Model Output Discussion - Heading Away From Easter

[Summer Sun]

Ridge of high pressure building once the low starts to clear away

[Captain Shortwave]

Ridge of high pressure building once the low starts to clear away

Azores high is then flattened as next low takes exactly the same path as the previous one, straight across the south of the UK. Nowhere else for it the go as there is a wedge of heights to the north.

[Stuie]

The thing is Gavin, who is to say the jet will actually go as far north as you're hoping? It's quite feasible we'll pull it north to our latitude and barrell lows at us for the foreseeable?

Considering the principles of warmer weather below the jet stream and colder above, this doesn`t look too fab.

Next week could be interesting, cold air, warmer air trying to break in, looks a mess.

EDIT:

The UKMO jet stream chart for tomorrow. Can somebody please give some insight into the speed please. I have not seen it at this speed before but I also have to say my viewing has been limited.

Edited April 2, 2013 by StuieW

[Captain Shortwave]

Considering the principles of warmer weather below the jet stream and colder above, this doesn`t look too fab.

Next week could be interesting, cold air, warmer air trying to break in, looks a mess.

Nothing interesting I'm afraid, this would be all rain affairs. Wouldn't like to stuck under the slow moving fronts associated with these lows. Very similar set up shown to last summer, low pressure crossing pretty much in-line with my house. Below average temperatures and wet.

[snowmadchrisuk]

main thing that has amazed me , is the length of time that we have been in an Easterly flow unyet so little Snow overall.

[Purga]

Nice surprise from ECM !!

Finishes with a decent cold swipe after a slightly milder phase - not warm though

That should keep the home fires burning a bit longer..

[Stuie]

Nothing interesting I'm afraid, this would be all rain affairs. Wouldn't like to stuck under the slow moving fronts associated with these lows. Very similar set up shown to last summer, low pressure crossing pretty much in-line with my house. Below average temperatures and wet.

A mess it is then.

[Captain Shortwave]

A mess it is then.

Good news for canoe makers

[Tim Bland]

Azores high is then flattened as next low takes exactly the same path as the previous one, straight across the south of the UK. Nowhere else for it the go as there is a wedge of heights to the north.

Looks suspiciously like a block to me. This keeps temps below average and with plenty of rain / showers and hill sleet around it won't be pleasant!

[Purga]

Will be interesting to see if

A The pattern does the familiar shift south in forthcoming runs

B The ECM trends towards the GFS easterly type solution after day 10

A fascinating evolution and still not a 100% done deal yet for the mildanistas brigade.

PS: Now who was it that was laughing at me this morning for posting NAVGEM charts that were showing pretty much what ECM has moved to now??

Edited April 2, 2013 by Purga

[Captain Shortwave]

Looks suspiciously like a block to me. This keeps temps below average and with plenty of rain / showers and hill sleet around it won't be pleasant!

I'm not surprised at all. I will go further and say temperatures will remain below average throughout the next 2 weeks at least. Blocking never goes away like the GFS was showing a few days back, and the route to mild from a Greenland high is a lot harder than a Scandi high. Both GFS and ECM develop an amplified pattern which shoots heights northwards later on and with residual heights to the north, all you do is maintain a southerly tracking jet or even rebuild a strong block again.

[chionomaniac]

I have been focussing on mid April onwards for a warmer more settled outlook being increasingly likely ( subject to the MJO/GWO) however it is worth pointing out that we have two weeks worth of weather first before we get there. And this intervening period we are likely to see an April Phase 4 MJO type scenario as suggested by the MJO forecasts:

http://www.cpc.ncep....clivar_wh.shtml

And the suggested H500 anomaly chart?

You guessed it - UK trough!

So we have some weather to get through first - phase 3 keeps the trough more to the west. The greater the amplitude of the MJO, the more emphatic the phase, so keep an eye on these forecasts!

Edited April 2, 2013 by chionomaniac

[stodge]

Evening all

A chance for me to peruse the 12Z operational output from the world of climate models:

http://modeles.meteociel.fr/modeles/gfs/runs/2013040212/gfs-0-144.png?12

GFS, as always, opens the batting and the kind of chart we haven't seen for a while with the Atlantic poised to take charge and the last embers of HP hanging on. This chart still says dry and settled but with the approaching LP set to bring wind and rain into the far NW. It's still cold though with perhaps no more than 6-8c on offer generally so nothing mild yet on this.

http://www.meteociel.fr/modeles/ecmwf/runs/2013040212/ECM1-144.GIF?02-0

ECM, as has been the case over the past few days, is more progressive but paints the future path for the GFS 12Z op as the Atlantic LP deepens and then moves across the UK presumably in response to ther southerly tracking jet. It would, I suspect, have already turned wet on this evolution (snow to higher elevations) and with the possibility of more spells of rain or showers and possibly strong winds to the SW.

http://www.meteociel.fr/ukmo/runs/2013040212/UW144-21.GIF?02-19

A traditional UK chart from almost anytime of the year. The south stays dry and settled while the North and especially the NW face wind and rain. There is more than a hint that the LP might yet dumb-bell south so this evolution might not be as far away from GFS/ECM as first appears.

http://www.meteociel.fr/modeles/jma/runs/2013040212/J144-21.GIF?02-12

A much slower evolution from JMA. The ridge from the Greenland HP is still holding on in the east but with a vigorous mid-Atlantic LP seemingly closing in. The trajectory of the LP looks quite far south but it's hgard to be definite about the evolution from there except that it looks likely to become more unsettled and possibly windier in the west.

http://modeles.meteociel.fr/modeles/gem/runs/2013040212/gem-0-144.png?12

A much more progressive evolution from GEM with unsettled conditions already in place across much of the UK although always drier to the south. It's possible the secondary LP further to the west will swing rapidly ESE and affect southern parts with a spell of heavy rain but that's conjecture.

http://modeles.meteociel.fr/modeles/navgem/runs/2013040212/navgem-0-144.png?02-18

NAVGEM is with JMA in the "slow evolution" camp. The remnants of the cold HP are hanging on and the milder air is still in the wings.

http://modeles.meteociel.fr/modeles/bom/runs/2013040212/bom-0-144.png?12

BOM looks even slower with HP firmly in charge though it's a milder scenario than we are currently witnessing with the re-oriented HP sourcing warmer air but it's a long way from the more progressive models.

So, we have a change on the way though NAVGEM/JMA/BOM are slow to bring it about. ECM and to an extent GFS hint at a transition to a very much more unsettled regime so, yes, warmer than now but very much more unsettled and snow to higher elevations cannot be ruled out. I can't see a transition to warm, dry, "springlike" (whatever that means) conditions without a period of more unsettled and potentially quite wet weather.

[No Balls Like Snow Balls]

Will be interesting to see if

A The pattern does the familiar shift south in forthcoming runs

B The ECM trends towards the GFS easterly type solution after day 10

A fascinating evolution and still not a 100% done deal yet for the mildanistas brigade.

PS: Now who was it that was laughing at me this morning for posting NAVGEM charts that were showing pretty much what ECM has moved to now??

In the reliable timeframe its going to be less cold and unsettled. Nothing particulary mild nor cold.

Day 10+ charts pretty much change with every run regardless of what model it is. I thought you might have noticed that as it is basic common sense when viewing models. A trend isn't 1 chart over 1 run on the last frame.

[Guest pjl20101]

The latest CPC output is in for 8-14 days time and looking like the high from the azores will extend further:

http://www.cpc.ncep.noaa.gov/products/predictions/814day/814day.03.gif

Gets better each time.

[johnholmes]

see in depth for update on my am issue

[Panayiotis]

Considering the principles of warmer weather below the jet stream and colder above, this doesn`t look too fab.

Next week could be interesting, cold air, warmer air trying to break in, looks a mess.

EDIT:

The UKMO jet stream chart for tomorrow. Can somebody please give some insight into the speed please. I have not seen it at this speed before but I also have to say my viewing has been limited.

Around 300km/h, it does seem a lot but not unheard of. Edited April 2, 2013 by Panayiotis

[Gibby]

Hi folks. Here is the report on the 12z output from GFS, UKMO, GEM and ECM for today Tuesday April 2nd 2013.

All models show the end in sight to the relentless spell of Easterly winds the UK have endured of late. In the short term though changes are slow with two or three more days of cold and windy weather, especially in the South where a few wintry showers are possible over the next few days as cloudier weather moves in. By the weekend the NE wind will finally give way to calmer conditions at the same time as daytime temperatures will be on the rise and it will feel much warmer early in the weekend than for some time. By Sunday the winds of change will be blowing in from off the Atlantic as wind and rain gradually moves East over Sunday.

GFS holds fine weather for rather longer keeping broadly dry conditions through Sunday and Monday as high pressure holds on to the South before fronts eventually make it into the UK on Tuesday with it's attendant Low pressure following on behind crossing the UK and away to the east midweek dragging in a colder Northerly phase again with showers late next week. FI then brings High pressure across the UK from the West and away to Scandinavia with several days of fine and dry weather with average temperatures in a cooling ESE wind. The High gives way then to more unsettled weather as Low pressure areas move ESE to the South of the UK with rain at times in the South and East with the driest but coolest conditions likely in the far NE with an onshore wind.

The GFS Ensembles show that the colder interlude later next week is unsupported with the general trend for milder conditions still very much in evidence on a more Westerly flow with a Jet Stream flowing near or over the UK. No huge amounts of rainfall are shown though with High pressure never far away.

The Jet Stream continues to show a movement North of the flow to latitudes close to that of the British Isles by a week or so time.

UKMO for the start of next week shows High pressure giving way close to SE Britain with cloud and some rain moving gently East early next week. Amounts of rain in the South and east may be small with temperatures steadily recovering towards normal values with far less risk of night frosts.

GEM tonight shows windy and unsettled weather developing early next week as low pressure areas cross NE close to NW Scotland with rain at times for all, heaviest in the North and West. Temperatures would recover to near normal.

ECM shows a disappointing start to next week with a deep Low pressure being progged further South run by run now allowing rather chilly and wet conditions early in the week gradually give way to more NE or North winds for a time later in the week with showers, wintry on hills as the Low crosses from SW England to Germany by Friday.

In summary we have the first signs of a wobble from the models tonight in the progress and extent of the milder weather still expected next week. Both GFS and more especially ECM show a Low cell transferring East through next week opening the door to a hopefully temporary Northerly phase of winds in the wake of the depression exiting East out of the UK. It will be interesting how the models handle this in the coming days as the extent of any spring mildness hinges on the movement of the depression early next week and how it interacts with the Jet stream and it's positioning over the Atlantic and Europe.

[Panayiotis]

Ye you're right guys no need commenting on the GFS 18Z! Zonal rubbish!

The CFS still hinting at a prolonged period of high pressure and warmer temperatures where 20C could easily be reached in the south after a couple of days of some rain cloud and warmer temperatures . It has been showing this since the 28th and I find when the 12z (I only look at the 12z) is consistent there is some truth behind it.

Period of low pressure (9th-14th):

http://modeles.meteo...fs-0-174.png?12

http://modeles.meteo...fs-0-216.png?12

http://modeles.meteo...fs-0-240.png?12

Period of high pressure (14th-26th):

http://modeles.meteo...fs-0-288.png?12

http://modeles.meteo...fs-0-336.png?12

http://modeles.meteo...fs-0-378.png?12

http://modeles.meteo...fs-0-456.png?12

http://modeles.meteo...fs-0-534.png?12

http://modeles.meteo...fs-0-564.png?12

http://modeles.meteo...fs-2-318.png?12

As this dry spell is forecast to go on another 5 days that makes it 14 days (as the dry spell started on the 25th) without or v.little rain, so if this period of high pressure does verify and depending on how much rain does fall later next week we could be looking at drought condtiond come the end of April.

Edited April 3, 2013 by Panayiotis

[CongletonHeat]

Ye youre right guys no need commenting on the GFS 18Z! Zonal rubbish!

Pub run seems to have gone a bit mental but I'd still take "zonal rubbish" over cold easterlies and snow showers every time.

[mike Meehan]

Ye you're right guys no need commenting on the GFS 18Z! Zonal rubbish!

The CFS still hinting at a prolonged period of high pressure and warmer temperatures where 20C could easily be reached in the south after a couple of days of some rain cloud and warmer temperatures . It has been showing this since the 28th and I find when the 12z (I only look at the 12z) is consistent there is some truth behind it.

Period of low pressure (9th-14th):

http://modeles.meteo...fs-0-174.png?12

http://modeles.meteo...fs-0-216.png?12

http://modeles.meteo...fs-0-240.png?12

Period of high pressure:

http://modeles.meteo...fs-0-288.png?12

http://modeles.meteo...fs-0-336.png?12

http://modeles.meteo...fs-0-378.png?12

http://modeles.meteo...fs-0-456.png?12

http://modeles.meteo...fs-0-534.png?12

http://modeles.meteo...fs-0-564.png?12

http://modeles.meteo...fs-2-318.png?12

If only

[CongletonHeat]

As this dry spell is forecast to go on another 5 days that makes it 14 days (as the dry spell started on the 25th) without or v.little rain, so if this period of high pressure does verify and depending on how much rain does fall later next week we could be looking at drought condtiond come the end of April.

Do you know what drought actually means? it takes months to reach that and we've had plenty of rain/snow to top up the reserves this year, fields are still flooded here, there is still groundwater flooding in the south east, reservoirs are almost full.

[Nigel Langton]

Perhaps it was said a little sarcastically. After all we do seem to go into drought very quickly these days. Onto the models, and there are hint in Fi that after a less cold unsettled period, High pressure could move up from the azores. Let's hope it's a pattern that verifys and inline with how our weather has evolved in recent years, it sticks with us for several months. Cold snowy winters and warm sunny summers, with so amazing thunderstorms - yes please.

[AWD]

Looks like the GFS Op is one to be sceptical of in FI this morning, going. From a cold member to a warm member and back cold again. Certainly would bring some topsy turvy weather;

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

well i must say when someone on here said a drought my eyes nearly popped out fields around here are still very wet and if you look deep into fantasy world we could get a blizzard in middle of April !!!