Model Output Discussion - What does April have in store?

[Methuselah]

Onwards and upwards!  

But not a lot of rain:         

[MATTWOLVES 3]

GFS 6z showing the improving situation towards mid month with settled conditions hopefully taking hold. I no folks don't take much notice of the daily express, but there is an interesting piece in there from weather outlooks Brian Gaze, stating the possibility of a Spanish plume and very high temps later in May.... One to keep an eye on for sure. 

Edited April 30, 2019 by Mattwolves

[knocker]

Currently temps quite respectable away from some west coast regions, in particular N. Ireland and western Scotland. Here because the double front structure at midday is still causing some patchy rain. This will be the last sat image posted from the facility at Dundee as funding has ceased and it has to close. A great shame.

Through this evening and overnight the cold front and showery rain will progress slowly east covering much of the country by dawn with only eastern regions retaining clear skies

Edited April 30, 2019 by knocker

[johnholmes]

That is really sad, I've used it for a good many years, and never put much in either!

[SunnyDazee]

5 hours ago, Mattwolves said:

Quite an area for disagreement, usually when they state Northern and Central areas, its a reference to Scotland and the central swathe of the UK, (ie) Northern England, and to say Central, Southern parts would include larger parts of the Midlands, Southwards! I suppose you could put the North Midlands on the boundary to the more central section of the uk. Just looking at the GFS 6z out to day 8, still looking pretty ridgey, temps nothing special, probaly around average, so a rather uncertain start to May. Perhaps it will be the mid or final 3rd before we see an upturn in the more settled and warmer conditions. 

Thanks for that mate, as for the weather I agree, MO 3 month outlook had it 50% hottest category for the next 3 months but it’s weird considering there’s currently no signs of it. Early to Mid May will be below average, wondering if late May will rescue it as it usually does. Late May has been a pre summer for the last few years hopefully comes up trumps again 

[Methuselah]

Oh for God's sake, God. Why now!

[Frosty.]

Looking at the ukmo 12h, first we get the arctic plunge with a general increasing frost risk and showers, the showers mainly for the eastern side of the UK and far north which could be wintry on hills but then by day 5 there is a noticeable improvement as pressure rises, the northerly cut off at this point and then day 6 looks even better as in warmer and largely fine, especially further s / se but still chilly nights with slight overnight frosts.

Edited April 30, 2019 by Frosty.

[Cheshire Freeze]

20 minutes ago, Ed Stone said:

Oh for God's sake, God. Why now!

Quite a potent Arctic blast for May. 

12z has a lovely profile by days 5-7, if it was winter we'd see the - 10 and possibly - 15 upper temp barrelling down through the UK. 

The GFS is diverging with the UKMO though. The former gets sufficient heights into Greenland and retrogrades continental troughing. 

Edited April 30, 2019 by CreweCold

[knocker]

The main problem, as I see it and according to the gfs, vis the beginning of next week is that any retreat east of the trough to allow warmer air in from the south west is delayed by a further disturbance tracking south within the upper trough. But detail of all of this is still very uncertain

Edited April 30, 2019 by knocker

[mushymanrob]

not liking the emerging trend, a southerly tracking jet, strong block over greenland, low pressure over scandinavia... a recipe for missery.

 

[Derecho]

GFS is cold yet again but the UKMO is a lot better, keeping the high over the UK rather then shifting it out west. Here is hoping that comes off to give a good bank holiday after a cold end to the week...

[Methuselah]

A glimmer of hope, by Day 16 -- but, otherwise, it's as you were:

 

[Don]

40 minutes ago, CreweCold said:

Quite a potent Arctic blast for May. 

12z has a lovely profile by days 5-7, if it was winter we'd see the - 10 and possibly - 15 upper temp barrelling down through the UK. 

The GFS is diverging with the UKMO though. The former gets sufficient heights into Greenland and retrogrades continental troughing. 

Problem is, it wouldn't come off it was winter!  A different start to May compared to last year, though!

[Cheshire Freeze]

21 minutes ago, Quicksilver1989 said:

GFS is cold yet again but the UKMO is a lot better, keeping the high over the UK rather then shifting it out west. Here is hoping that comes off to give a good bank holiday after a cold end to the week...

The thing is, looking at plausibility, the GFS looks to be a shade ahead. The UKMO output is an 'on the fence' type of scenario--the major players being the Scandi and Atlantic troughs. Something would have to give. 

[Derecho]

2 minutes ago, CreweCold said:

The thing is, looking at plausibility, the GFS looks to be a shade ahead. The UKMO output is an 'on the fence' type of scenario--the major players being the Scandi and Atlantic troughs. Something would have to give. 

Agreed, it looks like the GFS has more backing at the moment... fine margins these setups aren't they?

If GFS comes off we stay in a cold NE flow for a fair bit of time and probably see a below average CET for the first half of the month. If the UKMO comes off then that could easily pave the way for a warm first half.

[knocker]

11 minutes ago, Quicksilver1989 said:

Agreed, it looks like the GFS has more backing at the moment... fine margins these setups aren't they?

If GFS comes off we stay in a cold NE flow for a fair bit of time and probably see a below average CET for the first half of the month. If the UKMO comes off then that could easily pave the way for a warm first half.

If the gfs comes of this is the 5-110 scenario.

 

Edited April 30, 2019 by knocker

[Methuselah]

I can see see some really quite horrible weather, early next week: 10C, largish patches of cloud and not enough convection for anything exciting to happen?

 I hope I'm wrong!

[I remember Atlantic 252]

1 minute ago, Ed Stone said:

I can see see some really quite horrible weather, early next week: 10C, largish patches of cloud and not enough convection for anything exciting to happen?

 I hope I'm wrong!

Same as January, but of course wind would be from other direction with much warmer nights

[Frosty.]

As per the 6z, the GEFS 12z mean looks incredibly good later with high pressure extending from the azores to scandinavia  and much warmer surface conditions and the PFJ up near Iceland across to northern Norway.

Edited April 30, 2019 by Frosty.

[Methuselah]

Et voila, c'est improvement! 

[Methuselah]

Here are the 12Z temp and precip ensembles:

  

[chrisbell-nottheweatherman]

18 minutes ago, Ed Stone said:

Here are the 12Z temp and precip ensembles:

  

At least there are a few more prominent ppn. spikes there than in some other recent outputs!

[Mike Poole]

ECM at T96 (Saturday)

Looks chilly but largely dry, through to T144 (Monday)

Similar,gradually warming.  Current model output not clear on way forward from this weekend.  T144 chart on NH view

Likely a response to the strong final warming in the strat?  

GFS forecast taking it beyond -2SD and quickly too, think we need to see some clarity on the final warming out of the vortex before the summer pattern will become more apparent.  So I'd give a week or so before expecting to make any tentative predictions for summer other  than the way the models are leaning and the MO contingency planners forecast, which both are still for likely substantially warmer than average, no clear signal on precipitation.  But for the operational models at this point the long term destination is far from clear....

Edited April 30, 2019 by Mike Poole

[knocker]

This would appear to be about energy distribution with the Atlantic winning a partial victory by Tuesday but temps still below average, particularly over northern Scotland. Still all to play for

 

[Frosty.]

Amazing how cold it stays on the Ecm 12z, especially further north..plenty of frosty nights I would think.

Edited April 30, 2019 by Frosty.