Model output discussion 02/02/20

[Frosty.]

Looking at the latest models the ECM 0z operational is in no mood to settle down, indeed its cranking up for a further bout of very unsettled weather @ T+240 hours, the GFS 0z op ends anticyclonic, the GEFS 0z mean eventually goes for a north / south split..for a time with some drier weather further south and finally, looking at the longer term perturbations there is potential for a wintry sting in the tail around mid March but also some spring like options..the duality of early spring.

[Alexis]

When has the ECMWF ever been right at day 10 though?

P.S. would it be an idea to have a fresh thread for the first day of meteorological spring?

Edited March 1, 2020 by Alexis

[mb018538]

1 hour ago, Alexis said:

When has the ECMWF ever been right at day 10 though?

P.S. would it be an idea to have a fresh thread for the first day of meteorological spring?

It verifies as the best model consistently. You’d back it over gfs at day 10 every day and twice on a Sunday!

[Methuselah]

2 hours ago, Weather-history said:

High pressure is needed but I can't help feel that we are being suckered by GFS

Look at ECM at 240hrs

GEM

That, Mr D, is always a possibility. But, for now, better weather still looks like arriving on or around 10/3:

     

As Jon Snow keeps saying, it's all down to the 'duality of Spring'!

[mushymanrob]

Looking fairly average to me... im not buying the GFS more settled outlook, because the NOAA Anomaly charts retain high pressure to our near southwest towards mid month, The SPV is still expected to be very strong and not start to ease for the next 3 weeks, the MJO (ec version) heads to phase 4 of which the composit for march can be seen in the centre. That is eerily similar to this ECM chart for t240.

[Djdazzle]

1 hour ago, mb018538 said:

It verifies as the best model consistently. You’d back it over gfs at day 10 every day and twice on a Sunday!

At day 10 I’d say no more than a 10% chance of verifying. You only have to look at all of the let-downs in this thread over the years.

[damianslaw]

Kept out if this thread all February. Anyhow.. what are the models showing, more if the same.. unsettled chilly conditions, heights to the sw and a broadly west-NW airflow. Bouts of wind and rain, with chance of temporary spells of snow at fairly low levels in the north. Longer term signs might see a ridge build in from the sw, but with such a strong Polar vortex knocking on its door likelihood it will be quickly shunted back sw and another disturbed spell takes over with a cold northerly shot following on before mid month. 

[Methuselah]

Still on for an improvement by mid-March...But, would that shift (it looks rather minor in the great scheme of things?) even register on NOAA's upper-wind charts?

    

It [the weather, not NOAA's chart!] would, however, still dry things out?

 

 

Edited March 1, 2020 by General Cluster
clarity

[Zak M]

The latest run of the GEM isn't really showing much in terms of snow tomorrow. Maybe sleet.

The GFS, on the other hand, is showing the rain tracking the same route as the GEM, but it has some snow falling in only one area of the rain.

I think snow accumulations tomorrow over lower ground aren't likely. Probably a bit of slush at best.

And then later into March, the signs of more settled and perhaps warmer weather could be possible.

Perhaps the north could be treated to a bit cold weather and perhaps scattered sleet/snow showers, while the south could be treated to some settled weather, so basically, it's a north and south split.

Edited March 1, 2020 by Zak M

[Nick F]

03z UKV (which goes to T+120), like the 00z UKMO-GM, shows a channel low for Thursday, which it indicates sleet/snow on the N and NW flank of the rain shield as it moves east.

00z/06z GFS and 00z EC track the low east much further south entering western France from the Bay of Biscay.

Be interesting to see if subsequent runs of GFS and EC correct the low further north, as UKMO has performed quite well with the trickier tracks of these secondary lows at 4-5 day range recently.

Looking at the 50 00z EPS members for mslp Thursday morning more than a third show low crossing east over southern counties, or English Channel or far N of France.

Tonight some back edge sleet and wet snow looks possible over southern counties of England, with the wave low running along the south coast, wet snow most likely over higher ground such as Mendips, Cotswolds, Wiltshire Downs and Chilterns. 

Wintry showers across the north and west at times too over next few days, with snow falling over hills.

 

Edited March 1, 2020 by Nick F

[MATTWOLVES 3]

Well folks today is officially Spring, that can mean only one thing.... Let the winter chase begin.. This spell of settled weather GFS has been flagging up lately.... Well, I'm not so sure! More and more ensembles keep high pressure to the S/SW. A load more rain is the last thing I want, but I feel we could be trending a tad more unsettled than previously thought! Still some wintry surprises in the offing to... 

[shaky]

7 minutes ago, Nick F said:

03z UKV (which goes to T+120), like the 00z UKMO-GM, shows a channel low for Thursday, which it indicates sleet/snow on the N and NW flank of the rain shield as it moves east.

00z/06z GFS and 00z EC track the low east much further south entering western France from the Bay of Biscay.

Be interesting to see if subsequent runs of GFS and EC correct the low further north, as UKMO has performed quite well with the trickier tracks of these secondary lows at 4-5 day range recently.

Looking at the 50 00z EPS members for mslp Thursday morning more than a third show low crossing east over southern counties, or English Channel or far N of France.

Tonight some back edge sleet and wet snow looks possible over southern counties of England, with the wave low running along the south coast, wet snow most likely over higher ground such as Mendips, Cotswolds, Wiltshire Downs and Chilterns. 

Wintry showers across the north and west at times too over next few days, with snow falling over hills.

 

The question is why is the ukmo outperforming the mighty gfs and ecm at such a short time frame in regards to these channel lows?i personally think ecm will join ukmo this evening with gfs joining in as well!lets see!!

[Nick F]

1 minute ago, shaky said:

The question is why is the ukmo outperforming the mighty gfs and ecm at such a short time frame in regards to these channel lows?i personally think ecm will join ukmo this evening with gfs joining in as well!lets see!!

As it is a short range model the UKV is run at higher horizontal resolution than EC and GFS, so perhaps why it could be doing better at short range with more mesoscale features.

[shaky]

20 minutes ago, Nick F said:

As it is a short range model the UKV is run at higher horizontal resolution than EC and GFS, so perhaps why it could be doing better at short range with more mesoscale features.

Sorry let me rephrase that i meant to say the ukmo global model that runs out to 144 hours!!!seems to  out do the ecm and gfs quite often even at short range!!!whats the ukv showing for tonight with that potential snowfall for the south east?

[snowray]

Euro4 still going for a period of snow tomorrow morning, the model seems to over do the snowfall though these days. None the less places like the Chilterns/Cotswolds might see some wet snow and a temporary covering in the heavier PPN.

 

[Interitus]

59 minutes ago, Nick F said:

As it is a short range model the UKV is run at higher horizontal resolution than EC and GFS, so perhaps why it could be doing better at short range with more mesoscale features.

It should do, assuming the global model providing the boundary conditions performs accurately.

[Nick F]

43 minutes ago, shaky said:

Sorry let me rephrase that i meant to say the ukmo global model that runs out to 144 hours!!!seems to  out do the ecm and gfs quite often even at short range!!!whats the ukv showing for tonight with that potential snowfall for the south east?

UKMO and UKV are part of the same unified model as far as I'm aware, just UKV is run at higher res than its global parent, so picks up mesoscale stuff better than lesser res models  at short range, but not as far out. Not sure why UKMO global is outperforming in the short range, they must have some secret in their supercomputers. 

Nothing too exciting for tonight, maybe some snow over higher ground in the south, as I mentioned a few posts back.

Edited March 1, 2020 by Nick F

[Zak M]

Looks like quite a nasty storm off the coast of Greenland. The models don't show the possible storm to hit us (thankfully) but instead, it fizzles out as it travels to Iceland.

We just need the next 4-5 runs to show something similar to the 06z run. Due to all the floods and saturated ground this year, having another storm knocking on our doorstep isn't what we all like!!

Edited March 1, 2020 by Zak M

[Mike Poole]

1 hour ago, Nick F said:

UKMO and UKV are part of the same unified model as far as I'm aware, just UKV is run at higher res than its global parent, so picks up mesoscale stuff better than lesser res models  at short range, but not as far out. Not sure why UKMO global is outperforming in the short range, they must have some secret in their supercomputers. 

Nothing too exciting for tonight, maybe some snow over higher ground in the south, as I mentioned a few posts back.

Just to comment on a point of interest from Nick's post, here's a look at the models performance over the NH as a whole, then at the moment, day 6/T144 it looks like this:

ECM in front, with UKMO, GFS and GEM in joint second place. What these stats don't show is how the models are performing in a more localized region like the UK.  There isn't really any data on this that I know of, but it kind of stands to reason that the GFS may be better suited to scenarios that affect the US, and the UKMO better suited to scenarios that affect the UK, because that is the purpose of each model.  That's my impression from my decade or so watching the models, that the UKMO is probably the best model for things that affect us!

Edited March 1, 2020 by Mike Poole

[snowray]

25 minutes ago, Mike Poole said:

Just to comment on a point of interest from Nick's post, here's a look at the models performance over the NH as a whole, then at the moment, day 6/T144 it looks like this:

 

You can see from that chart how bad the CFS is, if it's so far out at T144 you can forget the rest, not even worth looking at.

[Mike Poole]

2 minutes ago, snowray said:

You can see from that chart how bad the CFS is, if it's so far out at T144 you can forget the rest, not even worth looking at.

Yes, but short to medium range weather prediction is not what the CFS is for.  What you see there compared to GFS is probably the much coarser resolution, because the CFS has to do other stuff as well i.e. model the oceans.  It is designed to model both the atmosphere and oceans in order, when run probabilistically, to predict increased or decreased likelihood of certain scenarios over months.  

Which is why I always laugh when someone posts charts from a single CFS run - no good, it has to be treated probabilistically. 

[Methuselah]

2 minutes ago, Mike Poole said:

Yes, but short to medium range weather prediction is not what the CFS is for.  What you see there compared to GFS is probably the much coarser resolution, because the CFS has to do other stuff as well i.e. model the oceans.  It is designed to model both the atmosphere and oceans in order, when run probabilistically, to predict increased or decreased likelihood of certain scenarios over months.  

Which is why I always laugh when someone posts charts from a single CFS run - no good, it has to be treated probabilistically. 

I always view the CFS probabilistically, Mike: I just assume that it'll probably be wrong!

[Zak M]

The GFS 12z takes on Monday morning:

I doubt that the sleet/snow will be that widespread but it is a nice chart to look at especially for the south nevertheless.

[nick sussex]

The GFS now has the shortwave running east .

Quite a climb down considering this is within T72 hrs .

 

[shaky]

2 minutes ago, nick sussex said:

The GFS now has the shortwave running east .

Quite a climb down considering this is within T72 hrs .

 

I did mention it earlier i think ecm and gfs will climb down and go towards the ukmo this evening!!i dont know what it is but ukmo has had this knack of outperforming both those models recently especially earlier on!!