Model output discussion 9th April onwards

[I remember Atlantic 252]

14 minutes ago, damianslaw said:

Entering second half of April, when the atlantic traditionally settles into its deep sleep state, stirring slightly through May and awakening in June... 

Models continue to show a blocked set up, something slightly more unsettled in the north west by the end of the week into next week, before high pressure comes back on the scene and once again moving into a position that probably fails to deliver anything appreciably warm.. 

Not very exciting!

Aye, so normally the NW/Scotland sunniest period of the year? I always think April to mid June, then from late June, unsettled NW

[Methuselah]

20 minutes ago, Jon Snow said:

Just a reminder, if one were needed?..that winter could bite back in late April, on the cusp of May according to the GEFS 12z perturbation 4...and it it certainly did in late April 1981 when parts of the u k had over a foot deep of level snow with deep drifts...just saying!..we ain’t out of the woods yet! ️ 

[Northwest NI]

17 minutes ago, I remember Atlantic 252 said:

Aye, so normally the NW/Scotland sunniest period of the year? I always think April to mid June, then from late June, unsettled NW

I would concur with this assessment as a Northwesterner though April to July in a good year (2018). August is almost always poor but first two weeks of August last year was a great spell.

[Mike Poole]

ECM mean and spread T240:

Almost as nailed as it can be...the only way it could have been nailed better is a 1030 contour on the mean.  But we’ve got settled weather from now to at least the next 10 days, very little uncertainty for UK on the spread.  I doubt the clusters will show any different.  Dry, and a gradual warm up, that is the order of the days to come.  

[Mike Poole]

ECM clusters, just 1 until T168, then these for T192-T240, and T264+

Apart from cluster 4 the others seem to hold the UK high, but different things happen around it, in the later timeframe, heights towards Greenland look likely.  

[I remember Atlantic 252]

22 minutes ago, Northwest NI said:

I would concur with this assessment as a Northwesterner though April to July in a good year (2018). August is almost always poor but first two weeks of August last year was a great spell.

August probably the 4th most westerly month of the year, behind the obvious 3 DJF

[ANYWEATHER]

A very Blocked pattern but in the wrong place for warmth....lots of dry weather to come in the next ten days ahead ,Early next week potential for some slow moving perhaps severe thunderstorms  for England and Wales in picticular. ...looking forward to the potential. ..!

[Cambrian]

ECM 12z - life as an Atlantic low pressure system in the hard times of meridional flow.....

Day 3 : low, eastern seaboard, 1000mb, - hey yeah, I’ve made it to the coast!

 

Day 5 - this is easy man, past Newfoundland, 992mb, I’ll catch the jet for sure!

Day 7 - this is the life, mid-Atlantic and deepening, 976mb!

Day 8 - you know what, I fancy hangin’ out for a bit just off Greenland, 984mb

Day 9 - nowhere to go so just filling in time, 1000mb

 

Day 10 - Oh dear....hey, I’ll fall in with this new low, I’ve made it to the coast!

 

[Cheshire Freeze]

14 minutes ago, ANYWEATHER said:

A very Blocked pattern but in the wrong place for warmth....lots of dry weather to come in the next ten days ahead ,Early next week potential for some slow moving perhaps severe thunderstorms  for England and Wales in picticular. ...looking forward to the potential. ..!

None of the seasonals are promoting a scenario where we have a prolonged spell of HP to our E- (late spring to early summer are showing as returning a HP anomaly that stretches from the UK into the Atlantic). This would suggest settled and benign conditions will be the order of the day as we move forward over the next few weeks and into May. 

[Frosty.]

Looking at the ECM 0z operational we may actually feel warmth at some point next week, well, warm uppers (850’s) at least as we develop a SE’ly continental  air flow?...looking at the 0z runs generally..it’s a predominantly settled / anticyclonic  outlook but with some occasional very short-lived unsettled ?  interludes..as the Gfs 0z op shows. ️  

 

[mb018538]

All we can safely say at the moment is that it looks like staying very dry for much of the rest of April.

Doesn't appear that any heatwaves are likely with the high orientated in the wrong position, but just a slight change so we can cut off the cooler flow and see some mid to high teens days would be nice. I'm a bit sick of seeing 9-12c days now. Thankfully next week is looking a bit warmer!

[Methuselah]

This morning's GEFS temperature ensembles are still a bit naff:

    

[minus10]

20 minutes ago, Jon Snow said:

Looking at the ECM 0z operational we may actually feel warmth at some point next week, well, warm uppers (850’s) at least as we develop a SE’ly continental  air flow?...looking at the 0z runs generally..it’s a predominantly settled / anticyclonic  outlook but with some occasional very short-lived unsettled ?  interludes..as the Gfs 0z op shows. ️  

 

Yes nice to see a bit of warmth back on the table from the ecm0z Jon.

Not so much the gfs, however with the increasing strength of the sun and the continent hopefully warming up especially to the south it is only a matter of time for warmer temps to start showing(barring any further unwanted incursions from the north!)

A bit of rain is also welcome for the dry areas in the south and east. Patience needed i think.....

[Winter1981]

Hi All.  Occasional poster but regular viewer here. Something that has been puzzling me this week, is why when pressure has been so relatively high across the UK, have we seen such large amount of cloud build up during the day and a fair few showers? If you were simply looking at the pressure charts you would be expecting fairly sunny weather and certainly dry weather. Clearly there must be other factors at play other than just air pressure. Any meteorological explanations or pointing to existing material on the site would be most welcome. Apologies if this post does not belong here, but could not find a good place to post it.

[Methuselah]

19 minutes ago, Winter1981 said:

Hi All.  Occasional poster but regular viewer here. Something that has been puzzling me this week, is why when pressure has been so relatively high across the UK, have we seen such large amount of cloud build up during the day and a fair few showers? If you were simply looking at the pressure charts you would be expecting fairly sunny weather and certainly dry weather. Clearly there must be other factors at play other than just air pressure. Any meteorological explanations or pointing to existing material on the site would be most welcome. Apologies if this post does not belong here, but could not find a good place to post it.

These GFS charts (next Wednesday) may shed some light on your question: pressure is high right enough, but it's dragging the air in from the worst possible direction:

    

And then we're left under a coolish ridge -- none too warm and great if you like infill?

    

Edited April 15, 2021 by General Cluster

[Northwest NI]

25 minutes ago, Winter1981 said:

Hi All.  Occasional poster but regular viewer here. Something that has been puzzling me this week, is why when pressure has been so relatively high across the UK, have we seen such large amount of cloud build up during the day and a fair few showers? If you were simply looking at the pressure charts you would be expecting fairly sunny weather and certainly dry weather. Clearly there must be other factors at play other than just air pressure. Any meteorological explanations or pointing to existing material on the site would be most welcome. Apologies if this post does not belong here, but could not find a good place to post it.

Location, location, location. This type of high pressure and time of year favours sunshine in the West. Your location will do much better than mine 75% of the time so I wouldn’t worry too much.

[wellington boot]

Can anyone tell me which forecasting site/sites use ECM data exclusively? Is this even advertised?

[mb018538]

38 minutes ago, Winter1981 said:

Hi All.  Occasional poster but regular viewer here. Something that has been puzzling me this week, is why when pressure has been so relatively high across the UK, have we seen such large amount of cloud build up during the day and a fair few showers? If you were simply looking at the pressure charts you would be expecting fairly sunny weather and certainly dry weather. Clearly there must be other factors at play other than just air pressure. Any meteorological explanations or pointing to existing material on the site would be most welcome. Apologies if this post does not belong here, but could not find a good place to post it.

It's quite common in maritime climates such as the UK, where the air is often not dry enough higher up in the atmosphere to prevent cloud development from solar heating, hence why the cloud bubbles up through the morning from a clear start. The joys of being surrounded by the ocean! The surface high pressure caps the clouds from becoming tall cumulonimbus clouds, so you tend to see the sky full of fluffy cumulus clouds that don't usually produce rain. Just annoying infill that can spoil a good day. A good dry continental feed in the summer can eliminate much of this though.

We've also had a little bit of instability (vorticity) in the upper atmosphere in recent days, which has meant there has been enough energy and instability to develop some scattered showers - despite high pressure at the surface. 

Also there have been a few showers along the south coast where sea breezes have developed and been forced against the main northerly flow. Where these collide the air is forced to rise, which can produce showers. Mostly light or not reaching the ground as the air below the clouds is very dry and low humidity.

Lots going on as usual! Hope this helps answer some of your questions.

Edited April 15, 2021 by mb018538

[knocker]

1 hour ago, Winter1981 said:

Hi All.  Occasional poster but regular viewer here. Something that has been puzzling me this week, is why when pressure has been so relatively high across the UK, have we seen such large amount of cloud build up during the day and a fair few showers? If you were simply looking at the pressure charts you would be expecting fairly sunny weather and certainly dry weather. Clearly there must be other factors at play other than cloud tops up to just air pressure. Any meteorological explanations or pointing to existing material on the site would be most welcome. Apologies if this post does not belong here, but could not find a good place to post it.

A quick look at the Larkhill sounding for 0900 yesterday for one reason. The surface pressure is 1017mb but the lower levels are potentialy unstable and any trigger, say some surface heating,  could see cloud tops up to 12,000 fet or there abouts with the odd shower

Edited April 15, 2021 by knocker

[Methuselah]

Is the tail-end of the 06Z signalling the long-hoped-for demise of the cold air, or what? Or nothing? I do prefer green snot to blue snot!

    

[Guest]

The GFS Ops run only seems to be able to produce the coldest solutions possible from its ensemble pack. Time and time again the Ops running is a bit of a train wreck and again that's shown on the 06Z run. Feels like GFS is sniffing out a miserable trend to me.....:-(

 

 

[Methuselah]

06Z temperature ensembles are a right barrel of laughs!

    

 

[Methuselah]

Well, wouldn't this be just typical!

    

[Frosty.]

13 minutes ago, General Cluster said:

Well, wouldn't this be just typical!

    

Even some snaw Ed..now we’re talking! ️ come back coldies!!!...  

titttttter ye not  

[PiscesStar]

22 minutes ago, Jon Snow said:

Even some snaw Ed..now we’re talking! ️ come back coldies!!!...  

titttttter ye not  

YES I'LL TELL matt Wolves!!