Model Output Discussion 12z 03/04/13

[Cloud 10]

As my mum always used to tell me: so is Christmas!

Christmas you say?..

Edited April 9, 2013 by Cloud 10

[Gibby]

Good evening. Here is the report of the 12z output from GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday April 9th 2013.

All models show the next depression in the series as the last one responsible for keeping cold weather over the UK as a deep depression at the end of the week winds itself up in the Atlantic and feeds mild Southerly or SW winds across the UK then together with strong winds and some rain for a time.

GFS then shows a spell of fresh to strong but mild SW winds across all areas with spells of rain in the North and West extending to the South at times. Through FI High pressure extends North across Britain and away to the North setting up a warm East to SE flow across the UK. Later on in FI the weather will become cooler as winds back more East and colder uppers begin to be dragged towards the UK from the East.

The GFS Ensembles a change to rather milder conditions imminent with some pleasant conditions at times especially in the South. the warm ESE flow indicated by the operational mid run was not well supported with some wide spread between the members later in the run, the majority still on the mild side of average.

The Jet Stream shows a change in the orientation of the flow with the main core moving NE across the UK next week.

UKMO tonight shows a blustery South or SW flow with some rain possible in the West while the East sees some bright and potentially warm spells though with plenty of cloud.

GEM shows a much more unsettled and blustery start to next week with rain at times for all until midweek when a ridge builds from the South with attendant drier, brighter and warmer conditions.

NAVGEM tonight shows a strong SW flow early in the week before pressure steadily builds from the South towards midweek. After some rain for many early in the week the weather perks up somewhat in the South by Thursday.

ECM shows a couple of unsettled and breezy days early next week with some rain at times from troughs as they pass east in the flow. By midweek and thereafter, High pressure builds strongly from the South with some settled and warm weather developing in light winds with some warm sunshine for many, especially in the South.

In Summary it still looks like the weather will warm up considerably next week with some warm sunshine developing as we move deeper into next week as pressure builds from the South replacing the strong and blustery SW flow and occasional rain of early in the week.

[Frosty.]

I think there are very encouraging signs looking further ahead because both the gfs and ecm 12z are pretty similar at T+240 hours with a settled and warm pattern becoming established across the uk. Before then though it looks generally unsettled apart from a possibly fine and warm day for southern britain on sunday with temps of 20c 68f but then returning to an average 12-14c with unsettled weather from the atlantic for most of next week although improving later in the week as pressure rises from the south with warm and dry weather for southern areas by the end of next week onwards.

[Guest pjl20101]

Still looking +ve now across the SE corner of the british isles, if anything that signal has increased to a +ve across the country now according to the latest CPC 8-14 day output by this link I'm posting:

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

Thumbs up from me tonight.

[shaky]

Still looking +ve now across the SE corner of the british isles, if anything that signal has increased to a +ve across the country now according to the latest CPC 8-14 day output by this link I'm posting:

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

Thumbs up from me tonight.

Beautiful!!that will bring some warm humid days and night hopefully!!been waiting a long time for this!!

[Summer Sun]

The ECM Debilt is only going one way now finally and thats up

[itsnowjoke]

I've heard that one before

yes was it Winter

[J10]

Looks a very pleasant week in store for the southern half of the UK next week. Monday and Tuesday look rather showery and there could be one or two more organised bands of rain mixed in but these look fairly weak features. From midweek onwards dry and warm conditions move in, mainly to southern Britiain.

To me looks worse than recent weeks over many western areas, gone will be the dry, mostly sunny and albeit cold conditions to be replaced with damp misty and mild conditions. Thumbs Down from me.

(Unless the SE "plume" flow comes off )

[weather_it_will]

It looks as though this weekend could be milder, or even warmish on sunday.

But the models are very uncertain beyond 7-days, as some are hinting at a NE or SE wind which is going to pull down the colder air possibly to take us in to the next May Bank Holiday.

[Scorcher]

But the models are very uncertain beyond 7-days, as some are hinting at a NE or SE wind which is going to pull down the colder air possibly to take us in to the next May Bank Holiday.

Yes many of us will be hoping that doesn't come off, but when are the models ever certain beyond 7 days?

[Thundery wintry showers]

It is looking increasingly likely IMHO that we will move into a warmer and more changeable pattern into next week. While I've seen posts referencing a settled outlook, I don't see much evidence of one away from the south-eastern corner until at least 8 days out. I think the signals do suggest that high pressure will build over eastern and/or southern England at some point during the rest of April, promising an interlude of generally warm dry sunny weather, but we may find that, as with the upcoming change to warmer temperatures, it may end up being delayed until late in the month.

For instance if we take the MJO, Phase 5 is strongly consistent with a build of pressure over those areas:

http://raleighwx.ame...mbAnomalies.gif

...but the present MJO forecasts have it sticking around in Phase 4, which features a UK trough instead:

http://raleighwx.ame...AprilPhase4.gif

The MJO is only one variable of course, but I won't be surprised if the month's main warm dry sunny spell ends up falling around the 25th of the month rather than the 15th-20th as is currently being suggested by most GFS and ECMWF runs.

Friday could well be a day to watch for the convection/thunderstorm fans in the southern third of England, for to the south of a frontal system, some pretty high convective available potential energy has been shown by the GFS for a few runs:

http://cdn.nwstatic....69/ukcapeli.png

Sunday is looking increasingly likely to see the dry sunny weather largely restricted to East Anglia and the southeast in my view, though much of the rest of central and eastern England is likely to be markedly warmer than we've seen for a long time, and the change will be noticeable even though it will probably be mostly cloudy.

Next week's surface weather is up in the air. The GFS 18Z precipitation outputs are suggesting a persistent tropical maritime airflow with dull wet weather in the west and drier but mainly cloudy weather to the east of high ground, but the ECMWF 12Z has us in polar maritime air for most of the time, which would translate to some rain belts but also much brighter, showery interludes in between, and not many showers in eastern and southern England.

Edited April 9, 2013 by Thundery wintry showers

[Peejayem]

It looks as though this weekend could be milder, or even warmish on sunday.

But the models are very uncertain beyond 7-days, as some are hinting at a NE or SE wind which is going to pull down the colder air possibly to take us in to the next May Bank Holiday.

Ermmm....there's still 2 weeks to go between that BOM FI chart and the May Bank Holiday!

[summer blizzard]

[mushymanrob]

the outlooks good ...

into next week we look like getting a pretty normal, average regime which for mid april will be pretty pleasant at times. the gfs and ecm suggest a mobile atlantic but the gfs has the jet crossing further south then the ecm. the north and west wont fare as well as the south and east, but theres nothing new there. the ecms version would be drier, sunier and warmer.

the building blocks though are in place for a possible plume, the evolution of which could easily form from current suggested synoptics in fi.

[Frosty.]

The Gfs 00z is looking very anticyclonic through most of FI with an atlantic high slowly pushing east across the uk and then migrating towards scandinavia, the scandi high becomes a major feature for our weather during late april but with winds from the east or northeast, temps for the uk would be below the seasonal average and feeling even colder on east facing coasts as the north sea will still be only around 6-7c in late april and a lot of misty low cloud but clearer and sunnier in sheltered western/nw areas. A lot to happen before that possible outlook though, this weekend and especially sunday looks like being a relatively very warm day with temps of 18-20c across the southern half of the uk and 12-15c across the northern half which will also feel warm following the persistent cold spring so far, this is all being brought about by a vigorous large atlantic depression which will also bring wet and windy weather across the uk but sunday brings that window of sunny and warm but breezy weather to southeastern britain. By early next week the azores high ridges towards southern england and pressure remains rather higher across the far south next week so some very mild and fine spells across the south but occasionally unsettled, the majority of the wind and rain next week looks like being across northern and western britain with temps close to average, beyond that, the gfs shows a cooler spell of polar maritime or rPm with some showers for a time but beyond that it becomes increasingly anticyclonic, sunny for a time with overnight frosts.

[Captain Shortwave]

Why hello there

Good morning Azores high, the UK says hello. Not bad for a mean chart.

[Summer Sun]

It looks as though this weekend could be milder, or even warmish on sunday.

But the models are very uncertain beyond 7-days, as some are hinting at a NE or SE wind which is going to pull down the colder air possibly to take us in to the next May Bank Holiday.

You do realize that the May bank holiday is May 6th? that chart above has nothing what so ever to do with the May bank holiday

Anyway back to the here and now and the models continue to promote a mild or even warm weekend deepening on where you live

FI from ECM shows the high continues to stay put and given its position we'd see lots of warm sunny weather

GFS at deepest FI also has the high firmly in place but that would bring easterly winds

Edited April 10, 2013 by Gavin.

[Gibby]

Good morning. Here is this morning's report on the 00z output from GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday April 10th 2013.

All models show the cold spell as all but over as the next few days see the encroachment of the Atlantic move slowly North across England and Wales over the coming 48 hours and then quickly across the far North at the start of the weekend. As is to be expected some rain or showers is expected in the process with some heavy rain then showers expected for the South before a deep Atlantic depression at the weekend whisks mild air quickly North over all areas by the end of Saturday with temperatures normal or slightly above by then. however, with a trough edging slowly east in the flow most areas will see rain at some point through the weekend, though the East will be last to see it.

GFS then takes us through next week with some dry and bright weather at times but with occasional rainfall too, especially in the North and West where some could be heavy. Southern and Eastern parts of the UK will see the longest and brightest drier spells where winds will tend to be rather lighter too. Through FI today GFS wants to build High pressure in from the Atlantic and across the UK and then on to Scandinavia meaning dry and bright weather developing for all in temperatures close to average but with the risk of slight grass frost returning overnight as uppers cool. Late in FI the High migrating to Scandinavia introduces a Easterly flow which could be grey and cold, especially near Eastern coasts while the best of the sunshine develops to the far West and NW.

The GFS Ensembles show a spell of weather where temperatures are above average at the surface as Low pressure moves NE to the NW. The attendant SW winds will bring occasional rain, shared by most members with a slow trend towards something a little cooler towards the end of the output today. The cold snap when frost at night could develop described above though is not supported. Total rainfall amounts are slightly below average through the period of the run.

The Jet Stream currently knocking on the door of the SW will continue to edge North over the coming days settling blowing in a NE direction across the UK for much of next week.

UKMO shows quite an unsettled picture to start with next week with a trough carrying a band of weakening rainfall East later on Sunday while a more vigorous feature with strong and gusty winds looks like moving East through Tuesday. Temperatures though would be well up to the seasonal average in fresh and gusty SW winds for much of the time.

GEM today shows a vigorous system too moving into the UK on Tuesday with rain and gales for all followed by squally showers and chilly NW winds midweek. Pressure then builds with High pressure dominant over the UK over the weekend but it too cools the air down sufficiently to allow the risk of grass frost to return but some bright and compensatory sunny days with temperatures not too far from average.

NAVGEM maintains a SW feed throughout the latter stages of it's run with some pleasant enough temperatures over the UK with occasional rainfall from passing troughs, more especially to the NW while the South and East see small amounts of rainfall and the best of the drier and brighter spells.

ECM finally maintains it's warmer and more settled theme the deeper we move into next week as it builds High pressure up from the South later in the week replacing the breezy and damp conditions of early in the week to warm and potentially quite sunny weather by the weekend with high pressure sitting right over the UK by then bringing the far north into the good weather too.

In Summary today the milder weather is almost with us with just another 48 hours of mediocre temperatures and showery rainfall to get through. However, there is varying signals between the output as to whether the conditions next week will be windy, wet and mild or drier and mild. In any event all models which go out to beyond 6 days indicate a build of pressure later next week and dependent on where this High locates will vastly alter conditions at the surface. The Americans want to position the High too far North and then NE which will open the gates to a chilly Easterly feed while NAVGEM and ECM look far more favourable for Spring warmth and sunshine as they locate high pressure either over or just South of the UK with some fine almost early summer like weather should they verify. One thing is well supported between all of the output there looks to be no repeat of last April's monsoon type weather with drier than average conditions likely through the above period.

[Frosty.]

The latest Ecm 00z ensemble mean is looking very encouraging for a warmer and more settled further outlook, a Northwest-Southeast split develops during next week with pressure rising significantly to the south and east of the uk but low pressure dominating across the northwest of the uk for a considerable period, however, pressure continues to rise across more and more of the uk as time goes on and eventually we are all settled and warm which would be nice. The GEFS 00z mean is not as good, it does bring higher pressure to the south and east but the north and west remain unsettled througout and later on the gefs shows the jet tilting nw-se which would bring a cooler/colder more amplified pattern, so the implications are huge, the ecm brings a summery further outlook and the gefs eventually brings colder and showery conditions back with a return of overnight frosts.

[snowmadchrisuk]

Beautiful 6z GFS , Looks like were going to be heading towards a prolonged period of high pressure in the South , with temps in there High teens shown for most of the run after the weekend, but in reality as the warm air really starts to bottle up to our South , I expect we are probably heading towards a period of 25-30 degree days come the end of the month .... Also the 6z even looks good for the W/SW now from Sun/Tue with the weather fronts not making it into the country .....

[shaky]

Beautiful 6z GFS , Looks like were going to be heading towards a prolonged period of high pressure in the South , with temps in there High teens shown for most of the run after the weekend, but in reality as the warm air really starts to bottle up to our South , I expect we are probably heading towards a period of 25-30 degree days come the end of the month .... Also the 6z even looks good for the W/SW now from Sun/Tue with the weather fronts not making it into the country .....

Time to get the bbq ready!!!

[Frosty.]

The Gfs 06z shows much better azores ridging into the southern half of the uk early next week with fine and warm weather, temps of 17-18c, more unsettled and cooler to the north and west as low pressure is more persistent there, later next week the low begins to squash the high further south but only briefly because once the low is away to the northeast, pressure rises strongly again and the good news would be that northern areas also become more settled to bring a nationwide fine spell, a nice trend from the 6z and proper spring weather at last. In the meantime. the big pattern change arrives on saturday due to that big atlantic low, wet and windy weather sweeping across the uk on saturday but also becoming much milder everywhere, then sunday is more of an east/west split with sunnier and warm weather for central and eastern areas but cloudier, windier and wetter further west and north.

[Summer Sun]

The ECM ensemble shows high pressure starting to become dominant across Europe during next week

Sunday and Monday will see the peak for the highest temperatures with 20c to 22c possible in the east where the cloud thins and breaks

[phil nw.]

It looks like a much more traditional April pattern will develop for the next couple of weeks at least.The vortex gradually shrinking and the jetstream easing it`s way north during the next few days.

The mean outputs indicate some influence still from the Atlantic towards the NW but it looks like the building heights further south will become more dominate towards the end of next week.

http://www.meteociel...1-168.GIF?10-12

That`s a nice mean chart with the promise of some warm and sunny weather spreading further north in time.

There will always be some exceptions in this SW flow though with perhaps some coasts and west facing slopes getting some low cloud or drizzle at times but generally a decent picture for many i would think.

The mean precipitation graphs also continue to show little rain in the outlook with many southern and eastern areas looking quite dry in the second half of the month.

http://modeles.meteo...run=6&runpara=0

Certainly a different pattern to last April.

[Frosty.]

Another very promising met office update for those who live in more southeastern parts of the uk because it looks like pressure will become highest in those areas over time with lots of warm and sunny weather at times with just the occasional unsettled/changeable interlude. It's a completely different story for northern and western parts of the uk though, the further north and west you are, the more unsettled it will be with temps closer to the seasonal average but even these areas will have the occasional fine and warmer interval but very few and far between, low pressure looks like becoming a persistent feature for nw britain in the near/mid range outlook. The meto update does not back the Ecm 00z ens mean trend for an eventual nationwide warm and settled spell, it suggests that n and w areas will continue unsettled which is more reflective of the gefs 00z mean, still. there is plenty of time for the generally drier, warmer and sunnier ecm mean to gather momentum and bring a nice spell for all.

Edited April 10, 2013 by Frosty039