Model Output Discussion - What does April have in store?

[Frosty.]

The longer term GEFS 12z offers hope!!!!!!

[knocker]

Difficult to have much confidence in any detail outside the short range with the gfs, given the differences in 12 hours

[Frosty.]

And...a bit more hope!!!!!!!!

[Methuselah]

Hope springs from a place of not knowing!

 

[Fourty Point Three Degrees]

Latest gfs run suggests nothing of a return to the weather we had over Easter and nothing comes as warm for the whole run. Looks like the jet stream is getting itself into gear in FI aswell.  If this pattern really is a carbon copy of the same pattern we were seeing exactly this time last year then Summer should roaring in during week 1 of May.

[knocker]

This low west of Ireland seems to be causing problems as the gfs and ecm differ widely on it's intensity and track over the weekend The ecm version

 

[Frosty.]

The Ecm 12z becomes much cooler and trough dominated with bands of rain interspersed with sunshine and heavy showers which is the main theme with a risk of hail and thunder but also some drier, brighter interludes, mainly further s / se. Temperatures improve a bit early next week.

Edited April 23, 2019 by Frosty.

[Frosty.]

Signs of improvement waiting in the wings by day 10 but a lot of water from the sky before then!

[Mike Poole]

Looking at the ECM 12z on northern hemisphere view, I'm struck by how much of a dogs breakfast the next week or so looks.  I think the models are struggling at the moment, so what we can say is unsettled for the foreseeable 5 days or so, beyond that it is difficult to make any prediction from the op runs.  Notwithstanding longer term views of where we might be headed.  ECM:

[Frosty.]

Signs of recovery later on the Ecm 12z ensemble mean with trough filling next week and day 10 hinting at further improvement to follow.

[ANYWEATHER]

Evening! Cant wait for a change of airmass. I hate this European dusty airmass, roll on the Atlantic , we will have some wonderful cloudscapes ,fresh clean air and will be able to see the glorious hills in spendour from far away.  Good Riddance European air.

[I remember Atlantic 252]

41 minutes ago, ANYWEATHER said:

Evening! Cant wait for a change of airmass. I hate this European dusty airmass, roll on the Atlantic , we will have some wonderful cloudscapes ,fresh clean air and will be able to see the glorious hills in spendour from far away.  Good Riddance European air.

You and your Atlantic, It will be in charge Dec to Feb

[damianslaw]

40 minutes ago, Frosty. said:

Signs of recovery later on the Ecm 12z ensemble mean with trough filling next week and day 10 hinting at further improvement to follow.

Best sticking with the reliable at the moment which is quite a short timeframe 120hrs tops - quite a messy outlook probably prone to short-term developments.

The main force appears to be heights building to our NW, locking the trough into a position over the UK, however, as you say we may see it fill in situ becoming squeezed by heights both to the NW and also over the azores. Much will then depend on the behaviour of the PV lobe over N Russia and any developments off the eastern seaboard. We might see a build of heights through the UK aided by some warm air advection to our west, consequently we might see a northerly surface thanks to the impact of the PV lobe to our NE, if Greenland heights dig SW - this could occur should the trough fill and no further energy is spawned from the NE USA/Canadian seaboard.

This time of year is our most interesting synoptic wise, unusual synoptics often occur, northerlies and easterlies are more likely now than at any other stage of the year as the atlantic traditionally goes into its annual hibernation mode. 

 

[johnholmes]

This is the oddest chart I have ever seen from NOAA for their 6-10 day 500 mb anomaly chart.

Bear in mind I have checked them daily for 7-8 years at least!

The flow south of the heights rises and the elongated trough beneath it show a general westerly flow, of no great strength, into the UK.

Edited April 23, 2019 by johnholmes
spellings

[Frosty.]

7 minutes ago, I remember Atlantic 252 said:

You and your Atlantic, It will be in charge Dec to Feb

The first winter is over post on April 23rd..

Anyway, looking increasingly cool and unsettled but signs of improvement next week, becoming less troughy and temps recovering?

[viking_smb]

9 minutes ago, I remember Atlantic 252 said:

You and your Atlantic, It will be in charge Dec to Feb

nothing wrong with good old cold atlantic weather, hate this humid thundery weather.

[MATTWOLVES 3]

It's madness to be looking  up to day 5 with current patterns.... Shame on you!!!! So let's have a look deep into may..... Its all good, plenty of high pressure... Atlantic is in slumber mode... By by cool and miserable Atlantic garbage!!! Summer will soon be here and I can't wait... 

[knocker]

15 minutes ago, johnholmes said:

This is the oddest chart I have ever seen from NOAA for their 6-10 day 500 mb anomaly chart.

Bear in mind I have checked them daily for 7-8 years at least!

The flow south of the heights rises and the elongated trough beneath it show a general westerly flow, of no great strength, into the UK.

This evening's EPS John

[Flash bang flash bang etc]

32 minutes ago, viking_smb said:

nothing wrong with good old cold atlantic weather, hate this humid thundery weather.

What thunder?  

[Cheshire Freeze]

3 minutes ago, Flash bang flash bang etc said:

What thunder?  

Can't even remember the last time I heard thunder!

Fingers crossed that changes over the next few days. There should be a few possibilities with LP loitering around the UK.

[MP-R]

So much uncertainty across the models - makes for interesting watching. A reminder from years gone by what early May can often be like:

       

You get the picture. If we can avoid the Atlantic we're not doing bad at all. Both GFS models going for something from between north and southeast, the FV3 playing with a chilly northerly and the golden oldie showing a sinking low scenario with a warmer easterly over the top. I think it may be beyond May 10th that we see the next lengthy settled spell, although not dispelling a day or two before then between weather systems.

[knocker]

This simplistic progression overview may give an indication why it's quite difficult to pin down detail in the medium term at the moment

The NH 500mb profile and the Atlantic surface analysis for midnight

Today is transition day and showery rain is already into the south west. This will track NNE during the day, following the movement of the cold front, and quite intense thundery outbreaks will occur as the front hits the warmer air. In particular across the midlands and then further north, and leaving fresher and showery conditions in it's wake, Again much cooler in the north east courtesy of the onshpre breeze off the north Sea

Things get a tad complex through the night as the front continues north with thundery outbreaks over N. Ireland and western Scotland and then later in the night over north east Scotland  Further to this another band moves north into the south of England, courtesy of the occlusion associated with a low south west of Ireland.

This band moves north through Thursday but as the aforementioned low moves into southern Ireland it will be followed by frequent quite intense thundery showers, mainly concentrated down the western half of the country. Quite a breezy day and cooler than of late.

The low and occlusion quickly clear overnight and through Friday but conditions are very unstable under the umbrella of the upper trough and thus a very showery day on Friday. But another low is looming west of southern Ireland

The low tracks across the south half of the UK on Saturday bringing with it some wet and quite windy, perhaps reaching gale force along south west coasts, weather followed by showers.

This clears overnight and a transient ridge portends a much better day on Sunday, albeit a warm front associated with the next system is poised over Ireland

 

 

[knocker]

This is where it gets tricky as I suspect the METO are going to track the warm front through on Sunday bringing more wet weather but at this point the gfs goes into NH amplification overdrive. Because of the uncertainty I will avoid any detail and just stick to the gfs take on the amplification of the high pressure zones which relegates the Atlantic trough south resulting in a light easterly over the UK

Edited April 24, 2019 by knocker

[knocker]

Keeping in mind earlier comments the ecm doesn't push the amplification button a la gfs and does push some fronts through next week

Edited April 24, 2019 by knocker

[Fourty Point Three Degrees]

A million miles better looking run on the gfs 00z this morning, the kind of pattern that could suggest a quick return to dry weather as early as next week, although SE England may remain unsettled with a cut off low over France. The ecm run can be dragged & dropped into the recycle bin.