Model Output Discussion - early October

[damianslaw]

Mmm models playing around with things for the end of the week and into next week - what they all agree on though is a very slow moving trough inching its way over the UK as the week wears on. ECM and UKMO both show heights building in behind the trough and notably to the north, GFS showing the atlantic having an easier time to move back in after a couple of quieter settled days.

Next week not looking quite as clear as perhaps first thought.

A very plausible set up would be heights ridging through the UK on an east-west axis, before the trough moves back down from the NW, sending heights out west and pulling in a NW, then possible northerly. The other scenario is for heights to orientate more on a SW-NE axis building into the near continent with frontal activity much weaker breaking through splitting the ridge into two parts, sinking SE in one direction and moving west in another. Either way the ridge looks preety weak and unlikely to last that long, based on this evening's models, but also importantly never too far away to enable a different atlantic profile to what we have been accustomed too over recent weeks - the classic westerly, exchanged perhaps for something more meridional.,, with polar air having an easier time to invade perhaps..

[Frosty.]

My eyes light up when I see Arctic potential whatever the timeframe..and even more when I see snow appearing on the ensembles..in october!!..here's hoping for a looooong winter with plenty more charts like these..white Halloween anyone?!!!!❄❄❄❄❄❄

 

[feb1991blizzard]

2 hours ago, BLAST FROM THE PAST said:

Correct Feb, with luck with potency

 

BFTP

Right on cue, fairly potent (for the time of year) this run came out with a few ens members to back it up.

[Allseasons-Si]

What is it with the control run of late spawning charts worth dwelling over

lets take a look at it

it all happens around day ten(yes i know it's day ten sigh)

deep trough in N Canada forces WAA ahead of it up the west side of Greenland(black arrow),also notice the arctic high(white circle) creating some reverse -AO(arctic oscillation)(orange arrow) forcing the trough west of Greenland south 

lets have a look at the animated sequence of both the 500mb height's and 850.

' 

will it set a trend?

 

 

[feb1991blizzard]

3 minutes ago, Allseasons-si said:

What is it with the control run of late spawning charts worth dwelling over

lets take a look at it

it all happens around day ten(yes i know it's day ten sigh)

deep trough in N Canada forces WAA ahead of it up the west side of Greenland(black arrow),also notice the arctic high(white circle) creating some reverse -AO(arctic oscillation)(orange arrow) forcing the trough west of Greenland south 

will it set a trend?

 

 

Op at it now as well.

Here she comes.

[Allseasons-Si]

The gfs 18z is starting to look like the 12z control at 228 hrs.

lol,you just bet me to it Feb...

Edited October 14, 2019 by Allseasons-si

[Allseasons-Si]

5 minutes ago, jordan smith said:

A pity that's in the unreliable range wouldn't mind that coming off thankyou.. I do have that little feeling something really special will happen this winter but we shall see love model watching in autumn and winter really is fascinating. Wonder if high pressure next week will last I have a feeling it will be transient in nature thus not staying dry for too long but atleast enjoy the dry weather while it may last then. 

Yes it is but nice to look at though,the 18z just doesn't get there in terms of potency but on the same track,we will have a look in the morning to see if it  still picks this signal up. 

Edited October 14, 2019 by Allseasons-si

[Mapantz]

A post moved to the banter/moans/chat thread as it's it falls in to one of those categories. 

[Allseasons-Si]

The control is at it again all be it deep in FL.

[booferking]

1 minute ago, Allseasons-si said:

The control is at it again all be it deep in FL.

You mean control and SOME..

[feb1991blizzard]

Surely we couldn't get pumped this early in season.

 

Or could we??

[feb1991blizzard]

Another trigger over Greenland about to be pulled for second more potent go.

-6c already there with -8c just waiting in the wings.

 

Heavy snow for some places.

Edited October 15, 2019 by feb1991blizzard

[knocker]

outlook - This weeks weather will be dominated by the Atlantic low as it drifts east and fills

The North Atlantic 500mb and surface analysis for midnight and current sat image

With yesterdays wave and front out of the way it will be a pretty overcast start to the day in many central and eastern regions but this should improve with everywhere having not a bad day with some sunshine. A few showers in the south east this morning and the south west later but other wise pretty dry which is a tad unusual of late.

But the fronts associated with the aforementioned low are approaching from the west and rain will effect N' Ireland and the south west by evening and this will track across the country overnight to be aligned western Scotland > south east England by dawn

The fronts will continue to track east through Wednesday and much of the rain should clear by lunchtime but a few hours later in the north and south east. It should quite sunny behind all of this, albeit a few showers in western regions

By Thursday the low is west of Ireland with the associated occlusion over same thus the UK in a brisk south westerly wind with sunny interval and showers which will be mainly concentrated in the west.

Over Friday and Saturday the low continues to fill over th UK as it nestles between the amplifying subtropical high zones but a lot of pressure is being exerted  in the Atlantic as energy sweeps east across the US. Essentially then a couple of days of sunshine and showers which could well be heavy with thunder in the mix. Temps around average

Edited October 15, 2019 by knocker

[knocker]

Sunday another unsettled day with showers but the surface wind veers northerly as the upper low starts to be relegated south east. Quite a chilly day with temps below average

The eastward movement of the pattern across the Atlantic continues over the next 24 hours resulting in further adjustments of the position of the trough as the subtropical ridges across the UK.

Best left there until the GEFS have been perused

[knocker]

Looking at the GEFS the indications are that the pressure will not only cause trough disruption in the Atlantic but also wear down the ridge quite quickly resulting in a position not far away from what has been indicated from recent anomaly output

[knocker]

A cursory glance the latest EC46 update for the first couple of weeks for November leaves one a tad optimistic. Generally pressure is quite high over the UK in the fairly weak upper flow with low pressure developing over Greenland during the second week so still tending towards a N/S split. The precipitation spread indicates this whilst temps are around average, It would be grand if this presaged the winter trend

[Methuselah]

Ding dong! Some early-season FI eye-candy to enjoy...?

   

Not a great deal of support from the GEFS 00Z ensembles, though:

   

   

Winter, she's a'comin'!!!!

Edited October 15, 2019 by Ed Stone

[feb1991blizzard]

23 minutes ago, knocker said:

A cursory glance the latest EC46 update for the first couple of weeks for November leaves one a tad optimistic. Generally pressure is quite high over the UK in the fairly weak upper flow with low pressure developing over Greenland during the second week so still tending towards a N/S split. The precipitation spread indicates this whilst temps are around average, It would be grand if this presaged the winter trend

It certainly would, above average heights NW with a\ trough over Italy w3 then above average heights over Scandi w4.

[Frosty.]

The GEFS 0z mean is certainly very interesting further ahead, portends increasing chances of Polar / Arctic maritime shots!❄

Edited October 15, 2019 by JON SNOW

[knocker]

27 minutes ago, feb1991blizzard said:

It certainly would, above average heights NW with a\ trough over Italy w3 then above average heights over Scandi w4.

I am surprised as I didn't realize you were into south westerly zephyrs

 

[I remember Atlantic 252]

2 hours ago, feb1991blizzard said:

Another trigger over Greenland about to be pulled for second more potent go.

-6c already there with -8c just waiting in the wings.

 

Heavy snow for some places.

Aye, Scotland only, no excitement for me living here for cold setups, would rather an Indian Summer

[knocker]

The amplification of the subtropical high zones and subsequent trough disruption is certainly causing a certain amount of mayhem in the latter part of the ten day period vis the det output

[BLAST FROM THE PAST]

9 hours ago, feb1991blizzard said:

Right on cue, fairly potent (for the time of year) this run came out with a few ens members to back it up.

I’ll be doing my LRF early this year as I believe Nov has a chance of being classed as a winter month.  But the issue I’m dwelling on is that I believe we’ll be relying on pM air turning into arctic maritime shots with HP to our W/SW playing it’s part (and with pronounced energy peaks could be very tasty)and I’m not wavering from that POV.  Scotland, NI and Northern England to definitely benefit but what about the rest....it needs the type of GFS set ups in deep FI we are seeing to come to fruition.

 

BFTP

Edited October 15, 2019 by BLAST FROM THE PAST

[feb1991blizzard]

1 hour ago, knocker said:

I am surprised as I didn't realize you were into south westerly zephyrs

 

Didn't think the surface pressure would look like that, although still would think with the h500 profile, if it persisted throughout winter, would throw in some cold, never greedy these days with the rubbish snow totals and patterns the last few years, if i could have 1 or 2 weeks worth of dumpings, i would gladly give you the other 10 weeks of mild.

[Singularity]

A Nina-like atmospheric state with a poorly organised tropospheric polar vortex (despite the stratospheric one being much more so) can facilitate some nice 'tall' mid-Atlantic ridges in Oct-Nov, maybe early Dec. Not sure how much longer the trop. vortex will really be able to stay so disorganised, though. Anomalously large Arctic heat + moisture fluxes are a wildcard, as usual in these times of huge sea ice deficits.

Regardless, I expect we'll have a few 'toppler' scenarios to ponder over in the coming weeks. Going to be tough for low levels to get much wintry weather out of such things, though. 

It's not going to help sanity levels that the FV3 core of GFS still seems to have a bit of a cold bias with troposphere temps.