Model Output Discussion - early October

[MATTWOLVES 3]

On a positive note the ECM again ending with Height rises over Greenland! Deep low pressure to our NW and perhaps a colder shot of air as the low moves Eastwards! 

[SMU]

9 hours ago, Interitus said:

This is probably unlikely. The geopotential anomaly plot shows the combined effects of virtual temperature in the stratosphere and all the levels of the troposphere below. In this instance it does indicate a warmer stratosphere, but looking at all the charts shows that in the 1980s there was a positive stratospheric anomaly more or less every summer, many stronger than 1981. In the 1990s it is more mixed around the average, whilst since the millenium there has been a persistent negative anomaly. This is consistent with the recorded stratospheric cooling as expected from global warming and greenhouse theory.

With regards to December, note there was a SSW on December 4th.

I prefer using these ones just focussing in on the lower levels 

Anyway what you say may be true - I remember way back in the early 2000s when the Stratospheric knowledge was in its infancy the charts posted online were always of warm 80s & cold 90s so of course the average is skewed downwards when just in comparison with the 80s it was probably close to the norm however there was definite movement downwards to lower levels in Oct -

Also note the reduction of the 10HPA + 100 HPW zonal wind at the start of oct -

I missed the early Dec warming though !

 

 

Tonights models continue to toy with height rises over the pole at day 9-10, much to be resolved though -

S

[knocker]

The North Atlantic 500mb and surface analysis for midnight

Now that the remnants of Lorenzo are out of the way the frontal system associated with the deep low in mid Atlantic can make some headway east.So after a dry and relatively clear start in many areas cloud and rain will encroach from the west during the day, The rain is already into north west Scotland and this will spread east with the heavier rain concentrated in the north until the cold front arrives across west Wales and the south west of England by mid afternoon

The heavy rain belt continues to track east across the country this evening and overnight but is slowing down as a wave starts to form on the front which is not good news, Meanwhile out in the western Atlantic another deep surface low has developed in the complex upper trough

During Sunday the wave grinds to a halt as the UK is perched between the high cell to the NE and the deepening trough in mid Atlantic. Precisely where will determine where the continuous rain will fall and there could well be significant falls in some areas But behind the system it could well be a fairly sunny and pleasant day

The front will clear over Sunday night so a better start to the day for most but more fronts associated with the now deep low 958mb south of Iceland will track across the country accompanies by a band of rain and quite strong winds with possibly gales  in the NW

Over Tuesday the filling low to the north west will continue to influence our weather with the country in a showery brisk westerly regime with some longer periods of rain as the showers coalesce courtesy of the odd trough in the circulation.

On Wednesday a not dissimilar scenario with the country still in a brisk westerly and thus more showers with more frontal systems waiting in the wings

 

Edited October 5, 2019 by knocker

[northwestsnow]

00z runs summed up -

More wind and rain.

When will it end!???

[knocker]

According to the gfs the key feature of the 5-10 period is the amplification of the subtropical high zones in eastern Europe and the NW Atlantic accompanied by the usual WAA. which results in the eastern Atlantic and northern Europe being under the umbrella of a trough. Ergo continuing unsettled for the UK , perhaps tending towards a N/S split

A couple of spot charts

[tinybill]

55 minutes ago, northwestsnow said:

00z runs summed up -

More wind and rain.

When will it end!???

looking into  gfs  fantasy land  up to 260 hr then i looks a bit better!!

[JeffC]

1 hour ago, northwestsnow said:

00z runs summed up -

More wind and rain.

When will it end!???

May

[NO LONGER POSTING]

GFS 00z is strange in the later stages (no surprises) but when ever does a low drop down like that from the north stall over the UK then head north again.. Don't think I've ever really seen that happen... 

[knocker]

In the latter stages of the run the ecm is not amplifying the subtropical zones anywhere near like the gfs but still unsettled for the UK with a positively tilted trough initially dominating the Atlantic before deconstructing under pressure another trough tracking east

Edited October 5, 2019 by knocker

[knocker]

Nothing particularly surprising about the anomalies this morning The EPS has an amplified Atlantic in the bearer time frame with strong ridging in the NW Atlantic and a trough dropping south over the UK in the east thus remaining unsettled with temps around average with perhaps some marked regional variations. The upper flow becoming flatter across the Atlantic in the ext period

Last night's NOAA not adverse to this scenario

 

Edited October 5, 2019 by knocker

[Frosty.]

The GEFS 0z mean indicates a generally unsettled outlook, especially further n / nw but further s / se there are some fine intervals / spells, especially from mid month onwards when there is a tendency towards a North / South split..it should also be noted that there is a moderate / high chance of a polar / arctic maritime shot around mid october, especially for the north (scotland).

[Methuselah]

A rather messy-looking set of GEFS 00Z ensembles, this morning -- temperature-wise especially?

   

   

And, IMO, the limits of NWP forecasting are clearly there to see?

[knocker]

The rainfall in the north and east in the next 48 hours still dependent on the precise movement of the frontal wave

 

[Methuselah]

Could be interesting?  -7C T850s into Scotland?

[Frosty.]

The Gfs 6z operational nicely ties in with my comment above regarding the chances of a mid october cold plunge..as Bruce Forsyth used to say, nice to see you, to see you..nice..and if we play our cards right, similar charts to these might verify!!!❄❄

winter is coming!

Edited October 5, 2019 by JON SNOW

[MATTWOLVES 3]

Indeed Karl, the ECM ensemble mean does drop that bit lower towards mid month. The op was on the warmer side of the pack... Infact looking at the extended mean to day 14, we have the mean close to 0C for the far North, and around 1.5c for Northern England. Pressure stays steady towards the South... Around 1015mb...

[Methuselah]

The only downside in the GEFS 06Z ensembles is that, and by no means for the first time, the Operational loses touch with 'reality', post Day 10!

   

   

Baby steps, eh? Baby steps?

[Sky Full]

2 hours ago, JON SNOW said:

The Gfs 6z operational nicely ties in with my comment above regarding the chances of a mid october cold plunge..as Bruce Forsyth used to say, nice to see you, to see you..nice..and if we play our cards right, similar charts to these might verify!!!❄❄

winter is coming!

......or perhaps we could say "ICE to see you, to see you ICE".    No?

 

I'll get my coat.

[Methuselah]

Can someone turn the deflector shield down a bit, Captain?

 

[knocker]

Purely out of interest. The gfs has a trough developing around the southern tip of Greenland along the NE flank of the resuging subtropical high and along the jet at t156

And it deepens quickly over the next 24 hours to be 976mb in mid Atlantic

Edited October 5, 2019 by knocker

[Frosty.]

Now this is what I call a North / South split!!

[Mike Poole]

ECM 12z:

Very unsettled outlook for the UK over the next week and more according to this, but I posted the NH view because it is nonetheless of interest that the high heights to the north somewhere never go away and you could hardly say the vortex is taking early shape.  

What that might mean for winter remains to be seen - I've posted some early thoughts as to that in the winter speculation thread.

Edited October 5, 2019 by Mike Poole

[knocker]

The ecm doesn't develop the low developing over Greenland a la gfs but it does serve to reinforce the major trough in the east resulting in a not unexpected 5-10 NH profile  Ergo unsettled

[Zak M]

It's currently early October, but it feels like December where I am! I decided to bike to school in the morning a few days ago and oh boy, that was a huge mistake, my hands were frozen for like 10 minutes  And because it's early October, seeing weather fronts like this lying in the Atlantic is just a typical Autumn weather pattern.

 

Speaking of weather fronts, one of them is going to travel across the UK late at night tonight and bring some heavy rain. When it reaches Norfolk/SE England, it is expected to stall there for a good half a day or so, with the threat of flooding. 

As for someone who loves summer and thunderstorms, I hate to say this, but winter is coming 

[Jordan S]

Aswell as being very wet for central and particularly Eastern areas of the UK tomorrow it also looks as though as the the frontal system develops a centre of circulation it may turn very windy for east anglia and particularly the far southeast later in the day tomorrow as the low sinks into the near continent something to bare in mind perhaps?

Arome.. 

Arpege..