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Paul

Please keep this thread solely to discussing the model output. The model banter thread is available for more loosely model related chat, ramps and moans.

Message added by Paul

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4 minutes ago, karlos1983 said:

Agree, but this summer the UKMO didn’t do well in Hurricane season. ECM was supreme, even 7 days out, which with tropical storms is no mean feat, never mind cat4/5 hurricanes. UKMO does tend to struggle upstreamwhen there’s a lot of noise, so I’m cautiously optimistic. I don’t have any factual evidence of that, but Hurricane season is my 2nd favourite time of year, so it just sticks in my mind. 😀

ENS looking good still, although a bit more spread towards the end than of late. But nothing really to grumble about too much 

A0D106A8-ED16-4398-BD14-221CF064AAB7.thumb.gif.38546fdea35299d543139f3eebec8ef5.gif

And the mean is still the same apart from right at the end, so because a lot more runs are going higher, a lot more are also going lower as well, much more look like they are supporting these ridiculous -5c max for most of England type op runs we've seen today.

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1 minute ago, feb1991blizzard said:

And the mean is still the same apart from right at the end, so because a lot more runs are going higher, a lot more are also going lower as well, much more look like they are supporting these ridiculous -5c max for most of England type op runs we've seen today.

It’s certainly a tighter cold cluster 

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And just to round off the day nicely, a loadf more runs on the GEFS are going to have a good go at a Greeny post 300.

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2 minutes ago, feb1991blizzard said:

And the mean is still the same apart from right at the end, so because a lot more runs are going higher, a lot more are also going lower as well, much more look like they are supporting these ridiculous -5c max for most of England type op runs we've seen today.

Worth noting they will be night time temps, maybe just above freezing in the day - not too bad. 🙂

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Ok, KEY period to watch is between 84-96hrs. That is when  the para accelerates the LP off to the NE whilst the GFS op and ECM hangs back.

Once that is agreed upon things will rapidly slip into place. I'd probably suggest that tomorrow MAY be the key day as we'd be near 48hrs by that point.

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Just now, Mucka said:

Worth noting they will be night time temps, maybe just above freezing in the day - not too bad. 🙂

No - im talking about a good few that have max temps just below freezing - been in London that would mean you could take off another few degrees without the urban heat effect in rural SE England - presume they are those runs backing the ECM 12z / GFS 18z op runswith the frigid Easterly.

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6 minutes ago, feb1991blizzard said:

No - im talking about a good few that have max temps just below freezing - been in London that would mean you could take off another few degrees without the urban heat effect in rural SE England - presume they are those runs backing the ECM 12z / GFS 18z op runswith the frigid Easterly.

I haven't seen any output support -5 max daytime temps but with snow cover there would be ice days and subzero max daytime temps on some of the ECM/GFS output which is all that matters for snow retention.

 

EDIT

I will add that temps would also very quickly drop away late afternoon and only slowly recover from the mornings. 

Obviously the longer the cold air and any snow cover is in place then the colder it will become at the surface all things being equal.

Edited by Mucka
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15 minutes ago, karlos1983 said:

Agree, but this summer the UKMO didn’t do well in Hurricane season. ECM was supreme, even 7 days out, which with tropical storms is no mean feat, never mind cat4/5 hurricanes. UKMO does tend to struggle upstream when there’s a lot of noise, so I’m cautiously optimistic. I don’t have any factual evidence of that, but Hurricane season is my 2nd favourite time of year, so it just sticks in my mind. 😀

ENS looking good still, although a bit more spread towards the end than of late. But nothing really to grumble about too much 

A0D106A8-ED16-4398-BD14-221CF064AAB7.thumb.gif.38546fdea35299d543139f3eebec8ef5.gif

Where do you find these charts? Do they have them for other UK cities as well (I'm in Edinburgh, as my username may suggest 😂 )?

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Well this is what makes model watching so good. Honestly like watching a thriller football match at times, flipping one way, then another. Fascinating viewing. 

The intense cold is essentially dependent on the behaviour of that storm coming out of the US. Which model handles those most accurately? As the experts have said, ECM. The ECM shows that low heading south down the UK which results in a much better synoptic set up for us. Looks like the GFS has finally gotten with the programme and fallen in line with the ECM

The UKMO is still the odd one out. However, we have an SSW, favourable teleconnections, low solar activity. It seems as though everything points towards a cold spell and because the ECM handles those storms better, and the cold spell is dependent on the storm, I think the logical step is to back the ECM on this one. Expect the UKMO to come on board soon. Nothing is ever guaranteed in this business but my eggs are in the ECM basket. 

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Just now, edinburgh_1992 said:

Where do you find these charts? Do they have them for other UK cities as well (I'm in Edinburgh, as my username may suggest 😂 )?

No but the best i can do is this.

https://meteologix.com/ie/forecast/2650225-edinburgh/ensemble/euro

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4 minutes ago, ZK099 said:

Well this is what makes model watching so good. Honestly like watching a thriller football match at times, flipping one way, then another. Fascinating viewing. 

The intense cold is essentially dependent on the behaviour of that storm coming out of the US. Which model handles those most accurately? As the experts have said, ECM. The ECM shows that low heading south down the UK which results in a much better synoptic set up for us. Looks like the GFS has finally gotten with the programme and fallen in line with the ECM

The UKMO is still the odd one out. However, we have an SSW, favourable teleconnections, low solar activity. It seems as though everything points towards a cold spell and because the ECM handles those storms better, and the cold spell is dependent on the storm, I think the logical step is to back the ECM on this one. Expect the UKMO to come on board soon. Nothing is ever guaranteed in this business but my eggs are in the ECM basket. 

Looks good doesnt it. The easterly is around a week long on gfs! Haven't seen anything like it se would be buried?  Ecm very similar 

Edited by snowfish1

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The 18z GFS ensembles are better BUT still a large variety of solutions at 144hrs, everything from the Azores high pilling into Europe, through to a strong Greenland High setting up and everything inbetween. No real agreement still, though more loaded towards cold than earlier suites for sure.

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7 minutes ago, Mucka said:

I haven't seen any output support -5 max daytime temps but with snow cover there would be ice days and subzero max daytime temps on some of the ECM/GFS output which is all that matters for snow retention.

Not quite but not a million miles away -

 

image.thumb.png.8348b768d0cbfd1e1f1a5d8ff40367d4.pngimage.thumb.png.0ee7628e9b0301e67eace245a8422a25.png

 

Edited by feb1991blizzard
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11 minutes ago, feb1991blizzard said:

No - im talking about a good few that have max temps just below freezing - been in London that would mean you could take off another few degrees without the urban heat effect in rural SE England - presume they are those runs backing the ECM 12z / GFS 18z op runswith the frigid Easterly.

I found -5 for you for one day central England, that would be amazing. BrrRRrr.

graphe6_1000_260_82___.gif

Edited by Mucka
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Clusters!

144

144.thumb.png.9eb8361380c42e32fe43188abe252433.png

6 Clusters at 144 though every single one of them has blocking to the W/NW of the UK, no real majority with 21% being the biggest cluster so that shows just how uncertain the pattern continues to be going forward, thankfully very little support for the flatter patterns we've seen on some models today.

240 the "majority" cluster is with the Op though again, not really much of a majority at 21%

240.thumb.png.82148edaf08fc1396e72e4fe9d962839.png

Still wouldn't be too confident on the ECM being right with the deeper cold scenario given the continued spread, though even some of the "lesser" clusters wouldn't exactly be terrible for cold and snow.

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2 minutes ago, feb1991blizzard said:

Not quite but not a million miles away -

 

image.thumb.png.8348b768d0cbfd1e1f1a5d8ff40367d4.png

 

Evening temps don't count as temps drop away rapidly after daylight in such conditions but see above 😝

Edited by Mucka

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Tonights 18z Next Wednesday night looks very snowy and windy. And several days after.

Anyone noticed the worried tone and seriousness in stavs video forecast .

19012406_1718.gif

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1 hour ago, Mike Poole said:

I think it's because of the timescale we see it, we're in the pub at the time it comes out.   And it has a habit apparently of spewing out cold winter runs, there may be a correlation there...beyond that I don't know, netweather folklore maybe?

It’s because some of the output looked as if GFS had been on a serious bender 

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Of course, most of those experienced on here will be highly wary of a significant cold incursion from the NE given the overall pattern indicated by the charts. 

Granted, everything is interconnected including all the teleconnections, stratospheric trends, tropical convection anamolies and so forth. What the experts will (among other factors) be looking for is how the polar vortex behaves, bifurcates, decays, etc in the next T144 hours. The pattern upstream is not particularly promising west of Greenland and how much warm-air is able to advect northward in order to give time for things to fall into place east of the Atlantic High is speculative. We will have to wait and see how this very cold trough from Greenland affects us from T96 onwards and its pretty much F.I. from that point. All too often we have seen steep upper temperature gradients reappear just west and SW of Greenland to weaken and bleed energy into the northern arm enough to flatten and reduce the amplification. The result is for our dear European trough to sink southwards towards Greece....

 

 

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1 minute ago, Mucka said:

Evening temps don't count as temps drop away rapidly after daylight in such conditions but see above 😝

See the other chart i have added - -6c in Wales.

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18 minutes ago, Roger J Smith said:

18z run can be described as extremely cold and snowy, with the thickness values below 510 dm in southeast at times, as to the U.S. low, that has to go where large scale features determine, it's not the other way around, with the low "interfering" with some otherwise possible pattern. May be an unprovable hypothesis but the next step in that sort of reasoning is to "explain" a weather pattern "because of the jet stream." This sort of reasoning keeps us a long way from developing real science. The question to explore is really, what causes the weather pattern? Then the details fall into place. 

Surely it works both ways Roger. Macro and micro are intertwined and bound by the balancing Laws of Thermodynamics.

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Well GFS para takes two bites of the cherry but does get there by 276hrs, probably a good solution IF the first attempt doesn't take hold like the GFS/ECM are advertising. Still not convinced by that dartboard low however, as I said before you don't tend to get 950mbs low in a set-up with a fractured jet flow, but we will see!

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Good rule of thumb for daytime max's in December / January from a fully embedded true polar continental airmass is take the 850 temp and add 7. You won't be far out, so -13 850 gives -6c so some of the figures quoted are not at all unreasonable. Other factors come into play such as big city heat island effect and coastal water temps but for newbies you will be thereabouts.

Contrast that with a PM airmass from the NW and you can probably add 9 or 10. So a fully embedded -6 850 (you just wouldn't get -13 850) is giving 3 or 4c in lowland England.

By mid Feb though this doesn't work so well as solar input begins to ramp up quickly and cloud cover becomes key.

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