Model Output Discussion 18z 30/09/15

[Singularity]

 

The pattern here is more amplified than the 00z det. (jet buckling more sharply S. of Greenland and then heading more N than NNE), and 24 hours later the results become clear over Scandinavia with an impressive easterly for the time of year advancing west, later southwest:

 

 

Signs that if the Atlantic wakes up, it may have to beat down some blocking before it can reach the UK.

 

Looking at the GEFS 500mb height anomalies, we can clearly see the strong high near or just west of the UK, and also that trough to the south of it which is lendig support. Seeing such a small feature so clearly in the 6-10 day range (below-left) indicates particularly high confidence in the outcome. Notice also some weak +ve anomalies from Svalbard to Siberia - these are what look to be in with a chance of advancing west days 11-15. That is evident to some extent in the corresponding 11-15 day range GEFS anomalies (below-right).

 

 

...but the anomalies look too weak to have much confidence in the easterly across Scandinavia at this stage - let alone one reaching the UK.

 

p.s. JH, am I doing it right? 

[Ali1977]

 

The wind direction chart for the Netherlands shows how unpredictable the next few weeks are!!!

[carinthian]

Latest 12 run show little difference from UKMO and GFS at 144hrs with high centre located in Eastern Atlantic and low heights over Southern Europe. Post 10 days, the GFS on this run removes the European lower heights and cuts off the cold flow out from the east. Maybe, Euro run will show something different ?

C

Edited October 12, 2015 by carinthian

[Mucka]

 

 

Move along please, nothing to see here...

[Met4Cast]

 

 

Move along please, nothing to see here...

 

Really liking the fact that low pressure is trapped in the Scandi region thanks to that thin Arctic high. As long as we can keep the PV over the Canadian side and across Scandi we're going to be laughing come mid November. 

[IDO]

 

 

Move along please, nothing to see here...

 

 

Looking at the GEFS at the above time and very few now support the (probably over amplified) op:

 

Meteociel_-_Panel_GEFS.pdf

 

Further on as the mean shows, at D16 for example, the continued loss of heights over the UK remains a trend:

 

 

Not saying the op is wrong, but it does tend to get into a HP rut at times like this and especially as it is contrary to the clear pattern change amongst its ensembles.

 

For the south it looks like another two weeks of HP according to the mean, though after D10 there are now signs from the ensembles of a possible earlier shift to a more unsettled flow, and GEM moving in that direction as well:

 

D10:

 

This does tie in with the amplified CFS MJO signal:  

 

Phase 1 a gradual declining of heights; into phase 2, a more progressive zonal Atlantic (around the start of week 2 of November).

[knocker]

The GEFS anomalies are introducing a weak trough Greenland/Iceland area in the later period and flattening the flow so more zonal with the HP weakening and drifting south. Nothing dramatic and average temps It's been a cracking day here today. At this rate the yellow shoots will soon be a shooting.

http://www.tropicaltidbits.com/

 

 

[knocker]

It has to be said that NOAA is not going along with the GEFS scenario and retains the HP adjacent to the UK

 

[ANYWEATHER]

Evening All. The fine rather settled conditions,continue for the rest of the week into the weekend and into next week. Feeling rather cold too as some parts of Europe are seeing some of the coldest and earliest snowfall on record ,and  as the winds will be blowing in from that direction, its not surprising that temps will be surpresed!  Its nice to see something different brewing down the line at T+240 from the Ecm! Of course that's a long way a way, but a synoptic change will be very welcome from me by day 10.....      In My Opinion , at least its better than viewing last nights paint drying synpotics    

[Nouska]

Yes, it's a tad early for the old bones to be seeing accumulated snowfall charts getting this close to home.

 

[Mucka]

I really don't mind this quiet weather at all. It makes a nice change from wind and rain and as someone else pointed out is making for a lovely autumnal display.

I would rather it be HP dominated now than in Winter as well as frost and fog aren't really my thing, give me cold and snow or mild and dry.

There are some hints that we may begin to see a breakdown from the NW in the last week of October but even within many GFS ensembles that paint this picture it does not result in typical zonal conditions setting up - more a temporary breakdown with little sign of the PV getting organised.

 

ECM breakdown also looks fairly temporary but comes about with low pressure forming over the continent and retrograding West into the Atlantic before breaking down the HP and heading North.

 

So whether from the S or from the NW the high does look to come under some duress as we head toward last week of October but we are a very long way from calling a return to zonal as yet.

[Singularity]

Indeed Mucka, the ECM det. run has a very meridional jet stream at +240 with the possibility of low pressure becoming cut-off somewhere S or SW of the UK over the following couple of days.

 

It's a bit of a wild evolution from +192 to +240 really, as LP moves from just west of the Mediterranean to just west of the UK in the space of two days. There would be some unusually warm air to be experienced across the southeast in particular if that transpired - along with the potential for a lot of rain in a short space of time for a slice of the UK.

 

Meanwhile GEFS seem keen to keep those cut-off lows going anywhere from well SE of the UK to well SW, supporting a ridge in our vicinity for the foreseeable. There's still hints of higher heights extending toward Svalbard from Siberia, but they seem to be slipping away now having never been all that convincing to begin with.

 

 

In theory this tendency for trough disruption well west of the UK that deposits cut-off lows somewhere south of us has to come to an end at some point and it seems that the predicted MJO amplification ought to do the trick - assuming, of course, that the models are right about that development in that phase.

 

Strange things do happen sometimes though. The years of 1975-76 and, most of all in recorded history, 1921 managed to sustain high pressure near or over the UK for ridiculously long periods of time. I'm not saying I expect such things to happen this year, I hasten to add! Just that it's possible.

[knocker]

Latest EC32 update.

 

The anomaly analysis on the 23^rd  is ridging over the UK and Alaska over the Pole, LP Siberia,  troughs eastern Europe and Greenland running down mid Atlantic around into Spain.  Thus HP still in situ over the UK.

 

During the next week up  until 1^st November the HP over the UK gradually erodes Leaving low pressure to the NW and high pressure away to the south west and a more zonal flow under the influence of the LP.

 

From there on in until the 13^th November I think it’s fair to say low pressure and Atlantic domination.

 

Summary.

 

A slow transition from out current HP dominated weather staring around the 25^th  to a more zonal set up which progresses into a very influential Atlantic heralding, no doubt, some wet and possibly windy weather. Initially for a time prior to the transition the temps may well be a little above average but from then on around average.

Edited October 13, 2015 by knocker

[bluearmy]

Latest EC32 update.

 

The anomaly analysis on the 23^rd  is ridging over the UK and Alaska over the Pole, LP Siberia,  troughs eastern Europe and Greenland running down mid Atlantic around into Spain.  Thus HP still in situ over the UK.

 

During the next week up  until 1^st November the HP over the UK gradually erodes Leaving low pressure to the NW and high pressure away to the south west and a more zonal flow under the influence of the LP.

 

From there on in until the 13^th November I think it’s fair to say low pressure and Atlantic domination.

 

Summary.

 

A slow transition from out current HP dominated weather staring around the 25^th  to a more zonal set up which progresses into a very influential Atlantic heralding, no doubt, some wet and possibly windy weather. Initially for a time prior to the transition the temps may well be a little above average but from then on around average.

Yes knocks, whilst the mean upper flow has its usual smoothed out appearance over the Atlantic, those anomolys are stark with the Atlantic low becoming marked and stretching East to affect nw Europe by the time we get to bonfire night.

I wonder if this will be repeated on Tuesday and how the groupings look. The extended meto was talking about possibly settling down again early November. If that now gets dropped, then that's quite revealing.

[bluearmy]

Just looking at the Arctic profile of the ecm op at day 6/7 and its out of kilter with previous output and ens

I wouldn't advise spending any time extrapolating this run

[knocker]

The GEFS anomalies are certainly flattening the flow towards the end of the run and bringing the trough more into play accompanied by the Atlantic.

http://www.tropicaltidbits.com/

[MR EXTREMES]

ecm today looks barmy and really bullish pushing heights into europe im hiding behind the sofa please no uncle barty to ruin the party lol.

but in all fairness a massive flip after 12hours from the ecm.

although im finding it hard to which weather type i prefer at the moment  atlantic domination to switch up the weather patterns of what we have now with a gradual progression towards something like the gfs later runs.

still looks as if the cet for october wont be above.

 

but the ao tanking that would be nice but then this is only a reflection of one model be good if they had a combined ao index with input from all models and worked on percentages from each model to come up with an over all index.

 

although im not 100% sure how the ao indexs works but still looks nice but be gone tomorrow i excpect.

 

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON TUESDAY OCT 13TH 2015

 

THE CURRENT GENERAL SITUATION  A High pressure ridge remains extended across Scotland from the East with a cold NE flow across the South of Britain.

 

http://www.wetterzentrale.de/pics/Rtavn001.gif

 

CURRENT SNOW LYING UK AND NORTHERN HEMISPHERE There is currently no snow lying in the UK with the freezing level ranging from just over 8000ft across the far SW while nearer to 5000ft the further North and East one goes across the UK. The snow cover above 60 deg North continues to expand across mainland Russia and the States which extends to 55 deg North in western Russia.

 

http://www.snow-forecast.com/maps/dynamic/uk

 

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

 

MODELS-2 WEEK HEADLINE  Remaining mostly fine and settled with frost and fog patches at night and only very small chances of rain at times.

 

THE GFS JET STREAM FORECAST  The GFS Jet Stream Forecast shows the flow remaining positioned well to the NW of the UK for a considerable while yet before a slow trend to bring it further South later in the period when it becomes sharply undulating between 50-55 deg North.

 

http://www.netweather.tv/index.cgi?action=jetstream

 

GFS OPERATIONAL The GFS Operational Run today shows the weather continuing to be influenced by High pressure to the North and then NW with a chilly NE flow across the South and East of the UK in association with Low pressure across Southern Europe. Some showers are possible across the South-east. Then later in the period the High slips further South cutting off the chilly NE flow but opening the door to the NW for a surge of more unsettled and windy weather briefly with an equally chill North or NW flow for a time, especially over the North and East.

 

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

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif

 

THE GFS CONTROL The theme of the GFS Control Run is almost identical to the operational today ending the period back where we started with a ridge across the North of the UK with a cold NE flow across Southernmost Britain following a short period of windy and cold North or NW winds for all with showers, wintry on hills in the North.

 

http://www.meteociel.fr/modeles/gefs_cartes.php

 

THE GFS CLUSTERS(14 Days) The GFS Clusters in 14 days seem to endorse a 65/35 split in favour of something a little more unsettled likely by Day 14 with Low pressure to the North extending influence down across all areas with some wind and rain in a Westerly flow. there is still 35% of members that disagree with this outcome with fine weather from a ridge across the UK persisting.

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

 

UKMO UKMO today shows very little change in conditions synoptically in the coming week with High pressure remaining close to or over the North or NW while the cool NE or east flow persists across the South perhaps with the odd shower at times.

 

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

 

THE FAX CHARTS The Fax Charts this morning still show High pressure in control through the rest of this week. however, the pattern is not straightforward with fronts biting away at the edges of the ridge delivering occasional cloud and rain or showers to the Northern, Southern and particularly SE fringes of the UK.

 

http://www.weathercharts.org/ukmomslp.htm#t120

 

GEM GEM today shows High pressure across the North for another week at least while Southernmost Britain largely maintains a cool NE or East flow and with Low pressure persisting across Southern Europe enough influence from that could give the occasional shower in the extreme South at times. Towards the end of the run High pressure finally slips away to the East opening the door to fronts moving in from the West with some rain at times for many by Day 10.

 

http://www.wetterzentrale.de/pics/Rgem2401.gif

 

NAVGEM NAVGEM today is largely quite similar only differing in as much that High pressure slowly slips South to lie across the heart of the UK in a weeks time cutting off the cool NE flow from the South and delivering countrywide fine and settled weather with frost and fog night and morning likely becoming an issue.

 

http://www.wetterzentrale.de/pics/Rnvg1681.gif

 

ECM ECM this morning shows very slow changes in the next week with the same pattern of quiet and settled weather for many with frost and fog patches night and morning in the North and rather more cloud and a chilly easterly breeze across the South at times with just a few showers. This run then shows High pressure sinking slowly South across the UK later next week with fine and quiet weather in the South with frost and fog patches more likely here while the North slowly becomes breezier and more changeable but milder with the risk of some rain late next week.

 

http://www.wetterzentrale.de/pics/Recm2401.gif

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last night shows High pressure having moved out into the North Sea but maintaining largely fine and settled weather across the UK at that time.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS There remains little evidence to support anything other than fine weather under High pressure continuing across the UK for some considerable while again this morning.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM leading UKMO at 99.6 pts to 99.5 pts with GFS closely behind at 99.4 pts.  At 3 days ECM is leading with 97.4 pts to UKMO's 97.3 pts while GFS lags behind at 96.4 pts. At 5 days ECM leads with 88.5 pts to UKMO at 87.9 pts then GFS at 85.3 pts. Then at 8 Days ECM still leads at 57.4 pts over GFS's 50.3 pts. Finally at Day 10 ECM leads GFS at 35.7 pts to 30.2 pts.

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png

 

MY THOUGHTS   There is still sound support for few changes in the weather over the period of most of the forecast output this morning. A large blocking belt of High pressure from Eastern Europe remains positioned over the North of the UK. While there is a lot of fine weather for many due to this the far South remains afflicted by a cold and blustery NE flow in association with lower pressure over Southern Europe. This could give rise to a few showers here at times but help restrict the widespread mist, fog and frost that could be encountered here if winds were lighter. However, the North will see plenty of this as the synoptic pattern remains slow moving. It's not until later next week that signs of a slow move in the High is shown with the popular consensus being for it to drift slowly South across the UK which could bring the worst of any fog and frost issues further South as the cold NE flow finally decays at the same time as pressure falls over the North with an increasing threat of westerly breezes returning with occasional rain late in the period. It should also be mentioned that GFS seems attracted towards delivering a cold NW, North and then NE flow across the UK late in the run which could deliver some snowfall to Northern peaks and moors but all very speculative at such a range. So without any major shift towards a more unsettled and long lasting pattern shift within the next two weeks we can continue to enjoy largely pleasant weather given the time of year while those of us looking for day to day nuances have to keep focused on chasing areas of cloud or the odd shower and the extents of overnight mist, fogs and frosts rather than anything more disruptive to travel.

 

WORST CHART OF THE DAY 00z RUN

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=312&mode=0&carte=0

 

For the worse chart of the day I have chosen the 312hrs chart from the GFS Control Run which shows a deep Scandinavian Low pulling very strong and cold NNW winds down over all areas with plenty of showers, wintry on all high ground of the North and an eventual shift back towards better weather but with overnight sharp frosts for many.

 

BEST CHART OF THE DAY 00z RUN

 

http://www.meteociel.fr/modeles/navgeme_cartes.php?&ech=168&mode=0&carte=0

 

The best chart today goes to NAVGEM 1 week from today with High pressure shown locked over the heart of the UK which would deliver a continuation of fine weather for all but with probably much risk of overnight frost and fog patches.

 

Next update from 09:00 Wednesday Oct 14th 2015

[Met4Cast]

All these posts about the GFS flattening the flow towards the end of the run.

 

Doesn't the GFS do that on every run? It always defaults to zonal come FI, I don't know why this is a surprise to anyone still. Even more so when it comes to the GEFS anomaly charts, they're completely useless beyond 7 days generally.

Edited October 13, 2015 by Daniel Smith

[Man With Beard]

_{Some late October warmth showing up this morning:}

 

_{May yet see 20C  again reached if these models are close to the mark.}

 

_{Meanwhile, look how close the snow/cold gets to us this week - just a couple of hundred miles from Dover:}

 

[knocker]

All these posts about the GFS flattening the flow towards the end of the run.

 

Doesn't the GFS do that on every run? It always defaults to zonal come FI, I don't know why this is a surprise to anyone still. Even more so when it comes to the GEFS anomaly charts, they're completely useless beyond 7 days generally.

 

Well it's not only the GEFS. The ext ecm has the trough mid Atlantic with the trend towards the Atlantic taking a greater interest.

[Nouska]

Mean charts at +360 are too blended to be of much value but as people are discussing extended ECM on a paywalled site, here's a limited and localised view from IMO charts of the ECM. There's no direct link, sorry - all cached.

 

Z500   T850    MSLP 

[mountain shadow]

I would say a return of the Atlantic is looking increasingly likely in the 8-14 day range, as IDO has pointed out, this has been well modelled in the extended charts for a while.

 

No sign of a rampant PV though.

[Mucka]

I would say a return of the Atlantic is looking increasingly likely in the 8-14 day range, as IDO has pointed out, this has been well modelled in the extended charts for a while.

 

No sign of a rampant PV though.

 

I agree. We are not seeing a breakdown being consistently modeled at all but we are seeing the models want to have pressure decline over the UK as we head into last week of October.

Currently it is too far away to know exactly how that will develop or whether it will be temporary but we are seeing the first signs of the PV organising around Greenland and a flatter Jet through Canada as we lose the Alaskan/Canadian ridge

 

 

 

 

However there are also signs that the jet will only power up temporarily and the anomalies my return although this does go against our usual autumn trend and descent into a more unsettled regime.

Even the ECM day 10 chart which may look like it is returning to flatter zonal at first glance actually looks like it is about to drop a trough into Scandinavia and amplify the pattern behind again building an Atlantic ridge.

 

Probably best to keep an an eye on the 14 day anomaly charts for the next few days to see if they begin to rebuild anomalous heights in the Atlantic to determine whether any breakdown will lead to typical November fare or be more temporary in nature.

Edited October 13, 2015 by Mucka

[nick sussex]

The GFS and ECM have failed miserably in their extended outputs. Both were  overamplified towards day ten and have since flattened things out with the high meandering around further south.

 

Signs towards day ten that the Atlantic might start eroding the high with more unsettled conditions and lower heights developing towards the north and nw.

 

We'll have to wait and see whether this is on the right track but both the ECM and GFS recent outputs should be a warning to snow and cold lovers of their bias, last winter the ECM took first prize for overamplifying and the GFS seems to not want to be overshadowed going by its recent outputs.