Model output discussion 10/02/21

[Griff]

GFS is having the morning off on the French website, so here's the Canadian model all the way from Germany... Clear? 

[Griff]

ECM Monday to Wednesday 

[Griff]

A brief lull on Thursday gives way to this by Saturday 

[ICE COLD]

The GEM going full on again this morning

[Griff]

3 minutes ago, ICE COLD said:

The GEM going full on again this morning

I know a certain @MattHugowho rates the gem highly at short range

[ICE COLD]

Just now, Griff said:

I know a certain @MattHugowho rates the gem highly at short range

Very cold at ground level as well griff . Certainly not your standard April

[SLEETY]

This depth of cold is unusual for January now,, nevermind April! must be odds- on some records are broken next regarding cold temps and maybe even snowfall!

[Griff]

And finally the GFS... 

[Griff]

UKMO 850s

[Methuselah]

Just think of all that lovely inland convection? Could be some splendid clouds around...

    

But, GFS is still going for a warm-up post Snowmageddon. Sort of!

    

[johnholmes]

I think we will begin to see a marked change in the weather pattern in 6-10 days time. The outputs from the anomaly charts is starting to show this.

I'll post in a bit with charts

 

[feb1991blizzard]

8 minutes ago, johnholmes said:

I think we will begin to see a marked change in the weather pattern in 6-10 days time. The outputs from the anomaly charts is starting to show this.

I'll post in a bit with charts

 

To be honest John, i would be a heck of a lot more surprised if we didn't, given the -10c isotherm and snow showers are going to be powering down the country in 5 days time.

[Methuselah]

8 minutes ago, feb1991blizzard said:

To be honest John, i would be a heck of a lot more surprised if we didn't, given the -10c isotherm and snow showers are going to be powering down the country in 5 days time.

I get your point, feb -- but the springs of 1975 and 1996 come to mind: the cold just seemed to go on and on and on?

[feb1991blizzard]

1 minute ago, General Cluster said:

I get your point, feb -- but the springs of 1975 and 1996 come to mind: the cold just seemed to go on and on and on?

Yes, but the -10c uppers would have to get cut off for a mild sector, as troughs have to keep coming down from the North for a N'ly to continue, and at this time of year, the mild sector will mean a big change in surface temps so if only brief, where as in Jan, the troughs might just mean an injection of moisture and heavy snow, so you might not really notice much difference apart from the flakes getting bigger and juicier, now it will almost certainly mean rain / much warmer temps, that was a very long winded way of saying that i don't know if its even scientifically possible to have everything that falls from the sky to be snow with the -8 to -10c 850hpa isotherm over us for ages in April, where as in Jan it probably is although unlikely these days.

[topo]

Crazy pressure over Greenland. GFS 06z 

[Methuselah]

And here it comes: Bish, bash, bosh!

    

[I remember Atlantic 252]

06Z not quite as good? further east with the northerly

[The Northern Ramper]

Just cold all the way through the 6z

[johnholmes]

Friday 2 April and looking at the 500 mb anomaly charts

Ec-gfs, just ec, anyone any idea where gfs 500 output is please?

Ec shows very little ridging on the latest output with marked troughing from n of Alaska/n canada all the way ne of Greenland down over n’ern Scandinavia but not quite as pronounced as 24 hours ago into southern Europe. The flow over the uk n of w but less n’ly component than 24 hours ago

Noaa and it continues its idea of shifting the area of maximum +ve heights westwards. It is now over where usually the deepest upper trough sits, so its centre of 210 DM, effectively cancels out most of the usual troughing, leaving a segment off sw Newfoundland. The effect is still sufficient to give a n if w flow across the uk, but it shunts the trough a bit further east and makes it less sharp into Europe.

What do these changes on both models suggest fr uk surface weather?

Well, as I often post, we need continuity from the models and agreement between them, each for 48-72 hours. Noaa is not usually wrong but it does happen. IF the pattern suggested by both models continues along the lines of the last 24-48 hours then a more westerly upper air pattern would follow. Currently about 30% in my estimation. I’ll wait for at least another, preferably two, before I become convinced.

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

WWW.METEO.PSU.EDU

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

WWW.METEO.PSU.EDU

 

The 8-14 noaa is very similar to 24 hours ago and it shows more general w'ly flow into the uk, so perhaps a touch more reliability to the 30% I suggested, time will tell!

[mushymanrob]

39 minutes ago, johnholmes said:

Friday 2 April and looking at the 500 mb anomaly charts

Ec-gfs, just ec, anyone any idea where gfs 500 output is please?

Ec shows very little ridging on the latest output with marked troughing from n of Alaska/n canada all the way ne of Greenland down over n’ern Scandinavia but not quite as pronounced as 24 hours ago into southern Europe. The flow over the uk n of w but less n’ly component than 24 hours ago

Noaa and it continues its idea of shifting the area of maximum +ve heights westwards. It is now over where usually the deepest upper trough sits, so its centre of 210 DM, effectively cancels out most of the usual troughing, leaving a segment off sw Newfoundland. The effect is still sufficient to give a n if w flow across the uk, but it shunts the trough a bit further east and makes it less sharp into Europe.

What do these changes on both models suggest fr uk surface weather?

Well, as I often post, we need continuity from the models and agreement between them, each for 48-72 hours. Noaa is not usually wrong but it does happen. IF the pattern suggested by both models continues along the lines of the last 24-48 hours then a more westerly upper air pattern would follow. Currently about 30% in my estimation. I’ll wait for at least another, preferably two, before I become convinced.

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

WWW.METEO.PSU.EDU

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

WWW.METEO.PSU.EDU

 

The 8-14 noaa is very similar to 24 hours ago and it shows more general w'ly flow into the uk, so perhaps a touch more reliability to the 30% I suggested, time will tell!

Im a little more optimistic than you John.. timing may be open to change but a return to a Westerly is going to happen, and so the current evolution of the NOAAs is more likely than 30% imho, but i may well be wrong! lol, im just hopeful .

[Frosty.]

1 hour ago, Ramp said:

Just cold all the way through the 6z

Couldn’t agree more, I’m not saying the 6z op is right by any means but it’s certainly the coldest Gfs run I’ve seen for a while in the build up to this upcoming unusually severe arctic outbreak (for the time of year)...!   

Edited April 2, 2021 by Jon Snow

[MATTWOLVES 3]

Tell you what lads my HQ is going crazy...the radio signals and phone calls are now of the scale for a jump aboard the cold train! Like my great granny always used to say...never put your coat away till May is out of the way Matthew!

Bring it on,I'm all fired up for this one...let's kick the tyres and light the fires

[Jeremy Shockey]

Pretty brutal April 5th till 10th that's for sure.

Edited April 2, 2021 by Jeremy Shockey

[Frosty.]

Just looking at the GEFS 6z mean for next mon / tues..nobody can tell me this isn’t severe for the time of year?..(hey it even rhymes) ....it’s as wintry as a coldie could dream of in early April..nuff said! ..Happy Christmas.....I mean Easter..  

 

 

Edited April 2, 2021 by Jon Snow

[johnholmes]

Definitely the prediction can be rated pretty severe. Even the change from the very mild/warm of a few days ago to the next 24 hours when, here for example, there was a drop from 24.1 to 6.3 C in 24 hours, a drop of 14.2 C. In mid winter that would have been unusual for a fall of 14 C. Similarly the maxes of 6-8 C for Monday would be some 6-10 C lower in mid winter so pretty unusual synoptics I would agree.