Model Output Discussion - 15th April Onwards

[ANYWEATHER]

GFS 12z remains on course to bring changes as we move to May with high pressure building strongly to our east before moving over the UK as we enter May, although the warmth GFS was showing this morning has gone the high pressure to our east hasn't

UKMO is unsettled for all its run

Check out the Cfs. Shows a low pressure dominated picture in the months ahead allbeit some settled anticyclonic shortlived spells as well. Also a pattern from the Cfs as I ran through the sequence I noticed was that Northern Blocking looking possible ,showing signs of the Northern half of the Uk drier than the South......

[Cheshire Freeze]

Check out the Cfs. Shows a low pressure dominated picture in the months ahead allbeit some settled anticyclonic shortlived spells as well. Also a pattern from the Cfs as I ran through the sequence I noticed was that Northern Blocking looking possible ,showing signs of the Northern half of the Uk drier than the South......

This is something I have been keeping half an eye on. Not for one moment do I think summer will be a write off; however late May into June I envisage to feature southerly tracking, slow moving lows and have done for quite a few weeks now. This would fit with what you are suggesting the CFS is showing. Late July into August for a shot at some real heat IMO.

[keithlucky]

Dear mother nature,

Would you please hurry up high pressure establishing it's self across the U.K, for Gavin's sake

Thank you

lol

[bluearmy]

I can see both posts as being correct if that makes sense.

I think its possibly too soon ba to seem (note I say 'seem') ba to be as beieiving as you appear to be about the trend and its end result. I agree the trend is there but I would want to see this, from all 3 ouputs I use, over another 3-4 days before I would start to think that a pattern change is under way.

I perhaps err more towards GP's version at the moment but see my comments in the above paragraph.

3-4 more days of the same trend happening, especially if the upper pattern way west over N America and the Pacific appears to be showing a change, then it would be time to suggest a change is on its way. Not before early May at the earliest is my estimation at the moment?

that is a fair point john re timing. when a well set pattern changes, the models do tend to write the epitaph a bit too soon and the result is that any change is more likely to be delayed by 5 to 7 days.

[Milhouse]

At least the next 10 days will see a gradual rise in pressure over the continent. At the moment its unusually low pressure over central Europe which isnt going to do our chances any good of getting something warm. In 10 days time pressure looks much higher over Europe which will lead to a greater chance of a southerly developing. I dont expext low pressure to be departing our shores for good any time soon but once HP takes hold over Europe it can possibly exert its influence quite widely.

[coldwinter]

CPC 8-14 dayer looks the same as yesterdays, not overly warm but as step in the right direction for those looking for warmer weather.

Ryan.

[bluearmy]

CPC 8-14 dayer looks the same as yesterdays, not overly warm but as step in the right direction for those looking for warmer weather.

Ryan.

ryan - note the mean position 552 dam thickness remains almost clear of the entire country through two weeks. that means the upper air remains cool and surface conditions are unlikely to be above average, temp wise, the odd day apart. beyond that, we wait to see how the picture is likely to settle.

[PubliusEnigma]

Looking at the links/teleconnections I use throughout the year I honestly cannot see any real change in the weather pattern for the UK this month. Indeed it does begin to look like this weather pattern is with us into May-how far into May I have no idea.

Looking at the links/teleconnections I use throughout the year I honestly cannot see any real change in the weather pattern for the UK this month. Indeed it does begin to look like this weather pattern is with us into May-how far into May I have no idea.

John, I fear for a very cool albeit occasionally sunny spring with frosts lasting possibly until the end of May. well outside the current longest range teleconnections.. well maybe a couple of weeks more than you have speculated on. The problem for any lovers of warmth is the deep rooted and persistent trough established around the 0oW roughly speaking.. As we get into May the Russian High will become established as has been the case each summer since 2007 which causes a downwind trough over or close to the UK with the Azores being pushed back out into the western atlantic. So as you say another month perhaps of temps by day 12 to 13oC on average or in the region of. We need to look for signs of the Greenland HP asserting itself towards the end of April as this will lock us in to a potentially long spell of weather from the Northerly quarter. This could have dire consequences for the ongoing drought as late spring Northerlies are notoriously dry.. I can't honestly see a pattern change. Could March end up as our warmest month until June or even July.. speculation of course ;o)

[coldwinter]

ryan - note the mean position 552 dam thickness remains almost clear of the entire country through two weeks. that means the upper air remains cool and surface conditions are unlikely to be above average, temp wise, the odd day apart. beyond that, we wait to see how the picture is likely to settle.

Thanks, but its a step in the right direction for those looking for warmer weather.

Ryan.

[johnholmes]

John, I fear for a very cool albeit occasionally sunny spring with frosts lasting possibly until the end of May. well outside the current longest range teleconnections.. well maybe a couple of weeks more than you have speculated on. The problem for any lovers of warmth is the deep rooted and persistent trough established around the 0oW roughly speaking.. As we get into May the Russian High will become established as has been the case each summer since 2007 which causes a downwind trough over or close to the UK with the Azores being pushed back out into the western atlantic. So as you say another month perhaps of temps by day 12 to 13oC on average or in the region of. We need to look for signs of the Greenland HP asserting itself towards the end of April as this will lock us in to a potentially long spell of weather from the Northerly quarter. This could have dire consequences for the ongoing drought as late spring Northerlies are notoriously dry.. I can't honestly see a pattern change. Could March end up as our warmest month until June or even July.. speculation of course ;o)

I really have no idea beyond the first week or two in May-you may be right

[johnholmes]

that is a fair point john re timing. when a well set pattern changes, the models do tend to write the epitaph a bit too soon and the result is that any change is more likely to be delayed by 5 to 7 days.

yes I think another 3 days and we can get a fair idea of which way the overall pattern is trending from the 3 outputs. It does suggest at the moment that the trend for both the UK trough and the +ve area/ridge way east is westwards. I'll give another comment in about 3 days but its an interesting set up.

[Lewis]

A very unsettled period coming up this week, after a mostly dry and bright day for many areas yesterday, the change will be brought about by a large area of precipitation associated with an approaching low pressure system off the western coast of Ireland.

If you look on the latest fax chart you can clearly see the messy pattern that we have, it's a continuing theme throughout the week but I have a feeling tomorrow afternoon and early evening may bring a few surprises to some people looking for electrical activity/convective weather.

The latest fax chart illustrates the occluded front brought about a low pressure system

http://cdn.nwstatic.co.uk/fax/PPVE89.png

It's very possible that we may see some thunderstorms embedded as the occluded front moves through, it happens, but it all depends on a few ingredients/key features, what we'll see tomorrow is a warm occlusion, the air mass overtaking the warm front is warmer than the cold air ahead of the warm front and rides over the colder air mass while lifting the warm air.

Behind the occluded front we have a different boundary of warmer, more moist air, with low surface pressure, they will be a couple of hundred K/JG CAPE kicking about, with a negative LI (Lifted index).

As the occluded front pushes through, showers will form quite widely across North Western parts of England, along with Wales & North Western Scotland experiencing a rash of slow moving heavy showers, becoming very organised at times, so plenty of precipitation to be had tomorrow.

As we head in to the afternoon tomorrow, showers will start cropping up just about anywhere, with some fairly heavy ones for the midlands running into Lincolnshire and later East Yorkshire.

A messy picture, but with it comes much needed rainfall, it's going to be a fairly active week this week, with rain, gales, thunderstorms, hail...

Will keep an eye on developments tomorrow of the convective type

Regards

Lewis

Edited April 16, 2012 by UK Storm Chasers

[Snowmad79]

Much needed rain for some and too much for those who are sick of it. What happened to the strong AH ? It bums our winter then just when things turn gorgeous in the NW it goes into hiding!

The Jet looks to be interested in staying more south than we saw during most of winter so cold, wet and windy sums up the forseable for me.

I honestly thought we'd be seeing another bout of the Azores showing by now or Mild mucky SWerlies so not amused by what I see. On that note I'd just like to say how horrible this cold wet windy weather is!

[ANYWEATHER]

The days ahead show some support from the Ecm and Gfs with a Southerly tracking jet courtesy of Northern Blocking. Good news for the drought affected areas of the Uk as this synoptic pattern often brings plenty of rain to the Southern Uk as flabby ,slow moving areas of low pressure affect more picticularly Southern parts of the Uk, as Highlighted here......

[shedhead]

Yes AW certaintly a very unsettled outlook and yet more signs that the lastest declartion of another 17 drough areas was another needless, knee jerk reaction. Things are shaping up to ensure this cool, wet spell could well be a protracted one imo, maybe dominating the remainder of Spring and regrettably perhaps even early Summer. Massive get out of jail card free here for those water companies that have and continue to allow billions of gallons to leak away annually, had it remained dry perhaps the heat would finally have been turned up on them, but alas that's now looking increasingly unlikely.

Edited April 17, 2012 by shedhead

[johnholmes]

Yes AW certaintly a very unsettled outlook Things are shaping up to ensure this cool, wet spell could well be a protracted one imo, maybe dominating the remainder of Spring and regrettably perhaps even early Summer.

that is about the model the rest of your post has nothing to do with model discussion shed so come on stop misusing the thread please?

[Coast]

Can we stick to the model discussion please and use this thread to talk about the UK drought and how you think the authorities or service companies are performing:

http://forum.netweather.tv/topic/71020-2012-uk-drought/

[Cheshire Freeze]

Looking at the model output, some places have the potential to turn very wet during the last week of April as the trough stalls just to the west against rising pressure to the east. After this I suspect that pressure may rise for a short period (as per MetOffice long ranger) before unsettled conditions take over once more. It looks like warming up gradually though.

[Alex]

Looking at the model output, some places have the potential to turn very wet during the last week of April as the trough stalls just to the west against rising pressure to the east. After this I suspect that pressure may rise for a short period (as per MetOffice long ranger) before unsettled conditions take over once more. It looks like warming up gradually though.

No different to this week which in my eyes looks very wet with the low only slowly receeding away!

The big difference towards the end of April on the 12z is the trough pushing west allowing us to be on the warmer side and thus, temps really warming up also slowly but surely the settled weather comes later in the run as an anticyclone settles to our north promoting easterly winds.

This trend has been evident for a few days now so the big question will it come to fruition?

[Cheshire Freeze]

This trend has been evident for a few days now so the big question will it come to fruition?

Quite probably, I've been advertising a drier, warmer start to May for the past few weeks.......then the unsettled fun and games start later in May?

All very consistent with CFS modelling

Edited April 17, 2012 by CreweCold

[Alex]

Well hopefully in line with 2006, then June/July can be left to the warmth and sun!

[Robbie Garrett]

I reckon it wont be as settled as people think, slightly think models are overdoing this situation and that the trough is possibly positioning itself in a good position for some persistent thunderstorms and probably temperatures in the mid-to high 20s. Settled, far from it. But correct me if I am wrong we are well overdue something like this.

[Robbie Garrett]

Also just thought I'd like to add, that the MetOffice have also noted something very similar to what I have just said. "Towards the end of the month, however, temperatures will perhaps rise above average, especially in southeast England, bringing an increased chance of humid and thundery conditions."

Spanish Plume bigtime anyone???

That said, conditions into May look likely that some places could become quite settled (I take it high pressure across Europe) but the trough will be near by, settling up nicely for Summer and for ONCE we could be in for a scorching few months aswell as some pretty damn wet ones. Seems to me that the case is, Summer will be a mixed bag but far from dull, some hot days (probably late 20s/low 30's) with the evenings and nights being very wet (this is probably where the CFS has got it's precipitation levels from) with the idea of high pressure across western europe with a trough situated where the GFS is indicating slightly to our west, providing some very humid and thundery conditions.

Let's see how this develops but the GFS agree in the shorter ranged long term for the above.

[Summer Sun]

ECM is unsettled for its run tonight with Low Pressure dominating at the end of ECM's run some warm air get's dragged up from southern Europe and moves close to the south east

That could have the potential for some thunderstorms if it moved west a bit more

Edited April 17, 2012 by Gavin D

[damianslaw]

Its a very unsettled outlook with the trough anchoring itself directly over the country going nowhere fast. Slow moving heavy rain or showers for many - in such set ups always very tricky to say just where the heaviest precipitation will form.

Next week - some signals that the trough will advect slightly to the west (only slightly) as we see rising pressure to our east begin to edge westwards which could result in a warm up but also a very thundery picture as we see significant convection take hold.

Its an interesting synoptic set up - very much a July-August type set up rather than an April set up, thundery plumes don't tend to stick around for long in the spring, and I very much doubt we will get rid of the trough that quickly, indeed a quick return to chilly easterlies/northeasterlies and status quo (i.e. what we have now) would probably occur suggesting a continuation of the very unsettled and average at best temps for the start of May.