Model Output Discussion 12z 03/04/13

[Milhouse]

Mobile westerlies dominate the second half of the ECM with the best of the dry and settled weather to be found across southern Britain where it could become briefly warm for a time during next week. A cool northerly is shown at day 10 ahead of an advancing area of high pressure.

[Frosty.]

Ecm 12z op run also looking anticyclonic for the south next week, not as peachy as the gfs 12z but high pressure does hold across southern areas, gfs is rather better though for more of the uk to be fine next week, on balance it looks like high pressure will hold the upper hand next week but nw britain is likely to be unsettled, cooler and windy for much of the time.

[Gibby]

Good evening. Here is the report on the 12z output of GFS, UKMO, GEM, NAVGEM and ECM for tonight Tuesday April 16th 2013.

 

All models show a deep depression running NE to the NW of Scotland over the next 24hrs followed by a showery Westerly flow behind a cold front crossing East on Thursday. By friday a strong build of pressure from the SW forms an anticyclone over Southern Britain at the start of the weekend declining away East by the end. Weatherwise the North and West will see wind and rain over the coming 24 hours while Southern and Eastern areas stay largely dry and rather warm with some sunshine tomorrow afternoon. The airflow will freshen and veer towards the west on Thursday with a mix of sunshine and heavy showers before all areas see the weather settle down with sunny days and cool nights with a patchy ground frost in places. Sunday sees cloud increase again from the West over Northern Britain as winds freshen from the SW.

 

GFS then shows a weakening trough meandering East across Britain early next week with a little rain in places. By midweek things will be largely dry again in the South as a High pressure ridge lies west to East across the UK with bright and dry conditions in temperatures close to average. Through FI tonight things turn more unsettled and colder from the NW as Low pressure bears down on the UK from the North. A mix of rain then showers would affect the UK with the air cold enough for wintry showers over the hills. Late in FI the Low sinks South over NW Europe with a NE flow developing under a ridge extending NE over Scotland from the Atlantic. It would likely be rather chilly for late April in a chill NE wind but bright conditions.

 

The GFS Ensembles show a fairly tight average run tonight with the mean never straying far from the long term mean tonight. In the absence of any clear trend one should expect a mix of typical April weather with some warm sunshine mixed with cooler and more unsettled spells with relatively small amounts of rainfall when taken as a total.

 

The Jet Stream forecast maintains the flow across the Atlantic and over the UK with an interlude of time when the flow disintegrates over the UK for a time early next week.

 

UKMO also shows a weakening front cross the UK on Monday with some rain in places, lessening in extent and intensity as it moves East slowly through the day.

 

GEM tonight shows a similar evolution next week though with a rather more noticeable westerly flow as we move into the week with rain at times, especially in the north under average temperatures.

 

NAVGEM too shows a more vigorous WSW flow for a time over all areas early next week as a weakening front again crosses East bringing some rain in places. By day 10 pressure has built again just South of the UK with lighter winds here with largely dry conditions.

 

ECM keeps a rather changeable theme as we go through next week with winds blowing strongly from the West in the North with rain or showers at times while the South, although seeing a little rain from weakening Eastwards moving troughs see the best and longest of the drier and brighter periods when temperatures may become rather warm at times. Temperatures in the North will be near to normal but will feel cool in the strength of the wind coupled with more rainfall.

 

In Summary tonight after another day of rather humid and changeable weather with some warm conditions in the South tomorrow things are then set to turn fresher with lower humidities and weather steadily settling down for several days. The weather would be dry and bright with sunshine by day but with chilly nights for a few mornings when a slight ground frost is possible. thereafter, winds settle Westerly once more and it appears the most likely outcome will be for a North/South split in the weather to develop with the North seeing spells of wind and rain or showers at times and temperatures close to average. the South too may see a little rain at times but here there looks like being quite long dry and bright spells and it could become rather warm at times in the shelter of the westerly breeze.

[Frosty.]

The Gefs 12z mean shows an unsettled interval early next week but then pressure rising from the southwest/south with increasingly fine/sunnier and rather warmer weather but n.ireland, western and northern scotland look like remaining locked in a prolonged unsettled spell, next week looks breezy at times in the south but v mild to rather warm and further north it looks progressively cooler in the rain with temps struggling to reach average in the wet and windy northwest corner of the uk, hopefully the nw corner of the uk will join in with the fine spring weather beyond next week.

[itsnowjoke]

Does this mean Winters over then lol

[Carlrg]

Have been watching bats feeding above my back garden this evening. Yes I do think winter's over.  Thankfully.

[johnholmes]

It is quite amusing looking at the various charts from the same model that folk above are showing to give an angle to their preference, be it cold or mild; one chart shows the mild weather for one day and the same model shows the chart on another day for less mild perhaps colder.

Not arguing with the charts and the prognosis from them, just amusing to see how the same run can give folk on both the mild and cold side something to be pleased about!

would the winter brigade were able to do this without the ill temper so often shown.

[Iceni]

Have been watching bats feeding above my back garden this evening. Yes I do think winter's over.  Thankfully.

 

On the walk today saw 3 peacock butterflies and several bumblebees. All the April violets are out looking gorgeous. Still a nagging cold NE wind though, which spoils things a bit.

Edited April 16, 2013 by Iceni

[mushymanrob]

after the wettest summer (or something close to it last year), the coldest march since ages ago.... are we in for the windiest april? its looking to me like the jet stream has us in its sights for some time. the anomaly charts suggest more wind again next week after a temporary lul over the weekend. tbh we need some rain!!!!!

On the walk today saw 3 peacock butterflies and several bumblebees. All the April violets are out looking gorgeous. Still a nagging cold NE wind though, which spoils things a bit.

 

you had a nagging ne wind yesterday?... how odd... ours was a brisk southwesterly...

[Frosty.]

GFS 00z is looking nice and settled across most of the uk both this weekend and throughout next week with high pressure in control. it does wax and wane a bit but holds across the south and is the pick of the models for fine and rather warm weather next week, the only exception to the fine story is the n and w of scotland and n.ireland where low pressure will hold the upper hand. The ukmo 00z looks a bit more changeable on mon/tues but if we use the Gem 00z as a template, the gem and ukmo look very similar at T+144 but then see how the gem 0z improves as next week goes on with high pressure across the south of the uk, the ecm 00z also looks good for the majority of next week after a bit of a slow start, so, all in all, the models are still looking good next week with high pressure in control of at least the southern half of the uk and a lovely weekend to look forward to, especially saturday.

[Summer Sun]

So looking at UKMO this morning the bulk of England and Wales should manage to get 3 decent days at the end of this week Friday to Sunday the exception to Sunday looks to be Northern Scotland

 

 

ECM and GFS also agree on this now so thats an upgrade from last night

 

Into next week and it looks like the further south you are the better it will be

 

Edited April 17, 2013 by Gavin.

[Frosty.]

Synoptically, this afternoon is very similar to sunday when temps reached a magical 22c 72f in kent, today it could get very close to 22c in the southeast, 19-21c seems likely. remember how the gfs undercooked the max temps by 2 or 3c on sunday, something similar could occur this afternoon, feeling more like summer in the southeast/east anglia this afternoon/evening.

Edited April 17, 2013 by Frosty039

[Frosty.]

The Gfs 06z is another very encouraging run in terms of fine and pleasantly warm/rather warm anticyclonic weather, much of the uk has a good settled spell, especially the further south you go although even scotland gets to enjoy some fine and sunny weather on this run, it's only beyond T+200 hours when there is a gradual breakdown to something more unsettled but very FI range, next week is looking very good for a large chunk of the uk apart from the far northwest.

[Geordiesnow]

The models are still showing the classic NW/SE split with the driest and sunniest of the weather being the further South and East you are. I don't think it will take too much movement for the NW to get more in the way of drier and sunnier weather but equally it won't take too much to have other areas of the UK to be affected by cloud and rain. 

 

One thing does look more certain is that after tonight's and tomorrow's potential strong gusty winds, the winds should become less of a feature especially if the jet stream is far enough North to keep those low pressures around Iceland. 

[Frosty.]

More good news from the latest gefs 06z mean together with the ecm 00z ensemble mean, after a briefly unsettled start to next week, it's a gradually improving picture as a large area of high pressure becomes centred to the southwest of the uk and extends strong ridging across more and more of the uk as time goes on, the southwest being the first to improve, and then like ripples in a pond, the pressure begins to rise across the rest of southern britain and even extends into central and northern parts of the uk, pressure also becomes high to the southeast of the uk across the near continent.There would be increasing amounts of sunshine and temperatures, which would start next week close to average, would rise to above average and rather warm levels, especially to the east of high ground and to the southern half of britain in general. The latest mean charts indicate that low pressure will be retreating further north during next week but this goes against the latest met office update today which is sounding like a more unsettled outlook for next week, at least for the north and west of the uk generally, it does indicate spells of sunshine and rather warm temps for the south and east but doesn't sound as settled (anticyclonic) as the gfs 00z-06z op runs, or the ecm 00z op, together with the gem 00z op and the latest gefs/ecm mean are currently showing.

 

As for the near future, severe gales are forecast for this evening and tonight across central britain, especially bad across the pennines and more especially to the east of the pennines with gusts of 60-65 mph, together with a spell of heavy rain, so a nasty night ahead and yellow warnings have been issued, but things will really calm down by friday and the weekend with high pressure pushing northeastwards, saturday looks the sunniest day but with a frost early and late but sunday will tend to become more unsettled to the north and west, but further southeast across england may escape with a largely fine day with temps around average by day.

[Barry12]

GFS T96

 

[Barry12]

GFS T120

[Barry12]

GFS T144, warm and dry

 

[Summer Sun]

UKMO continues to give the bulk of the country a settled start to the weekend this afternoon

 

 

 

The start of this weekend could well be the first BBQ one of the year for many yes it won't be hot but with light winds and plenty of sunshine it will feel very pleasant with a temperature range of 11c to 14c (lowest in the north highest in the south) it wouldn't surprise me if one or two spots got to around 16c this weekend given how strong the sun is now

 

Onto Sunday and we see the south staying under high pressure so a north south divide looks likely

 

 

By Tuesday and Wednesday the high starts to edge northwards again with only the far north of Scotland staying unsettled

 

 

Both UKMO and GFS look fairly similar at t120

 

 

So all in all a after tomorrows strong winds the end of the week see's pressure rising so winds fall light although we'll see an attack from the north high pressure clings onto the south and never really leaves here before it pushes north again early next week giving England and Wales another settled spell of weather.

 

Rainfall looks staying below average for a long time yet which after last years washout will be welcomed by many especially farmers who's fields will still be drying out in some of the worst hit spots

 

My only concern tonight is the emergence of high pressure rebuilding up north t240 has this

 

 

GFS could just be going off on one need to wait for ECM later on before we can get a clearer picture

Edited April 17, 2013 by Gavin.

[Milhouse]

Next week was looking rather unsettled and cool woth northwest winds. Now theres the potential for some rather nice almost summer like conditions if the GFS is to be believed. Much lighter winds than at present so we would feel every bit of the warmth on next Tuesday and Wednesday before a cold front moves south for Thursday.

[Tim Bland]

Shame GFS is a Mild outlier. http://www.netweather.tv/index.cgi?action=charts;type=ens;sess=

I love your optimism Gav but it will take more than 12c for me to dust off the BBQ and get the deck chairs out!

Models continue to sinal a below average end to April I'm afraid

[Summer Sun]

Mid next week from ECM shows the high to the south pushing further north once more as per GFS its only the far north of Scotland which remains prone to any unsettled weather

 

 

The ensembles show good agreement for some warm uppers around the 24th

 

Edited April 17, 2013 by Gavin.

[peterf]

ECM looks bliddy cold to me.

[Gibby]

Hi everyone. Here is the report of the 12z output from GFS, UKMO, GEM, NAVGEM and ECM for tonight Thursday April 17th 2013.

All models continue the theme of rising pressure over the next 48hrs as todays squally depression slides NE over Northern Britain. Another 24 hours of strong winds is likely with the persistent rain in the North of today moving away NE and being replaced by 24 hours or so of sunshine and showers in fresher and rather cooler WSW winds. Tomorrow night and Friday a ridge of High pressure builds strongly from the SW over Britain with a couple of dry and bright days with sunny spells, average temperatures and cool, misty nights with a touch of ground frost in places over Friday and Saturday nights. On Sunday pressure will begin to fall again as a trough approaches from the West later in the day with cloud and some rain arriving in the west late in the day in a freshening SW breeze.

GFS then shows High pressure out in the Atlantic throwing a ridge across the UK from the west by midweek with any cloud and rain reserved for the far North while Southern areas remain drier and brighter with average temperatures. Late in the week and weekend pressure falls from the North as Low pressure sinks it's influence South across the UK with rain at times occurring more widely. Things remain somewhat unsettled late in the run as pressure becomes Low in the Atlantic with slack winds and occasional thundery showers likely for many in temperatures rather above average if rather humid.

The GFS Ensembles show the warm end of the operational unsupported with much more support for rather chillier conditions with an increasing likelihood of rain in the South through Week 2.

The Jet Stream maintains it's flow East across the UK albeit with a brief collapse of the flow for a time early next week.

UKMO for next Tuesday shows low pressure east of Iceland with a Westerly flow over the UK. the North would see cloud and rain at times but with High pressure close to Southern Britain rather drier conditions are likely with some sunny intervals and temperatures well up to average if not a bit above in the SE.

GEM today shows a WNW flow over the UK with the same North/South split in the weather that UKMO shows.

NAVGEM shows a slack flow over the South as we move towards Day 7 following a spell of Westerly winds and a North/South split in conditions earlier in the week. There could be a few showery outbreaks of rain at times almost anywhere with shallow troughs caught up in the air mass over the UK.

ECM finally shows the same division in the weather North to South at Day 6 with some fairly decent weather around in the south early next week while the North stays more windy with rain at times. As the week goes by the South warms up for a time with some warm sunny spells in light winds. No such warm up in the North with cooler and breezier and cloudier conditions maintained with some rain at times which extends South to other areas late in the week with the best of the weather being in the SW while elsewhere showers would occur in rather colder and breezy conditions in a blustery NW wind.
 
In Summary it still remains a basically North/South divide in the weather next week. The North will see windier and cloudier conditions with some rain at times but a few drier intervals at times. In the South the weather remains drier with sunny intervals at times which will make conditions feel reasonably warm and springlike at times. In time it still looks like a change to cooler conditions with rain more widely over the UK in what will become cyclonic conditions as we move out towards next weekend and beyond.

[SP1986]

If, for now, we consign the GFS operationals to the side (as it has no support from its ensembles at all), and concentrate on the ECM, we see a slack-ish, benign episode developing, if there was ever one. This would probably mean heavy slow moving showers under largely cloudy skies, potentially in the longer term? I think in most cases also it would be too cloudy/cool for thunderstorms? It looks on the surface to moving toward below average temperatures for at least a time, and wetter weather, based on the ECM output.

Edited April 17, 2013 by SP1986