Model Output Discussion - 15th March onwards

[Rain All Night]

There are no dramas from this afternoon's ensembles concerning next week, but beyond that, the ECM ensemble is just as keen as it was this morning (and as keen as the 12z deterministic is) to give us a cold Easter... 

EDIT: Lol, I just remembered having posted the below chart yesterday morning. I've seen it said here that the GFS likes to pick up signals first, and then drop them before the other models pick them up...

Edited March 28, 2023 by RainAllNight

[Allseasons-Si]

The ECM has been consistant in bringing a colder flow from the NE from day 8>10 over the past few runs

the control follows somewhat with the same pattern...

and a pretty cold outlook from the EPS ens with blocking the form horse to our N/NW 

a waisted situation i know at this time of the year but snow isn't unheard of going into the easter period but i wan't some warmth now as i think the majority in here does

hang on in there peeps.

[Alexis]

Quite big disagreements this morning.
 

GFS and GEM cleanly bring in the high pressure belt.

UKMO briefly brings it in before a low shunts it aside.

ECMWF brings in the low and it departs leaving an easterly in its wake.

[Nick2373]

 

And finally the 00z  brings in long awaited warmth, the trend as been there a few days now things starting to firm out.

[Rain All Night]

1 hour ago, Alexis said:

Quite big disagreements this morning.
 

GFS and GEM cleanly bring in the high pressure belt.

UKMO briefly brings it in before a low shunts it aside.

ECMWF brings in the low and it departs leaving an easterly in its wake.

I guess we will have to wait until the models can see the nature of the second low pressure system more clearly.

The ensembles seem to just about favour the ridge fending off the low from the west, with ECM's North Sea low option also seen in a few of the MOGREPS-G ensemble members.

These ECM ensemble meteograms for the south coast depict the initial change this weekend, then a possible wet blip on Tuesday, followed by a spell of northeasterly winds and below-average temps running through the Easter bank holiday weekend...

Edited March 29, 2023 by RainAllNight

[ANYWEATHER]

All I can say it's a massive gamble for any forecast going out over Easter, although I do see a trend of it being quite chilly out of any sunshine ,if that's we are lucky

[Daniel*]

2 hours ago, Nick2373 said:

 

And finally the 00z  brings in long awaited warmth, the trend as been there a few days now things starting to firm out.

Meanwhile ECM ens more bullish on very cool theme.

[Rain All Night]

If you watch the 2m temp anomaly animation for the ECM ensemble, it looks like it wants to give us both of the cold shots that have previously been seen on different ensembles - a shot from the east for southern Britain in the working week before Easter, and then shot(s) from the north/northeast over the bank holiday weekend...

Another small update, which contradicts the above, GFS 6z lets the second low (merged with another one behind it) breach the ridge on Tuesday and lets the resulting westerly flow continue through until the ridge pushes north again on Good Friday (which is still FI)...

EDIT: Another twist - although we didn't get an ECM para det run on Meteociel this morning, we do have a set of meteograms from this morning's ECM para ensemble run, which suggest that the para is more firmly against the "Tuesday blip" idea than the operational is. I will leave it to you to look these up for your own locations should you wish:

Current ensemble: https://charts.ecmwf.int/products/opencharts_meteogram/overview/epsgram?base_time=202303290000&epsgram=classical_10d&lat=50.7167&lon=-2.0&station_name=Poole

Upgraded ensemble: https://charts-dev.ecmwf.int/products/opencharts_meteogram_esuite/overview/epsgram?base_time=202303290000&epsgram=classical_10d_48r1&lat=50.7167&lon=-2.0&station_name=Poole

Edited March 29, 2023 by RainAllNight

[Nick2373]

1 hour ago, Daniel* said:

Meanwhile ECM ens more bullish on very cool theme.

Control and GFS Op will drop in line with the mean next few days, delivering warm just slightly above average temps

[ANYWEATHER]

32 minutes ago, Nick2373 said:

Control and GFS Op will drop in line with the mean next few days, delivering warm just slightly above average temps

Really....how can you be so certain?

[Cambrian]

The 6z GFS op at day 10 and day 12.

Ah, if only these charts were for the Easter weekend….

  

then this high pressure might look very apt too.

 

The GFS clearly having the UK and Ireland in mind with its very kind placing of a 1030mb+ gift, though of course at this (free) range, it might well be over-egging it. It certainly deserves a Grade A for now. 

[mushymanrob]

I dont like this, at all. High pressure ridging just West of us, linking with the strong high over Greenland. Low pressure to our far Northeast, this smacks of a surface flow from the northeasterly quadrant.. although itll be predominantly dry, itll be cool too, with Eastern and Central areas prone to that dreadful low grey Northsea cloud.

This isnt what we want to see in April..

[Rain All Night]

4 minutes ago, mushymanrob said:

I dont like this, at all. High pressure ridging just West of us, linking with the strong high over Greenland. Low pressure to our far Northeast, this smacks of a surface flow from the northeasterly quadrant.. although itll be predominantly dry, itll be cool too, with Eastern and Central areas prone to that dreadful low grey Northsea cloud.

This isnt what we want to see in April..

Not sure how much reassurance this will be, but the GEFS has been losing interest in Greenland over the last few runs. The 6z moving average mean below shows this:

[Nick2373]

1 hour ago, ANYWEATHER said:

Really....how can you be so certain?

Trend which seems to picking up momentum on each run, granted things can change at a drop of an hat, note ppn spikes at the bottom are dropping each run which is also usually a good indicator 

[Rain All Night]

MOGREPS-G 6z has its control member and a few perturbations contemplating the minor cold shot from the east next week that we've seen suggested in other ensembles.

For what it's worth, while MOGREPS 6z has plenty of members showing the possible westerly relapse on Tuesday, the ECM ensemble 6z hardly shows that possibility at all, preferring any attack to look like this instead (sort of from the north but not, I don't know quite how you describe it):

Edited March 29, 2023 by RainAllNight

[Rain All Night]

This isn't looking as amplified in the semi-reliable timeframe any more, it's got me a little nervous...

The GFS ensemble mean manages to stay just about the right side of a fail up to T+168h...

FI looks like it's going to be fine again though, the ridge starts pushing north again around day 8.

Edited March 29, 2023 by RainAllNight

[Methuselah]

And here's the latest from the Met. Office:

 

[Rain All Night]

1 hour ago, RainAllNight said:

This isn't looking as amplified in the semi-reliable timeframe any more, it's got me a little nervous...

The GFS ensemble mean manages to stay just about the right side of a fail up to T+168h...

FI looks like it's going to be fine again though, the ridge starts pushing north again around day 8.

GFS ensemble FI looks pretty much spot on for Easter!

Edited March 29, 2023 by RainAllNight

[stodge]

Evening all

My eyes are drawn to the trough and LP developing over Iberia. It’s this rather than Greenland blocking which opens the door to an E’ly. It’s something we see in late spring and brings unsettled weather with showers and storms to southern Britain while the north and especially north west Scotland does well.

The trough develops over the Western Sahara and Canaries and moves north - a broad but shallow feature on 12Z GEM but deeper and more defined with time on 12z GFS.

Let’s see if ECM develops a similar idea.

 

 

[Cheshire Freeze]

51 minutes ago, RainAllNight said:

GFS ensemble FI looks pretty much spot on for Easter!

Looks like the chance of a chilly easterly undercut to me. Perhaps sheltered N and W parts best looking at that?

[Rain All Night]

59 minutes ago, CreweCold said:

Looks like the chance of a chilly easterly undercut to me. Perhaps sheltered N and W parts best looking at that?

Dry though, right?!

Might need someone to explain ECM to me today, I can see it's dropped its unique North Sea low idea, but not sure other than that...

Edited March 29, 2023 by RainAllNight

[Polar Maritime]

Yes looking more settled into next week.

An active day especially for the South on Friday, With Gales and rough seas across the Channel.. Warnings are issued and will possibly upgrade nearer the time, Or warning areas could be further inland. One to keep an eye on. 

 

Edited March 29, 2023 by Polar Maritime

[Scorcher]

6 hours ago, mushymanrob said:

I dont like this, at all. High pressure ridging just West of us, linking with the strong high over Greenland. Low pressure to our far Northeast, this smacks of a surface flow from the northeasterly quadrant.. although itll be predominantly dry, itll be cool too, with Eastern and Central areas prone to that dreadful low grey Northsea cloud.

This isnt what we want to see in April..

It's not the worst setup for areas further west though where temps could end up average to above. It's definitely not ideal for the time of year but there are worse scenarios that could happen. I'd take that sort of setup over an April 2012 setup for example.

[I remember Atlantic 252]

Just now, Scorcher said:

It's not the worst setup for areas further west though where temps could end up average to above. It's definitely not ideal for the time of year but there are worse scenarios that could happen. I'd take that sort of setup over an April 2012 setup for example.

Agree with poster from Derby! horrible setup for this area, cold, max min around 6 degrees, grey with drizzle, all about location, W areas looking at sun and 15 degrees, very normal setup for this time of year

[Summer tyre]

2 hours ago, Methuselah said:

And here's the latest from the Met. Office:

 

Thank you for that. That's the clearest explanation of amplification I have seen. So while the AMPLITUDE of the waveform increases, this causes the lows piling in from the west to slow down and eventually, the pattern of the scandi high (in this instance, i recognise) blocks it so we get weather systems moving more slowly towards and over us, yes?