General Model Output Discussion

[La Bise]

You say that C but that chart I posted must have shown now on about 6 of the last 7 runs on different models, A gigantic Scandi Hi, very unusual to see that sort of thing come up across a broad model spectrum.

It's a Lovecraftian thing Weather "The chart that should not be"...

[Tom D]

18z coming out, Tuesday's blizzard is an all rain affair for SW England but with a good chance of snow for Wales, though very marginal to say the least. Beacons will get pasted I bet. Atlantic seems to be making more inroads than 12z.

I was about to say the complete opposite (re Atlantic).

Very cold at the surface until Friday when the third low charges in but it's progress is stopped by the high.

This run shifts things east so the next weekend low manages to smash into the entire country rather than just the west.

Edited January 10, 2010 by Tommyd1258

[January Snowstorm]

The 18z continues the warm up trend for late this week

I wonder could the next attack come from the Northwest

By the way 11 hours of contant snow here, inches on the ground and still falling. Cork airport shut

[Bobby]

I must be looking at different 18 run to you! Low pressure looks further south, precip doesn't get as far east, looks like a snow event for SW to me before it retreats and the block fights back

Not according to Meteociel, too warm uppers:

I was about to say the complete opposite (re Atlantic).

There's more mild air over us than the 12z op, compare them:

[conor123]

The GFS shows the front stalling literally probably about 5 miles west of here, id rather it slam in and give something eventful even if it was just freezing rain..

[chionomaniac]

You say that C but that chart I posted must have shown now on about 6 of the last 7 runs on different models, A gigantic Scandi Hi, very unusual to see that sort of thing come up across a broad model spectrum.

I have no doubt that this Scandi high is going to materialise in some form or another. It is it's westward extent that is determining our FI.

[bluearmy]

latest T120 FAX does show what appears to be a increasing s flow across the uk. the block appears to be retreating east. however, as if by magic, the 528dam thickness line appears off the east coast at T120. it may look as if the flow is w to e but this movement west of the lower thicknesses tells a different tale.

[MP-R]

Where's my suncream?

Mate that's a week away! Let's try and get to grips with the here and now to start with. As someone said earlier, last weekend predicted this weekend to see widespread decent snowfalls and it turned out to be virtually nothing. This weekend predicts much milder on that chart for next weekend and no doubt it will turn out to be virtually nothing.

[TEITS]

The 18z continues the warm up trend for late this week

I wonder could the next attack come from the Northwest

By the way 11 hours of contant snow here, inches on the ground and still falling. Cork airport shut

Absolutely no chance of a NW,ly im afraid.

The evidence for the strong Scandi HP is overwhelming at the moment. This isn't just based on the ECM/JMA either. Look at the 12Z SLP ensembles for Moscow/Oslo. Quiet incredible SLP ensembles.

http://charts.netweather.tv/ensimages/ens.20100110/12/prmslOslo.png

http://charts.netweather.tv/ensimages/ens.20100110/12/prmslMoscow.png

I strongly disagree with some of the comments about it turning milder with the atlantic returning. We may find SW/W areas see a brief period of less cold weather before the Scandi HP brings back colder temps.

[conor123]

I don't see how we'd see anything decent if we do get a Scandi High again anyway with all the mild uppers going across Europe, just cold grey 1-3c like this week.

Bring on the Greenland highs i say

[damianslaw]

A very difficult situation at the moment in terms of predicting the likely weather by the end of the week, will the atlantic break through or will the block to the NE hold firm?.

We may see a repeat of what happened just after christmas, with easterlies returning by the end of the week. Its certainly going to be an interesting couple of days ahead guessing the eventual outcome, its anyones guess at the moment.

[TEITS]

A very difficult situation at the moment in terms of predicting the likely weather by the end of the week, will the atlantic break through or will the block to the NE hold firm?.

Let me put it this way I would be amazed if the possible snow during midweek gets any further than W midlands.

What im finding fasinating is we all know the GFS tends to uncerestimate blocking and yet its adamant we're going to see a 1050mb Scandi HP. Even more fasinating is how this block remains in F.I.

Some very unusual model output at the moment which is getting me rather excited. Makes you wonder whats looming!!

[swilliam]

Not according to Meteociel, too warm uppers:

There's more mild air over us than the 12z op, compare them:

Not according to the high resolution NAE - nearly all snow for the SW and Wales - and lots of it as well. I know what my money is on (and which you would prefer).

Edited January 10, 2010 by swilliam

[SMU]

Not according to the high resolution NAE - nearly all snow for the SW and Wales - and lots of it as well. I know what my money is on (and which you would prefer).

Liking that NAE RUN- pity there wasnt a 54 chart... a tad excited now!

S

[weather eater]

Let me put it this way I would be amazed if the possible snow during midweek gets any further than W midlands.

What im finding fasinating is we all know the GFS tends to uncerestimate blocking and yet its adamant we're going to see a 1050mb Scandi HP. Even more fasinating is how this block remains in F.I.

Some very unusual model output at the moment which is getting me rather excited. Makes you wonder whats looming!!

Its the placement of the high that's crucial, looking through all the model output including the likes of the JMA, gives an insight into the wide variety of that placement, could be an interesting next few days of model watching. The JMA is very interesting and while I it would be wise to view its output with caution in does demonstrate what could happen.

[Thundery wintry showers]

I don't see how we'd see anything decent if we do get a Scandi High again anyway with all the mild uppers going across Europe, just cold grey 1-3c like this week.

Bring on the Greenland highs i say

I prefer Greenland Highs as well, but the consistent theme among runs that bring the Scandinavian High westwards is that in about a week's time it draws a renewed pool of cold air across from the east, with thicknesses of 520 dam and 850hPa values of -10C. So if the Atlantic loses the battle and we get an easterly starting in a week's time, like the ECMWF suggests, then we would most likely end up back to sunshine and snow showers.

I see that the JMA goes for the same scenario.

[SMU]

seeing as we have every tom dick & harry saying get the t-shirts out next week I thought id post the ensembles for London from the best model- ECM

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble_forecast.html

LONDON MAX next 10 days- a whopping 3c

steve

Edited January 10, 2010 by Steve Murr

[Thundery wintry showers]

Note, though, that the ECMWF operational appears to be on the cold side of its ensembles- by no means is it an outlier, but there are a lot of milder solutions in there as well.

[john mac]

seeing as we have every tom dick & harry saying get the t-shirts out next week I thought id post the ensembles for London from the best model- ECM

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble_forecast.html

LONDON MAX next 10 days- a whopping 3c

steve

Great stuff steve, i think some people have been spoilt by this cold spell, i have to agree with you that i cant see anything mild coming to our shore, the beebs headline was a cold week for this week

[Bobby]

GFS ensembles don't look too good, op was a cold outlier in the middle part of the run.

Flicking through the 18z GFS ensembles and there's very strong agreement on Tuesday's event. Mostly rain affair for SW England (apart from moors) but more on a knife edge in Wales with a good chance of significant snow. Precip never really makes it to N. Wales before stalling. Perhaps something inbetween the NAE and GFS will be the outcome... I'd take that.

[Great Plum]

Liking that NAE RUN- pity there wasnt a 54 chart... a tad excited now!

S

Steve and others - do you think that this front will make it further east then the models currently show?

[swilliam]

Steve and others - do you think that this front will make it further east then the models currently show?

It could but it is impossible to tell at the moment I am afraid - probably won't know till 24 hrs before.

[anvilhead]

NAE has that lp down to 962mb oat 48 hours! .. ukmo 970mb, gfs 978mb ..

[Guest FireStorm]

Bit of a noob question, but what does that mean? Haha.

The air pressure measured in millibars. The lower the number the stronger the winds to keep it very simple.

I wonder if this is BFTP's post on the apparent "wind storm".

[West is Best]

Although the extreme cold supply looks set to be cut off the outlook still doesn't look particularly mild. Even with a southerly feed the GFS 0z run shows supressed surface temperatures for at least another week. UKMO perhaps hints at something milder later. With a Scandinavian high there is enough upper air cold nearby off the continent for things to remain below average for the time of year. Not until we return to true south-westerlies and westerlies will we see genuinely mild conditions returning at the moment.

Ahead of all that tomorrow/Wednesday looks interesting. I must admit to some surprise that the MetO are progging heavy snow off the advancing front, rather than sleety-rain, but they may be absolutely right. If they are then it could be serious with the strong winds causing considerable drifting. It was a stalling front which brought us such heavy snow here in north Devon in February 2009. This time it shouldn't stall, and a partial thaw ought to set in behind only for it to re-freeze by night.

This is marginal indeed. Who'd be a professional forecaster when the slightest change brings the national scrum down on top of you?