Model output discussion - 7th January onwards

[feb1991blizzard]

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 -

 

 

Edited January 17, 2019 by feb1991blizzard

[Mucka]

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.

Edited January 17, 2019 by Mucka

[Met4Cast]

Clusters!

144

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%

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.

[Mucka]

2 minutes ago, feb1991blizzard said:

Not quite but not a million miles away -

 

 

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

Edited January 17, 2019 by Mucka

[sorepaw1]

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 .

[jam]

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 

[PersianPaladin]

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....

 

 

[feb1991blizzard]

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.

[kumquat]

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.

[edinburgh_1992]

5 minutes ago, feb1991blizzard said:

No but the best i can do is this.

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

Cheers, nice to see some GFS members below -10 already on the 25th! 

[kold weather]

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!

[Jason M]

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.

[Kirkcaldy Weather]

I think  sums up the GEFS nicely ( and if the possible easterly comes off like some runs have shown  could / would sum up the snow amounts for many areas nicely)

   possible ice days too  http://www.meteociel.fr/modeles/gefs_table.php?x=0&y=0&lat=56.10878&lon=-3.16202&run=18&ext=fr&mode=0&sort=0 http://www.meteociel.fr/modeles/gefs_table.php?x=0&y=0&lat=56.10878&lon=-3.16202&run=18&ext=fr&mode=7&sort=0

still more runs needed for firming up but things could be getting even more busy very soon if / when those conditions affect the UK  

[Mucka]

Just now, feb1991blizzard said:

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

On a mountain. 

But you win, there is at least now some output that does show a -5 max daytime temp.

[ZK099]

7 minutes ago, snowfish1 said:

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

I wouldn't worry about length too much yet. If that storm out of the US behaves the way we want it to, to perfection, then we could be locked in for some while, which is what the EC46 is suggesting if I'm not mistaken. Tbh it's shown a pretty constant theme of HL Blocking and Euro Troughing throughout January, February and even March. By no means nailed on yet. Let's see what the UKMO says... 

[Eskimo]

6 minutes ago, sorepaw1 said:

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 .

Who's forecast?

 

[feb1991blizzard]

Just now, Mucka said:

On a mountain. 

But you win, there is at least now some output that does show a -5 max daytime temp.

Anytime you have uppers of -15c or less, whic hthe 18z GFS does have -will mean -5c max's at this time of year, we didn't get much above -5c here on some days in late Feb / Early March cold spell. 

 

Anyway - stonking output today -take it you'll be on the night shift at 330 am.

[snowfish1]

2 minutes ago, ZK099 said:

I wouldn't worry about length too much yet. If that storm out of the US behaves the way we want it to, to perfection, then we could be locked in for some while, which is what the EC46 is suggesting if I'm not mistaken. Tbh it's shown a pretty constant theme of HL Blocking and Euro Troughing throughout January, February and even March. By no means nailed on yet. Let's see what the UKMO says... 

Cheers for reply. Whens the UKMO out

[Guest Delete Me]

2 minutes ago, PerfectStorm said:

Who's forecast?

 

Stav Danaos BBC

[Cloud 10]

GFS P gets there after a second bite of the cherry.

 

[sorepaw1]

2 minutes ago, PerfectStorm said:

Who's forecast?

 

Stav Danaos BBC video forecast for the outlook. 

Keep up the good posts perfect storm

[northwestsnow]

2 minutes ago, feb1991blizzard said:

Anytime you have uppers of -15c or less, whic hthe 18z GFS does have -will mean -5c max's at this time of year, we didn't get much above -5c here on some days in late Feb / Early March cold spell. 

 

Anyway - stonking output today -take it you'll be on the night shift at 330 am.

The sun still has next to no strength in it, certainly i would always suggest mid Jan to mid Feb is prime time for a cold spell.

Im so hoping UKMO looks better come 00z runs...

 

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

13 minutes ago, feb1991blizzard said:

Not quite but not a million miles away -

 

 

Those are minimums

[feb1991blizzard]

Just now, northwestsnow said:

The sun still has next to no strength in it, certainly i would always suggest mid Jan to mid Feb is prime time for a cold spell.

Im so hoping UKMO looks better come 00z runs...

 

Yes, main thing though is ECM ensembles.

[feb1991blizzard]

Just now, RAIN RAIN RAIN said:

Those are minimums

Yes, so they are within the spread.