winter model output Winter Model Output Discussion -12Z 07/02/13 onwards

[Dunstable Snow]

Yes but that is not what the metoffice update mentioned for next week, their update did not suggest any slider lows or undercut after this weekends episode, if anything, what the ecm 12z is showing is more in line with latest metoffice thoughts.

Agree with your analysis but things can and do change quickly and we could see a flip back to disruption and energy under. It just looks as though the energy from the waning PV is weakening and taking the easiest route in a meandering sort of way and that is north.. Its a bloody pain and just typical of how things work out for the UK. you would think that a declining PV to the north west would work in our favour and the scandi high would march west. It would be great if we could have a technical explanation of why the models are showing this ( in non technical language !). BTW have already succumbed and now on my second glass !

[R.P. McMurphy]

Looks like a slush fest to me only -4 uppers in the south of England, not sure what the Dew points are progged to be though.

Yes Dave. I think as current models are showing anywhere Birmingham North, especially Yorkshire could see quite a total in snowfall.

Will be eager to see the NAE tomorrow once it's updated. I fully expect amber warnings for the NE, Midlands, and Yorkshire with perhaps parts of the NW there too.

[joggs]

Joggs, often in this situation low pressures like this trend further South or stay to the West - however here we do not have HP close to the North or close to the East - the wedge of 552 is to the West of Northern Norway, so there is no reason why there should be any trending South of Sundays LP.

Anyway, the ECM looks wrong tonight because at T120 I would expect the Low pressure to dive SE in the same way that the GFS shows, splitting the AH and the Scandi High but it doesnt and if that's not right then the rest of the ECM is wrong.

Cheers Ian.

[Frosty.]

The glass half full position would be that you could get to something very wintry across the south (north seems already assured) without changing pattern or large-scale features, just tweaking details on models. Probably each model has ensemble members that could support snow but this at the moment is the minority position for southern England. I think there could be a somewhat different outcome once this slider actually starts to slide. It would not be the first time that a system not yet in existence turned out to be 100-200 miles off the consensus track or (related) that the thickness pattern was one interval (6 dam) off. The ripple effects of explosive cyclogenesis on the other side of the Ocean may become apparent in future model runs.

Lots of things to hold our interest even if the prospects seem a bit dull for some. Meso-scale but retrograde system over eastern Baltic could factor into the outcome also. Holland ought to like the results (as I'm sure we will hear).

I'm not liking the ecm 12z signal after next midweek, it's trending towards a flat looking pattern and i'm hoping for the cold block to the northeast to do something about that, a few days cold snap just won't cut it after expectations have been raised so high.

[chris55]

Check out how well the ECM has been verifying at +120 hrs this past 7 days...

http://www.emc.ncep..../html/acz5.html

GEM up with the big boys recently as well.

[Dunstable Snow]

The glass half full position would be that you could get to something very wintry across the south (north seems already assured) without changing pattern or large-scale features, just tweaking details on models. Probably each model has ensemble members that could support snow but this at the moment is the minority position for southern England. I think there could be a somewhat different outcome once this slider actually starts to slide. It would not be the first time that a system not yet in existence turned out to be 100-200 miles off the consensus track or (related) that the thickness pattern was one interval (6 dam) off. The ripple effects of explosive cyclogenesis on the other side of the Ocean may become apparent in future model runs.

Lots of things to hold our interest even if the prospects seem a bit dull for some. Meso-scale but retrograde system over eastern Baltic could factor into the outcome also. Holland ought to like the results (as I'm sure we will hear).

Thanks Roger - Having read that I will soon be pouring my third glass - doesnt sound great for us then ! Pleased for our jolly Dutch friend though.

[Froze were the Days]

The ECM's good if its early winter as it looks on the cold side throughout so you can have that as a holding pattern. At this stage with the winter heading towards its end its all a bit drab and uneventful.

Those hoping for a Greenland high look like they might be disappointed with no sign of the PV relenting sufficiently. Especially with the limpet east Pacific ridge seeming never to get bored.

As for the possible snow at the end of the weekend, still some uncertainty there but as for any convective easterly window, the ECM really dilutes the uppers. It's strange just how seemingly impossible its been to have any sort of convective easterly verify.

It's like regardless of how good the synoptics might look at T144hrs the models always find a way to not deliver on that front.

Hopefully the models either find a way to get the Scandi high more favourably orientated and further west and find a decent cold pool or theres some big changes upstream to remove those low heights to the nw otherwise one does get the sense that winter will draw to a close in a rather boring way.

Yep totally agree - no convectivity from an easterly at all this winter considering the opportunities, short waves and no real sliders going under the block as there hasn't really been strong heights to our north east and no decent heights towards Greenland/Iceland says it all, it's always been a case of weak heights to the north east developing against the Atlantic with the Greenland PV being prevalent.

[shaky]

Can anyone post the ecm precipitation charts!!

[johnholmes]

Joggs, often in this situation low pressures like this trend further South or stay to the West - however here we do not have HP close to the North or close to the East - the wedge of 552 is to the West of Northern Norway, so there is no reason why there should be any trending South of Sundays LP.

Anyway, the ECM looks wrong tonight because at T120 I would expect the Low pressure to dive SE in the same way that the GFS shows, splitting the AH and the Scandi High but it doesnt and if that's not right then the rest of the ECM is wrong.

Its fairly easy Ian if you look at the upper air, ECMWF shows the 500mb flow and that clearly indicates it should move north of east not south as you suggest presumably just looking at the surface chart?

In fact the situation is quite similar to what I wrote about in my two pdf items about 500mb charts. Just east of Iceland the flow is much as the 12z ECMWF run suggests, splitting either to N of east or S of east, the position of any surface feature being crucial to which direction it takes. In this case as it was behind the upper ridge and the main flow was s of west to its rear thennorth of east is the only logical place for it to go based on those charts.

Edited February 8, 2013 by johnholmes

[Dunstable Snow]

Its fairly easy Ian if you look at the upper air, ECMWF shows the 500mb flow and that clearly indicates it should move north of east not south as you suggest presumably just looking at the surface chart?

In fact the situation is quite similar to what I wrote about in my two pdf items about 500mb charts. Just east of Iceland the flow is much as the 12z ECMWF run suggests, splitting either to N of east or S of east, the position of any surface feature being crucial to which direction it takes. In this case as it was behind the upper ridge and the main flow was s of west to its rear thennorth of east is the only logical place for it to go based on those charts.

Great explanation - thank you. Wrong angle of approach presumably due to low uppers around greenland and a re-envigorating Azores high Grrrrr

[Tim Bland]

The glass half full position would be that you could get to something very wintry across the south (north seems already assured) without changing pattern or large-scale features, just tweaking details on models. Probably each model has ensemble members that could support snow but this at the moment is the minority position for southern England. I think there could be a somewhat different outcome once this slider actually starts to slide. It would not be the first time that a system not yet in existence turned out to be 100-200 miles off the consensus track or (related) that the thickness pattern was one interval (6 dam) off. The ripple effects of explosive cyclogenesis on the other side of the Ocean may become apparent in future model runs.

Lots of things to hold our interest even if the prospects seem a bit dull for some. Meso-scale but retrograde system over eastern Baltic could factor into the outcome also. Holland ought to like the results (as I'm sure we will hear).

Are you still standing by your forecast for record cold in Feb? Struggling to see where this could come from looking at the current NWP?

Not having a dig but yesterday you said. " I would basically ignore most of the model guidance beyond about 144h except to note the large-scale features, the details will change when snow cover feeds back into the boundary layer temperature field."

Are you still expecting a big shift towards your deep / record breaking cold for the uk?

Edited February 8, 2013 by Tim Bland

[cold snap]

ECM ensembles says it all really

Starting to trend milder

Edited February 8, 2013 by cold snap

[Summer Sun]

ECM short ensemble

[cooling climate]

Are you still standing by your forecast for record cold in Feb? Struggling to see where this could come from looking at the current NWP?

There has never been anything remotely indicating record cold for February. It would be nice to see

some proper cold uppers say -14c or -15c but record cold thats just hype.

[Frosty.]

Great explanation - thank you. Wrong angle of approach presumably due to low uppers around greenland and a re-envigorating Azores high Grrrrr

wish we could nuke the azores high, it's a winter killer and is useless in summer. We need a change in the ensembles or the cold block will collapse by the end of next week, still time for a miracle though.

[Summer Sun]

ECM full ensemble

Slowly starting to trend milder now record cold for February seems a long shot now

Edited February 8, 2013 by Gavin.

[Tim Bland]

There has never been anything remotely indicating record cold for February. It would be nice to see

some proper cold uppers say -14c or -15c but record cold thats just hype.

I personally agree but gauging the reactions to Rogers forecast many on here believe(d) it and I was wondering if he still does.?!

I'm not having a dig at Roger btw. Yesterday he said. "I would basically ignore most of the model guidance beyond about 144h except to note the large-scale features, the details will change when snow cover feeds back into the boundary layer temperature field."

I was asking if he still believes deep or record cold is coming although we can't see this on the NWP ?

Edited February 8, 2013 by Tim Bland

[mulzy]

wish we could nuke the azores high, it's a winter killer and is useless in summer. We need a change in the ensembles or the cold block will collapse by the end of next week, still time for a miracle though.

Absolutely, the winter killer been around most of this winter and last winter. Still, somehow we managed to see some snow over the last 2 winters, despite the Azores High being prominent.

[Frosty.]

Meh.

Might as well start looking for spring, TBH.

i'm looking at the 18z first to see if we can pull that low further south. : )

[Gowon]

ECM full ensemble

I like the way the control plunges towards the end...it might not stay boring for too long.

[Staffordshire]

Can almost garantee if the 18z gfs is a poor run it will be ignored and will just be passed away and said its typical of the 'pub run', however if it is good then it will be credited and fully took into account.

Edited February 8, 2013 by Staffordshire

[MrSunshine]

i'm looking at the 18z first to see if we can pull that low further south. : )

Surely being in West Yorkshire you wouldn't want to see the low go any further south?

[Frosty.]

Surely being in West Yorkshire you wouldn't want to see the low go any further south?

yes but I don't like seeing my friends in the south missing out either, anyway, the low hasn't even formed yet so we are all still in with a chance.

[Dunstable Snow]

Can almost garantee if the 18z gfs is a poor run it will be ignored and will just be passed away and said its typical of the 'pub run', however if it is good then it will be credited and fully took into account.

Normally I would agree but I dont think so tonight - I think many feel the writing is on the wall and TBH it will be a bit of a shock to me if things start to improve significantly for cold and snow down south from hereon in whatever the run/model... Hope I'm wrong though ! I am more interested in what happens mid week because I still feel there is a chance things could improve.

[bryan629]

well well, maybe something maybe nothing , just looking around various charts at various times within the reliable i guess.

spent a good 30 minuites trying to work out how to post pictures and charts on here and gave it up as bad job , decided to post links instead.

On the first link below Met office pressure map at t84 shows the shortwave over the Norwegian sea, and the high pressure riding over the top of it into or towards Greenland, good heighs been shown. seems that way anyway. The shortwave is ultimately just delaying the high heading towards the uk.

http://www.metoffice.gov.uk/weather/uk/surface_pressure.html met office at t84

However on the ECM the short wave is on this output just 12 hours later not that far off northern scotland , looking like its deflecting an incomming low into a much weaker heights and eventually punching through its alledged weak spot.

http://www.meteociel.fr/modeles/ecmwf.php ecm at t96

surely things cannot be that different in a 12 hour period.

If the met office is more accurate, and going with their projections, is it not likely the incomming low riding over the azores would undercut. insted of riding over the scandi high.

im just observing and taking nothing too seriously

im just learning and observing