Model Output Discussion 12z 03/04/13

[Captain Shortwave]

GFS/ECM ensembles are pretty much in line with each other, even to day 10 with a NW/SE divide with the drier, more settled weather moving north in time. By day 10 both have mean heights just to our south with an anti-cyclonic westerly over us

Edited April 10, 2013 by Captain shortwave

[damianslaw]

After a 3 month period of predominantly cold blocked conditions with a very ineffective atlantic and absence of southwesterlies, we are about to see a major change to more typical fayre - i.e. the return of the southwesterly with its associated humidity and rainy drizzle for the NW half of the country and drier milder conditions for the SE quarter of the country.

All models are keen to develop strong heights over central europe and a movement in the position of the jet much further north than it has been for quite some time.

As we move through next week, GFS and ECM are suggesting an amplified atlantic pattern, with the atlantic trough out to our west and strong ridge development ahead of it, allowing a warm plume from the south - so some welcome warmth for many from the weekend onwards, especially in the south and east.

Whether this is the start of a significant pattern change, or just a temporary blip remains to be seen, there are ominious signs that northern blocking is trying its best to sink everything southwards, and at this time of year, we are much more likely to see northerly and easterly airstreams outwin the atlantic and indeed euro heights - April 2007 and April 2011 were quite exceptional.. we could easily see the atlantic trough once again settling itself over the country in time for the summer season.

[Geordiesnow]

Typical spring charts really, some mild to very mild weather interspersed by something a little fresher and showery but nothing cold! In fairness on a widespread scale and in terms of length there is no charts which suggests anything long lasting warmth but i'm sure these milder but still probably fairly cloudy weather charts are to some extent welcomed, if the rainfall is not.

The difference between 12-14C this weekend compared to the 12C last weekend are the dew points will be higher so it will "feel" more like the said temperature.

[SP1986]

The 18z shows that while we return to around average (still below in the north and west), it'll be far far cooler than Europe. I think there is a good chance things will be corrected south, so cooler, wetter weather could be the evolution.. but the wider range of models say settling down with potential high pressure after a week..I'm not sure about that but we'll see.

Edited April 10, 2013 by SP1986

[Jimmy0127]

Hi Folks,

Sorry to post here, but it is essentially a model-related question...

Getting married on Saturday in Sussex, and the models keep moving the approach of that warm front; it's doing my head in. My interpretation of the models is very limited, but if anyone can offer guidance on this setup I would be eternally grateful. I can handle increasing high level cloud, but proper warm front rain would be very disappointing. Either way, we need to plan - can anyone offer guidance???

Sorry for the unabashed desperation!

[Panayiotis]

Hi Folks,

Sorry to post here, but it is essentially a model-related question...

Getting married on Saturday in Sussex, and the models keep moving the approach of that warm front; it's doing my head in. My interpretation of the models is very limited, but if anyone can offer guidance on this setup I would be eternally grateful. I can handle increasing high level cloud, but proper warm front rain would be very disappointing. Either way, we need to plan - can anyone offer guidance???

Sorry for the unabashed desperation!

Just keep up to date with the UKMO fax charts; for Sunday it has the warm front to the west of Wales:

Then moves over Wales to stretch across the west Midlands on Monday:

So for your location I would expect no rain with high cloud, a light to moderate wind and quite warm temperatures maybe reaching 18C in any sunshine.

The NAE is a useful guidance too if you want to know about precipitation rates etc when the date comes within 48hrs.

Links

UKMO

meteociel.fr - modèle UKMO pour la France, resolution 1.25 degré

NAE

weather model nae - united kingdom - rain/snowfall [base + 6] - weatheronline

Edited April 10, 2013 by Panayiotis

[Costa Del Fal]

The 18z shows that while we return to around average (still below in the north and west), it'll be far far cooler than Europe. I think there is a good chance things will be corrected south, so cooler, wetter weather could be the evolution.. but the wider range of models say settling down with potential high pressure after a week..I'm not sure about that but we'll see.

Id like more reasoning to your thoughts about this?

It seems your just going against the forecasted, generally settled outlook especially for the south. Is it pessimism driving your thoughts behind this or do you have examples of situations in the past of where this has happened?

This isnt a dig at you etc but I feel this is based more on doom and gloom and just seeing cool and wet weather as the form horse here for no real reason.

Edited April 11, 2013 by Blizzards

[Summer Sun]

UKMO shows the high starting to dominated across Europe next week





Certainly a different pattern to what we've had so far this year

The ensembles offer little in the way of rain over the next 2 weeks so this very dry period continues

Edited April 11, 2013 by Gavin.

[Captain Shortwave]

GFS/ECM ensembles want to bring in high pressure over the UK at days 9 and 10

 

 

I guess my only concern about this is only the particular notion of flattening the pattern and hence reducing the presence of high pressure as these dates approach T0.

[Frank Trough]

The 18z shows that while we return to around average (still below in the north and west), it'll be far far cooler than Europe. I think there is a good chance things will be corrected south, so cooler, wetter weather could be the evolution.. but the wider range of models say settling down with potential high pressure after a week..I'm not sure about that but we'll see.

Why will things be corrected south? because the Atlantic will be stronger than currently modeled? The thing is, a while ago you said you thought the deep cold would continue through April, presumably because Atlantic was too weak vs the cold block? I don't follow your logic. Mind you, given the recent past you would be forgiven for thinking there is never any chance of "nice" weather!

 

back to the models, and pretty good agreement for the general conditions between the ECM and GFS 06z at t+ 192  (didn't see that very often during the winter!)

 

 

 

Looks good for a period of drier, warmer weather especially the further south and east you go....but possibly not exclusively so. 

 

Altogether i'm feeling much happier about the outlook....sea temps starting rise and the fishing season now looming finally! 

Edited April 11, 2013 by Pharaoh Clutchstraw

[Captain Shortwave]

Why will things be corrected south? because the Atlantic will be stronger than currently modeled? The thing is, a while ago you said you thought the deep cold would continue through April, presumably because Atlantic was too weak vs the cold block? I don't follow your logic. Mind you, given the recent past you would be forgiven for thinking there is never any chance of "nice" weather! 

Simple because that's what the models have done. Just 36 hours ago the models for Sunday were showing a strong ridge of high pressure over Europe with a dry sunny and warm southerly flow. Now the ridge has been downgraded with us in a southwesterly flow with the frontal band coming through earlier than previously thought. Meaning there is a stronger jet which means heights don't build as strongly. At the moment high pressure dominated weather remains at 9/10 days out but isn't moving any nearer at the moment. It's just a feeling that whilst the South East might do ok out of this pattern change, many areas may experience disappointing conditions for the forseeable future either through outbreaks of rain or grey skies and drizzle from a broad moist southwesterly flow.

[Frank Trough]

Simple because that's what the models have done. Just 36 hours ago the models for Sunday were showing a strong ridge of high pressure over Europe with a dry sunny and warm southerly flow. Now the ridge has been downgraded with us in a southwesterly flow with the frontal band coming through earlier than previously thought. Meaning there is a stronger jet which means heights don't build as strongly. At the moment high pressure dominated weather remains at 9/10 days out but isn't moving any nearer at the moment. It's just a feeling that whilst the South East might do ok out of this pattern change, many areas may experience disappointing conditions for the forseeable future either through outbreaks of rain or grey skies and drizzle from a broad moist southwesterly flow.

 

yes, that's absolutely true and maybe i misread the original post. I read it as meaning that high pressure won't have any influence and lows will be more southerly tracking and crashing straight through. That still doesn't look the case at present, with the southeast still looking relatively dry. The ridge may be downgraded but it's still there and it's still influencing....and while it's there there's always the realistic chance it will ridge further north affecting more of the country. 

 

The influence is there on the ECM at day 4, just not for the further north and northwest but that's pretty normal for the UK, isn't it?

 

Edited April 11, 2013 by Pharaoh Clutchstraw

[snowmadchrisuk]

I must admit that this weekends warmth in the SW looks like it has been downgraded , to cloud and drizzle right out to Tuesday ... The radio keeps saying about it being a beautiful weekend , but think they may have to change there forecasts ...

[snowmadchrisuk]

A copy of Gibby's 00z report , as he hasn't posted on here today .....

All models show milder air making inroads across Southern areas of the UK today and tomorrow in association with Low pressure moving slowly ENE across Southern England and filling as it moves away East tomorrow. By the weekend the milder air accelerates North and East over remaining areas of the UK as a deep Low moves NE over the Atlantic to the NW of Britain. Mild South or SW winds will be pumped across all areas with rain at times in association with troughs moving across the UK in the flow. Then at the start of next week winds begin to ease from the South as High pressure builds over the near Continent.

GFS then shows pressure continuing to build through the middle of next week across the South bringing warm and settled weather for a time. The North continues to see more changeable weather with some rain at times. It will be rather warm in the South and mild in the North. Thereafter, after a few more fine and warm days under High pressure the High drifts into the Atlantic with Low pressure toppling around the top and down over Europe. The UK keeps under a ridge from it though keeping any colder and more unsettled weather away over Scandinavia with most of Britain maintaining fine and reasonably warm weather in any sunny sells between some cloudier spells.

The GFS Ensembles continue to promote a warmer phase of weather over the coming two weeks most effectively in the South. With rainfall limited from most members there is a good chance that many areas will see a good deal of dry weather with some warm sunshine at times, especially in the South with normal values in temperatures also in the North for most of the time.

The Jet Stream continues to feed further North settling in a NE direction across the British Isles through next week.

UKMO today shows a breezy, unsettled but mild start to the week with some rain at times before the start of a trend to drier and warm conditions from the South begins from midweek.

GEM follows the theme albeit rather slower with the mild and changeable weather lasting deeper into the second half of the week before High pressure finally wins over from the SE warming and drying things up for many in time for next weekend with some warm sunshine.

NAVGEM too sees the mild SW flow last until the second half of the week before High pressure builds across the South from France late next week with a warm settled spell with some sunshine likely beyond the end of it's run.

ECM too is no exception with the mild SW flow giving way to warm High pressure late next week as a centre of High pressure eventually develops in the warm air over much of NW Europe with warm air being drawn NW from France. Eastern coastal areas may be plagued by low cloud and low temperatures should the flow back more East.

In Summary there seem universal consensus for a change to warmer weather. this comes in two phases with a mild and rather unsettled period between the weekend and the middle of next week before things begin to loo potentially more summery later in the week as pressure builds from the South and settles not far from the UK. With the rains of early in the period it's good news for farmers, growers and the like as it looks like the risk of frost is much reduced or non-existent once we move out of the next few days and with warm sunshine developing with time the growing season will begin to race away.

[Paul]

Latest forecast from Michael Fish - warmer but often unsettled..

 

[MR EXTREMES]

GFS/ECM ensembles are pretty much in line with each other, even to day 10 with a NW/SE divide with the drier, more settled weather moving north in time. By day 10 both have mean heights just to our south with an anti-cyclonic westerly over us

Edited April 11, 2013 by model rollercoaster

[Milhouse]

Some parts of northern England may see higher minima on Saturday night than maxima during the last 2 months.

 

 

Unfortunately Sundays warmth has been toned down and it now looks a very mild day but not a warm one except for the far SE. But the general theme for next week remains the same, and that is one of much higher temperatures but spells of rain at times interspersed with drier interludes and remaining breezy. Typical April.

 

[Summer Sun]

Some parts of northern England may see higher minima on Saturday night than maxima during the last 2 months.

 

 

Unfortunately Sundays warmth has been toned down and it now looks a very mild day but not a warm one except for the far SE. But the general theme for next week remains the same, and that is one of much higher temperatures but spells of rain at times interspersed with drier interludes and remaining breezy. Typical April.

 

 

Sunday still looks warm to me 20c remains possible in any sunny periods it will feel quite warm especially with a warm wind

 

Edited April 11, 2013 by Gavin.

[Milhouse]

20c might just be achieved in East Anglia. Considering we are languishing at just 5c now its a big improvement for my area too.

 

GFS has a HP building at T+144.

 

 

Temperatures fairly cool in the north as -5c uppers make an appearance but maxes of 15-16c for southern areas.

 

Edited April 11, 2013 by Milhouse

[Summer Sun]

Fairly big differences at t120 tonight from GFS and UKMO

 

 

Miles apart at t144 as well

 

Edited April 11, 2013 by Gavin.

[Guest pjl20101]

It does now look like retrogression is on the cards with the HP moving NWwards towards Greenland according to the GFS 12Z. Would be interesting to hear from philnw with whether the NAEFS supports this too as that means our milder weather would be wiped out currently with northerlies. See if the ECM agrees.

[Milhouse]

It does now look like retrogression is on the cards with the HP moving NWwards towards Greenland according to the GFS 12Z. Would be interesting to hear from philnw with whether the NAEFS supports this too as that means our milder weather would be wiped out currently with northerlies. See if the ECM agrees.

Which it hasnt done up to now. The ECM 0z has low pressure firmly in place where high pressure would have to be for there to be a retrogression towards Greenland.

[mushymanrob]

not bothered by the apparent downgrade of sundays weather, its still going to be far better then of late. models still toying with the atlantic next week but detail uncertain. itll be interesting to see if that ecm hot spell is still there. worth commenting on a cold plunge again into central europe albeit in fi. one to keep an eye on.

[UV-RAY]

Which it hasnt done up to now. The ECM 0z has low pressure firmly in place where high pressure would have to be for there to be a retrogression towards Greenland.

Will be interesting to see which one is right, as a rule the GFS is good at picking up signals for Greenland blocking but after its woeful performance over the last few months I wouldn't back it just yet.

[Guest pjl20101]

I think sometimes the GFS goes OTT but there is a strong suggestion that the AO could do negative again as was mentioned Millhouse in one of the latest vids done by Gavin p. It would be very interesting to see what MJO phase 7 or 8 looks like in mid to late April. Because I think that is where we are heading.

That is one of the reasons why the atmosphere is so variable at the moment and having massive implications not just here but worldwide.