Model Output Discussion - Autumn 2018

[blizzard81]

10 hours ago, CreweCold said:

Well if people want a cold start to winter, the charts showing today (i'm looking specifically at the 12z and 18z GFS) are pretty on point.

Huge blocking to the E and NE which is enabling the trop vortex to remain perturbed.

The next thing we'd want to see after this is some pressure from the Canadian vortex pushing a trough ESE across the Atlantic, this troughing not making it much further E than the meridian (with HP remaining to the ENE). Once we get to this point, we're in November 2009 territory...

Can we get there, that's the question? However, the modelling is looking very closely aligned to EC seasonal thus far...

Indeed. This is exactly what needs to happen to increase our cold winter chances. The models seem to be firming up on an Indian summer scenario for us next week. However, we have to look at the bigger picture. The northern hemisphere views for next week show this perfectly. The eastern European block which will bring us the lovely late warmth is also the driving mechanism that delivers winter to central/eastern Russia during next week. Great early building blocks from where I am sitting. 

[summer blizzard]

I urge caution for the next 5 days. 91L in the Caribbean has been declared a cherry and will head north. How strong it gets, it's exact path and how it phases with the Jet Stream will all add to the potential for chaotic modelling changes in the 5-10 day range. 

Leaving out 91L and we see the continued monster westerly wind burst continuing and the development after mid October of something for the UK from the north/east.

 

[damianslaw]

Longer term as we approach latter part of the month - the synoptics on offer next week are good building blocks as others have said for something colder from the north and east - warm air advection in turn creating cold air advection over west russia..trigger for a retrogressive high pressure pattern, the fly in the ointment is the uncertainty caused by ex tropical storm/hurricane activity - its this factor which will either aid the transgression from warm/settled to possible cold/settled or not..

Always important to keep a look at the broad picture. The jet pattern shows no signs of going zonal and flat anytime soon, as it hasn't done in the main since February.

ECM hinting at such a evolution..

[Derecho]

If we can get some more retrogression then this could look interesting later, in the meantime it looks as the the week from the 13th - 20th could be remarkably warm for mid October.

What a week to take off if such charts verify! The weather can do all it likes thereafter, preferrably endless beasts from the east interspersed with Greenland highs and channel lows until mid March.

[mb018538]

I'm with quite a few others on here.....i love the cold in the winter, but the facts are it's too still too early for any of that yet, so if we can extract one more burst of warmer weather for the year then i'm all for it. Thankfully it appears we are going to get just that this week! From Monday onwards it looks like we are going to see temps in the high teens/low twenties for a good week.

ECM ensembles have slightly tipped towards the high winning out, but there is still a good chance that the low may push the best conditions further east.


 

[johnholmes]

The upper pattern which showed a NW-SE split the last time I posted has not changed markedly. However the slight shift to a more blocked pattern SE-E  even possibly NE (500 mb anomaly charts) does seem to imply that more than just the SE may have more settled rather than changeable weather over the next 2 weeks. That is once this current system has worked its way clear of the UK. 

As sb comments above this idea could become redundant if any TS's get into the N Atlantic, beyond the one that seems happy to stay where it is at the moment-not very usual what it is doing.

links

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Frosty.]

Stunning charts for the time of year on the Gfs 6z operational showing summer like conditions in the run up to mid october..and possibly beyond with temperatures well above the seasonal average, indeed, very warm, especially across southern uk..It looks like a memorable spell next week with temps into the low / mid 20's c for some of us..Enjoy.☺

Edited October 6, 2018 by Frosty.

[mb018538]

UKMO making more of the low tonight - looking more breezy and perhaps more unsettled than the gfs and gem, which still favour the high winning out tonight.

[Froze were the Days]

Never seen such a length of warm weather for so long going by the gfs 12z...it just goes on and on, if that is anywhere near the mark for the next fortnight then this October will be very warm heading towards record breaking.

[Frosty.]

The GEFS 12z mean indicates increasingly very warm conditions next week and next weekend also looks summery..incredible by mid october standards!☺

[ItNeverSnowsInWindsor]

The final third still up for grabs as some colder solutions appearing after mid month

[Frosty.]

Becoming incredibly warm next week (by early / mid october standards) is the main theme of the Ecm 12z, breezy / windy at times with a blow torch feel to some days, could be some very remarkable maxima recorded next week where the best of the dry sunny weather occurs further s / e / ne / se..and some very mild nights!

Edited October 6, 2018 by Frosty.

[bluearmy]

More runs driving that southerly flow well into the arctic in our part of the NH  - I’m thinking that’s good for preventing the strat vortex getting it’s act together 

[ICE COLD]

11 minutes ago, Frosty. said:

Becoming incredibly warm next week (by early / mid october standards) is the main theme of the Ecm 12z, breezy / windy at times with a blow torch feel to some days, could be some very remarkable maxima recorded next week where the best of the dry sunny weather occurs further s / e / ne / se!

Yes quite warm for October @frosty . Towards the end of the run the high gets shunted east , as the alantic comes in .

[blizzard81]

9 hours ago, blizzard81 said:

Indeed. This is exactly what needs to happen to increase our cold winter chances. The models seem to be firming up on an Indian summer scenario for us next week. However, we have to look at the bigger picture. The northern hemisphere views for next week show this perfectly. The eastern European block which will bring us the lovely late warmth is also the driving mechanism that delivers winter to central/eastern Russia during next week. Great early building blocks from where I am sitting. 

Me and my big mouth ha ha. Ecm ramps up the Atlantic again on it's latest run. A little deflated about that to be honest but at least the eastern block still looks strong. The models are struggling with the energy in the Atlantic. I just hope they haven't underestimated this. The wind and rain can come in November. 

[BlueHedgehog074]

I know it probably won’t occur exactly like this, but that is a seriously long drawn flow all the way from the South the 12Z GFS is showing towards next weekend. 

Some people may be looking forward to seeing an Easterly turn up at some point, but a beast from the South will have to do for now.

[blizzard81]

Ecm mean definitely going back to what it was showing up until yesterday's u-turn. A more mobile pattern post day 7. 

[Cheshire Freeze]

1 hour ago, blizzard81 said:

Me and my big mouth ha ha. Ecm ramps up the Atlantic again on it's latest run. A little deflated about that to be honest but at least the eastern block still looks strong. The models are struggling with the energy in the Atlantic. I just hope they haven't underestimated this. The wind and rain can come in November. 

A ramping up of the Atlantic is fine, as long as we maintain some form of heights to the NE...look at Nov 2009...extremely wet and Atlantic driven for the UK but with the main troughing not being allowed to progress much further than our shores.

It's when you see the jet complete a full circular loop around the NH, unabated, that we need to worry. As usually once the strat and trop vortex connect, you're reliant on a SSW (which with a wQBO and solar min combo are quite rare). Therefore, this season, we'll be looking at the trop pattern to lead us to wintry goodness further down the line.

Edited October 6, 2018 by CreweCold

[blizzard81]

1 hour ago, CreweCold said:

A ramping up of the Atlantic is fine, as long as we maintain some form of heights to the NE...look at Nov 2009...extremely wet and Atlantic driven for the UK but with the main troughing not being allowed to progress much further than our shores.

It's when you see the jet complete a full circular loop around the NH, unabated, that we need to worry. As usually once the strat and trop vortex connect, you're reliant on a SSW (which with a wQBO and solar min combo are quite rare). Therefore, this season, we'll be looking at the trop pattern to lead us to wintry goodness further down the line.

I totally agree Crewe. As with most things though, timing is everything. I remember looking at the charts during November 09 and comparing them to early Nov 62. Trough hitting the block to the east and negatively tilting. I had that great gut feeling about it. The rest is history of course. Anyway, going back to the timing aspect. I don't want Nov 62/09 to happen in Oct 18. Just a tad too early for my liking. We need the Euro southerly draw first. 

[BlueHedgehog074]

Just a little look at the 00Z GFS and it looks, in general, High Pressure spends most of its trip over the UK. Blocking to the East still evident for this week (as I would expect) bringing warmer weather with it, especially towards Eastern areas. Sunny and bright at times, too. But... the Atlantic Lows do try to give the Eastern UK High a punch later in the week:

...and hurts the poor Eastern UK High Pressure system’s tummy. Western and North-Western areas of the U.K. feeling the main affect from the determined Atlantic Lows - those areas experiencing some wind and rain at times and perhaps briefly towards South-Eastern UK areas too. Especially Thursday! Nevertheless, the Eastern UK High Pressure system just does not want to give up getting real mad at those Atlantic Lows,

trying so hard to push those sneaky monsters out West away from the U.K. As you can see, though, it’s a nail-biting battle. And some one has to win at some point. Suspect there will continue to be variations of this combat between the two forces from run to run.

Heading towards the later part of the run, the Scandinavian and European High Pressure system gets reinforcements from the South-West. Ridging from the Azores area moves over the UK and partners up with the European High to our East. They try to gang up on the Atlantic Lows.

While the Eastern/Scandinavian UK High Pressure system does get trampled on by the bad boys (aka Atlantic Lows), it seems like the Azores ridging has enough fight to send the Jet Stream on a Northerly track with High Pressure clinging to the UK, like blu-tac! This especially so over Southern UK, which would see the best of the dry and bright weather towards the end of the GFS run.

If I were to rate how both combatants performed on this run, this is what the results would be.

For strength and bravery:

Eastern UK High - (6.9/10). Atlantic Lows - (5/10)

UK domination:

Eastern UK High - (8/10). Atlantic Lows - (3.8/10) 

The Eastern UK High wins!

The Eastern UK block could have had a full 20/20 score in total, but it did have to rely on the Azores High coming to the rescue and the Atlantic Lows did sorta flatten out the block a bit. The block did well on the whole, though.

[ICE COLD]

ECM 00z has definitely took a turn for the worse this morning . From day 5 through to day 10 it's unsettled and no where near as warm as it has been showing in the last few days . The west and north west taking the brunt of the unsettled weather but even in the south it becomes unsettled with one day ok and the next not so good . Changeable is the word of the day . 

[mb018538]

All models have started to show this - there’s also a spoiler low lurking at day 7 now which wasn’t previously shown. Shame really, was looking forward to a brilliant week and next weekend!

[Man With Beard]

11 hours ago, blizzard81 said:

Ecm mean definitely going back to what it was showing up until yesterday's u-turn. A more mobile pattern post day 7. 

Yes the general consensus is moving back to a *still very mild* but less settled picture even by next weekend through regular brushes with gale force storms. 

Into the following week, the ensembles continue to suggest a gradual return to normal temperatures and a much wetter outlook for all, with visits from Atlantic systems affecting more areas. 

[Frosty.]

Stunning charts from the Gfs 00z operational..high summer in mid october!!!!

[blizzard81]

2 hours ago, Man With Beard said:

Yes the general consensus is moving back to a *still very mild* but less settled picture even by next weekend through regular brushes with gale force storms. 

Into the following week, the ensembles continue to suggest a gradual return to normal temperatures and a much wetter outlook for all, with visits from Atlantic systems affecting more areas. 

Yep, those Atlantic systems are definitely closer to the uk in the reliable time frame as well. Something has contributed to the ramping up of the Atlantic. 

Edited October 7, 2018 by blizzard81