Model Output Discussion 12z 01/06/13

[Milhouse]

Some decent warmth making its way into southern England by the end of the week and into the weekend.

 

 

The 6z has things turning more unsettled thereafter. However the ensemble means from the ECM and GEFS are encouraging.

[nitro_deluxe]

Another step towards the first 80f of the year - some cracking charts for those seeking a little warmth.Higher chance of a thundery plume type event as those higher values push North out of Spain/France. Could see a classic set up

[johnholmes]

Beat me to it Phil,

 

The GFS and ECM ensemble means looking remarkably similar to one another today at day 10:

 

 

We can also view them as height anomalies here:

 

 

As Phil says, you would describe such an upper pattern as more 'unsettled' or showery as opposed to full on cyclogenesis.

 

The 11-15 day GEFS mean offers a continuation of this setup:

 

 

Bearing in mind this is of course a height anomaly chart, whilst the significant feature initially looks to be the positive anomaly to the North-East, the real story for me is the lowering of heights through the Eastern Atlantic, meaning that lower pressure will never be too far away from the North-West of the UK, and is likely to see a continuation of the showery type setup.

 

Though it should be noted we are still seeing a fairly considerable swing between even ensemble means on the final position of the longwave pattern at present. It's good to see a little continuity between suites this morning, and hopefully we can carry this forward and start to get a more stable outlook from medium range NWP.

 

SK

I would agree with both phil and sk in their caution with the anomaly models seeming, not all that similar in some aspects, but overall they suggest the upper ridge giving the mainly fine settled weather prior to the upper trough to the south coming north, and the 6-15 day outlook to me looks more unsettled than settled and possibly a reversion on the cool side. The output this morning from ECMWF and GFS is an indicator, rather earlier than NOAA is currently suggesting of this pattern developing. Do not take too much notice of the +/-ve areas those not used to trying to analyse these types of charts but simply look at the 'black' lines indicating the upper air pattern. From that you can see that the upper flow is governed largely by the upper low and not the upper ridge, the direction giving mainl Pm (Polar Maritime) type air.

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Edited June 2, 2013 by johnholmes

[Frosty.]

A very interesting Gfs 06z op run this morning, generally fine, warm and sunny in the week ahead but just for a time there is a risk of cooler weather with mist/low cloud rolling in across eastern counties bordering the north sea but it's only a risk, however, this only lasts a day or two before the position of the high changes and the wind direction backs from NEly to NWly so it warms up and becomes sunnier again but also an increasing risk of heavy showers breaking out across the south and perhaps torrential downpours being imported from the channel islands towards the end of the week, the odd heavy shower elsewhere but most areas continuing fine, warm and sunny into next weekend. Early the following week the 6z becomes very unsettled across the south with heavy rain and briefly much cooler but drier further north, later on the azores anticyclone builds northeastwards across the uk with much warmer and more settled weather returning, crucially, we get high pressure just to the east and we even develop a spanish plume with temps into the high 70's and possibly into the low 80's for a time with very warm and humid air but the run ends with a bang, widespread thundery rain and storms with a trough over the top of the BI.

Edited June 2, 2013 by Frosty039

[AWD]

I would agree with both phil and sk in their caution with the anomaly models seeming, not all that similar in some aspects, but overall they suggest the upper ridge giving the mainly fine settled weather prior to the upper trough to the south coming north, and the 6-15 day outlook to me looks more unsettled than settled and possibly a reversion on the cool side. The output this morning from ECMWF and GFS is an indicator, rather earlier than NOAA is currently suggesting of this pattern developing. Do not take too much notice of the +/-ve areas those not used to trying to analyse these types of charts but simply look at the 'black' lines indicating the upper air pattern. From that you can see that the upper flow is governed largely by the upper low and not the upper ridge, the direction giving mainl Pm (Polar Maritime) type air.

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Thanks for that John. Something I didn't really consider when analysing these type of charts, but something I will look at in future analysis now.

Seems they have turned to a more unsettled theme compared to the overnight versions which I posted earlier this morning. Will be interesting to see future output and what consistency it can generate though.

[rmc1987]

http://www.meteociel.fr/modeles/gefs_cartes.php?code=16&ech=192&carte=&mode=0

morning all just had a look in to fantasy world things could get a bit hot here in the uk if fantasy world right might be able to keep the heating off at last!!!

If only, if only

[Backtrack]

Beat me to it Phil,

 

The GFS and ECM ensemble means looking remarkably similar to one another today at day 10:

 

 

We can also view them as height anomalies here:

 

 

 

As Phil says, you would describe such an upper pattern as more 'unsettled' or showery as opposed to full on cyclogenesis.

 

The 11-15 day GEFS mean offers a continuation of this setup:

 

 

 

Bearing in mind this is of course a height anomaly chart, whilst the significant feature initially looks to be the positive anomaly to the North-East, the real story for me is the lowering of heights through the Eastern Atlantic, meaning that lower pressure will never be too far away from the North-West of the UK, and is likely to see a continuation of the showery type setup.

 

Though it should be noted we are still seeing a fairly considerable swing between even ensemble means on the final position of the longwave pattern at present. It's good to see a little continuity between suites this morning, and hopefully we can carry this forward and start to get a more stable outlook from medium range NWP.

 

SK

 

So would I be right in thinking that a NW-SE split is likely to develop at some point during week 2, the lower pressure giving cloudier, cooler conditions to the NW, where as the SE being more high pressure influence are offered a more settled regime?

[049balt]

There is a real possibility  that we will have a deep  low knocking on our door by the end of next week, the question is will it be diverted to the North or alternatively  will bring an end to the sunshine.

[Frosty.]

The latest met office update seems to be going in the same direction as the Ecm 00z operational run with an atlantic depression heading towards northwest scotland beyond the week ahead, there is also a dash of 6z in there too with heavy rain from northern france/channel islands  threatening southern england at the end of the week but the week ahead will be fine and pleasantly warm or rather warm with sunny periods but more cloud across northern britain with a few sharp showers here and there, next weekend should see the fine weather continue, bar the south of england where it could be wetter but then there is a risk we could be heading towards a cooler zonal atlantic pattern but the more likely outcome would be for a northwest-southeast split with northwestern britain becoming cooler, windier and more unsettled but for the azores high pressure to continue ridging in from the southwest across southeastern parts of the uk with the sunniest and warmest weather towards the southeast, in other words, normal summer conditions but with unseasonably cool seas around the uk, the likelihood is that from mid june we could be looking at a mixed weather pattern with no particular weather type dominating and temperatures close to average, no indication from the experts that any heatwaves are on the way, pleasantly warm seems to be as good as it gets for most.

Edited June 2, 2013 by Frosty039

[Tony27]

GFS was almost right again with the max temp predictions for my area, it predicted 16c and today it is 15.4c, it is a myth that it underdoes max temps, that used to be the case but not so much any more, it is also predicting a very chilly night tonight for the midlands with temps down to 1c or 2c, whilst the bbc shows temps of 7c or 8c, last night it got down to 5c here and the GFS predicted 5c and the bbc predicted 8c, so GFS was right again, i hope its not right about the temps for tonight as it could damage my crops, plus it is ridiculous that under these synoptics we can still get cold nights and its now june

Edited June 2, 2013 by Tony27

[mushymanrob]

GFS was almost right again with the max temp predictions for my area, it predicted 16c and today it is 15.4c, it is a myth that it underdoes max temps, that used to be the case but not so much any more, it is also predicting a very chilly night tonight for the midlands with temps down to 1c or 2c, whilst the bbc shows temps of 7c or 8c, last night it got down to 5c here and the GFS predicted 5c and the bbc predicted 8c, so GFS was right again, i hope its not right about the temps for tonight as it could damage my crops, plus it is ridiculous that under these synoptics we can still get cold nights and its now june

 

 

one correct call doesnt equate to every prediction being correct though... the gfs temp predictions are notoriously wrong quite frequently.

[Tony27]

one correct call doesnt equate to every prediction being correct though... the gfs temp predictions are notoriously wrong quite frequently.

i agree about min temps, but not max temps, anyway i can only judge for my area and with its max temps predictions it's not often wrong, min temps are wrong at times but other times like last night it is right, the UKMO always predicts high night time mins,  the bbc website is predicting 10c for my area tonight whilst GFS is predicting 4c, a silly difference when we are talking only 12 hours away, i'll make my own prediction and say it will be 7c so my crops should be fine

Edited June 2, 2013 by Tony27

[Summer Sun]

UKMO keeps the settled theme going into the weekend that would be the 3rd successive dry weekend if it happened

 

 

GFS for next Saturday suggests thundery showers in the south

 

 

Longer term we see a few days of lower pressure before we see another build of pressure

 

 

No heatwave is on the cards but its a dam sight better than 12 months ago with average temperatures for many

Edited June 2, 2013 by Gavin.

[johnholmes]

GFS was almost right again with the max temp predictions for my area, it predicted 16c and today it is 15.4c, it is a myth that it underdoes max temps, that used to be the case but not so much any more, it is also predicting a very chilly night tonight for the midlands with temps down to 1c or 2c, whilst the bbc shows temps of 7c or 8c, last night it got down to 5c here and the GFS predicted 5c and the bbc predicted 8c, so GFS was right again, i hope its not right about the temps for tonight as it could damage my crops, plus it is ridiculous that under these synoptics we can still get cold nights and its now june

that is an interesting comment Tony. I have to admit I have not checked how it is fairing for my area as I tend to use basic forecasting knowledge and do my own. But I will keep an eye on it for a few days and see how it does in a basically high pressure type pattern.Incidentally I would think 4C is a bit low but depending on any cloud cover and if the wind drops out light and variable then somewhere between 5 and 7C seems about right. Your local topograpghy will play quite a part in that, cold air drains down into valleys etc. Edited June 2, 2013 by johnholmes

[J10]

I must admit that my views on "warm and settled" not telling enough of the story are coloured by my many years of living near the Tyne and Wear coast.  In that area of the country, it isn't that unusual for warm settled spells with easterly winds to be generally overcast with the warmth stemming from high night-time minima, while conversely in changeable westerly and south-westerly types it sometimes ranks among the UK's sunniest regions.  I get the impression that in central and western parts of the UK "warm and settled" is more reliably associated with sunshine and high daytime maxima in spring and summer, with only rare exceptions such as the last week of August 2008.

 

I expect the above to be highly relevant to the upcoming spell of weather and I won't be surprised if, come the 10th June, many central and western parts of the country notch up sunshine aggregates close to 100 hours (about 50% above the long-term normal) while some eastern coastal spots remain short of the 20 hour mark.  The main question is whether or not the low cloud will frequently penetrate inland or whether it will readily burn back to the east coast. 

 

Tonight's ECMWF is more similar to the UKMO than the GFS which suggests to me that there is a general backtrack away from the stronger east to north-easterly flow and therefore more chance of negative maximum temperature and sunshine anomalies being largely confined to the east coast, with positive anomalies in most other areas.  The forecast synoptic evolution is still evolving though and I won't rule out further swings in either direction.  It is worth noting, incidentally, that the strength of any troughing from the south is also likely to be correlated with the strength of the easterlies and westward penetration of North Sea stratus, so the most anticyclonic/settled outcome with high pressure furthest south is also generally the most likely to have minimal low cloud.

 

I can fully understand the frustration caused by onshore winds giving damp and drizzly conditions, if often happens here, with SW winds, when it damp drizzly and misty here, and hot in other parts of the UK, You might have experienced that at your time at Exeter.

 

The worst case of this was in August 2003, a few days before I joined this forum. While much of SE England was having very hot weather, it was damp and drizzly here on the 6th August 2003, possibly the most frustrating weather ever, the following Saturday (9th August) was very warm here,

 

http://onlinelibrary.wiley.com/doi/10.1256/wea.10.04A/pdf

 

Going back to today's models

 

GFS - goes for a rinse and reload, it goes for the breakdown from the SE, with 3/4 unsettled days, before then re-establishing High pressure from the South west.

 

ECM - Interestingly this now continues the theme of the breakdown from the West, after being the first to go with the unsettled weather from the west.

 

UKMO - Keeps High pressure (largely) in control until the end of the run. Is the UKMO done to the same resolution to T+144, as is always looks clearer with less short waves etc.

[J10]

GFS was almost right again with the max temp predictions for my area, it predicted 16c and today it is 15.4c, it is a myth that it underdoes max temps, that used to be the case but not so much any more, it is also predicting a very chilly night tonight for the midlands with temps down to 1c or 2c, whilst the bbc shows temps of 7c or 8c, last night it got down to 5c here and the GFS predicted 5c and the bbc predicted 8c, so GFS was right again, i hope its not right about the temps for tonight as it could damage my crops, plus it is ridiculous that under these synoptics we can still get cold nights and its now june

 

GFS is worse around Coastal areas, it tends to overdo temps in winter, especially overnight temps, many times by over 5c, and it tends to underdo temps in summer but by a lesser amount.

[Frosty.]

The Gfs 12z op run only brings a partial temporary breakdown to the warm and generally settled pattern rather than the full on atlantic assault like the ecm 00z shows, the low which moves in from the west beyond the next week is a much shallower feature, it can't really be described as an atlantic depression and it only brings a short spell of rain to southern and western areas before high pressure begins to rebuild the current settled pattern. This coming week looks mainly dry and pleasantly warm with sunny periods and only isolated showers but the next few days look much duller across scotland despite there being an intensifying anticyclone migrating northwards through the uk, it looks much clearer and sunnier across the southern half of the uk, it becomes sunnier across scotland from about midweek onwards but with some heavy showers across the far northeast as a shallow trough drifts through northeast scotland later in the week. By friday, there is a threat of scattered heavy showers across southern england and south wales as pressure falls to the south of the uk, there is even a risk of thundery rain moving north from the channel islands to reach southern coastal counties of england later on friday or into saturday but most northern and central areas look fine and settled next weekend with a strong ridge of high pressure across the north. After that brief unsettled interlude early the following week, the Gfs 12z shows a warm anticyclonic spell taking us through to the end of the run with warm and fairly sunny weather across all parts of the uk, the north of the uk escapes all the persistent rain on this run and only has a few showers during the next couple of weeks.

[johnholmes]

I can fully understand the frustration caused by onshore winds giving damp and drizzly conditions, if often happens here, with SW winds, when it damp drizzly and misty here, and hot in other parts of the UK, You might have experienced that at your time at Exeter.

the difference bewteen damp and misty conditions in the areas prone to them is that the eastern areas are unpleasantly cold winter or summer when the wind is onshore. The exposed areas to the SW sure enough get the mist, low cloud, etc but NOT the biting cold that is a feature in the east. Trust me I've worked and lived in the SW and W areas so affected and worked and lived in the east. Give me the SW version any day! Edited June 2, 2013 by johnholmes

[Neilsouth]

Like today for example, feeling rather nippy this morning even though the sun was warm. Was fine in the afternoon but as soon as that sun starts lowering again and with the added wind off the north sea, it does not feel warm AT ALL. I'm hopeful that the wind direction isn't picking up from the north sea during this upcoming dry spell, but the models are not favourable. Unless we get a southerly to westerly you'll not be sun bathing half nakid on the beach.

[J10]

the difference bewteen damp and misty conditions in the areas prone to them is that the eastern areas are unpleasantly cold winter or summer when the wind is onshore. The exposed areas to the SW sure enough get the mist, low cloud, etc but NOT the biting cold that is a feature in the east. Trust me I've worked and lived in the SW and W areas so affected and worked and lived in the east. Give me the SW version any day!

 

It is bad enough in the west, so if it worse in the east, it must be really bad. Wouldn't wish it on anyone.

 

Thinking about it it does make total sense that an easterly on shore wind, would be cooler than a SW onshore wind.

Edited June 2, 2013 by Jackone

[Summer Sun]

Rather dry for many of us over the next 16 days according to GFS

 

[Methuselah]

It is bad enough in the west, so if it worse in the east, it must be really bad. Wouldn't wish it on anyone.

 

Thinking about it it does make total sense that an easterly on shore wind, would be cooler than a SW onshore wind.

Don't fret...haar haar...I'll get me coat...

[Summer Sun]

ECM is lining up a 3rd successive dry and warm weekend this evening

 

 

[049balt]

ECM is lining up a 3rd successive dry and warm weekend this evening

 

 

Monday 10  our low arrives.

Edited June 2, 2013 by 049balt

[Summer Sun]

Where has that low gone?

 

T192 onwards is when it was showing

 

t168 keeps us settled and warm for Sunday