Model Output Discussion - 31/10/2014 and Beyond

[Man With Beard]

Blimey peeps...We'll be knee-deep in 'potential' by this time next week!  

If I interpret you correctly, I kind of agree with you - encouraging developments over the pole, but the reality in the next 10 days is we have a jet sharpening its teeth, and that could well continue into mid-November. To get really cold weather right now needs some very special synoptics - yes they do happen this time of year every so often but they require much more than a weak PV or a negative AO, they also need the shape of the PV to work in our favour, and at the moment that's actually quite some way from happening due to the strength of the jet. Give it another month and by then, the mere displacement of the PV will allow lots of other cold options, such as a moderate easterly or a back-edge north-westerly. I'm still seeing cooler, drier spells coming up this month but rain (not particularly stormy) is the first course for many this month.

[Cloud 10]

The ECM day 10 ensemble mean sums it up pretty well with the UK looking like some sort of meteorological sink hole for LP's dropping down from the North-West.

 

 

 

No sign of the PV getting its act together as yet.

[MR EXTREMES]

If I interpret you correctly, I kind of agree with you - encouraging developments over the pole, but the reality in the next 10 days is we have a jet sharpening its teeth, and that could well continue into mid-November. To get really cold weather right now needs some very special synoptics - yes they do happen this time of year every so often but they require much more than a weak PV or a negative AO, they also need the shape of the PV to work in our favour, and at the moment that's actually quite some way from happening due to the strength of the jet. Give it another month and by then, the mere displacement of the PV will allow lots of other cold options, such as a moderate easterly or a back-edge north-westerly. I'm still seeing cooler, drier spells coming up this month but rain (not particularly stormy) is the first course for many this month.

Absolutely agree but this is a slow progression and this has potential to really rock and roll the forum.

There is undoubtably going to be some mountain and hill snow in the north from time to time.

Although very exciting times with more autumnal feel to the weather through November there remains the threat of something colder still as the month progresses,

It's rare to see so many models all getting the idea of blocking !

But last year autumn was chaos with models throwing up blocks only for them to fail.

But all the background scenarios this year do seem to favour better chance of a wintry period.

[Methuselah]

Absolutely agree but this is a slow progression and this has potential to really rock and roll the forum.

There is undoubtably going to be some mountain and hill snow in the north from time to time.

Although very exciting times with more autumnal feel to the weather through November there remains the threat of something colder still as the month progresses,

It's rare to see so many models all getting the idea of blocking !

But last year autumn was chaos with models throwing up blocks only for them to fail.

But all the background scenarios this year do seem to favour better chance of a wintry period.

I think I'll remain sceptical until everything is primed, come December 15th?

[Polar Maritime]

Back to what the Models are showing please.

Many thanks, PM.

[summer blizzard]

GFS in the high resolution period ends on an unsettled but relatively cool note with a deep trough filling..

 

 

Well into FI and we get a pressure build to the north and then north east of the UK which while useless for snow would bring a good chill to many of us..

 

 

[Barry12]

 

Well into FI and we get a pressure build to the north and then north east of the UK which while useless for snow would bring a good chill to many of us..

 

 

 

The FI is from the 12z.

Edited November 1, 2014 by Barry95

[Barry12]

Wheres the pv?

 

Edited November 1, 2014 by Barry95

[shaky]

Wheres the pv?

 

somebody looking at those charts would think a pv doesn't exist!!lol the pv has been zapped up!!

[Mucka]

Plenty of interest in this morning charts.

 UKMO has gone back to pushing heights through Scandi and while the GFS 00z still has shortwaves running through that area it still builds pressure quickly behind but the parallel is sticking to lower pressure over the region around day 4. Comparisons UKMO, GFS, GFS (P)

 

 

 

Enough of that though because things are looking very interesting for blocking potential (I would go for a potential Scandi or Icelandic high from this UK chart for example)

 

 

And here is GFS for day 7, 

 

 

Not bad at all with plenty of promise (see, I didn't say potential)

 

And finally the parallel day 7

 

 

That ridge looks so promising doesn't it but it gets flattened. Even so it is hardly Atlantic dominated weather by the end of hi res.

 

 

I would wager ECM 10 day chart will look tasty later this morning. We have the chance of something wintry developing around mid month which is very different to last year.

 

[IDO]

The ECM run digs the trough to Iberia and sends the associated LP system onto the UK:

 

D9   850s around average: 

 

D10: 

 

Not a great set up for the UK and again its the US that will feel the cold with upper troughs dropping very cold uppers into Eastern conus areas.

The PV remains blistered on the ECM. Again like last year you need the luck and although early days its the US getting an early taste of Winter.

 

GEM is similar with the US getting an even colder flow at D10: 

 

Variations as to where the northern blocking is and how strong it is. ECM as usual, keener than the other models. For instance the GFS Parallel is rather tame compared to the ECM:

 

 It also fills the UK low in the trough quicker so a relatively slack setup around D8-12.

 

Be interesting to see in the next few days who is right and how the upgraded GFS handles the possibility or not of HLB.

 

 

[bluearmy]

I dislike over analysis of op charts post day 7 but would advise you to take a hemispheric view of the op runs through the first half of November. if you are seeing blobs of yellows, greens (or oranges) over the arctic then winter remains on course to be of interest for coldies. It's so rare for a decent wintry spell to happen in November that looking for one will undoubtedly return disappointment. However, the building blocks for something late in the month or into December can easily begin to show as we head through the modelling of the first half of the month.

from what I'm seeing of the NH modelling at the moment, coupled with further disruption to the strat vortex formation seeming likely via continued small warmings high up, I would wager that we may not have to wait until jan/feb to see snowfall.

The day 10 ECM NH view being a case in in point. even allowing for the bias for over amplification by the op run, it's pretty amazing for overall trend.

[knocker]

As mentioned by ido next weekend is the weekend of the low and average temps. In the longer term the anomaly for D10 has intensified heights Scandinavia, ridge Alaska and generally cool air from the N. America to the UK with a trough in eastern Atlantic. A somewhat complicated jet running south of the eastern trough. This results in a low pressure dominated Atlantic and at my pay grade I wouldn't like to predict the subsequent evolution of this pattern but the ECM is going for no significant change.

 

EDIT

Just seen Blue's post. THe ECM ops run. tagged on.

 

 

 

Edited November 2, 2014 by knocker

[Captain Shortwave]

Very unsettled ECM ens with a trough dominating just west of the UK with the UK in a cyclonic south to south westerly flow.

GFS probably the most positive this morning with respect to lower rainfall totals as the high to our East imposes more of an influence.

Though the ensembles tend to follow the ECM suite in keeping conditions unsettled.

[phil nw.]

A look at the ECM mean charts show plenty of warm anomalies over high latitudes but the unsettled spell looks like continuing for us.

We can see the troughing being squeezed se towards us in the overall pattern.

EDH101-168.gifEDH101-240 (1).gif

 

which means a fairly average Autumnal setup for now.

Two main areas for me for any height rises are to the east and over W.Canada.

I think the one area that may produce first is the Canadian heights which appear to have more pronounced warm air advection deep into the polar region.

Presently this isn't upwelliing sufficiently yet to disturb the pv greatly but this area continues to see ongoing +ve ht anomalies.  

 

Something i tried to highlight yesterday but BA has summed things up better!

Those 2 areas continue to show in week 2 with continued warm air advection towards the pole.

The ECM ht anom./means along with Naefs ht anom at T240hrs.

 

underlining the ongoing attack on the vortex.

At this early stage with the pv still cooling we shouldn't expect complete early disintegration but a better chance as Blue says of something maybe earlier than expected as we go into early Winter.

Meanwhile it's a waiting game as long as those lower heights to our north west continue to control  the Atlantic pattern.

[@actguk]

Hello to all...

 

A long term follower but my first ever post. (Sorry I am not a coldy, more of a windy).

 

I find the new GFS Parallel runs rather interesting & have been following for a few days now. While I understand this is still use with caution, it is worth noting how different the ops are when compared to the original GFS & other models.

 

Take for instance the track of the low due for the UK Thurs/Fri. The center of the low pressure system is just west of Ireland by Friday at 18:00hrs while the current GFS & other models have the low maybe a thousand miles away with a difference in pressure as well. I am suprised at such a difference and will follow the outcome with interest.

 

 

 

 

[johnholmes]

welcome to Net Wx or at least to posting, glad you found the courage to post as it can be quite daunting I am sure for the first post. So long since I cannot remember mine. Enjoy all available on here be it the forum or the data and forecast areas.

As you point out there are differences between the current operational model and the new one running in tandem. We all hope, as I am sure NOAA do that the newcomer is a big improvement and able to give ECMWF a run in the accuracy stakes.

Edited November 2, 2014 by johnholmes

[phil nw.]

Hello to all...

 

A long term follower but my first ever post. (Sorry I am not a coldy, more of a windy).

 

I find the new GFS Parallel runs rather interesting & have been following for a few days now. While I understand this is still use with caution, it is worth noting how different the ops are when compared to the original GFS & other models.

 

Take for instance the track of the low due for the UK Thurs/Fri. The center of the low pressure system is just west of Ireland by Friday at 18:00hrs while the current GFS & other models have the low maybe a thousand miles away with a difference in pressure as well. I am suprised at such a difference and will follow the outcome with interest.

Hi welcome aboard @actguk.

Yes whatever the the actual outcome the end of the week certainly looks wet and windy for many of us.

[johnholmes]

Something i tried to highlight yesterday but BA has summed things up better!

Those 2 areas continue to show in week 2 with continued warm air advection towards the pole.

The ECM ht anom./means along with Naefs ht anom at T240hrs.

EDH101-240 (2).gifnaefsnh-0-0-240 (1).pngEDH1-240.gif

 

underlining the ongoing attack on the vortex.

At this early stage with the pv still cooling we shouldn't expect complete early disintegration but a better chance as Blue says of something maybe earlier than expected as we go into early Winter.

Meanwhile it's a waiting game as long as those lower heights to our north west continue to control  the Atlantic pattern.

 

 

Yes you get the feeling looking at the various outputs when looking at the northern hemisphere range that the major trough/ridge pattern does seem to be setting up differently to how it has been for quite some time. All 3 of the anomaly charts I use daily do show some degree of meridionality developing. Whether this is being created by the +ve height anomaly that has been shown over the past 3 days on 6-10 and 8-14 outputs in the Alaska region I am not sure. One thing missing at the moment is the large +ve anomaly east of Russia/east Pacific area that was so often present during much of last winter.

Edited November 2, 2014 by johnholmes

[IDO]

It is interesting that the majority of the GEM and GFS ensemble members go for a much flatter pattern over the UK segment of the NH, giving D10 means of:

 

GEM    GFS mean:  

 

Have not got access to the ECM members but the mean is similar to the GFS: 

 

As expected the ECM op for heights over the the pole are extreme compared to the mean, by about +25hPa. Of course it could be its inherent bias or it may be picking up on something; more runs obviously needed, but without support from the GFS yet, including the GFS 06z op, that continues to remain less inclined to build HLB let alone charts like the ECM at the D8-D10 range, then caution advised on the ECM outlook:

 

 D14 GFS very flat NH flow: 

 

At the end of the GFS op run the core PV is in Eastern Siberia, which would in my opinion continue the upcoming pattern of a slack flow from the NW, of LP systems, stalling near the UK as the trough fills south/SE of us in Iberia. That should in time increase the PM flow, allowing transient cooler uppers to wash over the N/NW:

 

 

 

The parallel offers very little ECM like eye candy; similar to the GFS op but ending with the PV more on the Russian side: 

 

So still GFS offers little in the way of cold just run of the mill Autumnal stuff. Which model is correct?

 

 

 

 

 

[legritter]

Welcome  @ actguk ,we have plenty of followers reading our forums and its always good when we get some input from their first post .Net Weather i find is the most interesting around with plenty of posters sharing their knowledge in our many forums  .Charts and data today [so far ] shows some interesting autumn weather and at the far outlook we could see some early wintry weather turn up .things certainly look different this year with northern hemisphere Set up ,we all know how things can suddenly flip ,lets hope its an interesting flip ,I eagerly await this evenings charts ,cheers   

[ITSY]

 

Check out ptb 20 in this morning's ensembles! Now that gives us something to work with!

[knocker]

It has to be said GEFS isn't making a great deal of this. Except some above average temps.

Edited November 2, 2014 by knocker

[Paul]

I've knocked up a quick page which won't be widely publicised on the site, but thought it may be handy for those who follow the models, it allows a side-by-side comparison of the existing GFS and the parallel upgraded GFS. 

 

http://www.netweather.tv/index.cgi?action=gfscomp;sess=

 

It's only for a selection of timeslots, and chart types, plus only uses the 00z and 12z runs at the moment (I'll look at adding the 06z and 18z's next week), but hopefully it'll come in useful while the parallel is running.

[knocker]

Very neat Paul.