Model Output Discussion

[carnun]

Constant slight downgrades now for about the last 36 hrs

Downgrades in that there will be little if any ppn around.

In fact with clear sunny weather at times it will feel positively Springlike in sunshine.

Yes frosty nights, but anything worthwhile being pushed further and further back, all the while we move gradually out of "Proper Winter" and more towards the drip drip of Spring snowfall

Yeah let's dismiss it all before it has even begun. This proper winter talk is mullarkey. Towards the end of February is usually our best time for snow. It's amazing people find something to complain about even when we are facing a renewed cold incursion. Sure we're not going to get a foot of snow in Ireland- for that we would need the perfect storm, but I reckon most of us will see a bit of snow at some stage before the Atlantic eventually ruins things for us in around nine or 10 days times, but the North East of England and Scotland may hold on to the cold for a bit longer.

Anyway, give me an outlook of cold and dry weather, with an increasing risk of snow at times goes on, over mild Atlantic muck any day.

[Mark Bayley]

Good ECM so far, Easterly followed by a northerly as the high retrogresses north westwards. There will be snow around, especially the further South and East you are. Most places would be at risk of seeing at least something wintry. Staying mostly dry, cold and frosty the further west you are

[ITSY]

I'm quite new to Netweather - I can't seem to find a media thread, so excuse me for posting this on here MODs

Has anyone seen the latest countryfile forecast at 6:50pm?

Good/Bad news?

[Bristawl Si]

Quick thoughts from Ian F just posted in South West thread; hope this adds to the debate on here:

"Quick note - some 'interest value' snow expected tonight; generally light accumulations; effectively from Wash across to Glos most prone but also some chance to N/S of this line; 0 - 4 cm in this swathe but highly variable.

Quick note 2: Baroclinic feature slipping southwards to possible bring snow for parts of our (eastern, generally) region Thurs into Fri.

Quick note 3: Main focus for any snow (daytime partial or whole thaw must be stressed) - next weekend; troughs (some quite broadly across southern UK) moving south as the anticipated genesis for this potential.

I do stress most snow potential this period is primarily for the E/SE and then transferring northwards in the latter stages of 6-15 day period. Kent could see some interesting totals due to convergence effects.

Can't current expand on the detail - if I get time tomorrow after work, I will.

Cheers

Ian "

[January Snowstorm]

Excellent ECM and far better than gfs in the reliable

Remarkable charts really from the ECM, though one cant help but feel that 216hrs synoptically couldn't happen. If it does we will all see the "S" word

Let's hope the 18z ditches the idea of the Friday high!

[shiver]

I'm quite new to Netweather - I can't seem to find a media thread, so excuse me for posting this on here MODs

Has anyone seen the latest countryfile forecast at 6:50pm?

Good/Bad news?

good news if you like snow

[PubliusEnigma]

This is a bit of a concern for me, the HP retrogresses so far it is now almost off the west

coast of Greenland. This leads to the cold plunge heading down the centre of the atlantic and

although we have SE winds in England, look where they are originating from, the Balearic Islands

so this would most certainly bring a thaw with rain from the Low pressure approaching the SW.

The chart looks ok for the north, but its the origin of this air that we need to keep an eye on.

[Frosty.]

Maybe 2 weeks of cold weather to look forward to according to the 12z runs today, the ecm again showing high pressure slowly being sucked towards Greenland and a deepening trough sweeping south from the arctic which would eventually bring heavy snow to the north, the most snow showers look confined to southeast during the coming week but from monday night onwards we should all get widespread frosts.

[TEITS]

Have to say after recent UKMO/ECM runs im very pleased with the trend between +72/+96. Far better than some of the runs were suggesting for this period.

The Greenland HP continues to be suggested and the latest JMA also continues with this trend. Very uncertain how this will pan out but I must say the potential of a big event remains possible. What I mean by big event is it remains possible of a LP system tracking along the S engaging with the colder air to the N. Also in these situations N areas could well see a pasting from troughs moving S.

So overall the potential for snow events remains for the whole of the UK. At the moment it just depends on your location for which timeframe. As an example for some areas its Wed onwards. However for others they may have to wait until week 2.

[Bobby]

New NOGAPS is nice

[Thundery wintry showers]

On this occasion I am backing the UKMO/ECM. Back around the 7th-10th January the GFS kept progging high pressure on top of Britain giving dry sunny days and just isolated showers for eastern England, while the UKMO and ECM placed it further north giving a north-easterly flow. In the end, the UKMO/ECM slightly overdid the NE airflow, but were much closer to the mark than the GFS, and the result was that snow showers from the 7th-9th were surprisingly widespread- then of course we had that snow event on the 10th which gave sleety slushy stuff for the majority.

In the longer term a west based negative NAO scenario is completely plausible and is also what happened in December- though on that occasion the jet was just far south enough, and the -ve NAO far east enough, to keep us on the cold side of the polar front jet. It is also supported by many of the teleconnections. However I think the outlook in FI is still going to change quite a lot in future runs, at the moment unsettled and on the cold side of average (how cold remains to be seen) is looking favourite.

[Jamie.]

This is a bit of a concern for me, the HP retrogresses so far it is now almost off the west

coast of Greenland. This leads to the cold plunge heading down the centre of the atlantic and

although we have SE winds in England, look where they are originating from, the Balearic Islands

so this would most certainly bring a thaw with rain from the Low pressure approaching the SW.

The chart looks ok for the north, but its the origin of this air that we need to keep an eye on.

I wouldn't be too concerned... yet, that chart is very likely to change and chances are it'll like completely different 24H before hand.

[Mark Bayley]

This is a bit of a concern for me, the HP retrogresses so far it is now almost off the west

coast of Greenland. This leads to the cold plunge heading down the centre of the atlantic and

although we have SE winds in England, look where they are originating from, the Balearic Islands

so this would most certainly bring a thaw with rain from the Low pressure approaching the SW.

The chart looks ok for the north, but its the origin of this air that we need to keep an eye on.

Here's the 850hpa temps for that period

Turning milder in the far south, colder from the midlands North. I wouldn't worry to much at this stage. There will be many evolutions over the coming days. I remember GP saying a west based NAO was likely, which then opened the risk of attack from the South West. We shall just have to watch the models over the coming days. The high retrogressing north westwards seems very likely after the initial easterly.

[stewfox]

This is a bit of a concern for me, the HP retrogresses so far it is now almost off the west

coast of Greenland. This leads to the cold plunge heading down the centre of the atlantic and

although we have SE winds in England, look where they are originating from, the Balearic Islands

so this would most certainly bring a thaw with rain from the Low pressure approaching the SW.

The chart looks ok for the north, but its the origin of this air that we need to keep an eye on.

Why would a chart deep deep in F1 land cause 'concerns'

[MAF]

Here's the 850hpa temps for that period

Turning milder in the far south, colder from the midlands North. I wouldn't worry to much at this stage. There will be many evolutions over the coming days. I remember GP saying a west based NAO was likely, which then opened the risk of attack from the South West. We shall just have to watch the models over the coming days. The high retrogressing north westwards seems very likely after the initial easterly.

but that is for 17th Feb its miles and miles away before then. i know it's a bit of a bugbear of mine. but why look past the next 3-5 days? blimey, the models have struggled past 48 hours in the recent past. let alone get it right for 10 days away.

sorry, not having a go at you. just can't see why people look so far ahead. (even Met O only goes to T+144)

[Glacier Point]

GFS ensemble mean is opening the door for a significant snow event, roughly t200 through t300 on current programming for southern UK and t200 - t360+ further north.

This is t264 but it's a good representation of a deep trough to our east filtering cold air south and south-west, and low heights right across the Atlantic allowing lows to approach from our south-west as the core upper ridge shifts towards Canada and western Greenland:

http://raleighwx.eas...nomalyNH264.gif

Projected 850s at this time are well below average:

http://raleighwx.eas...nomalyNH264.gif

Operational ECM guidance is very similar.

Based on Global Wind Oscillation composites, the evolution towards this west based -NAO will take some time and there may be a case for current model guidance being too progressive with an Atlantic low swinging in. With the AO likely to become strongly negative, a Scandinavian trough looks very sustained which will mean the cold puddle of air over NW Europe will take a lot of shifting. The snow threat from next weekend onwards should not be underestimated.

Edited February 7, 2010 by Glacier Point

[kent]

Havent had the event yet in any shape or form and already some are worrying over a possible breakdown in 10 days time. Ever heard the saying, what you never had you cant miss. lol.

[Geordiesnow]

ECM is an improvment regarding the high position in the early part of the run, i just hope that trend continue as it will bring colder uppers and more PPN activity which will please more people.

As usual, the long range looks good but its all a little irrelevant looking at the detail, especially when you don't the UKMO going pass 144 hours!

[January Snowstorm]

Thanks GP, in otherwords let's RAMP!!!! :lol:

You have been spot on all Winter, not like you to be so specific, you must see something really special, or at least the potential

[Frosty.]

I like the sound of that GP, something to look forward to because this coming week looks mostly dry away from the far east and south with hp in control. :lol:

[Cecil Hogmanay Melchett]

word of caution though with Ian f's post.talk of partial or full thaw through the daytime from the meto.Shame i thought we'd be ok in early to mid feb,maybe we need a deeper cold pool to prevent thaws?

[Jayces]

GFS ensemble mean is opening the door for a significant snow event, roughly t200 through t300 on current programming for southern UK and t200 - t360+ further north.

This is t264 but it's a good representation of a deep trough to our east filtering cold air south and south-west, and low heights right across the Atlantic allowing lows to approach from our south-west as the core upper ridge shifts towards Canada and western Greenland:

http://raleighwx.eas...nomalyNH264.gif

Projected 850s at this time are well below average:

http://raleighwx.eas...nomalyNH264.gif

Operational ECM guidance is very similar.

Based on Global Wind Oscillation composites, the evolution towards this west based -NAO will take some time and there may be a case for current model guidance being too progressive with an Atlantic low swinging in. With the AO likely to become strongly negative, a Scandinavian trough looks very sustained which will mean the cold puddle of air over NW Europe will take a lot of shifting. The snow threat from next weekend onwards should not be underestimated.

I see your name come up a lot in this thread as one of the most respected and knowledgeable posters here so it's reassuring to see your ideas on next weekend and beyond. Are we talking something like the US East coast snowmageddon or just a lot of snow similar to the last couple of wintry periods we have had this winter?

[guitarnutter]

The snow threat from next weekend onwards should not be underestimated.

Sounds good! Do you know when this will start to be reflected in the model output?

[Lewis]

word of caution though with Ian f's post.talk of partial or full thaw through the daytime from the meto.Shame i thought we'd be ok in early to mid feb,maybe we need a deeper cold pool to prevent thaws?

I think we'll be ok mate, it's early feb so we'll get away with it.

From the 20th onwards is when we will start to see quicker thaws as solar output increase's

Last week, it froze over here, and they was ice and frost everywhere, temp got too 2.6c and they was still frost about.

Temps will be from tuesday onwards typically 2-3c max, 4-5max further west you are.

[Frosty.]

Sounds good! Do you know when this will start to be reflected in the model output?

It already is, in FI.