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Model output discussion - 20th Feb onwards

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12 minutes ago, John Badrick said:

So the complete opposite to what we all thought the effects of the SSW would bring

I don't know about that, all I know is it's a very good result for those of us who wanted a marked pattern change to a settled spell following months of atlantic dross!:D

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Looking nice and settled for a week or 2 at least.   Im not complaining here!!

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3 hours ago, Frosty. said:

The Ecm 00z ensemble mean looks rock solid anticyclonic until towards the end when cracks start to appear but for those of us looking forward to a benign settled period with variable cloud and pleasantly warm sunny spells with light winds, the next 7-10 days are looking good.:)

 

beer-garden-01.jpg

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1 hour ago, John Badrick said:

So the complete opposite to what we all thought the effects of the SSW would bring

Quote

In a previous blog we talked about the current Sudden Stratospheric Warming (SSW) and this is linked to the weather we can expect over the next week or so.

The High pressure that is currently pushing into the North Atlantic is a common outcome from an SSW Warming event. This will then bring an easterly air flow to the south through next week.

When an SSW occurs in the middle of winter it often leads to a cold snap for the UK. As it is occurring in the middle of March it means many will see some fine weather with some decent temperatures, especially in the best of the sunshine towards the north.

http://blog.metoffice.gov.uk/2016/03/11/high-pressure-keeping-things-mostly-settled/

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5C downgrade on temps for next weekend on GFS 12, temps look around average with maybe slightly below average temps mid next week as we start to pull in cooler cloudier easterlies, nights and mornings remaining very chilly, hardly what you call decent temps in mid March when mid to late teens are achievable.

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Just not buying this from the current GFS 12z run, the high is retrograde right up to the moment the model starts to move into FI land and then the GFS sends it back east and packs in the zonals (just like its been doing for the past couple of runs)...yet we've seen time and again how the GFS over eggs any continental cold being displaced by the Atlantic only to correct at a later. I really think they're struggling with the SSW migration down through the atmosphere.

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h850t850eu.png h850t850eu.png

Who would bet from the left-hand chart (for +144 hours) against the low remaining cut-off in the mid-Atlantic as opposed to linking with the jet and then shoving its way through the ridge to the NE, as shown in the right-hand chart (for +192 hours)?

Go down the UKMO route to +144, however, and there's no way the low is going to flatten the ridge. Just look at the negative tilt to it:

UW144-21.GIF?11-18

It's also getting pulled further west by interaction with another low leaving the U.S.

I should think the safe bet is for the high to stick around near/over the UK rather than give way to low pressure. An import of very cold air from the east remains possible, but unless the models are wrong about the SSW hitting some kind of barrier in the lower stratosphere (see recent Recretos posts in strat. thread), that outcome is no longer looking to be among the most likely.

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gem-0-192.png?12    gem-0-240.png?12

Whilst it is the GEM, I personally buy it more than the GFS eastwards solution at the moment and fits in with remain ECM operations, we will see whether the 12z replicates this.

I still see no reason to back away from a prolonged settled spell continuing towards the end of the month. No real blowtorch or cold looks likely either with temperatures near normal, these varying depending on the orientation of the high and whether we can pull some milder air in from the south.

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The GEM 12z is a cracker with high pressure generally centred over the uk, much better than the Gfs 12z. Hopefully we are in for a prolonged settled spell with plenty of pleasantly warm sunshine.:)

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MY LATEST REPORT UPDATED WITH MARCH 11TH 2016 INPUT

Will We See A Strong SSW Impact?

If anything, as we draw closer to the (previously) widely anticipated surface impacts of the current stratospheric warming event (seemingly about 9 or days 10 days away) there is even greater uncertainty. I bracketed “previously” as there is some question now over whether the strong stratospheric reversal will fully propagate down through the troposphere and will it impact at the surface or not? Even if it does, the experts seem to be divided as to whether the impacts will be anything like as far reaching compared to a mid-Winter SSW event or, now that we are well into meteorological Spring, will the effects be far less, briefer or even insignificant.

For now, I will remain in the “greater impact” camp and expect to see significant broader pattern changes with much more meridional pressure patterns and at least some decent HLB. In fact, I still have a strong hunch that we will see a prolonged pattern change with considerable HLB which will deliver at least a period of cold conditions but accepting that a similar pattern might produce a warm up later on if it continued through to mid-April. So, perhaps, several weeks of cold (or even very cold at times) conditions at the wrong time of year for many. On the other hand, if the SSW fails to reach the surface, then we are likely to stay much closer to the climatological norm – which for the Spring season often sees a much weaker and meandering jet stream and rather less zonal weather anyway. Any colder spells (northerlies or easterlies), however, would probably be pretty short-lived as would any warmer (more southerly) spells.  

All this speculation can probably cease within about 2 weeks as we should know the likely outcome by then.

The Models Today:

I do not believe that the current high pressure in our neck of the woods will simply meander around the UK for days or weeks on end, although it is effectively a mid-latitude block. Any HLB is highly likely to become the more dominant feature later on. A few of the charts in the 6 -10 day period show strong heights over Greenland, a few show heights rising strongly over the high Arctic and a few show them over Scandinavia. Our high could link up with any of these. If Judah Cohen’s predictions are broadly accurate, then we should see the polar vortex lobes moving down into Europe and particularly into Siberia. A few of the models have hinted at this from time to time but then swung away from that. There is still no decisive trend one way or another.

Most of the recent GFS runs have shown far less blocking than they did two days ago. Like some others on this thread, I simply do not believe the GFS’s much more zonal outcome. It not only ignores the possible impacts of the SSW but also, even without the SSW, it would be an unusual early Spring pattern for such an extended zonal period.

The UKMO 12z T+144 does show a movement of the polar vortex away from NE Canada and moving across towards NE Europe and also Siberia. How they develop that from there is not certain but you can move through the previous charts up to that period. The European lobe may be too far east to impact on us. Their T+144 in 3 days’ time might be interesting.

UKMO Northern Hemisphere Pressure 11th March, 2016 12z T+144:

http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=72&nh=1&archive=0

The GEM shows this more strongly by around T+192 and develops both lobes further but still retain a small lobe over N E Canada and then move away from that pattern to some extent by the end of their run.

GEM Northern Hemisphere Pressure 11th March, 2016 12z T+192:

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=192&mode=0&carte=1

Update:  The ECM 12z has just finished rolling out ( March 11th):  Rather like a cross between UKMO and GEM. They try to develop that European lobe but it is a little too far east. At T+144 to T+192 but they have another go at T+240 They also retain some of the lobe in NE Canada but weaken it and move it towards the pole. I note strong heights over the North Pole. Overall, they are getting much closer to the European lobe but no strong Siberian lobe. Room for further changes and developments.

ECM Northern Hemisphere Pressure 11th March, 2016 12z T+240:

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&type=0&archive=0

AO Ensemble Charts: 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml

Very mixed again with the 11 ensemble members all over the place between today (March 11th) and in the next 14 days (to March 25th in the top panel). All are slightly positive today and return to neutral on March 16th. Then 9 go slightly negative on March 17th with the other 2 staying positive thereafter. Then 3 ensemble members go temporarily positive again (for 1 to 2 days) before going negative again. The others stay negative, some more strongly. By March 25th we end up with 3 ensembles members quite strongly positive, 1 neutral and the other 6 in negative territory, with 3 of these going sharply negative. The 7 day mean chart (2nd panel to March 17th) shows the AO around neutral. The 14 day mean chart (4th panel to March 25th) shows the trend broadly between neutral and very slightly negative.

All this just reflects the extreme uncertainty of how strongly the SSW will impact in the lower troposphere and at the surface. The NOAA AO index may trend more negative indicating greater HLB but might stay neutral or even trend positive indicating little or no blocking. I feel that if we could see the individual ensemble members for the NOAA mean 8-14 day anomaly charts, that they would also reflect this uncertain mix. I believe that this is a very rare occasion when “mean” charts do not really help us and we need something much more decisive with the main pattern either changing to something much more meridional with strong HLB or going back to weak zonality for a while.

MJO Ensemble charts:

Here are todays MJO ensemble charts for the big 3 (now 4) and Kyle MacRitchie’s for March 11th. 

UKMO  http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml

ECM:   http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml

NCEP/GEFS:    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml

JMA:  http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml

Kyle MacRitchie:  http://www.kylemacritchie.com/real-time-maps/realtime-mjo/

UKMO: Slight changes today. They entered circle of death yesterday and moved out into phase 3 today and on into phase 4 by March 13th at very lower amplitude. Then they progress on towards phase 5 by March 21st with a wider spread of ensemble members with some going for rather higher amplitude – so not as dead as the last few runs

ECM:  Very similar to UKMO initially up to March 20th/20th. Then, with their longer forecast period they progress steadily through phase 5, with many members at decent amplitude and on into phases 6 around March 22nd but with a wide ensemble spread. Several members re-enter the circle of death but the majority show much higher amplitude. Then after 2 weeks by (March 25th) 2 members make it to phase 7 at good amplitude) but several others seem to stall..

NCEP/GEFS: Continue to take quite a different view which is almost unchanged to yesterday’s forecast.  All the ensemble members have entered the circle of death today and most stall there. Several stray members re=emerge at several points (phases 3, 4, 5 & 7 but at very low amplitude).

JMA:  After several days in phase 2 all the ensemble members stall in the circle of death, some already have. This is what GloSea5 showed 4 days ago – please can Fergie provide another update.

Kyle MacRitchie:  There is very little change with his continued consistency and much more positive view. He still retains good amplitude throughout. He shows the MJO still in mid phase 8 today and on into phase 1 tomorrow and then on to phase 2 around March 16th (as yesterday). All 4 of his ensemble members progress all the way though phases 3, 4, 5 and 6 between about March 21st and April 4th (slightly slower than yesterday) and then on towards phase 8 around April 11th  at high amplitude.

I still wonder if Kyle MacRitchie is on to something or is he completely wrong, continuing to defy the big 4 and GloSea5? I have spent some time trying to find good verification statistics for comparing the big 4 to Kyle but this search has proved fruitless so far. Please can a fellow poster point me in the right direction – if there is one! 

Current Arctic Temperatures:

GFS – Northern Hemisphere Current Temperatures:

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=9&carte=1

The link to this chart updates 6 hourly with each GFS run. At the time of writing it is showing a chart for 1900 today (Friday, 11th March***). As this is T0 to T6 hours, it should be pretty accurate. In the Arctic, temperatures around the North Pole are around -28c to -32c (-32c yesterday). In “our” part of the high Arctic (around the Barents Sea) temperatures are still much higher around -4c to -12c– (around 0c to -8c yesterday). Most of Scandinavia is around -4c to -12c (as yesterday) and much of northern Siberia is currently around -32c to -40c (slightly colder than yesterday’s -28c to -40c and rather more widespread deeper cold)..

*** Please note:   At the time of posting this link it was showing 1900 on Thursday, March 11th. The charts are automatically updated 4 times a day, so the temperatures shown will be different to those I just mentioned above. We can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/nighttime variations. So for like for like comparisons, for example the 1900 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 or about 4 hours later. This also applies to some of the other charts I link to in this post.

Svalbard “Maximum” Temperature Forecast:

Here are the links to the 3 Svalbard stations that I am monitoring.

Central Svalbard – Longyearbyen 28 m asl:

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf

March 14th  -5c;   March 17th  -12c;    March 20th  -11c.

West Svalbard – Ny-Alesund:                                                            

http://www.yr.no/place/Norway/Svalbard/Ny-%C3%85lesund/forecast.pdf

March 14th  -5c;   March 17th  -12c;    March 20th  -16c.

South Svalbard – Sveagruva:                                          

http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf

March 14th  -7c;   March 17th  -14c;    March 20th  -18c.

The overall trend remains downwards.

These links will update automatically several times a day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at short range. 

To put the above figures into context, here is a link to the main Longyearbyen site:  

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html

This shows monthly means, and actual highest/lowest temperatures recorded during this winter and goes back further. Apart from a couple of days in December, Svalbard is likely to see temperatures falling to average and then below, for the first time since Winter 2014/15

Final Comment:

Overall today, it is again very difficult to say whether we are trending colder or not. Some of the latest models look to be going for some mid-term HLB with a possible European lobe developing and a more definite Siberian lobe.  The forecast Svalbard temperatures are indicating some very cold air shifting into that part of the Arctic our side of the North Pole. So, some of the signs are there. Impossible to say in which direction we will go from here. It remains very exciting to follow all of this. More tomorrow.

 

Edited by Guest
ensure links all working + grammar, spelling

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ECM at day 7.

 

Cold air will be very close to the UK in the next few frames.

 

ECH1-168.GIF.thumb.png.5a3184999f53b1c12

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Which ever model run you look at the  next week looks high pressure dominated.

The Atlantic fronts currently giving rain and unsettled weather to parts of Scotland,N.Ireland and N.England gradually weakening and retreating by early next week. 

fax72s.thumb.gif.c00a381e2c4b7f1fdbc0155

as Cloud 10 has noted maybe the se quarter seeing some chillier continental air as an easterly picks up.

ECM0-120.thumb.gif.2ac98a1706ae8a05fb797

 

We do look like entering quite a long dry period though which i guess is a blessing for many of us.

A lot of the country should see some sunny breaks but day to day cloud amounts will no doubt vary and we will be chasing these around through the week.Pretty normal temps in the sun away from the cooler se and in light winds feeling quite decent i would think but clear spells at night will permit some frosts and locally fog patches.

 

 

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Spring delayed in southern Europe but great news for anyone going skiing, the flow mainly from the east/ne and some further snow possible.

The conditions across most resorts are excellent, here the Pyrenees have stunning skiing with lots of new snow. Could be a fantastic Easter period if high pressure hangs onto the north.

For the UK dry for a good while yet, colder towards the east/se, frost likely in any overnight clear periods. The PV does set up over Scandi, it still looks a bit of a stalemate with the lack of block sufficiently north and orientated favourably to direct that deeper cold into the UK.

I think we are seeing more signs of the recent major SSW with the AO dropping sharply and with the PV to the east still impossible to totally rule out some of that cold getting into the UK.

 

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21 minutes ago, fat chad said:

I for one am now hoping for nice warm and pleasant sunny days from now until autumn...

 I'm hoping this anticyclonic spell delivers plenty of pleasantly warm early spring sunshine, however, I would still love to see a potent cold blast before it's too late, at least the SSW is to thank for the transition which is now taking place with the unsettled Atlantic dross being replaced by high pressure!:D

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6 minutes ago, nick sussex said:

Spring delayed in southern Europe but great news for anyone going skiing, the flow mainly from the east/ne and some further snow possible.

The conditions across most resorts are excellent, here the Pyrenees have stunning skiing with lots of new snow. Could be a fantastic Easter period if high pressure hangs onto the north.

For the UK dry for a good while yet, colder towards the east/se, frost likely in any overnight clear periods. The PV does set up over Scandi, it still looks a bit of a stalemate with the lack of block sufficiently north and orientated favourably to direct that deeper cold into the UK.

I think we are seeing more signs of the recent major SSW with the AO dropping sharply and with the PV to the east still impossible to totally rule out some of that cold getting into the UK.

 

Indeed some very conditions for the Alps.

Latest Ski Blog now out.

 

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41 minutes ago, Bring Back1962-63 said:

MY LATEST REPORT UPDATED WITH MARCH 11TH 2016 INPUT

Will We See A Strong SSW Impact?

Final Comment:

Overall today, it is again very difficult to say whether we are trending colder or not. Some of the latest models look to be going for some mid-term HLB with a possible European lobe developing and a more definite Siberian lobe.  The forecast Svalbard temperatures are indicating some very cold air shifting into that part of the Arctic our side of the North Pole. So, some of the signs are there. Impossible to say in which direction we will go from here. It remains very exciting to follow all of this. More tomorrow.

 

Sorry to partly quote your excellent comment.

Given the very cold temps around Svalbard forecast, it would be good now to get the Northerly over the UK.

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10 hours ago, Gibby said:

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 FRIDAY MAR 11TH 2016

 

Would you say the chances/possibilities of cold outbursts this March are bigger than last year? Chances of snow at easter?

Edited by phil nw.
Reduced quote size

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Excellent Ecm 12z if it's pleasant settled weather you are looking for, very much like the Gem 12z with high pressure centred over the uk for many days bringing good early spring conditions with variable cloud, spells of sunshine and generally light winds with chilly nights bringing a risk of frost and fog patches..this is just what the doctor ordered following month after month of gales and driving rain!:)

ecm500.096.png

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The GEFS anomalies tonight start making the transition from our resident high cell next weekend with the HP ridging into Iceland but this only a temporary feature as the Atlantic trough moves east and by day ten we have weak ridging over the UK with the trough to the SW and weak upper flow from WSW. Quite good with temps a little above average. The Russian trough still locked over NE Europe and weakening,

gefs_z500a_nh_41.thumb.png.6b3ed460ad4e1

Moving forward through the ext period the trough to the west weakens with zonality being the order of the day until another weak trough forms in the Atlantic moving east until the net result is a broad area of low pressure over NW Europe. With weak ridging south of Iceland the upper flow veers to the WNW  with temps around average.

gefs_z500a_nh_61.thumb.png.701ad37bca0cb

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Just looking at the overall NH trends in the latest runs and they all show the movement of a good chunk of the split pv heading towards the Siberian side by day 8/9 over the top of our High.I don't think we can rule out a chance we see the edge of that colder plunge especially further south and east-gefs/ecm op 

gensnh-21-1-192.pngECH0-192.GIF?11-0

It still doubtful though whether it comes to anything more as there are signs of further development of low heights over the Canadian side later on.

gensnh-21-1-300.pnggensnh-21-5-300.png

so week 2 promising a less settled outlook with pressure falling across the UK and more of a westerly influence again.

 

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LOL just realized my glaring mistake, sorry guys, Ecm 12z charts from yesterday...I blame model fatigue:crazy:

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Latest Ecm 12z showing plenty of high pressure and also colder air arriving, the day 10 chart looks interesting for coldies, again, apologies for posting obsolete charts...I will try harder in future!:whistling::D

Recm721.gif

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I have hinted at this before, sometimes clumsily :closedeyes:,but whenever we hear the word SSW, all the normal rules here go out the window, e.g "keep to the models" and "anything beyond day 6 is FI". Instead we look forward to long fetch easterlies or artic blasts whose time frame extends into the far distance.

A look at the current strat thread shows just how tentative our understanding of SSWs and their effect on weather is. Even the current Met quote posted by Knocker seems a bit bold to me. Never the less given the knowledge and enthusiasm of the strat posters and with a lot of us still hungry for cold and snow, doubtless we will be at it again next winter..:)

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First to note is tonight's NOAA 6-10 is very similar to the GEFS. With the LP to the SW and a warm SW flow.

610day.03.thumb.gif.29892f7b479914c6b415

The ecm is not quite as quick to break down the HP and intruce some influence from the LP to the SW by day ten.

ecm_eps_z500a_nh_11.thumb.png.ed30063454

But during the ext EPS period it eventually does and goes zonal before introducing a trough in the western Atlantic courtesy the Canadian vortex whilst at the same time weakening the NE trough and forming a general area of low pressure over NW Europe. The combination of all this produces a W upper flow, possible a little S of W, giving periods of unsettled weather with temps a tad below normal.

The upshot of all this is although NW Europe is in the cooler air it's not that cold. The nearest shot for that is probably Mexico  with their deep upper low.

I feel a song by Leah West coming on.

 

Edited by knocker

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