Model output discussion 9th April onwards

[Frosty.]

The thing I like about the Gfs 12z operational is the increasing chances of water falling out of the sky!...even a bit of snaw across Scotland!... ? ️ ...better than the tinder-dry drought like conditions surely?   

Edited April 25, 2021 by Jon Snow

[Methuselah]

Oh look -- is this the inevitable demise of those annoying tPV remnants? Or is it best put down to wishful thinking?

    

It is Day 10, when all's said and done!

[Frosty.]

May 8th looks interesting if you’re in the snow zone!... ...but really these charts show the duality of spring in a nutshell..or case as far as I’m concerned ....with cold air to the north and warmer air pumping up from the s / sw....one of the many reasons I’m a weather nut!  

 

[Methuselah]

Summer's on its way:         

 

[minus10]

9 minutes ago, General Cluster said:

Summer's on its way:         

 

Yes, at last some charts with at least some promise of warmth and rain.....for now....

[Methuselah]

No need to worry chaps and chapesses, the GFS operational run has only gone and flipped to the warm end of the ensemble. Bugger!

    

[Snowy L]

2 hours ago, Djdazzle said:

Thought I’d pop in looking for some warmth! At least those vile cold charts are in deep FI.

I’d rather get the iffy synoptics out of the way in May rather than having them in summer.

We said this about April. Our weather isn't mobile anymore, patterns get stuck for months at a time. If even half of what FI is suggesting actually happens then I worry for June and July too.

[Djdazzle]

10 minutes ago, Snowy L said:

We said this about April. Our weather isn't mobile anymore, patterns get stuck for months at a time. If even half of what FI is suggesting actually happens then I worry for June and July too.

On the other hand, patterns can flip at quite short notice. We have no clue about summer, apart from the fact that we are highly likely to get a couple of very hot spells, even if it’s generally unsettled.

[Don]

Just now, Djdazzle said:

On the other hand, patterns can flip at quite short notice. We have no clue about summer, apart from the fact that we are highly likely to get a couple of very hot spells, even if it’s generally unsettled.

2013 springs to mind there.  Following six below average months on the trot, July 2013 marked a return to a prolonged warmer phase again.

[Djdazzle]

1 minute ago, Don said:

2013 springs to mind there.  Following six below average months on the trot, July 2013 marked a return to a prolonged warmer phase again.

It felt like July 13 ended the run of quite poor summer months, stretching all the way back to August 2006. Since July 13, we’ve seen a plethora of average to warm summer months.

[minus10]

Thats more like it ecm.....

Business as (used to be) usual. At least it would bring back warmer conditions with much needed rain (and a bit of wind)

[damianslaw]

Models continue suggest something much more unsettled as we enter May, be it cyclonic, cold northerly feed with low pressure sat just to our east and showers or longer spells of rain rotating around it, or more of a westerly feed, with the jet trapped between heights to our NW and SW - which would quite readily allow a trough to develop in situ over the UK.

Not good prospects for the Bank Holiday weekend, hospitality venues will need there heaters in gear, and canopies ready at hand..

[Mike Poole]

11 minutes ago, minus10 said:

Thats more like it ecm.....

Business as (used to be) usual. At least it would bring back warmer conditions with much needed rain (and a bit of wind)

Well, we see this argument in winter sometimes in a stuck adverse pattern, zonal reset and better luck down the line.  Problem is, ECM T240 isn’t a zonal pattern.  It is a depression that chances over the UK in a still largely very meridional pattern NH wide.

The weather has been very weird all winter and all spring in my view.  What comes next is very uncertain.  The long range models point to a chance of a decent first half of summer, but it cannot be called now at all, far too much uncertainty.

[damianslaw]

12 minutes ago, Mike Poole said:

Well, we see this argument in winter sometimes in a stuck adverse pattern, zonal reset and better luck down the line.  Problem is, ECM T240 isn’t a zonal pattern.  It is a depression that chances over the UK in a still largely very meridional pattern NH wide.

The weather has been very weird all winter and all spring in my view.  What comes next is very uncertain.  The long range models point to a chance of a decent first half of summer, but it cannot be called now at all, far too much uncertainty.

The last 5 months have seen a rather ineffective jetstream zonal flow, short bursts of activity that haven't managed to get into fourth gear.. the three most recent periods that followed the same suit were 2008-2009, 2009-2010 and 2012-2013, all brought alot of northerly and easterly airflows, fairly dry in the main, and some intense cold with significant northerly clocking. We haven't had the same depth of cold relative to average this year, or northern blocking, though the first half of April you could say was notably cold. The following three summers were mixed, with some good conditions at times, notably July 2013.. interesting to note the three years mentioned had low solar activity just like this year, 2012-2013  bit of an oddity given the increased levels the two years previous..

[minus10]

13 minutes ago, Mike Poole said:

Well, we see this argument in winter sometimes in a stuck adverse pattern, zonal reset and better luck down the line.  Problem is, ECM T240 isn’t a zonal pattern.  It is a depression that chances over the UK in a still largely very meridional pattern NH wide.

The weather has been very weird all winter and all spring in my view.  What comes next is very uncertain.  The long range models point to a chance of a decent first half of summer, but it cannot be called now at all, far too much uncertainty.

Take your point Mike. Overall pattern is still meridional. Perhaps not business as usual however would be a change of sorts to what we are currently experiencing...

[Methuselah]

11 minutes ago, Mike Poole said:

Well, we see this argument in winter sometimes in a stuck adverse pattern, zonal reset and better luck down the line.  Problem is, ECM T240 isn’t a zonal pattern.  It is a depression that chances over the UK in a still largely very meridional pattern NH wide.

The weather has been very weird all winter and all spring in my view.  What comes next is very uncertain.  The long range models point to a chance of a decent first half of summer, but it cannot be called now at all, far too much uncertainty.

Fifteen years' back, I suggested that only quantum computers would solve the weather-forecasting conundrum. But, I don't know, Mike. Am I off my trolley!

[Mike Poole]

9 minutes ago, General Cluster said:

Fifteen years' back, I suggested that only quantum computers would solve the weather-forecasting conundrum. But, I don't know, Mike. Am I off my trolley!

Pete, I think the big problem in getting any longer term forecasts accurate, is not so much the solution algorithm for the physics going forward, but getting as accurate as possible representation of T0!  This is I’m sure why GFS has never caught up with ECM, it doesn’t use full 4DVar (I think it is called) to get the T0 right, given observations are made at various times before this time.  

I think there is a geninue limit on how much we can forecast forwards based on T0.  But I think the teleconnections, GWO and MJO, SSTs can maybe meet us half way from the longer term perspective to give better predictions. But they will always be probabilistic, never certain. 

Just my view...

Edited April 25, 2021 by Mike Poole

[ANYWEATHER]

 

Cold is the overall pattern ....and we greet May Brrhhhh. PS not much rain in southern Britain..this week ....but night time frosts and Wintry showers will see us into May....

[Methuselah]

It has to be said, that the GFS 00Z is most definitely not a thing of beauty:

Day 10:             We are clearly on the right testicle!

Day 16:          

[Guest]

Looks like any milder solutions out there from yesterday were clearly outliers. Last nights 18z ensembles were possibly even more below average than the mornings and this mornings GFS Ops just becomes cold and damp for days on end. 8-10c maxes under cloud, showers or longer spells of rain and strong winds day after day just doesn’t cut it in early May. 5 or 6 of the days towards to end of the fall to make 10c in London. I’m not saying it’ll happen and yes it’s FI but the pattern is so consistent you really can’t ignore it.

Have a good Monday everyone! 

[PiscesStar]

13 minutes ago, Alderc said:

Looks like any milder solutions out there from yesterday were clearly outliers. Last nights 18z ensembles were possibly even more below average than the mornings and this mornings GFS Ops just becomes cold and damp for days on end. 8-10c maxes under cloud, showers or longer spells of rain and strong winds day after day just doesn’t cut it in early May. 5 or 6 of the days towards to end of the fall to make 10c in London. I’m not saying it’ll happen and yes it’s FI but the pattern is so consistent you really can’t ignore it.

Have a good Monday everyone! 

Hi. I'm not surprised in the least.... Have u please got a link to the ensembles? 

[Guest]

6 minutes ago, Snowfish2 said:

Hi. I'm not surprised in the least.... Have u please got a link to the ensembles? 

Wetterzentrale.de - Diagrams

WWW.WETTERZENTRALE.DE

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Forecasted 850 hPa Temp. from GFS, 18Z

 

[Guest]

Ugh.....little in the way of positivity here.

 

 

 

[johnholmes]

Looking at the 500 mb anomaly charts

Ec shows upper low off n’ern Norway down over UK with upper ridge over Greenland, so not much change since Friday.

NOAA also has upper ridge Greenland and trough centre n of Norway with it troughing fairly similar to ec, perhaps a shade further west, and far s of UK more under slack Atlantic flow

In neither case is there any signal for major warmth, probably more unsettled than it has been for sometime? The 8-14 has much less of any ridging, and the upper closed trough is further away and less pronounced with the overall upper flow into the uk more influenced by the atlantic, not strong but very little sign of any ridging s of uk

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

[ChannelThunder]

Nice to see some actual rain on the latest Euro runs! Not that I want May to be a washout, I would just like some actual weather and for everything to get watered before we're into summer.