Model Output Discussion 01/09/17

[bluearmy]

the  potential high anomoly the other side of the pole has strong upper strat support on the GEFS so we could well see the trop pv settled further this side of the NH prompting a deeper sceuro trough than might be expected for early November. 

of course, this likely means diddly squat in respect of what winter will bring but it would take me back to real winters past if bonfire night was cold rather than mild as is generally the case

mind you, better to have boulders in the river rather than little stones - should hopefully deliver and maintain a more amplified hemispheric pattern. 

[knocker]

Yesterday it was noted that just small changes in the upper air pattern could result in significant differences in the interpretation of the surface analysis and the det runs later rather proved that point although generally pointing in the direction of one of the likely options. Anyway more of the anomalies perhaps later. At the moment yesterdays low has filled and is duly in the North Sea so after early rain, mainly in the north west clears, most of the UK will be in a breezy north west airstream with more showers concentrated more in the W/SW.

Thus a quieter day for everyone but by 00 fronts and rain associated with the deep low out in Atlantic will already be impacting NW and W parts of the UK and they will track eastwards tomorrow before clearing.

Meanwhile back on the farm. Early Tuesday the next front arrive along with a small wave that is just north of Scotland at 06. The front tracks SE during the day clearing the north before eventually by 12 Wednesday we have the classic N/S split as the filling Atlantic low is north west of Scotland and the Euro high pushes up from the south as the much mentioned amplification gets underway. Temps a little above average.

As can be noted on the last chart the upper trough to the west has split and over the next 48 hours the cut off feature to the south west becomes quite prominent as high pressure in the western Atlantic ridges around the large surface low to phase with the Euro high over the UK. thus the UK remains dry with temps around average or a little above at the end of the week. But by so doing this the high block to the west is not so effective and energy from the trough machine over N. Canada can track east and then south east to phase with the trough in eastern Europe. The timing and precise execution of how this pans out, Vis the orientation of the major players is crucial to the weather over the UK in the following few days.

The gfs this morning has the trough to the north making the winning play over the weekend and with very strong NW to SE jet the low to the north tracks south east into southern Scandinavia initiating north westerly gales in the North Sea and veering the wind northerly over the UK and introducing cooler air from the north

The low quickly clears to the east after the weekend and after some brief ridging and an air frost Monday morning normal service is resumed with fronts encroaching from the west. But this not a done deal and to repeat, just minor alterations to the upper air pattern and next weekend could e a lot different.

Edited October 22, 2017 by knocker

[ICE COLD]

And now the ecm gives us Winds from the north . 

[knocker]

Well the ecm has the deep low 964mb west of Norway 12 Saturday with the UK in a very strong, showery,  westerly airstream, By 12 Sunday the low has tracked south east across the Baltic with secondary features forming in the circulation in the easterly quadrant running south resulting in the wind veering NW over the UK and gales, particularly in the North Sea with temps a little below average. The northerly wind eases through Monday (apart from the North Sea) as the ridge moves in from the west and then fronts encroach on Tuesday. This actually is not a million miles away from the gfs but it is from it's previous run.

Edited October 22, 2017 by knocker

[Summer Sun]

The beeb are saying the south will hit 22c on Thursday GFS and ECM both show the upper teens with highs around 17c possibly 18c in one or two places

[northwestsnow]

Wonder if we can squeeze some high pressure next week as it literally hasn't stopped raining here for days, and days.

http://old.wetterzentrale.de/pics/Recm961.html

[stainesbloke]

2 minutes ago, northwestsnow said:

Wonder if we can squeeze some high pressure next week as it literally hasn't stopped raining here for days, and days.

http://old.wetterzentrale.de/pics/Recm961.html

Would be nice. Low pressure seems to have dominated since July. A nice, sunny, cool high would be great for a few weeks.

[snowflakey]

Rather short lived warm spell with most GFS members going for a cool outlook with temps well below normal.

[snowflakey]

Sorry for the last post. here are the London ens I meant to post

[Fergie]

Too early to be getting hopes up over snow. How many times do we get excited only for the charts to break down closer to the time. You can't be sure of these things until 48 hours before said weather. Caution please.

[IDO]

7 minutes ago, snowflakey said:

Sorry for the last post. here are the London ens I meant to post

I can assure you the upper air temp over London is not currently 13c! 

That graph looks like something went wrong.

This is the latest from Meteociel:

Looking pleasant, even mild for a few days, then remaining dry but not so warm, though possibly still above average away from a strengthening cooler wind later in the period. 

After that (D8 plus), the usual uncertainty at that range, but a chilly spell looking the likely favorite from the recent output.

Though the fast-moving Rossby wave activity due will mean periods of cooler and milder interludes as the wave(s) propagates east. The MJO signal overriding any El-Nino trend for the next 2 weeks and then hopefully we will see what November holds going forward.

[knocker]

Something else to take into account in the 6-10 range is the impact that super typhoon Lan is having on the Pacific jet and the pattern over N.America The predicted first freeze in the Plains and Midwest. This could well have a knock on effect downstream as well

Edited October 22, 2017 by knocker

[chrisbell-nottheweatherman]

8 minutes ago, knocker said:

Something else to take into account in the 6-10 range is the impact that super typhoon Lan is having on the Pacific jet and the pattern over N.America The predicted first freeze in the Plains and Midwest. This could well have a knock on effect downstream as well

Would it be accurate to assume that a cold trough over the Midwest is less likely to fire a powerful zonal Jet at the UK than a similar plunge of cold on the East Coast of the US, Malcolm?  Possibly a western Atlantic ridge with possibly the Azores High retrogressing to join up with it?

[Met4Cast]

Much better 12z, sharper ridging up into Greenland, colder air flooding Southwards across the UK. 

[Daniel*]

7 minutes ago, chrisbell-nottheweatherman said:

Would it be accurate to assume that a cold trough over the Midwest is less likely to fire a powerful zonal Jet at the UK than a similar plunge of cold on the East Coast of the US, Malcolm?  Possibly a western Atlantic ridge with possibly the Azores High retrogressing to join up with it?

While I’m not Knocker (Malcolm) but right. Rather strong support for NAO to take a ‘dive’ of sorts.

 

[blizzard81]

The models setting up the possibility of a cold first half to November. When was the last time that happened? I know 1993 had a cold November. 

[booferking]

43 minutes ago, Fergie said:

Too early to be getting hopes up over snow. How many times do we get excited only for the charts to break down closer to the time. You can't be sure of these things until 48 hours before said weather. Caution please.

It's not snow were looking for it just your normal Autumn feel frosty crispy weather while snow fields build just to the east of us. 

That will do me at this early stage.

[knocker]

47 minutes ago, chrisbell-nottheweatherman said:

Would it be accurate to assume that a cold trough over the Midwest is less likely to fire a powerful zonal Jet at the UK than a similar plunge of cold on the East Coast of the US, Malcolm?  Possibly a western Atlantic ridge with possibly the Azores High retrogressing to join up with it?

I don't know whether it's less likely Chris but both create a strong jet around the west Atlantic high pressure, a long way from zonal, and not so much the Euro high retrogressing as being suppressed that has been sign posted to some extent by the anomalies As perhaps illustrated by evenings gfs Not forgetting the role of the cut off upper low

 

Edited October 22, 2017 by knocker

[blizzard81]

I sense a very war weary set of cold lovers on this forum today. The last few mild dross winters have taken their toll lol. If it wasn't for the last 4 or 5 years, there would have been much more interest in the forth coming synoptics. Keep the faith. 

[The Northern Ramper]

So it's October 22nd and the lesser spotted ramp makes an early entrance to this winters model thread.

Signs so far this autumn are of the positive nature, coldies pre-season optimism is lower than the arctic sea ice but times are a changing and next weekend could see the first cool spell for months.

 

let the fun commence 

[ICE COLD]

Evening All 

Its certainly looking very interesting as we head towards November . Probley the best it's looked for quite a few years . Not a bad Set of ens there , if it's cool / cold your looking for . 

[knocker]

I can recommend a good rest home for chionophiles. Evening tranquilizers are augmented by videos of 47 and 62-3. Minimum stay four months.

[comet]

1 hour ago, booferking said:

It's not snow were looking for it just your normal Autumn feel frosty crispy weather while snow fields build just to the east of us. 

That will do me at this early stage.

It will be a welcome change if it comes off with a much more seasonal feel to the weather  and yes although no one is realistically looking for snow at this stage we know it isn't outside the realms of possibility either.

[J-Man]

Did it snow in London one late October in maybe 2009/2010....can anyone find the chart, if they can verify that it did snow, so we can compare that to this potential cold snap.

[Chris.R]

 2008, last week of the month.