Model Output Discussion - early October

[Mapantz]

28 minutes ago, feb1991blizzard said:

 

Don't worry about the uppers too much, it only needs a potent shortwave in the right position with evaporative cooling and you could easily get hours and hours of heavy lowland snow with a setup like that.

Can you upload a better image? That's the size of a postage stamp. 

[West is Best]

Well it's that time of year when it's time to dust off the keyboard. I hope you have all had great summertimes.

What a thing of beauty the GFS12z is today. It's been in the offing for 48 hours and, truth be told, we'd all much rather we saw it in December than October. Still, it's comforting to know that blocking hasn't disappeared from the earth or that the fabled Greenland High is just a thing of legend.

 

[Kirkcaldy Weather]

On 09/10/2019 at 14:47, Kirkcaldy Weather said:

Referring back to my last post concerning the MJO 

It has persisted in phase 1 and the unsettled pattern has continued, certainly more autumnal but not ideal for those looking for drier weather. Pattern has matched closely with the expected for phase 1 (also amplitude 1) with the higher pressure that developed over scandi   looks like a brief crossover back into phase 8 before returning to phase 1     so perhaps a brief settled spell before a return the the unsettled autumnal conditions we are currently experiencing, here is phase 8 October with higher pressure through the UK up toward Greenland which a few of the ensembles are hinting at           

MJO did crossover back into phase 8 briefly and has now moved back into phase 1, very fascinating behaviour with either phase 8 or 1 since 15th September so now a whole month and looking like at least a bit longer on top of that http://www.bom.gov.au/climate/mjo/graphics/rmm.74toRealtime.txt so something similar to the latest GFS run may not be too far off the mark with the general idea of higher pressure toward Greenland (possibly still some drier weather over UK during next week) then possibly the higher pressure moving from Greenland toward Scandi like the GFS hints at  https://docs.wixstatic.com/ugd/31d9e0_3c062d439cb841d2eea3ea174256642b.pdf 

Certainly shaping up to be an interesting few weeks.

 

[feb1991blizzard]

2 minutes ago, Mapantz said:

Can you upload a better image? That's the size of a postage stamp. 

[West is Best]

... and I still remember the bone chilling November of 1985 when this very similar chart:

 

became this:

 

which then turned into this:

 

 

Edited October 15, 2019 by West is Best

[Jordan S]

Definitely a rather interesting output from the gfs to say the least would feel wintry indeed at times but unreliable time frame so health warning with that.

High pressure struggles to build in according to the gfs next week too.. We'll see. 

Edited October 15, 2019 by jordan smith

[Mike Poole]

Some respite after the weekend from the relentless rain, but thereafter, it is not easy to see the path.  Consider the T240 charts from GFS, GEM and ECM 12z:

Tropospheric vortex looks in considerable turmoil, but up above it's a different story as the icy whirlwind in the stratosphere really takes hold, getting cold up there, GFS T240:

And the forecast is for a considerable strengthening of the vortex now, zonal wind:

This disconnect cannot go on for ever, so does the trop fall in line with the strat and we get a horrid wet and windy Atlantic dominated November, or are we headed towards an early warming for the strat, putting the brakes on or more...well we will need to see some pressure put on the strat vortex, GFS T384...???

We will see...

[feb1991blizzard]

Big cold pool building on the continent at 240 on the ECM

[summer blizzard]

It's been a long time since such a cold shot was forecast in October although worth saying that 2012 and 2017 did see short snaps.

[Methuselah]

Here are the GEFS 12Z ensembles: something quite cold (judging from the Op and Control runs) looks quite likely; however, when T850 and 2m temps are at their lowest, there's little or no precipitation predicted.  Sod's Law or what!

   

   

Even for here on the Norfolk-Suffolk border!

[Mike Poole]

Long fetch northerly at T240 on the FIM8:

Just for fun! 

[damianslaw]

In my post yesterday I said one possible scenario for later in the month was for a NW then northerly flow - indeed GFS showing this today with strong Greenland high. ECM less keen, but still shows blocking by the end of this week and into next week to our north and north west. 

[sorepaw1]

12z looking interesting. 

A slice of early wintery conditions possible 1040mb high.

Not to be sniffed at.

[Zak M]

Wednesday morning looks like a wet start for many eastern and central areas of England, with a band of rain, perhaps heavy, will move NE across the British Isles. Places like northern England and Scotland should also be under this heavy rain too. SW England, Wales and Northern Ireland will wake up with a dry start, but not TOO dry, as the band of heavy rain should of progressed over these places in the early hours of Wednesday. Northern Ireland has the best chance of waking up to some glorious sunshine, which a small chance of catching the odd shower or two.

As the day progresses, and we head into the afternoon, it should start to brighten up across the majority of England and Wales as the band of rain spreads NE, except Norfolk, where they might catch some drizzle.

Where places across England get sunshine, it won't be crystal clear, there might just be some fair weather clouds lurking in the sky. Wales should remain dry for the rest of the afternoon, with the small chance of catching an isolated shower.

The band of rain also clears NE across northern England and Scotland, and into the afternoon the majority of those areas should also remain dry for the rest of the afternoon, except NE Scotland, where they could catch some drizzle. Northern Ireland could remain dry for the whole day, with, once again, the exception of the small shower. If you do catch a shower, it shouldn't be too heavy.

Into the evening, most places of the United Kingdom should remain dry, with the chance of catching the odd shower across SW England, Wales, northern England, Scotland, and Northern Ireland. To the far SE of England, there is a small chance that they could catch some rain into the evening. Other than that, some places have the chance of catching some sunshine to end the day.

The peak temperatures in the afternoon in the south should range from 10-16c, and in the north should range from 7-15c.

[Mike Poole]

Looking a bit further ahead, here's the last 5 NH Z500 anomalies for December from the CFS (averaged over the month):

Setting aside UK potential, how many scream a raging +AO?  None.  Hmmm...

Edited October 15, 2019 by Mike Poole

[Allseasons-Si]

Evening everyone,i see the gfs is still at it with forecasting a northerly outbreak later next week so it is consistent,just need the ecm to come on board,if you look at the mean at day ten from both the gfs and ecm they both look broadly similar with the height's pushing up into Greenland so i think the ecm op may come on board tomorrow

the latest from cpc days 8-14 show this with height's pushing up into Greenland with trough down into Scandinavia

now for the flip of the coin,the NAO/AO was forecast to go +ve positive yesterday,now look at them,if this continues then the Atlantic door may be come ad-jarred or even shut

i know i am ramping a little bit but who wouldn't

now for the 18z,buckle up.

[Allseasons-Si]

The 18z a little slower on the evolution than the 12z,so finer days for longer,i would take that

at 192.

we still have the Atlantic ridge so variations of the theme around that time frame.

 

Edited October 15, 2019 by Allseasons-si

[feb1991blizzard]

Still early in the run yet but if we can get some frigid air pulled down the line of that wave then wont it be all GFS's today that have been cold? something afoot, BBC were still going with ECM op.

[Allseasons-Si]

She's still cometh

[Mike Poole]

So to the pub run, first at T156, ridge of high pressure will be a relief to those who have had incessant rain recently.

From then on, well this looks like a flying pig:

Well it does to me anyway, coming at you view... you can clearly see its snout, that colder rush becoming more likely?

Edited October 15, 2019 by Mike Poole

[Allseasons-Si]

.Another surge of colder air coming down from this trough circled red.

this could be a stonker of a run.

Edited October 15, 2019 by Allseasons-si

[Jordan S]

A bizarre but very interesting evolution at day ten haven't seen outputs like this in a while.. Colder and also rain seemingly coming from all sorts of directions well I say rain but mabye the magic S word would be used in this such scenario for some areas. 

 

[feb1991blizzard]

Nearly again - just can't get those -6 and -8 lines down.

[Mike Poole]

Pub run T324:

Quite something for October!

[Allseasons-Si]

1 minute ago, feb1991blizzard said:

Nearly again - just can't get those -6 and -8 lines down.

Give it time feb,it's still around day ten>

like i said earlier,the op and control have been screaming these charts out for days,2010 was a good signal that the gfs picked up,will this one be the same?