Model output discussion 10/02/21

[stodge]

1 minute ago, damianslaw said:

Its just an observation based on past viewing, but yes the GFS can overdo heights over Greenland on occasion..

In terms of wintry precipitation it isn't just uppers that determine where snow falls, lots of other factors including dewpoints, lapse rates, intensity of precipitation - the heavier the more conducive to snowfall, time of day, strength of wind, whether there are any trough features.... admittedly by April uppers need to be appreciably lower than in January lets say, but April snowfalls are very surprising affairs - the added convective activity being a key factor. 

Agreed - I'm not expecting anything over lowland East London but wouldn't be surprised to see hail and thunder in a heavy shower. Further north and especially over high ground, snow is much more likely and over the Scottish mountains blizzard conditions for extended periods look probable and that would be welcome news if the Scottish ski resorts can re-open after April 12th.

[Methuselah]

2 minutes ago, Jon Snow said:

To my untrained ? ? tonight’s ECM 12z ensemble mean seems a bit further east than the operational at the end?..meh, don’t care...just kidding coldies!

East a bit, west a bit, south a bit, north a bit... Bernie, the bolt... FIRE!

[LRD]

7 minutes ago, Mike Poole said:

ECM clusters T192-T240, the key timeframe!

Cluster 1 is essentially the ECM op, cluster 2 is the UK significant cold spell, and cluster 3 is a surprise move to warm and settled.  I’d weight cluster 1 down a bit, and 2 up a bit, given what we’ve seen from GFS, and noting that model performs better re proper Greenland highs, to maybe put the cluster 2 scenario as slight favourite.  Where’s your money?

Thanks Mike

What I would say is that clusters 1 and 2 have pushed any potential proper cold back to Easter Sunday at the earliest where GFS is still looking at late Thursday/Good Friday for the change over (it was Wednesday into Thursday earlier in the week I seem to recall). Cluster 3 gives us spring with no cold at all! Unbelievable Jeff

Cluster 2 represents 1 in 3 members so if you were basing it on that without knowing what the GFS is showing you'd have to say it's the underdog

Edited March 27, 2021 by LRD

[minus10]

4 minutes ago, Mike Poole said:

ECM clusters T192-T240, the key timeframe!

Cluster 1 is essentially the ECM op, cluster 2 is the UK significant cold spell, and cluster 3 is a surprise move to warm and settled.  I’d weight cluster 1 down a bit, and 2 up a bit, given what we’ve seen from GFS, and noting that model performs better re proper Greenland highs, to maybe put the cluster 2 scenario as slight favourite.  Where’s your money?

Yes the mystery deepens. The 12z ecm is nowhere near as cold as the previous few runs with the clusters showing more runs for less cold or indeed warm outcomes than the very cold runs of late. Could the very warm air make a bid to get in via the south east backdoor so to speak courtesy of the west based NAO...Roll on the gfs 18z....

[minus10]

16 minutes ago, stodge said:

Evening all

Have to say the weather in the area between Greenland and Svalbard at T+192 might be "interesting". That's a 10m wind speed of 90-100 Km/hr - a constant wind speed of 55-60 mph, gusts to who knows what? That's a N'ly wind so anyone want to hazard a guess at the windchill - 850s are -24. 

So that's a -24c 850 and a steady windspeed of 60 mph, I'll leave someone to work that out.

Still looks very interesting for early April. One or two looking at the 12Z ECM run and calling it game over - to be fair, southern and eastern Britain wouldn't see much but that's a solid long fetch NNE'ly over western parts and the traditional eastwards correction so going to work out well for cold fans.

GFS OP keeps the cold going well into next month with a series of troughs forming close to the British isles - Control takes the HP further south more quickly and then send sit back over the British isles.

Yes Stodge, some of these synoptics being presented by the models are pretty amazing resulting in some extreme weather even for this time of year. You get the impression that whatever happens over in the UK, that part of the world from Greenland eastwards is in for a rough time. A lot of (pent up) energy in the atmosphere?...

[Mike Poole]

This really is such a weird set up.  GFS 18z at T72, Z500 and 2m temps:

Warm in the south! And then you’ve got the heights heading to Greenland for the cold plunge.  You couldn’t make it up, except this year has been worse than anything anyone could have made up, by a country mile!  

[Mike Poole]

Big difference here between ECM T144 and GFS 18z T138 at same time, this will determine which way this goes, the difference in the highlighted region is remarkable:

[Daniel*]

GFS returns with direct hit solution.

 

[Man With Beard]

2 hours ago, Mike Poole said:

ECM clusters T192-T240, the key timeframe!

Cluster 1 is essentially the ECM op, cluster 2 is the UK significant cold spell, and cluster 3 is a surprise move to warm and settled.  I’d weight cluster 1 down a bit, and 2 up a bit, given what we’ve seen from GFS, and noting that model performs better re proper Greenland highs, to maybe put the cluster 2 scenario as slight favourite.  Where’s your money?

Cluster 1 looks the middle ground, considering all three

[feb1991blizzard]

4 hours ago, LRD said:

Am I missing something here? The 850s don't get near -10 in England do they? Christ we couldn't even get snow of an E'ly in January with -5 or -6 uppers!

I

[Scorcher]

GFS continues to put the cold back. Yes there may be a brief direct hit later on, but it's still a long way off.

Interesting to see a warmer Wednesday on this run as well for most of England and Wales.

[Guest]

Just now, Scorcher said:

GFS continues to put the cold back. Yes there may be a brief direct hit later on, but it's still a long way off.

Interesting to see a warmer Wednesday on this run as well for most of England and Wales.

Put it back biggest understatement ever. GFS 18z has 17-18c in Scotland on Easter Sunday. This morning it had snow down to the south coast. 

[Iceman2606]

Why couldn't this happen in January!

[Don]

1 hour ago, Iceman2606 said:

Why couldn't this happen in January!

I doubt it will happen on the 6th April either.  Just teasers and nothing more......

Once the models start putting cold weather back, we know where it's going!  Expect a further delay on the morning runs.

Edited March 28, 2021 by Don

[Frosty.]

 

I’ve seen some extreme charts in my time on here but this from the GEFS 0z P12 takes the biscuit...for the time of year it’s sensational, no matter how unlikely but actually, the mean is still rock solid in support of the kind of charts that in winter would cause absolute meltdown on netweather!  

 

[Guest]

Phew, the major backtrack continues from GFS, firstly the a much warmer Wednesday and Thursday on offer and the snow risk for most has been completely removed for the Easter weekend (certainly down here anyway) and any cold spell looks like a standard chilly few days in April now. 

[Griff]

33 minutes ago, Alderc said:

Phew, the major backtrack continues from GFS, firstly the a much warmer Wednesday and Thursday on offer and the snow risk for most has been completely removed for the Easter weekend (certainly down here anyway) and any cold spell looks like a standard chilly few days in April now. 

To be fair it's around about this time frame that it abandons the correct solution for absolutely no reason

I wouldn't be planning for a BBQ next weekend just yet

[IDO]

...we all now must adjust our expectations with post-d8 GFS ops as it is now the latest version that was quite erratic over the winter, over-blowing mid and high latitude blocking. So both ECM and GFS post-d8 will agree more often with blocking but inevitably downgrades based on the data of the last six months.

However, as expected both overdid this, still the dropping of the trough and where the heights fixate are very tough for the models post-d7, so no surprise they have been fiddling around with the cold shot. Looking like the trend on the ops is for it to be too far west and therefore cool rather than wintry IMBY over the Easter long weekend (typical):

IMBY: Monday-Wednesday looks very mild and settled for the time of year. Looking fairly dry after the cold front arrives Thursday, so maybe not a total loss for Easter. The unsettled spell from the low arrives late Monday into Tuesday and both ECM and GFS agree here. A bit of a mix as we would expect at this time of year...

[LRD]

9 hours ago, feb1991blizzard said:

I was commenting on yesterday's 12z runs which seriously downgraded the cold and then you quote me using an 18z chart. Bit disingenuous that I have to say. Besides that chart is well over a week away. GFS was bringing in snow-ageddon by around Thursday/Good Friday 2 or 3 days back. Keeps getting pushed back. As often happens

Anyway on to the 0z runs and I'm still struggling to find any 'real' cold. Even GFS looks lame and that was the model which was predicting the worst/best* conditions

*depending on your preference

Edited March 28, 2021 by LRD

[LRD]

54 minutes ago, IDO said:

...we all now must adjust our expectations with post-d8 GFS ops as it is now the latest version that was quite erratic over the winter, over-blowing mid and high latitude blocking. So both ECM and GFS post-d8 will agree more often with blocking but inevitably downgrades based on the data of the last six months.

However, as expected both overdid this, still the dropping of the trough and where the heights fixate are very tough for the models post-d7, so no surprise they have been fiddling around with the cold shot. Looking like the trend on the ops is for it to be too far west and therefore cool rather than wintry IMBY over the Easter long weekend (typical):

IMBY: Monday-Wednesday looks very mild and settled for the time of year. Looking fairly dry after the cold front arrives Thursday, so maybe not a total loss for Easter. The unsettled spell from the low arrives late Monday into Tuesday and both ECM and GFS agree here. A bit of a mix as we would expect at this time of year...

The warmth is going by Thursday but the south might just squeeze one more day of relatively high temps as per the 0z ECM:

Easter weekend is looking cool but dry. If the sun breaks through it might be pleasant but too early to pin down detail of course

[Weather-history]

How's this for  absurdity by GFS on one of its ensembles, that has -21C air!!!, Lerwick -23C 850hpa air

Edited March 28, 2021 by Weather-history

[Cambrian]

Marked difference at 192h between the midnight runs of ECM and GFS. ECM goes for a straight northerly blast already into Scotland by that time, while the GFS develops a low between Greenland and Iceland during the previous day and brings it SE to the northwest of Scotland holding the cold air back a while. It’ll be interesting to see what the 06z GFS looks like.

ECM 0z 192h

GFS 0z 192h

[damianslaw]

Best letting the models roll for a good 48hrs before can begin to comment with some confidence what may happen over Easter. Firmly expect flip flopping on next few runs in placement of heights to the NW, never an easy place to forecast.

 

[magicpatch]

18 minutes ago, Mr Frost said:

@Alderc get the hat/gloves out tomorrow - chilly on the South Coast - maximum of 11/12C expected for Bournemouth.

 

Warmest spots in the UK tomorrow...London area, parts of Norfolk and Lincolnshire. 
17/18/19C - maybe even the first official 20C of the year. 

Very jealous - enjoy! 

Wow, that's puts these parts right on the border between 11/12c or 16c tomorrow!

I'm no expert in these weather charts, but really enjoy the posts by everyone. I'm keeping an eye on the 6/7/8/9th as we're planning to finally meet a friend outside of course, whom we've not seen for months, and right now it could be any sort of weather! 

[Guest]

26 minutes ago, Mr Frost said:

 

@Alderc get the hat/gloves out tomorrow - chilly on the South Coast - maximum of 11/12C expected for Bournemouth.

 

Warmest spots in the UK tomorrow...London area, parts of Norfolk and Lincolnshire. 
17/18/19C - maybe even the first official 20C of the year. 

Very jealous - enjoy! 

Yep always likely given ssts are only 8c and would surprise me to see plenty of coastal fog. Better to have that now opposed to May. That’s why really don’t want any more cold Shots, need the ssts to increase not decrease further from an already low base.