Model Output Discussion 12z 20/04/13

[phil nw.]

Trough sticking over the UK in the 6-10 day range

 

Whilst there is a slack very nondescript regime further out so no strong warm anticylconic signal as far as I can see.

 

Average at best.

You need to read between the lines so to speak on those though Purga.

These are anomalies against the average spread over several days.If you look closely and compare the 2 images you can see the UK trough filling and the next trough is held out into the Atlantic.Note pressure rises building to our east.

The end of the period on that second chart is when the mean outputs are signaling building heights around Europe/Scandinavia.

here's the ECM/GFS means at day 10 for example

http://www.meteociel.fr/modeles/ecmwf/runs/2013042412/EDM1-240.GIF?24-0

http://modeles.meteociel.fr/modeles/gens/run/gens-21-1-240.png?12

both going for a change to something more anticyclonic in week 2.

[chionomaniac]

Trough sticking over the UK in the 6-10 day range

 

Whilst there is a slack very nondescript regime further out so no strong warm anticylconic signal as far as I can see.

 

Average at best.

Looking at the day 8+ range I would rather stick with the ECM ensemble blend which is more in line with the downwelling strat profile:

 

[damianslaw]

Quite an average typical outlook for late April, northerly airstreams are more likely now than at any other time of year. The atlantic looks quite a weak affair, and after a showery few days, early next week looks like becoming quite settled, though nothing particularly warm is on the horizon.

 

In overview, a showery chilly immediate outlook - indeed in the north it is a cold outlook, becoming more settled next week though still chance of showers and average temperatures at best - for the northern half of the country, spring is still struggling to make its mark - exceptionally late start this year...

[cheeky_monkey]

Looking at the day 8+ range I would rather stick with the ECM ensemble blend which is more in line with the downwelling strat profile:

 

EDH101-240.GIF

Looks good for here..low pressure of the pacific NW coast High pressure over the eastern prairies nice gentle southerly drift where i am

[summer blizzard]

GFS ensemble mean is good to go for a pressure build from day 11. Backs up the signal in recent days and the Met Office long term outlook.

 

[SP1986]

The 18z is much better in both the realistic timeframe and beyond, than previous model outputs. It's messy but it removes the stagnant cold situation that was shown a few days ago by introducing a little mixing into the pressure, via some cut off lows, and small high pressure cells which get caught in the system in the mid-time frame. However I do think FI is just that, and regardless of signals, we've had enough chasing rainbows earlier on this Spring to suggest it's always a good idea to view T180+ with some healthy scepticism. So as much as it looks favourable at T+240, it's also so far out that it's unlikely at this juncture.

Edited April 24, 2013 by SP1986

[Cheshire Freeze]

Hi all,

just a quickie from me as still have no internet. From what I've seen there appears to be hints of that settled May I intimated at a couple of weeks ago, just creeping into the NWP tools. Good news for the HP lovers! Fits nicely with the last GLOSEA4 run I looked at with a belt of HP across the mid latitudes rather than further N.

Looking further ahead I don't see where talk of a mean 'sceuro trough' is coming from. Contrary to what I've seen/heard from various sources, I would say we're looking at 2 of the 3 summer months to be drier and warmer than average- a view I've held for the past 4-6 weeks. We'll see.

Will be back in the thick of it once my internet is up and running again!

[Sprites]

How did you post with no internet crewecold? lol.

High pressure dominating could limit storms for the Crewe area again, though may also allow a plume scenario.

Edited April 25, 2013 by Sprites

[mushymanrob]

great overnight discussion guys, i cannot add but wanted to let you know its read and appreciated!

[Frosty.]

This is my view of the GFS 00Z operational run

 

The warmest day of the year so far for the southeast of england today, 22-23c is expected because there is going to be more in the way of sunshine this afternoon for the southeast but then a cold front pushing south tonight with a band of rain but more importantly, a big drop in temperature so that tomorrow the max in the southeast will be nearer 11-12c. Further north and west from this warm zone it will be cooler and more cloudy with some rain around and sunshine & showers for scotland and n.ireland, the showers wintry on scottish hills. Tomorrow looks rather cold and showery across the uk once the overnight residual rain clears away from southeast england, most of the showers will be across northern and eastern areas, some heavy with hail and thunder but some areas will have a dry and fairly sunny day. On saturday, an atlantic ridge toppling southeast into scotland so a drier, brighter but cool day for them after an overnight frost but further south it looks like a showery day, some heavy and possibly thundery in the south but tending to become drier in northern england later, a slight frost overnight will be followed by a much better day for southern britain on sunday with a dry and fairly sunny day and just isolated showers, wind and rain for nw britain giving way to colder and showery weather later on sunday. On monday, more southern parts of the uk may get away with a fine day but showery and colder for most of the north and west but with sunny spells. On tuesday, an atlantic ridge builds across the uk so a fine and sunny day after an early frost and although it will be a cool day it will feel pleasant in the strong sunshine. Midweek there is a risk of rain in the south and more showery in the far west and north but possibly fine inbetween, another cool day nationwide, especially under the persistent rain in the south. Thursday also looks cool and unsettled and the further outlook remains unsettled with a trough to the west of the uk but slowly becoming milder and pressure rising to the east, eventually the anticyclonic spell we have been waiting for arrives towards the end of the first week in may hopefully it will last for a long time.

 

The UKMO 00z looks much better by the middle of next week with high pressure developing.

[Summer Sun]

How did you post with no internet crewecold? lol.

High pressure dominating could limit storms for the Crewe area again, though may also allow a plume scenario.

 

3G on his mobile / Ipad or something similar?

 

Anyway back to the models and ECM's settled end to next week from last night has gone on the 00z run

 

T240 between GFS and ECM is completely different with GFS going for a deep low whilst ECM is moving towards something more settled for the first full week of May

 

[Gibby]

Hi everyone. Here is the latest midnight report on the output from GFS, UKMO, GEM, NAVGEM and ECM for today Thursday April 25th 2013.

All models show a frontal zone across Central Britain separating cold, bright and showery conditions to the North and warm, bright and humid conditions to the south. Through tonight the front moves SE across the South followed by a bright but colder Northerly flow for all areas tomorrow. Saturday then shows a ridge moving SE over the North and on down over the South on Sunday maintaining the rather chilly conditions with frost at night but managing to kill off many of the showers leaving largely dry conditions by Sunday. Then the North becomes cloudy in association with a deep Low to the North pushing a front down across the Nation by Monday with a spell of rain followed by showers looking likely to start next week.

GFS then takes the cold front on away to the SE on Monday bringing the UK into a flatter pressure gradient through the week with a mix of sunshine and scattered showers though with the emphasis on the showers shifting from the South to the North as we move towards the holiday weekend. The Bank Holiday weekend is characterized by a deep Low centred to the West of the UK with warmer Southerly winds with rain and showers at times, especially in the West and North. Beyond the Bank Holiday Weekend and deeper into May High pressure builds NE across the UK bringing a spell of fine and settled weather with sunny spells when it would become increasingly warm.

The GFS Ensembles show a chilly spell next week before a slow recovery in uppers bring us into more settled conditions with sunny spells and temperatures at the surface at normal levels or above as we move deeper into May.

The Jet Stream shows the East moving flow over the UK sinking into a UK based trough over the late weekend and start to next week. through next week the flow near to the UK dissipates with just a flow moving out of Newfoundland and down over the Atlantic late next week.

UKMO for the middle of next week shows a complex pattern of synoptics with Low pressure over Scandinavia, Spain and NW of Ireland with a small High pressure area over the North Sea. Many places would be dry and bright but with Low pressure surrounding the UK the odd shower would undoubtedly occur almost anywhere in temperatures close to average if not a bit below.

GEM this morning shows a typically changeable April week with some areas of showers or rain at times interspersed by periods of drier and brighter conditions with temperatures fairly academically near to average if not slightly below for much of the week.

NAVGEM shows a cold and showery start to next week as Low pressure near Scandinavia influences conditions over the UK. By midweek the winds back towards the west with rather less cold conditions with scattered showers or rain becoming more confined towards the North.

ECM today shows next week as being a basically showery week under slack pressure patterns biased towards Low pressure until the end of the week. High pressure then looks to build over the UK with slowly warming uppers perhaps giving us a fine and pleasant Bank Holiday weekend.

In Summary today the influence of the showery weather over the coming few days has mellowed somewhat with showers more scattered allowing some areas to have a dry and pleasant if rather chilly weekend with sunshine by day but frost overnight. Then next week looks like a basically week of mixed fortunes from place to place as slack synoptics look most likely over the UK through the week with day to day differences from place to place likely throughout. In essence it would mean sunshine and showers but the distribution of the showers would change from day to day. It does look like temperatures will recover somewhat towards the second half of the week with the Bank Holiday weekend looking finely balanced at the moment between occasional rain chiefly in the North and a more general dry prospect with pleasantly warm sunny spells with the removal of the frost risk beyond the middle of next week.

[Summer Sun]

With the MJO heading into phases 1, 2 & 3 we should begin to see higher than average pressure as we move into May however before that we've got to get through next week and that is looking chilly for the time of year of course in any sunshine it will feel warm but the thermometer will say other wise

 

 

The ENS contiues with its strong signals for high pressure to build after next week

 

 

That however could well bring an east to south easterly wind which is not good for those in the east especially if you live near the coast as there would be a lot of cloud and maybe even sea mist around especially given how cold the north sea is currently

Edited April 25, 2013 by Gavin.

[Frosty.]

The Ecm 00z operational run is also a rather cool/cold and unsettled run but with a few fine days here and there, sunday in the south and then towards midweek and then by T+240 there are promising signs with the jet heading north and pressure rising to the southwest and east. Next week shows a lot of very cool and showery weather though but not a complete washout as there will also be at least a few dry and sunny but cool days too, overnight it looks cold enough for a touch of frost on most nights in the next 4-6 days.

Edited April 25, 2013 by Frosty039

[Frosty.]

The latest Ecm 00z ensemble mean shows a northwest-southeast split developing from later next week onwards with a trough keeping northwest britain cooler and more unsettled but pressure slowly rising to the south and east with gradually improving weather, becoming dry and brighter with sunny spells and temperatures slowly recovering after a cool start, the first half of next week shows a cold and showery northerly airflow but then comes the change in fortunes, the northwest of the uk looks set to continue to suffer the worst weather for a while yet although by early to mid may even the northwest should hopefully join the rest of the uk  enjoying a spell of warmer and settled weather.

[mushymanrob]

With the MJO heading into phases 1, 2 & 3 we should begin to see higher than average pressure as we move into May however before that we've got to get through next week and that is looking chilly for the time of year of course in any sunshine it will feel warm but the thermometer will say other wise

 

 

The ENS contiues with its strong signals for high pressure to build after next week

 

 

That however could well bring an east to south easterly wind which is not good for those in the east especially if you live near the coast as there would be a lot of cloud and maybe even sea mist around especially given how cold the north sea is currently

 

eek!

 

not the best of charts for sunshine and warmth, but the west would bask in the high teens whilst the east would be cool grey overcast... yes its that 'april 74' i keep harking on about, dull cold overcast mornings, sun burns back the cloud to reveal a splendid afternoon. so best in the west, coldest/dullest in the east.

[Frosty.]

Some GREAT NEWS from the latest Met Office update:-

 

During the Bank Holiday weekend, conditions are likely to become drier and more settled, initially across the south but likely to spread to all parts later that weekend. Temperatures rather cold initially, but recovering to near normal in the south and perhaps warm by the end of the period.

 

This is also what the ecm 00z ensemble mean is showing on the charts I posted earlier.

Edited April 25, 2013 by Frosty039

[Summer Sun]

eek!

 

not the best of charts for sunshine and warmth, but the west would bask in the high teens whilst the east would be cool grey overcast... yes its that 'april 74' i keep harking on about, dull cold overcast mornings, sun burns back the cloud to reveal a splendid afternoon. so best in the west, coldest/dullest in the east.

 

Yeah the unusually cold north sea won't help matters either for those east of the pennines however the shorter term met office update does offer some hope for all as frosty has posted above longer term will all depend on where the high places its self

[Paul]

Latest forecast from Michael Fish - cool, often unsettled, some frosts, but also some drier, brighter weather at times during the upcoming 7 days.

 

[summer blizzard]

Still looking good for a pressure build at day 10...

 

[Summer Sun]

Before we get to any warm up shorter term is concerning for the growers around the country with a ground frost looking likely this weekend

 

This is the lowest the temperature gets at 06:00 on Saturday

 

 

But its during the early hours of Sunday when we could see a damaging frost across the country these are the lowest the temperatures could get too

 

 

And this is the highest they could get too for the same time

 

 

During Sunday temperatures recover to double figures for many away from the west of Scotland and North west England

 

 

The ECM Birmingham ensemble is now trending warmer again during the first full week of May with highs around the average of 16c (This is something the monthly ensemble update on Tuesday wasn't showing)

 

 

Rainfall continues to balance its self out after last years deluge by staying very low

 

 

Just to compare the difference from the monthly update for the 5th to 9th here's the monthly update from Tuesday the difference is clear to see

 

[NeilN]

This is encouraging. Shame about the weekend...I'll have the heaters on full blast Saturday night.

[Frosty.]

This is encouraging. Shame about the weekend...I'll have the heaters on full blast Saturday night.

The weekend will be half decent I think, yes it will be rather cool but with sunny spells and a few showers around on saturday but sunday currently looks like being fairly sunny across southern britain after an early touch of frost thanks to a ridge, more unsettled for nw britain with the rain spreading down across northern england but looking good further south, monday may also be a fine day in the south after an early nip of frost. colder and showery further north and west.

Edited April 25, 2013 by Frosty039

[ANYWEATHER]

Certainly not liking the look of the gfs predictions for the weekend for overnight temps. If these frosts come off there is likely to be major damage to outside crops, especially given the last few warm days...

[Summer Sun]

Tonight's GFS is going for a weak pressure rise earlier next week now

 

 

UKMO follows suite

 

 

Doesn't look like it will last beyond mid week though

Edited April 25, 2013 by Gavin.