Model Output Discussion 31/03/14 onwards.

[Gibby]

HERE IS THE LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM TODAY SATURDAY 10TH MAY 2014.

 

THE CURRENT GENERAL SITUATION. A strong Westerly flow will cover the UK today with a parent low moving slowly East across the North of the UK into the North Sea tonight and tomorrow.

 

GFS GFS shows High pressure building strongly across the UK through the middle of next week with some warm sunshine developing midweek, especially across the South. After several days of this settled warm weather cloudier conditions on SW winds never leaving the NW is shown to sink South across all areas next weekend as Low pressure re-establishes itself in the vicinity of the UK with cooler weather and rain at times. in the far reached of this mornings run there is some evidence of quieter warmer conditions returning as pressure rises again.

 

UKMO UKMO shows High pressure from Denmark to Southern England with sunny and warm conditions hanging on across Southern Britain. Cloudier weather further North seems to be showing signs of edging South towards the South later with some rain likely I would feel before the weekend.

 

GEM The GEM operational also shows a rise of pressure bringing warm and settled weather around the mid to latter part of next week before it too shows a propensity for Low pressure to edge down from the NW just to the west of the U|K with the threat of rain returning to many areas ever increasing next weekend.

 

NAVGEM NAVGEM also follows the GEM route with a fine few days later next week being eroded away from the NW as we move into next weekend with some rain moving SE.

 

ECM shows High pressure building across the South midweek before cloud and rain on deepening Low pressure slips down across the UK next weekend to bring wet and windy conditions alternating with sun and showers in blustery Westerly winds again as we move towards the second week.

 

MY THOUGHTS  All models support a brief but pleasant spell of dry, fine, warm and possibly sunny weather for a period between midweek and next weekend. However, all output suggests that this weather type comes under attack quite quickly from developments out to the NW as Low pressure looks like trundling down towards the UK with a return to rain at times in a strong and blustery Westerly flow. For a few days and principally in the South it could well feel like Summer in the South later next week but overall any long lasting and universal spell of Summer weather across the UK looks some way off  still this morning with the Atlantic continuing to show it holds sway with regard to the weather across the UK as we approach the end of Spring.

[Summer Sun]

Amazing how quickly ECM goes from high pressure to low pressure next weekend

 

 

Looking at the 00z GFS ens the low may not hang around too long

 

The low starts to move in later next weekend

 

 

By the Monday and Tuesday the low is over all the UK turning it cooler and more unsettled for all

 

 

By the Thursday hints are pressure starts to rise from the SW once more

 

 

24 hours later and the high is back

 

 

And the high then dominates to the end of the ens run at d16

 

 

So low pressure looks likely to return but it may not last all that long if the ens is onto something the pressure ensemble for London is supporting another rise around the 22nd

 

[Gibby]

Seems good agreement within the ensembles from ECM for a breakdown too next weekend and beyond.

 

http://www.wetterzentrale.de/pics/Reem1681.gif

 

http://www.wetterzentrale.de/pics/Reem1921.gif

 

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

 

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

[knocker]

Yes I was just looking at the EPS

 

[damianslaw]

I said a few days back - May like April is a very difficult month to predict weatherwise as we see the northern hemisphere move from its winter state to its summer state - hence we often see rapid swings and roundabouts from one extreme to another in a short space of space.

 

The models are suggesting another shift in conditions come next week, from the chilly windy unsettled conditions of now to something much drier and settled and warmer by mid week thanks to the influence of the azores high which is projected to ridge NE enabling a build of heights to develop over southern parts and pulling in a much warmer southerly flow, though not necessarily a sunny clear sky airstream. However, longer term, ominous signs that heights want to build rapidly over Greenland and north mid atlantic - never a good sign for anyone hoping for a sustained settled spell, the result is a couple of warm dry days before a quick return to very unsettled cool wet conditions from the NW by next weekend as heights are pulled away to the west, never having the chance to establish themselves properly.

[bluearmy]

Whilst the retrogression seems to be firming up into delivering another nw euro trough, it should be noted that over the past few runs, the establishment of a very strong w russian block has tended to push this trough further west over us. i am wondering about this block to our east. We have seen summer seasons in the past when this feature delivered a pretty miserable period to our shores. Much too early to make calls on this yet but it does throw up the possibilities of very different conditions for us, depending where in the amplification we end up sitting. thing to watch on this one in the near term is how far west the -NAO can be pushed. is it possible it could end up taking the trough to our west and delivering a more southerly flow ??

[phil nw.]

Whilst the retrogression seems to be firming up into delivering another nw euro trough, it should be noted that over the past few runs, the establishment of a very strong w russian block has tended to push this trough further west over us. i am wondering about this block to our east. We have seen summer seasons in the past when this feature delivered a pretty miserable period to our shores. Much too early to make calls on this yet but it does throw up the possibilities of very different conditions for us, depending where in the amplification we end up sitting. thing to watch on this one in the near term is how far west the -NAO can be pushed. is it possible it could end up taking the trough to our west and delivering a more southerly flow ??

You may have a point there Nick.

Signs in the later Naefs anomalies of such a possibility

http://modeles.meteociel.fr/modeles/gens/naefs/run/naefsnh-0-0-360.png?0

 

when we get retrogression of the pattern then the possibilty of a Russian block coming west to form a Scandinavian block is an option.

Certainly something to watch.

[knocker]

Hmm

Edited May 10, 2014 by knocker

[Sweatyman]

Hmm

please explain to a dummy like me? Ta!

[Chris K]

Hmm

 

Is this the latest one? Says this chart output was initialised on the 8th of May at the top and I am not sure how often these get updated?

[knocker]

please explain to a dummy like me? Ta!

 

Its the EPS 32 day 51-member ensemble. To be honest I'm not that conversant with it.

 

http://www.ecmwf.int/en/forecasts/tools-and-guidance/documentation-and-support/ecmwf-monthly-forecasting-system

Is this the latest one? Says this chart output was initialised on the 8th of May at the top and I am not sure how often these get updated?

 

It's the latest one I've seen. I'm not sure how often it's updated.

[Captain Shortwave]

GFS still going for retrogression

Still looks decent until next Sunday when it would turn cooler and more unsettled.

 

UKMO

Definitely more of a push north east from the Azores high

[Gael_Force]

Its the EPS 32 day 51-member ensemble. To be honest I'm not that conversant with it.

 

http://www.ecmwf.int/en/forecasts/tools-and-guidance/documentation-and-support/ecmwf-monthly-forecasting-system

 

It's the latest one I've seen. I'm not sure how often it's updated.

 

It is updatd at 00Z Monday and 00Z Thursday.

 

There is a temp/precip freebie for only one UK location (Glasgow) on Speedwell weather.  Select monthly then location from drop-down menu.

 

http://www.speedwellweather.com/Pages/Forecast/ForecastViewer.aspx

[Summer Sun]

850's continue to rise during next week temps will be close to average in NW Scotland but elsewhere it will gradually turn warmer with the SE possibly turning very warm for a time

 

[Frosty.]

The Gfs 12z op run appears to have forgotton about it's usual eastward bias and hopefully overdoes the retrogressing anticyclone in FI, amazing as it sounds, a bit more eastward movement to the pattern shown here would bring a risk of wintry ppn to more parts of the uk instead of just briefly to the scottish mountains. There is very good agreement for high pressure to build across the south of the uk later next week bringing fine and warmer weather, unfortunately scotland will probably be in a changeable sw'ly atlantic flow and miss the nice weather but then it's all eyes to the northwest with significantly lowering heights with low pressure swinging southeastwards and bringing a change to cooler or colder and very unsettled weather after the brief fine spell, the ecm 00z showed it and now the gfs 12z does too.

[Summer Sun]

ECM and UKMO look pretty close at t144 this evening

 

 

ECM goes on to give an unsettled weekend with things turning cooler and more unsettled for all

 

 

The new working week starts how the weekend ends unsettled

 

Edited May 10, 2014 by Summer Sun

[Frank Trough]

very poor outlook (unless you like cold and wet weather). Make the most of the few days next week, because if this is anywhere near correct you can forget the rest of May:

 

 

Breezy, cool, wet at times. Roll on "flaming june".

[bluearmy]

very poor outlook (unless you like cold and wet weather). Make the most of the few days next week, because if this is anywhere near correct you can forget the rest of May:

 

 

Breezy, cool, wet at times. Roll on "flaming june".

Even if that verified, i dont think you could write off the whole of the rest of may. probably until the 25th. given that we are looking at a decent spell trough this week, the trough could be seen as an interruption to a fine period rather than a write off of the remainder of the month.??

[Winter Cold]

To me, this 'spell' isnt worth getting excited about. I know its kept the forum moving this week in the usual deathly quiet summer period but isnt it just normal UK weather? A few fine days then the next low comes in?

Its still on the models tonight, so pretty good agreement this far out that its only a quick few days and then back to what weve got now:

 

[ANYWEATHER]

Looks more and more that the high pressure for next week unfortunately is being slowly eroded, just like the model predictions for cold weather. Looks like a few nice days next week at best!    

[Polar Maritime]

Yes High Pressure is certainly looking like only lasting a few days before it pushes N/W over Greenland, Bringing a Northerly flow of types.. Wet/Cool and unsettled seems to be the theme for Mid-Month from the GFS & ECMWF.

 

Edited May 10, 2014 by Polar Maritime

[Summer Sun]

GFS ens is still going for a pressure rise again from around the 23rd

 

 

Whilst the other models show low pressure in charge at t192 JMA has other ideas....

 

Edited May 10, 2014 by Summer Sun

[Polar Maritime]

Please stick to Model Output Discussion, For everything else there's always the Model Moaning/Banter thread http://forum.netweather.tv/topic/79882-model-banter-moans-and-ramps-springsummer-2014/

 

Thanks.

Edited May 10, 2014 by Polar Maritime

[East_England_Stormchaser91]

I'm not really too bothered even if May turns out to be a "write off" to be honest, because we have until late September really for sun and warmth and as Summer Sun said, there are hints from all the models that high pressure will try to move in later on in the month, so it is really too early in a way, to write off May just yet.

Exactly, and to be honest, its way too far out to be even calling a certain retrogression. There's been rogue runs that actually bring a shortwave to the South of Greenland and stopping the high from retrogressing. Anything over 90 hours out should be taken with caution. The idea could easily be binned off as quick as it started.

[Captain Shortwave]

Exactly, and to be honest, its way too far out to be even calling a certain retrogression. There's been rogue runs that actually bring a shortwave to the South of Greenland and stopping the high from retrogressing. Anything over 90 hours out should be taken with caution. The idea could easily be binned off as quick as it started.

To be honest whilst the ensemble means looks bad, only a couple of hundred mile shift westwards and suddenly a thoroughly wet and miserable pattern will become a warm and showery southerly.

At this far out there is still a lot that can change, first of all if the high is more reluctant to clear than first thought, and of course the Russian high could influence our weather from time to time.

Later on there are signs of the Atlantic high retrogressing yet again in response to heights building over the central states. This could allow things to relax and build heights more generally over Europe. Worth a watch. I wouldn't write the rest of May off yet, far from it.