeed!😁:yahoo:😜

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13 hours ago, Allseasons-si said:

Go on CFSv2,keep em coming.

cfsnh-3-10-2020.thumb.png.c9a3c67f146c995a0827d7df39898a01.pngcfsnh-3-11-2020.thumb.png.263b9f36d0557871db56d66745bd510a.pngcfsnh-3-12-2020.thumb.png.a8b8d5a8861f7ff11678593f6755f2a9.pngcfsnh-3-1-2021.thumb.png.28892f154a8c2cd040b6c7f1bd55c66f.pngcfsnh-3-2-2021.thumb.png.73f8bbe91bc09b817765bbcdefb23864.pngcfsnh-3-3-2021.thumb.png.044ea5b7d8ea9159d19cf6d8422e6f0c.pngcfsnh-3-4-2021.thumb.png.2da95922ffdc4b51668a534c8fbdfd3e.pngcfsnh-3-5-2021.thumb.png.bded9bc0450553edc914f05d5bba6e5f.png

predominantly pressure to our north and has been keen on this over the last few days. 

If those anomalies come off, I could be eating my words on the near zero possibility of a cold season from start to finish. I am surprised to see such a prevalence of high pressure in the north atlantic - and similarly low pressure in the north pacific. Wonder what's tipping CFS that way.

But we all know it will flip flop around and around....and then when push comes to shove the icelandic low will never be too far away......

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On 15/09/2020 at 08:27, mb018538 said:

Could just be a blip @sheikhy !

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Looks like a slightly more unsettled spell by the middle of next week, but generally the main storm track looks like staying to the NW of the UK after:

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Could be your traditional NW/SE split towards the end of the month. With AAM staying relatively high, i don't see any plunge into full-on zonal trash here just for now:

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Turning very stormy next week across the whole UK

 

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Edited by NApplewhite
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Mixed October ahead followed by a wet November and average December . Slightly higher pressure than normally in June 2021. Is the Netweather Autumn forecast out yet? 

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Edited by NApplewhite
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I'd suggest looking long term that the riding in the Atlantic and further north could bring a quite interesting Oct-Nov. 😉😉

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Evening all 🙂

The GFS 12Z evolution is a classic "winter" scenario as the remnants of Hurricane Teddy create WAA to the west of Greenland allowing a significant build of pressure. In response, the LP drops through the British Isles and a Scandinavian trough develops leaving the British Isles in a cool NE'ly.

gfs-0-192.png?12gfs-0-276.png?12

A lobe of HP breaks off from Greenland and heads SE through the British Isles to set up just to the south and return much more settled conditions. 

gfs-0-378.png?12

Worth noting we still have a significant Scandinavian trough and heights over Greenland so it ain't going to be warm but the Atlantic is much quieter.

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A few CFS runs have been highlighted recently, but it is wise to view them as an ensemble rather than single runs at that range.  Here’s the last 8 Z500 anomalies for December 

3B3422A9-965E-4251-BEFA-9C3683058936.thumb.png.4a4ac194dba51159fd22e3d1a06c2297.png603E3A46-B84F-4E04-8161-4AE17AFA7D29.thumb.png.0a4840267452c3fa407ba1e7f21a2e8c.png47BF49CC-3926-4F82-901E-F86F52387341.thumb.png.7f34abb089ee7d041879d468282129bb.png0CF4823E-649A-4CF3-956A-64E9C03F612F.thumb.png.bda6d63ca0ac60d46eae37a5f6dd029a.pngCCFEB36B-8C86-46CD-8187-4D0B0BB70377.thumb.png.46a89c529e0ea910a726c9b75c2abecd.png8CADEED0-E23F-4C5A-B1D7-6E967E054998.thumb.png.a147b98b460a91405a33e1e3ff88c3f9.png88731D9F-BA61-4ED0-905E-E82716B368F9.thumb.png.265c64a8dc3dbab496daa34e01d5047e.png486EEBAB-36BC-4F01-863B-14C6B6FC63C0.thumb.png.efee43a2d42453ec87fa6602ecc4e9d8.png

There’s some promise there, all but one give at least some semblance that northern blocking might play a part at some point.  But still too far out to have any real idea.  I think there is no point looking beyond December this far out, firstly because it is possible with weak La Niña, solar input, mixed QBO that we might get early cold this winter but so uncertain,  secondly because what happens in December will affect the other months anyway.  

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While the models seem to be definitely firming up now on an autumnal few days next Wed to Friday it would appear that it may be pretty short lived after all as that huge swathe of high pressure in the south Atlantic looks poised to settle things down considerably again to end the month. 

Edited by Newberryone
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As I anticipated last evening, GFS has swung right round 180 degrees today and instead of a continuation of the current settled pleasantly warm weather it is now throwing up a chilly northerly airstream as we move into the latter part of the month. ECM also showing a classic northerly shot, as we see a scandi trough forming and heights ridging into Greenland, we are exposed to a chilly northerly feed with low pressure digging down to our east.

Ensembles also firming up on such a scenario. So I think we have a trend for the rest of the month now, the current spell of dry settled weather coming to an end by Tuesday, turning much more unsettled and cooler for all, with wind and rain or showers, perhaps something notably chilly for the north before the end of the month, with heights most likely to topple back in from the west but this time under a much cooler airmass. Unlike many Septembers, this one might end up quite an interesting one synoptic wise, with a bit of everything.

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4 minutes ago, Jon Snow said:

Just had a glance at the 12z output, it doesn’t look like there is any escape from a much cooler and very unsettled spell from next midweek onwards but we may not have finished with summery conditions yet?..I haven’t fully gone across to the dark side..I mean cold side of the force just yet!😜

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What is interesting is a change taking place to a much more meridional flow, with a buckled jet, a sign all not quite normal service, sometimes we will end up on the warm side of the jet, other times cold side - not the usual zonal westerly. Perhaps all down to the active tropical storm season this year interfering with the jet, and creating more anomalous conditions. The above would tie in with Met Office outlook suggesting first half of October will see alternations between warmer and colder weather, just as we will experience second half September if models verify (something colder for latter part of the month after a week plus of very warm/warm weather). 

Edited by damianslaw
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8 hours ago, Catacol said:

If those anomalies come off, I could be eating my words on the near zero possibility of a cold season from start to finish. I am surprised to see such a prevalence of high pressure in the north atlantic - and similarly low pressure in the north pacific. Wonder what's tipping CFS that way.

But we all know it will flip flop around and around....and then when push comes to shove the icelandic low will never be too far away......

CFS has actually been throwing out a lot of these types of chart over the past couple of months....

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5 hours ago, NApplewhite said:

Mixed October ahead followed by a wet November and average December . Slightly higher pressure than normally in June 2021. Is the Netweather Autumn forecast out yet? 

image.thumb.png.557fee457cb45a7aef452beb9792d4e3.pngimage.thumb.png.181a76117612cf08a46feadb4566c25e.pngimage.thumb.png.d481a008af849f5c85714b198b61a910.pngimage.thumb.png.fc9d0fcf32a2740be0cf530a4e047419.png

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I'm quite surprised how many are using the CFS to offer some kind of guidance moving this far forward. This model will do nothing but lead one up a massive Garden path! Not so sure about a mixed October. 

Tonight's EC weeklies does show a much more unsettled and cooler spell from next mid week.. It perhaps settles down a tad early the following week. Beyond this point a N/S split looks the most likely scenario with perhaps some of the unsettled Conditions spreading further SE at times... Out towards mid month and we still have indications of plenty of settled Conditions at times, and these perhaps more extensive at times.. All in all its not the worst of outlooks for the next few weeks... Early days being the only caveat! Still far to early to be talking of significant cold or Northern Blocking for me, but I will give an update of the EC46 anomalies at the beginning of October for any potential early signs of Winter. 

 

A very good night to you all. ☀️

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10 hours ago, Catacol said:

If those anomalies come off, I could be eating my words on the near zero possibility of a cold season from start to finish. I am surprised to see such a prevalence of high pressure in the north atlantic - and similarly low pressure in the north pacific. Wonder what's tipping CFS that way.

But we all know it will flip flop around and around....and then when push comes to shove the icelandic low will never be too far away......

I have a feeling The Euro models may be overestimating La Nina...GLOSEA is almost off the scale with its Nina prediction.

Some of the strat guys on twitter have been saying the same thing.

Edited by CreweCold
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What I'm finding really interesting in the model output is the fact if we do get some northerly flow of some sort, the ECM especially wants to develop a massive ridge over Western Russia with what probably be record breaking heat so you think, well if Western Russia is getting record heat, there must be some cold weather over Siberia forecast given there will be a dip in the jet stream. Well absolutely not, not only we got above average temperatures, there is barely any snow cover and there is hardly anything in the forecasts so for those who think lots of snow cover over Siberia is a good sign for winter will be very disappointed with the forecasts. I for one I'm not too convinced by that link but a lack of snow cover means above average temperatures and above average uppers so coupled with lots of warm open water over the Arctic then cold air could be in short supply I feel. 

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