Model Output Discussion - 18z 31/10/15 onwards

[joggs]

Yes Ali, its early but many at high altitude have snow cover in November. Presently the Alps are bare above 2500m or more. Of course it could be different by mid- December. This is the driest snow free Autumn many have seen over here, right now. I have lived here for 10 years and never seen the snow level so high.

C

we've got the big solar min to come and also the neg amo.Next 5-40 years should be interesting for us and alps

Just to mention the above been cyclical.

Edited November 5, 2015 by joggs

[phil nw.]

Let's back on topic please all. Plenty of other threads for general chat.

Thanks.

[Singularity]

 

It seems possible to me that the higher amplitude of the MJO predicted by GEFS as it moves back into phase 2, followed by increasing amplification in phase 1, explains part of the tendency we've seen to flatten and diminish the Euro High followed by a more meridional jet. It could be that the model has been overcooking the jet stream during the response to phase 1, so depositing the trough to our east when in reality it's more likely to be just west of the UK.

 

ECM's almost as amplified with the MJO into phase 2, but the det. run is less progressive with the Atlantic storms as the pattern in that sector responds, and is then keen to develop a notable trough west of the Azores rather than the UK, which could be seen as a version of the phase 1 MJO composite that's been modified to reflect El Nino forcing - though it may simply be that the MJO enters the COD before reaching phase 1 as per the last run of the extended version of the model.

 

I must say, I feel like a bit of a lone wolf in that I'm finding the potential for a record-warm November to be of great interest despite the often mundane day-to-day weather of late.

[summer blizzard]

That day 8 profile around Greenland on the 18z GFS is beautiful. One low providing WAA and another negatively tilted.

[Mucka]

GFS 18z ensembles were the coolest so far out in deep FI - a very clear cooling trend showing there.

 

[Mucka]

Similar picture this morning with ensembles showing a noticeable cool down in FI.

P 5,8 and 10 are probably the picks though the last frame of p20 would be quite exciting. 

 

 

If only. 

[knocker]

Morning campers, a brief overview of the latest EC32 update.

 

Saturday 14^th the anomaly has the HP to the SE, a positively tilted trough western Atlantic and ridging over NE Canada.  Thus a WSW anticyclonic circulation and above average temps.

 

By the 22^nd both the HP to the SE and Atlantic trough have weakened resulting in the streamlines veering to a zonal westerly sandwiched between LP to the NW and HP to the SW.  Thus the weather unsettled with temps around average.

 

From here until the 7^th December there is no sign of any significant change  The prevailing wind remaining in the westerly quadrant with the usual interplay between the cooler air to the north and warmer to the south resulting in a N/S split over the UK with periods of wet and windy interspersed with drier more pleasant conditions with temps varying around the average.

 

Summary

 

The latter half of the month and the first week in December will be unsettled with periods of wet and windy and dry and pleasant but this very much biased to a N/S split over the UK with temps around average but interspersed with colder and warmer periods. There is no sign at the moment of anything sinister lurking in the woodshed.

 

An overview of this morning's gfs run is pretty much what one would expect. Very mobile with the usual interplay between the cooler and warmer air which as usual will result in a N/S split although no doubt all areas will be affected by bouts of wet/drier conditions. A snapshot chart that exemplifies  this and is not be taken as a forecast.

Chart weatherbell

Edited November 6, 2015 by knocker

[Mucka]

Interesting ECM this morning albeit FI

 

 

All ensembles point to marked cool down from around mid month (from current mild synoptic) but no real cold signal as yet.

However a transient Northerly is obviously still in the running and if we could get a decent mid latitude block such as shown by ECM then there would be an opportunity to build some more sustained blocking.

Edited November 6, 2015 by Mucka

[knocker]

Yes it is interesting (not that it will verify) but I find it interesting because as that nasty little depression deepens rapidly and zips down from northern Scotland into eastern Europe into would briefly bring storm conditions to the southern North Sea with gusts around 80kts.

http://www.tropicaltidbits.com/

 

[fergieweather]

GloSea5 in good broad agreement with latest EC Monthly with prevalence of W'rly regime through into early Dec, albeit retaining the +ve temp anomaly across UK slightly longer than EC. This reflects GloSea's resurrection of occasional SW'rly phases into turn of month, whereas EC runs-in a more direct W'ly /rPm. Nonetheless, both suites see temps ultimately return to around average by early Dec.

[marksiwnc]

Yes it is interesting (not that it will verify) but I find it interesting because as that nasty little depression deepens rapidly and zips down from northern Scotland into eastern Europe into would briefly bring storm conditions to the southern North Sea with gusts around 80kts.

http://www.tropicaltidbits.com/

But anything is possible when it comes to meteorology so verification could still happen, but I agree that it's only a slim chance.

[IDO]

As others have said the block to our east now looking like you can call it's demise between D8-10.

 

D10 charts (last night's ECM mean):

 

Looking at the state of the trop vortex now and at D16 it is easy to see why the slower than normal trend to reduce HLB and MLB will continue:

 

Now:  D16:

 

The AO index goes very positive in the next week so that transient northerly remains a possibility, before the AO slides towards its base:

 

 

 

So it is a case of a further sinking of the four wave pattern and where the PV sets up assuming it is not mobile. Looking at the GEFS the majority now have a more organised PV but no trend as to where it will move: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=384

 

So the end of the Autumn pattern IMO by mid month, and by the end of November we should have an idea how the PV will set up for December. Looking at the CFS monthlies and other longer term models,  a negative AO looks likely early to mid-December but at this range that is just conjecture.

 

 

[Frosty.]

Much better from a coldies point of view later on the Ecm 00z compared with the 12z last night with a cold unsettled end to the run with N'ly winds, both the gfs and ecm 00z show rather colder w'ly/nw'ly winds later next week, occasionally cold enough for sleet / snow on high ground further north...I know it's only early november but it's about time coldies had something to look forward to following a very mild autumn so far!.  

[BLAST FROM THE PAST]

Similar picture this morning with ensembles showing a noticeable cool down in FI.

P 5,8 and 10 are probably the picks though the last frame of p20 would be quite exciting. 

 

 

If only. 

 

That's not outlandish Mucka imo, I think models continue the theme overall for midmonth onwards change, I do agree that no 2010 is coming but some of the stormy colder shots with have some potency if not long lived....and I think some severe weather warnings will get issued. 

 

 

BFTP

Edited November 6, 2015 by BLAST FROM THE PAST

[carinthian]

Hi Nick thanks for your analysis there, I always like to read. As much as I hate the ECM slug pellet charts for you lot and continued snow drought in the Alpine Region, I do think their present prog is the best route to cold. The high could easily retrogress NW ( post 240hours )  allowing the colder flow down the eastern flank, especially for my location. As you mention the very cold air now developing in the high Arctic could be locked up there with GFS still holding west to east block over Europe with the lows forming to the SW and joining the conveyer belt.

C

 

Further to my post yesterday  to Nick F, I hope the ECM is on to something. This is sure the best route to breaking this long mild spell throughout Europe.

C

Edited November 6, 2015 by carinthian

[knocker]

I'm not exactly sure what the ecm is supposed to be based on one chart at T240 but the EPS mean MSLP anomaly at T360 has LP to the NW and HP to the SW with a westerly airstream that also fits all of the other available evidence. The 500mb anomaly for the same time has ridge Greenland and trough east of Scandinavia and also a flat zonal flow bringing some unsettled weather (but not Too) to the UK with average temps.

Edited November 6, 2015 by knocker

[Nick F]

Further to my post yesterday  to Nick F, I hope the ECM is on to something. This is sure the best route to breaking this long mild spell throughout Europe.

Recm2401.gif

C

 

Morning Carinthian, nice to see these cold charts whilst in the midst of an exceptionally mild spell here in the sarf of England - 18-19C not out the question next few days. Could really do with something more seasonal to remind us that it's not still early autumn!

 

But can't help think ECM deter maybe a 'lone-wolf' now GFS has lost interest and the general signal from the ensembles and the wider pattern evident upstream - i.e. the flow is quite progressive upstream thanks to a strong trough over Alaska driving a strong Pacific jet in across N America. However, there does appear to be some waves in this flow upstream developing some amplitude, and as 00z ECM shows, if one of these can amplify and slow as it moves off the eastern seaboard, then we could see a ridge thrown up mid-Atlantic.

 

Difficult, though, to have any faith in day 10 verifying, ECM or GFS.

Edited November 6, 2015 by Nick F

[carinthian]

Further to my post yesterday  to Nick F, I hope the ECM is on to something. This is sure the best route to breaking this long mild spell throughout Europe.

Recm2401.gif

C

Several runs from ECM have shown a cut off of the westerly with warm air advection in Mid Atlantic towards Greenland. This would allow a rise in pressure to the west of the UK and allowing a route for the cold incursion down the eastern flank. Obviously very different thoughts to GFS. I would think the UKMO would not support the Europe charts at this stage but maybe one to watch for a possible speedy development. Will be talking with our snow portal service later with views on latest ECM outputs ( aka snow forecasting prospects for Eastern Alps ).

C

[Ravelin]

But can't help think ECM deter maybe a 'lone-wolf' now GFS has lost interest and the general signal from the ensembles and the wider pattern evident upstream - i.e. the flow is quite progressive upstream thanks to a strong trough over Alaska driving a strong Pacific jet in across N America. However, there does appear to be some waves in this flow upstream developing some amplitude, and as 00z ECM shows, if one of these can amplify and slow as it moves off the eastern seaboard, then we could see a ridge thrown up mid-Atlantic.

 

 

Have we not seen this before, the GFS sniffing around at something at long range, dropping it, then picking it back up again at a closer time-frame a day or two later? Or is my memory going?

 

Difficult, though, to have any faith in day 10 verifying, ECM or GFS.

 

I'd agree, but there is around a 1 in 3 or 4 chance if the stats are to be believed. Anyway, I think it's the general pattern that's important. If the models keep throwing up similar scenarios then even if they aren't exactly correct it might at least indicate that something is afoot. I'm not expecting sustained cold but, for Scotland at least, it's not that unusual to have a transitory snowfall in November.

[Nick F]

Have we not seen this before, the GFS sniffing around at something at long range, dropping it, then picking it back up again at a closer time-frame a day or two later? Or is my memory going?

 

 

No, it does happen with GFS, though equally it may pick up with a cold evolution for several operational runs before dropping it and not returning to it when it picks up newer and newer data that draws it on to a different evolution.

 

One thing with GFS, I find, is that can consistently stick with one theme at the end of the medium range and beyond for several runs, say day 8-10 onwards, before changing to a different theme and sticking with that. But that doesn't mean it's often more right. Whilst ECM seems to chop and change more run to run in that 8-10 day timeframe. Not a scientific observation, but one I've noticed over the years at times.

Edited November 6, 2015 by Nick F

[bobbydog]

today's star prize in the raffle-

[The PIT]

Models performing pretty well out to day 6. Interesting too see how much ukmo has improved over the years at times out performing the ECM. So close these days little to chose between them.

[Ravelin]

Quite different overall but both the ECM 0z and the GFS 6Z have high pressure in the Atlantic and around Greenland at day 10 ....

 

 

 

And the GFS then goes on to develop it's common, intermittent theme of recent days.....

 

 

Even if ultimately it's not accurate, it's persistent in trying.

Edited November 6, 2015 by Ravelin

[london and south east kent]

Hi still looking good for cold mid November onwards trending in the right Direction will the ecm start to see this in next few days .

HI ALL ECM IS COMING IN LINE WHAT GFS WAS SHOWING GETTING COOLER COLDER MID NOVEMBER ONWADS WILL THE METO UPDATE THIS

[knocker]

HI ALL ECM IS COMING IN LINE WHAT GFS WAS SHOWING GETTING COOLER COLDER MID NOVEMBER ONWADS WILL THE METO UPDATE THIS

 

They already have unless you want a twice daily update. Plus you have Fergie's earlier post.

 

UK Outlook for Friday 20 Nov 2015 to Friday 4 Dec 2015:

The second half of November and start of December are likely to be characterised by a north-south split in the weather. The north is likely to see periods of wet and windy weather with a risk of gales at times, although some drier spells are likely too. The south will probably have the greatest amount of dry and fine weather, but even here some rain will pass through at times. Temperatures will generally be around average, although there could be some cold nights where skies become clear leading to a risk of frost and fog.

 

Updated at: 0133 on Fri 06 Nov 2015

Edited November 6, 2015 by knocker