Model Output Discussion - 10th Jan Onwards

[Cecil Hogmanay Melchett]

Enjoy the ECM whilst you can as the easterly will be gone tommorrow and it will be agreeing with the GFS.

I must admit the ecm 12z has left me gobsmacked but it wont be the first time a model has picked up on a signal and the others have followed.

Its a huge leap of faith in view of the GEFS/UKMO/MOGREPS/METO OUTLOOK/BBC Mothly outlook though so im not getting my hopes up thats for sure.

[snowmadchrisuk]

Enjoy the ECM whilst you can as the easterly will be gone tommorrow and it will be agreeing with the GFS.

In the Weather world you have to forget the last failed Easterly and concentrate on what is happening now . It can not be the case because the ECM Easterly it shown for a couple of days last week didn't happen that it will be automatic be wrong again . People forget the GFS was also showing the Easterly for a few days as well. We have our initial condition's and the models are just moving the jigsaw around until it can agree on a likely way forward . 

[Stuie]

Well, for those who are a little sceptical of tonight`s ECM, here is a little comparison for 6 days time.

UKMO/ECM/JMA/GEFS

As we are basically looking at image output, spot the odd 1 out.

[cheshire snow]

I'm really trying to keep a lid on my excitement but its difficult after reading the prognostic discussions:

 

I'll just pull out the quotes that are important: 6 to 10 day

 

TODAY'S 500-HPA HEIGHT MANUAL BLEND REVEALS AN AMPLIFIED AND WELL-TELECONNECTED PATTERN ACROSS THE PACIFIC-NORTH AMERICA REGION, WITH DEEP TROUGHS SOUTH OF THE ALEUTIANS AND OVER THE EASTERN U.S., AND A RIDGE CENTERED ALONG THE WEST COAST. SUCH A PATTERN FAVORS NEAR- TO BELOW-NORMAL TEMPERATURES EAST OF THE MISSISSIPPI AND ABOVE-NORMAL TEMPERATURES ACROSS THE WESTERN CONUS. ANOMALOUS NORTHERLY FLOW ACROSS MOST OF THE CONUS FAVORS BELOW-MEDIAN PRECIPITATION ACROSS MUCH OF THE LOWER 48.

 

Confidence 5/5

 

And this almost had me breaking out into song!

 

8 to 14 day

 

TODAY'S WEEK-2 500-HPA HEIGHT MANUAL BLEND SUGGESTS A MORE AMPLIFIED PATTERN ACROSS THE CONUS THAN IN THE 6-10 DAY PERIOD; THIS IS A RARE OCCURRENCE, CONSIDERING THE AMPLITUDE OF THE PATTERN IN THE 6-10 DAY PERIOD AND THE USUAL INCREASE IN MODEL UNCERTAINTY AT LONGER LEADS TIMES. THIS SUGGESTS A SUBSTANTIAL SUBSEASONAL CLIMATE EVENT IS FORECAST TO UNFOLD ACROSS THE CONUS, WITH THE MEAN 500-HPA RIDGE FORECAST TO RETURN TO WHAT HAS BEEN ITS FAVORED POSITION OVER THE PAST COUPLE OF MONTHS: THE FAR NORTHEASTERN PACIFIC. THE DAILY PROGRESSION OF BOTH THE GFS AND ECMWF ENSEMBLE MEANS FROM DAYS 10 TO 15 IS IMPRESSIVE, WITH THE HIGH-AMPLITUDE RIDGE/TROUGH SYSTEM FORECAST TO SLOWLY RETROGRADE.

 

Confidence 4/5 

 hi Nick

 

 Please could you Briefly explain the above in simple terms

 

 Thanks

 

 C.S

[nick sussex]

Given those thoughts from NCEP it does give an opportunity for the UK to get some colder weather, surely something must finally break through the UK's cold defences!

[swfc]

I'm really trying to keep a lid on my excitement but its difficult after reading the prognostic discussions:

 

I'll just pull out the quotes that are important: 6 to 10 day

 

TODAY'S 500-HPA HEIGHT MANUAL BLEND REVEALS AN AMPLIFIED AND WELL-TELECONNECTED PATTERN ACROSS THE PACIFIC-NORTH AMERICA REGION, WITH DEEP TROUGHS SOUTH OF THE ALEUTIANS AND OVER THE EASTERN U.S., AND A RIDGE CENTERED ALONG THE WEST COAST. SUCH A PATTERN FAVORS NEAR- TO BELOW-NORMAL TEMPERATURES EAST OF THE MISSISSIPPI AND ABOVE-NORMAL TEMPERATURES ACROSS THE WESTERN CONUS. ANOMALOUS NORTHERLY FLOW ACROSS MOST OF THE CONUS FAVORS BELOW-MEDIAN PRECIPITATION ACROSS MUCH OF THE LOWER 48.

 

Confidence 5/5

 

And this almost had me breaking out into song!

 

8 to 14 day

 

TODAY'S WEEK-2 500-HPA HEIGHT MANUAL BLEND SUGGESTS A MORE AMPLIFIED PATTERN ACROSS THE CONUS THAN IN THE 6-10 DAY PERIOD; THIS IS A RARE OCCURRENCE, CONSIDERING THE AMPLITUDE OF THE PATTERN IN THE 6-10 DAY PERIOD AND THE USUAL INCREASE IN MODEL UNCERTAINTY AT LONGER LEADS TIMES. THIS SUGGESTS A SUBSTANTIAL SUBSEASONAL CLIMATE EVENT IS FORECAST TO UNFOLD ACROSS THE CONUS, WITH THE MEAN 500-HPA RIDGE FORECAST TO RETURN TO WHAT HAS BEEN ITS FAVORED POSITION OVER THE PAST COUPLE OF MONTHS: THE FAR NORTHEASTERN PACIFIC. THE DAILY PROGRESSION OF BOTH THE GFS AND ECMWF ENSEMBLE MEANS FROM DAYS 10 TO 15 IS IMPRESSIVE, WITH THE HIGH-AMPLITUDE RIDGE/TROUGH SYSTEM FORECAST TO SLOWLY RETROGRADE.

 

Confidence 4/5 

Sorry nick but can you explain in laymens terms what that means,thanks

[nick sussex]

 hi Nick

 

 Please could you Briefly explain the above in simple terms

 

 Thanks

 

 C.S

An amplified, pattern in the USA is favourable for the UK to get some colder weather, its not a total guarantee but especially as they mention even more amplification going forward.

 

It should at least mean that energy or lets say low pressure will cut se rather than ne, as long as high pressure is sufficiently west then any energy coming off the PV chunk will head towards Iberia.

 

If you look at tonights ECM operational run that should give you a good idea as to what could happen if things go well, of course we've been here during the last week and seen what can go wrong so although its exciting news from upstream we have to sit tight and hope for the best!

Edited January 13, 2014 by nick sussex

[cheshire snow]

An amplified, pattern in the USA is favourable for the UK to get some colder weather, its not a total guarantee but especially as they mention even more amplification going forward.

 

It should at least mean that energy or lets say low pressure will cut se rather than ne, as long as high pressure is sufficiently west then any energy coming off the PV chunk will head towards Iberia.

 

 Thanks for explaining Nick,i am sure you have been told before,but you are a credit to this thread

 Learning all the time from experience posters like yourself

 

 C.S

[Bobby]

The ECM ens mean doesn't back up the OP very well, looking like an outlier

 

Mean:   Op:

(+192hrs)

[nick sussex]

 Thanks for explaining Nick,i am sure you have been told before,but you are a credit to this thread

 Learning all the time from experience posters like yourself

 

 C.S

Thanks thats very nice of you, its difficult sometimes because I try to keep objective but at heart I'm just a kid who loves snow!

[phil nw.]

Hi Phil

 

Little to add what I said earlier - the ECM operational represents to me about the very best possible scenario we can squeeze out of the pattern at the moment. And a result like this would be a highly impressive bonus for sure.

 

My head tells me its too far west with the pattern, and for the time being at least under the current background circumstances it is once again overdoing the amplification - and hence why I said we best not have too high expectations, but my heart is telling me very different things !!

Yes a fair point of view Tamara.

 

My general thoughts are that the push back west of that Scandi high looks a long shot with the proximity of the Greenland vortex, but that does look like weakening hence the reluctance of the models to move the UK trough further east.

I think that's a growing trend and therefore the block now looks more likely to hold firm where before it was being eased away se with comparative ease.

 

I can understand the reluctance of many to view the ECM with any confidence based on last week's stella runs but i do believe with the Atlantic continuing to weaken then a build of heights from the east becomes more and more believable with time.

 

A good sign of a push back from the ne high is the negatively tilted trough into Europe at t144-even on the more progressive GFS

http://www.wetterzentrale.de/pics/Rtavn1441.png

http://www.wetterzentrale.de/pics/Rukm1441.gif

http://www.wetterzentrale.de/pics/Recm1441.gif

If the low heights to our nw do recede then our trough will split apart and you can imagine a cut off Euro low pressure and that high building across to the north.

 

OK it may not be as clear cut as this in reality but if we recall the models a few runs back were showing the demise of that high by the weekend so things have moved the other way.

I think the trend in the modeling has swung back towards at least the block establishing and with time we could see this holding sway ala ECM.

 

I have just seen the ECM mean charts-very promising for coldies.

The return of the westerlies continues to be postponed.

[mcweather]

The ECM ens mean doesn't back up the OP very well, looking like an outlier

 

Mean:   Op:

(+192hrs)

 

or trendsetter of course

[nick sussex]

The ECM ens mean doesn't back up the OP very well, looking like an outlier

 

Mean:   Op:

(+192hrs)

I think you need to view that from the context of the early timeframe and where the trough is located, there are bound to be some solutions with a positive tilt to the troughing and this further east therefore you'll get a somewhat diluted mean.

 

Take a look at the ECM postage stamps, the ones that say no are likely to be the ones with the rounded low at T120hrs and this tilted positively and too far east, they will not produce cold, the elongated solutions with the troughing held back and at worst neutral tilt will probably say yes:

 

 

http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014011312!!/

[Cloud 10]

The ECM ens mean doesn't back up the OP very well, looking like an outlier

 

 

 

Was always going to be on the cold side,although not without limited support.

 

[Gibby]

Good evening. Here is tonight's review of the midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday January 13th 2014.

 

All models show a similar pattern with just small differences on specifics for the next 6-7 days. Low pressure remains the driving force of the UK weather over this period with tomorrow offering the best day's weather as a weak ridge crosses East over the UK. By Wednesday Low pressure sends troughs NE across the UK followed by further unsettled weather with rain or showers at times. With Low pressure becoming slack and slow moving over or close to the UK later in the week areas of rain and showers will be slow moving in lighter winds which while heavy and even thundery in places will affect only limited places with plenty of dry weather around too for some. Temperatures will be non problematic on the whole though some frost at night could develop under clear skies and light winds here and there.

 

GFS then shows next week with continuing changeable conditions with winds largely between West and NW bringing rain and showers at times with the heaviest rainfalls gradually transferring more towards the North and West with time. All this due to Low pressure areas continuing to cross East just to the North of the UK and sending associated rain bearing troughs across the nation with sunshine and showers in average temperatures.

 

The GFS Ensembles continue the very average levels that have become the norm for much of this Winter Season. With plenty of rainfall shown nationwide spread throughout the run the Atlantic flow of Low pressure and troughs remains stubbornly persistent for all parts of the UK hindering any chance of any major improvement in alleviating the water from flood plains anytime soon.

 

UKMO tonight ends it's run with a slack Westerly flow under Low pressure with some dry weather but also a fair chance of heavy showers or longer outbreaks of rain continuing to plague the UK with temperatures close to the average for mid January.

 

GEM maintains Low pressure close to or over the UK with rain and showers for all continuing throughout the run with some heavy rain at times and just brief drier spells from a transitory ridge early next week.

 

NAVGEM also shows deep Low pressure close to Southern Britain moving away slowly next week but maintaining showers or longer spells of rain in temperatures close to or a little below average.

 

ECM tonight shows a cold SE breeze developing early next week as Low pressure transfers position from being over the UK to slipping SE to the SW of the UK by midweek. Some heavy rain or showers is very likely for many before drier weather eases down from the North with frost by night becoming much more of an issue. By the end of the run slack Low pressure to the SW and equally slack High pressure to the North setting up something rather colder from the East with the risk of wintry showers in the South.

 

The ECM 9 and 10 Day Mean Charts continue the theme of this morning with the bias of members showing a UK based trough as the most likely scenario through the middle of next week with Low pressure to the NW through the UK to the Med and High pressure well to the SW and NE too far away to be of a direct influence to the UK.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

http://www.wetterzentrale.de/pics/Reem2401.gif

 

The Jet Stream forecast from GFS show the flow riding across the Atlantic and then turning SE to the SW of the UK then East across Southern Europe. This general pattern is maintained through the period of the output which is hardly surprising given the uniformity of conditions for the UK shown by tonight's model output.

 

In Summary tonight the weather remains very changeable with rain at times, some of which will be heavy and prolonged but with an equal mix of drier interludes shown by some charts too. Temperatures look like never straying far from the long term average for this time in Winter. ECM has thrown a curve ball with it's operational tonight enhancing the effects of rising pressure from the North and lower pressure to the South next week resulting in an Easterly flow and even the risk of a wintry shower or two should it verify.

Edited January 13, 2014 by Gibby

[Panayiotis]

An amplified, pattern in the USA is favourable for the UK to get some colder weather, its not a total guarantee but especially as they mention even more amplification going forward.

 

It should at least mean that energy or lets say low pressure will cut se rather than ne, as long as high pressure is sufficiently west then any energy coming off the PV chunk will head towards Iberia.

 

If you look at tonights ECM operational run that should give you a good idea as to what could happen if things go well, of course we've been here during the last week and seen what can go wrong so although its exciting news from upstream we have to sit tight and hope for the best!

Hi Nick, do you remember if there was support from the NCEP last week for this week failed easterly?

[bluearmy]

the ecm op is out of the range of the spreads beyond day 7. i have never known this to be the case and the op to be showing the same extent of its solution on the following run. awaiting the extended ens but what is noticeable is the amount of split jet headed se at day 10 which follows on from nick's noaa cpc post. so it looks like the op could be onto something but is likely too progressive on that run.

Hi Nick, do you remember if there was support from the NCEP last week for this week failed easterly?

 

yes there was on their mean charts

[Bobby]

Something more like the mean, which is not without promise, looks more likely than the OP though, a real longshot to be realistic?

 

The upper air temp mean for +192

 

[Grimsby Snow Lover]

Was always going to be on the cold side,although not without limited support.

...including the control for the bulk of the run. Edited January 13, 2014 by Grimsby Snow Lover

[Severe Siberian icy blast]

I think you need to view that from the context of the early timeframe and where the trough is located, there are bound to be some solutions with a positive tilt to the troughing and this further east therefore you'll get a somewhat diluted mean. Take a look at the ECM postage stamps, the ones that say no are likely to be the ones with the rounded low at T120hrs and this tilted positively and too far east, they will not produce cold, the elongated solutions with the troughing held back and at worst neutral tilt will probably say yes:  http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014011312!!/

Well those postage stamps are apart from probably 4 or 5 either negatively tilted or straight with a southerly air flow .so those straight troughs with the southerly winds must be more of a 50 50 split further down the line. With only some of those eventually digging southeastwards . Hence the dilluted mean. But saying that the mean doesnt look too bad to me. Definitely signs of an undercut in there.

[Djdazzle]

Surely at some point one of these mouth watering runs will prove to be correct? I agree that we have been led up the garden path many times, but that doesn't mean that this will be the case forever.

Having said that, like many others I fear that it will be gone on the next run.

[Stuie]

 Thanks for explaining Nick,i am sure you have been told before,but you are a credit to this thread

 Learning all the time from experience posters like yourself

 

 C.S

Totally agree Cheshire and not just Nick. I don`t want to start reeling off names in case I miss someone out but I am learning all the time too. 

 

Anyway, back to the beast from the east.... ;-)

[Summer Sun]

For now the ECM ensemble is not supporting the Op's 850's

 

Edited January 13, 2014 by Summer Sun

[Stuie]

For now the ECM ensemble is not supporting the Op's 850's

 

I think they back up well, very well, unless I am missing something obvious?

[bluearmy]

For now the ECM ensemble is not supporting the Op's 850's

 

 

 

 

and they never will at that range gavin.