Model Output Discussion 12z 03/04/13

[Milhouse]

ECM op at T+240 was on the cool side of the ensembles

 

Still pleasantly mild and Springlike. Do i detect some are seeing the blues and greens on the charts later on and overhyping the cold. Perhaps influenced by recent events.

[Summer Sun]

The ECM ensemble continues to point towards high pressure building later next week

 

 

Towards the end of the run the Op looks to be on the cooler side when compared to the ensemble run

 

 

Thanks Paul I have now sorted the Image issued out all you do is post 2 images together without hitting the enter button that way they go side by side

[Guest pjl20101]

I think the ECM is toying with us a bit with these northerlies and north westerlies as the output for CPC 8-14 day is arguing with the ECM suggestion as its pretty much the same as it was yesterday.

[summer blizzard]

GFS18z can best be described as warm but never really settled until the very end.

[Frosty.]

The main message from the models this morning is :-

 

Turning Milder

 

Spells of Rain

 

Gales in the West

 

Things slowly going downhill today with clouds thickening and rain spreading into the south and west as the day goes on, today the temps will only reach about 10c generally but perhaps 12c in the southwest and only 6-8c across northern britain, all areas eventually have a spell of rain, some of it heavy and with the strongest winds in the west and northwest. Tomorrow, the east and south of the uk will be in tropical maritime air so temps closer to 15c generally but in the east of east anglia with a mix of clouds and sun, the temps should reach 19c 66f and london looks warm at 18c but with more cloud, most of the uk look rather cloudy tomorrow with patchy rain. Next week the chart below sums things up, a northwest-southeast split, the north and west of the uk look like suffering under low pressure with lots of rain and occasionally strong winds with temps struggling to reach average, the south and east of the uk, especially further southeast look much milder with temps generally above average and locally warm in places with generally fine and dry weather but occasional rain can't be ruled out. Towards the end of next week even the north and west look like having a few fine days as pressure rises but with overnight frosts returning to the north but then turning unsettled again but the further south you are in the uk, the outlook is milder, drier and brighter with high pressure close by throughout.

[peterf]

Not a cloud in the sky after a peasouper to begin with,already upto 8.5c from a 2.5c min.

[ANYWEATHER]

Good morning folks! Well both ecm and gfs show broadly in one shape or form a changable and unsettled picture for all with some high winds picticularly for the North next week. All in all a typical spring like pattern with transcient ridges more likely in the south and with winds coming in from a westerly /southwesterly and even northwesterly typical temps for this time of year look likely! Frosts not that common in the days ahead but not oit of the equation though given any quiet, clear spells overnight! April showers here we come!

[johnholmes]

I think the ECM is toying with us a bit with these northerlies and north westerlies as the output for CPC 8-14 day is arguing with the ECM suggestion as its pretty much the same as it was yesterday.

Yes the 500mb anomaly charts are changing very little. There are differences between NOAA and the ECMWF-GFS outputs but not sufficiently large enough to raise any threat of a major change in upper air pattern at the moment.

Do you remember that the synoptic output from ECMWF does tend to show the emphasis on surface pattern not upper air patterns so care is needed when comparing these two different types of output?

[Frosty.]

Good news from the latest Gefs 00z mean, becoming anticyclonic and warmer for all areas beyond the week ahead with plenty of sunshine and light winds, eventually a possible humid thundery breakdown and then pressure slowly rising again, the charts further into FI lack definition but for the north and west which will be hit hard by atlantic lows in the next 5 days, the latest gefs mean will bring some cheer.

[Frosty.]

This morning's Ecm 00z operational continues to paint a rather more unsettled picture, especially for the north and west of the uk, nw britain in particular with only very brief respite from the strong winds and rain towards T+144 to 168 hours when pressure briefly becomes higher, then it's back to unsettled. Southern uk does best, a clear north/south divide across central areas next week with fine and warm weather further south but even the south having a cooler more unsettled blip later next week, around thurs/fri, then pressure rising again. Beyond that, the ecm 0z looks more unsettled for all, mildest in the south but cool to the north and west with strong winds, it's chalk and cheese compared to what the latest gefs mean is showing beyond the next seven days.

 

 

[Frosty.]

The Gfs 06z op run is trending more unsettled and is similar to the ecm 0z with atlantic lows making more inroads at times, the warmest, driest and brightest weather will be further south and east and the north and west remain generally unsettled throughout with just the occasional fine day, the northwest-southeast split is very much the pattern ahead and the south/se does look like being warm at times. I think a lot will depend on the impact of a blocking high to the east and whether it could force the lows further west/sw as the gefs 00z mean showed, we could still develop a spanish plume type flow beyond next week which the 6z hints at.

[SP1986]

I find the 6z in recent days to be clearly the coldest run of them all, I think in the past few days it's clearly been biased towards a cooler, more unsettled situation. Whether that make it more/less likely we can't really say at this point.

Edited April 13, 2013 by SP1986

[Frosty.]

The Gefs 06z mean is showing a nationwide anticyclonic spell by this time next week with a gradual warming trend as winds then become southerly to sely drawing very warm and increasingly humid air northwards from spain, there is then what looks like a thundery breakdown as a trough moves east followed by much cooler and more unsettled conditions from the northwest with showers and longer spells of rain, sometimes heavy and thundery, so, a less settled outlook than the gefs 00z mean showed, but with potentially very warm and humid weather for a while beyond next week.

Just for fun, the cfs indicates a prolonged anticyclonic spell in may.

Edited April 13, 2013 by Frosty039

[phil nw.]

The later frames of the last 3 runs of the NAEF`s Height anomalies hint of another pattern change towards the last week of April.

http://176.31.229.228/modeles/gens/naefs/run/naefsnh-0-0-300.png?12

it may turn cooler again with the jet coming back south with pressure higher to our north as the remains of the vortex drifts towards Alaska.

[johnholmes]

a long long way off phil, I'm not sure the NAEFS is as reliable as the NOAA 8-15 day output either. But we shall see.

Granted it would not take too much for the chart frosty shows above on the last chart

Edited April 13, 2013 by johnholmes

[Summer Sun]

The latest NAO is suggesting it will stay positive for the rest of the month which means pressure should be low over Greenland

 

[AWD]

a long long way off phil, I'm not sure the NAEFS is as reliable as the NOAA 8-15 day output either. But we shall see.

Granted it would not take too much for the chart frosty shows above on the last chart

A change to cooler conditions is also support by the EC 32 ens come months end;

So it's a scenario that has some support, but like you say, a long way off in terms of weather, with plenty of springlike weather to come over the next fortnight or so first.

[Cheshire Freeze]

A change to cooler conditions is also support by the EC 32 ens come months end;

image.jpgimage.jpg

So it's a scenario that has some support, but like you say, a long way off in terms of weather, with plenty of springlike weather to come over the next fortnight or so first.

 

Lorenzo did say last night that he wondered just how much spring we'd get. Having looked at some of the evidence over the last couple of days it doesn't seem unfeasible that we enter May draining the remnants of the Arctic cold towards our locale. Could be some late sharpish frosts if that is the case. I'm still expecting a more emphatic warm up as we progress through May however, as I suspect the wandering HP will become much more of a full time mid (rather than high) latitude feature.

 

The glosea4 model is in agreement with the CFS consensus in this respect

 

http://www.metoffice.gov.uk/images/prob_ensemble/20130401/2cat_20130401_mslp_months24_global_deter_public.png

 

Certainly most of the CFS runs I've witnessed have advocated a ML block somewhere around the UK at some point over the summer period.

 

The prospect of a much better high season (for the majority that want warmth) looms large.

 

P.S just for a bit of fun, I'm yet to see a CFS anomaly for November which doesn't have a +ve height anomaly somewhere between Scandi and Greenland. Not one run I've looked at over the past month has suggested anything other than this sort of scenario....

 

 

Rather impressive agreement at 7 months out!

 

 

Edited April 13, 2013 by CreweCold

[johnholmes]

A change to cooler conditions is also support by the EC 32 ens come months end;

image.jpgimage.jpg

So it's a scenario that has some support, but like you say, a long way off in terms of weather, with plenty of springlike weather to come over the next fortnight or so first.

those ec 32 outputs are fascinating. Do they give data for 500mb at all?

[Carlrg]

Have just looked through all the models on Metrociel Android and cannot see anything significant in terms of a decent warm up. We'll all be straw clutching and hoping for an Indian summer at this rate.

[Summer Sun]

UKMO is showing the potential for a settled end to next week nicely now

 

 

Same as GFS

 

 

 

ECM is a bit slower

 

Edited April 13, 2013 by Gavin.

[Frosty.]

An Anticyclone building in for next weekend across the south on the Gfs 12z, it may hold long enough to bring a fine and pleasant weekend to southern britain but turning unsettled further north after a brief fine interlude. Thereafter, the gfs 12z creates a more amplified upstream pattern with a few shots of polar maritime air with a mix of sunshine and showers with strong and cold westerly to nwly winds, the showers turning wintry on northern hills and frosts returning when the winds fall light and some of the synoptics in FI are a reminder of winter but there is no sting anymore, temps in the south still get to 13c. Next week shows the often mentioned northwest-southeast split, wet and windy nw, mainly fine and warmer se, mixed bag in the middle.

[Frosty.]

More mixed fortunes on tonight's ecm 12z, the nw of the BI always in the firing line for lows racing in off the atlantic because that is how the jet is setting itself up with nw britain in depression alley, much better story towards the south and southeast of the uk, almost summerlike at times in comparison with temps occasionally close to 65f but nearer 46-54f in northern britain for most of the next 10 days, even some wintryness returning to scottish high ground as cold fronts sweep through.

[Gibby]

Good evening folks. Here is the report of the 12z outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Saturday April 13th 2013.

 

All models show a breezy and changeable pattern of weather over the next 7 days. With a series of low pressures moving NE close to NW Scotland all areas are at risk of rain at times but with some drier spells too, these more likely across Southern and Eastern areas closest to High pressure trying to build from the South later in the week. With winds always blowing from between West and South it will stay mild with night time temperatures much higher than of late with some warm sunny spells in between the rainier interludes.

 

GFS then takes us through the second half of it's run with a quieter anticyclonic spell of weather for a few days especially in the South before a stronger Westerly flow sets up with a tight pressure gradient over the UK meaning windy and cooler conditions than this week with rain at times coming with some frequency in the North. Late in the second week and through the second weekend the weather would turn unsettled and rather cool everywhere although less windy as Low pressure digs further down across the UK from the North. Heavy showers and thunderstorms would become commonplace through each daytime with some chilly nights meaning the return of night frosts, especially but not exclusively in the North.

 

The GFS Ensembles show the mildness of the weekend slowly giving way to somewhat cooler conditions with time though never overly cold. The trend towards rather more rainfall than has been shown on previous runs continues I'm afraid with less chance of an injection of serious warmth or a plume from the South anytime in the output term.

 

The Jet Stream shows the flow continuing NE over the UK through the next week. however, late in the reliable timeframe it ridges much further north to Greenland and setting up a trough across the UK which could bring rather cool and unsettled conditions here should it verify.

 

UKMO on it's closing chart shows High pressure having built close to SW England with fine and dry weather over the UK to start next weekend with some decent sunny spells in temperatures close to average.

 

GEM shows a replica of UKMO building high pressure to the sw late next week and start of the weekend with a fine and pleasant spell for most.

 

NAVGEM, though a little slower does the same thing in developing High pressure to the SW and sliding it slowly East over the UK next weekend with a SE flow developing to start the new week. The weather would be fine and dry with warmer temperatures developing as we move into the new week.

 

ECM finally follows a similar track and at a similar timescale with High pressure building NE into the SW next weekend. However, it becomes a short-lived feature as Westerly winds following a trough moves in from the Atlantic in response to a deep low moving East to the North of Scotland.

 

In Summary the weather looks like being changeable through the next few weeks with some rain at times for all. There are signs of a build of pressure across Southern Britain early next weekend which looks a temporary feature before a westerly flow takes back control in week 2. GFS brings in some deep convective synoptics in Week 2 which would delight storm chasers as they would be quite slow moving. However, it is just one of several options on offer tonight none of which offer anything particularly cold or warm with the standard variety of spring weather shown through the models. 

[Methuselah]

Thanks Gibby.

 

Standard spring weather sounds good to me; it'd be a vast improvement over last year's dross...