Model Output Discussions 12z 01/09/2016

[Scorcher]

18 minutes ago, Captain Shortwave said:

 

So by day 10 we have heights centred just west of the UK, at the moment the models suggest that temperatures will cool off at 850hPa, it is important to note that as potentially the surface temperatures might not be that different as despite having this Atlantic ridge, under light winds an inversion is likely and will restrict temperatures somewhat.

The charts for the end of next week look remarkably similar to the start of November last year- as then I imagine which places see the lingering fog could be very hit and miss with big differences over very short distances. Places that escape the fog could get very warm by day for the time of year under such a warm air mass- high teens and possibly low 20s in southern areas, but where the fog lingers it could struggle to reach the teens. Very hard to forecast I think.

They would be absolutely cracking summer charts had this been 2-3 months earlier. Interesting to see 15C isotherm amazingly close to the UK just across the channel on the ECM chart for next Saturday.

[Frosty.]

The Ecm 12z ensemble mean sure looks pretty if you like pleasant anticyclonic weather..what's not to like about these charts?

[pegg24]

2 hours ago, Scorcher said:

The charts for the end of next week look remarkably similar to the start of November last year- as then I imagine which places see the lingering fog could be very hit and miss with big differences over very short distances. Places that escape the fog could get very warm by day for the time of year under such a warm air mass- high teens and possibly low 20s in southern areas, but where the fog lingers it could struggle to reach the teens. Very hard to forecast I think.

They would be absolutely cracking summer charts had this been 2-3 months earlier. Interesting to see 15C isotherm amazingly close to the UK just across the channel on the ECM chart for next Saturday.

We all ways got the wrong charts wrong time of year. June we got cold chart be amazing if was February. in December be wow if this was July would be 35c. We can't win lol.

Edited October 21, 2016 by pegg24

[Polar Maritime]

The GFS this morning continues to show dry/settled weather as we head into November for the majority of the UK, With only the far N/W of Scotland clipping any weak systems as the Jet run's over Iceland. So some fine Autumnal weather on the cards with some chilly nights under clear sky's.

 

[Matthew.]

Continuing from last nights high-pressure theme the ECM 0z displays this for next saturday:

Edited October 22, 2016 by Matthew Wilson

[IDO]

11 minutes ago, Polar Maritime said:

The GFS this morning continues to show dry/settled weather as we head into November for the majority of the UK, With only the far N/W of Scotland clipping any weak systems as the Jet run's over Iceland. So some fine Autumnal weather on the cards with some chilly nights under clear sky's.

 

 

Hi

 

Yes the GFS and last night's ECM mean at D10 is pretty impressive,. Confidence high that UK HP dominates in the short-medium term; nice:

 

D12 on the GEFS also keeping the pattern going: 

Dr Cohen's update suggest's uncertainty into week 3-4 with background signals needing clarity, but if correct, likely a continued HLB'ing: https://www.aer.com/science-research/climate-weather/arctic-oscillation

"With the AO/NAO predicted to be negative through the end of October, confidence is growing that October Eurasian snow cover will be well above normal once again this year and in the range of the past four Octobers.  Above normal snow cover favors a strengthened Siberian high and a weakened polar vortex/negative AO this upcoming winter with cold temperatures across the continents of the NH"

This quote suggests that, although nothing is certain in weather dynamics, the potential for something more seasonal this winter in mid-latitudes, with normal caveats (UK et al). 

[Frosty.]

The GEFS 00z mean becomes very anticyclonic during next week with very pleasant surface conditions by day but with chilly nights, mist / fog..so, after the current showery spell in the east especially, and some rain across the south early next week, it looks like settling down across most of the uk until at least the end of october and for the south and west, into early november.

Edited October 22, 2016 by Frosty.

[SMU]

Morning -

Spectacular ECM again this morning, with what appears again to be a full reversal of the zonal train at day 10 with a solid 2 wave pattern-

clearly seen here the vortex is very displaced - miles off centre from the pole, & if you look there are 3 low pressures moving clockwise around ~ 60N - a true sign of reverse zonality-

of course this is day 10, however its where the transition sits being the crucial timeline- & this is around 168 where you see the cross polar ridging on the models- even the UKMO has some signature at 144-

The timing of the this next bout of -AO probably arriving past day 8 ushers the end of the month & the keenly awaited 2016 November - from a cold perspective it would feel like there has never been so much anticipation of the -AO/NAO being so negative at such an early point in Winter - the last -1.5 november was 16 years ago! Could we beat -2?

October is also on course to beat the record of negativity - beating the hyper winter ( -AO) of 2009-

here are yesterdays ensembles - watch for a move to better clustering on low values on todays updated ones around 4pm-

- All this is in response to the overwhelming model ensemble drop off in the midrange of the 60N zonal wind - which could drop into record breaking negative territory ....

S

[Frosty.]

The Ecm 00z op turns into a very pleasant anticyclonic run..nice benign weather looks to be on the way, especially for the southern half of the uk but further north too as time goes on.

[Summer Sun]

Some parts of the south might hit 20c later next week as we begin to pull up some warmer air

Another warm Halloween is possible

[Paul]

Nick's blog, written last night is well worth a read:

Blocking likely to continue toward early November

[Ali1977]

18 minutes ago, Paul said:

Nick's blog, written last night is well worth a read:

Blocking likely to continue toward early November

Makes for good reading for those that want a cold end to Autumn and start to Winter.

Edited October 22, 2016 by Ali1977

[Frosty.]

There is early wintry potential for early november showing on the control run and some of the GEFS 00z perturbations. 

Edited October 22, 2016 by Frosty.

[Frosty.]

The Ecm 00z ens mean becomes anticyclonic and stays that way, just like the op..becoming very pleasant with light winds, plenty of sun, mild temps for the time of year by day but nights on the chilly side where skies clear with a risk of frost, especially in the countryside and mist / fog becoming more frequent.

Edited October 22, 2016 by Frosty.

[legritter]

Morning fellow posters ,charts still showing mostly settled weather conditions with some good weather for getting out and about ,next few days could become dank and a little wet for some but there after just quiet Mid autumn days with some sun in favoured locations and some fog and frost about .

Looking at ECM there isa hint of high pressure setting up to our far north west but it will need more runs to convince me of this ,Gfs does show a large low moving to our far west in its later out put ,certainly upper air patterns a bit different this year across northern latitudes so i may this evening grab a STella ,and sit and relax and prepare my mind for the coming roller coaster season we are all heading towards ,cheers 

[bluearmy]

2 hours ago, Steve Murr said:

 

The timing of the this next bout of -AO probably arriving past day 8 ushers the end of the month & the keenly awaited 2016 November - from a cold perspective it would feel like there has never been so much anticipation of the -AO/NAO being so negative at such an early point in Winter - the last -1.5 november was 16 years ago! Could we beat -2?

October is also on course to beat the record of negativity - beating the hyper winter ( -AO) of 2009-

here are yesterdays ensembles - watch for a move to better clustering on low values on todays updated ones around 4pm-

- All this is in response to the overwhelming model ensemble drop off in the midrange of the 60N zonal wind - which could drop into record breaking negative territory ....

S

The eps having recently been fairly neutral through week 2 and potentially slightly positive now showing signs of drifting back to below neg 1 at that timescale whilst the gefs have been consistent around -1/-2 during that period.  The geps still looking neutral. 

If the next couple eps suites continue  with this drift back then momentum will be firmly behind a negative AO as we go through the first week November. I suspect a fair cluster of runs building an Arctic block northeast of Greenland maybe responsible for this. 

All adds to the current fervour 

[shaky]

Latest gfs has the high over the uk retrogressing to greenland at 208 hours!!previous run had a shortwave going over the top and therefore the high remained slap bang over the uk!!maybe the model is now starting to react to changes above!!

[Essex snowman]

[Essex snowman]

Positive signs hopefully like I've said I'm useless at reading charts but I love this site 

[Frosty.]

The Gfs 6z op run shows the uk getting close to some early wintry weather on more than a few occasions in low res..early November certainly holds cold potential.

Edited October 22, 2016 by Frosty.

[Barry12]

I've been looking at the GEFS ensembles over the last week and the signal for blocking to our NW has just been getting stronger and stronger, nearly every single perturbation has the block retrogressing to the NW, as well as a completely beaten up vortex, and as Steve Murr said this is starting at just day 7

I'm starting to think this November could be special!

Edited October 22, 2016 by Barry95

[knocker]

A brief look at this morning's anomalies and last night's NOAA.

No great problem with agreement in the 6-10 range. Quite intense Aleutian low, ridging into the Pole from Alaska and particularly Russia, a trough to our east and high pressure centred just to the south of the UK

So a few days of dry and pleasant weather with temps maybe a tad above average but cloud is always a problem with these scenarios and can affect both max and mins so that is merely a general observation. The one caveat would be the extension north of the HP. If it doesn't adequately cover Scotland it's distinctly possible that systems could swing around the it and bring some unsettled weather north of the border. Note that this morning's ecm det run has an 150kt west to east jet which the HP has pushed north just out of harm's way. It should also be noted WAA continues from both sides of the Pole.

The significant movement in the 10-15 time frame is a slight retrogression of the UK high pressure and the trough and the former tends to decline resulting in the upper flow veering W/NW and increasing a tad so  becoming more unsettled with temps a little below average.

[Zakos]

Remarkably blocked 06z

The jet stream profile at the present time, shows a disorgainised, relatively weak jet stream, kept away from the UK by the Scandinavian block.

The jet stream weakens throughout the run. However, as the block retreats eastwards, the Atlantic tries to encroach on Europe. Despite the Scandinavian block finally being removed, the UK remains under the influence of high pressure as the Atlantic block quickly encroaches, becoming centered over France

The block almost immediately retrogresses towards Greenland. Europe is put into the freezer, and the jet stream by the end of the run is almost non existant on our side of the hemisphere.

I believe this is roughly what will occur over the next couple weeks. October has been incredibly blocked and I cannot see this changing anytime soon based on the model outlook. I believe Europe will continue to cool down as the weeks progress. There is no sign of Atlantic conditions dominating whatsoever, and as long as this very blocked pattern continues it is only a matter of time before significant cold heads our way IMO.

There is still no sign of the PV setting up over Greenland. The trend is to pump warm air, from the Atlantic or the United States, directly into the Canadian Arctic which should further inhibit the establishment of the PV here. The trend is for the Polar vortex to be centered over Siberia/Alaska and this has been the case for a long time now.

 

 

 

 

 

 

Edited October 22, 2016 by Zakos

[Frosty.]

It does look like an Indian summer of sorts during the second half of next week as high pressure builds north drawing air sourced from southern europe up across the uk. I wouldn't be surprised to see somewhere in the south reach 19/20c 67f later next week.

[Zakos]

Height Anomaly snapshots from the GFS 06z, highlight the remarkable persistence of blocking in the Atlantic throughout the run.

Much the same from the ECM 00z.

There appears no end in sight for the incredibly blocked autumn conditions we have been experiencing.