Model Output Discussions 18z 31/01/2016

[nick sussex]

6 minutes ago, lukemc said:

Interesting outlook I am going to the Peak District on Sunday for 2 night staying in Glossop just asking if I have a chance of seeing snow on current projections? And do I have a chance of seeing something at home in Liverpool beforehand (sorry for the slightly off topic post - decided to post in here as it is quiet for the time of day)

 

Luke

Hi Luke you picked a good time to go. Yes looking at the outputs you'd be unlucky to not see snow , and for Liverpool a positive is the flow will be coming off the land rather than the Irish Sea but the track of those shortwaves is up in the air.

 

[Ali1977]

Rain in south over the weekend and a "risk" of that turning to snow....according to latest BBC, may become a now casting weekend.

i think even London could be in with a shout, if not from slider from the strong Easterly flow on Mon - in shower form.

Edited February 9, 2016 by Ali1977

[chris55]

Well John Hammonds model interpretation on the 6 0clock news suggested the weekend has potential risk of snow, "watch this space".

That pretty much sums up the output at the moment lol.

 

Snap Ali ha!

 

Well we are within pretty much the same region so heres to some of the white stuff!

 

But actually in such a situation, its helpful to add some of the pros views in this thread just to give the wider picture of what we are all thinking.

Edited February 9, 2016 by chris55

[feb1991blizzard]

5 minutes ago, nick sussex said:

Hi Luke you picked a good time to go. Yes looking at the outputs you'd be unlucky to not see snow , and for Liverpool a positive is the flow will be coming off the land rather than the Irish Sea but the track of those shortwaves is up in the air.

 

Not sure where the PPN is coming for from for Liverpool Nick.

[chris55]

ECM 144, thats going to be a good frost for many inland....and an easterly doesn't look to much of a fantasy from this point, slightly better than the 00z for that.

[nick sussex]

6 minutes ago, feb1991blizzard said:

Not sure where the PPN is coming for from for Liverpool Nick.

Well the lack of agreement between the outputs at T96hrs means its impossible to say at the moment the exact areas most at risk.

In terms of the ECM at T168hrs a few tweeks at T192hrs and a possible snow event.

[feb1991blizzard]

Just now, nick sussex said:

Well the lack of agreement between the outputs at T96hrs means its impossible to say at the moment the exact areas most at risk.

In terms of the ECM at T168hrs a few tweeks at T192hrs and a possible snow event.

Do you mean a 5th feb 2012 style event from the NW?

[Methuselah]

From what I can gather, having looked at the models and the Beeb's forecasts, there's nowt much to be getting excited about...Some snow for high ground, for sure, a possibility of some sleet to lower levels at times...But, with temps of, say, 5-6C in most places, widespread appreciable snowfall looks unlikely. Easterly or no easterly...

[nick sussex]

3 minutes ago, feb1991blizzard said:

Do you mean a 5th feb 2012 style event from the NW?

You can see the milder sector getting squeezed out, follow the 850's from T168hrs to T192hrs, we need to see a bit more sharpness from that troughing to disrupt some energy se'wards.

Edited February 9, 2016 by nick sussex

[snowice]

2 minutes ago, Ed Stone said:

From what I can gather, having looked at the models and the Beeb's forecasts, there's nowt much to be getting excited about...Some snow for high ground, for sure, a possibility of some sleet to lower levels at times...But, with temps of, say, 5-6C in most places, widespread appreciable snowfall looks unlikely. Easterly or no easterly...

I agree looks like the uppers are being mixed out again!

[winterof79]

12 minutes ago, Ed Stone said:

From what I can gather, having looked at the models and the Beeb's forecasts, there's nowt much to be getting excited about...Some snow for high ground, for sure, a possibility of some sleet to lower levels at times...But, with temps of, say, 5-6C in most places, widespread appreciable snowfall looks unlikely. Easterly or no easterly...

Met forecasting onshore winds to develop with snow showers for Yorkshire and Humberside on Saturday Feeling raw.Pretty much in line with the low sitting out in the North sea

Todays uppers were northing to shout about but it snowed here.

Edited February 9, 2016 by winterof79

[nick sussex]

I think looking at the outputs overall we could do with a couple of degrees colder 850's. The ECM does get some colder air in but this is as the low moves away. The UKMO looks colder than the ECM and this is because of its different view of the shortwave low at T96hrs.

The UKMO transports that deeper cold west from Scandi and this then gets pulled sw into the UK. The ECM is better however later.

I think each output has its good and bad points and it depends really where you live as to what you'd prefer to verify.

Purely from a potential point of view the ECM is the better output tonight and this is due to its more amplified upstream solution which allows a ridge to get ne and pull a ne flow back in to the UK, after this theres also some scope for the cold air to not get mixed out at the surface and then you'd have an unusual cold nw flow trying to displace colder surface air.

The ECM output looks a bit like the Azores high versus PV battle, its a bizarre scenario really, you've got the former amplifying desperately trying to carve the jet se and the PV desperately trying to flatten things.

I should say if the models are overdoing the PV then things could get a bit more interesting.

The GFS is my least favourite output because its flatter upstream and quick to spill energy eastwards.

Edited February 9, 2016 by nick sussex

[chris55]

It is all so marginal, but if things can come together then snow is not out of the question for some further south.

Ill check back in for the 00zs.

Have a good evening everyone

[Methuselah]

4 minutes ago, chris55 said:

It is all so marginal, but if things can come together then snow is not out of the question for some further south.

Ill check back in for the 00zs.

Have a good evening everyone

It is indeed marginal, chris; but, alas, the marginality seems to be on the wrong side, the noo...That said, it won't take much for things to go in the right direction: if the 'cold' air stays in place after, say, next Wednesday, I will start to feel a tad more confident. Until then - it's nail-biting time!

[blizzard81]

15 minutes ago, winterof79 said:

Met forecasting onshore winds to develop with snow showers for Yorkshire and Humberside on Saturday Feeling raw.Pretty much in line with the low sitting out in the North sea

Todays uppers were northing to shout about but it snowed here.

It just rained here. Another high ground event in the offing I fear. The 850's are just not low enough for the slack easterly to deliver snow to low ground over the weekend. I am a little surprised with the meto wording. I think wintry showers would be a more accurate description.

[karyo]

22 minutes ago, nick sussex said:

I think looking at the outputs overall we could do with a couple of degrees colder 850's. The ECM does get some colder air in but this is as the low moves away. The UKMO looks colder than the ECM and this is because of its different view of the shortwave low at T96hrs.

The UKMO transports that deeper cold west from Scandi and this then gets pulled sw into the UK. The ECM is better however later.

I think each output has its good and bad points and it depends really where you live as to what you'd prefer to verify.

Purely from a potential point of view the ECM is the better output tonight and this is due to its more amplified upstream solution which allows a ridge to get ne and pull a ne flow back in to the UK, after this theres also some scope for the cold air to not get mixed out at the surface and then you'd have an unusual cold nw flow trying to displace colder surface air.

The ECM output looks a bit like the Azores high versus PV battle, its a bizarre scenario really, you've got the former amplifying desperately trying to carve the jet se and the PV desperately trying to flatten things.

I should say if the models are overdoing the PV then things could get a bit more interesting.

The GFS is my least favourite output because its flatter upstream and quick to spill energy eastwards.

i am actually more interested in what happens later next week with the trough dropping from the northwest than this weekend. Any MJO update today? I know the Met Office is going for the return of the positive NAO and nothing of interest but if they are underplaying the MJO they may end up being wrong.

[mountain shadow]

2 minutes ago, karyo said:

i am actually more interested in what happens later next week with the trough dropping from the northwest than this weekend. Any MJO update today? I know the Met Office is going for the return of the positive NAO and nothing of interest but if they are underplaying the MJO they may end up being wrong.

The MJO isn't due to be in a favourable position (Phase 8/1) for another another two weeks or more. It will be the end of the month/start of Spring before we see any help there. At least the GEFS ensembles MJO forecast is fairly well amplified.

[nick sussex]

1 minute ago, karyo said:

i am actually more interested in what happens later next week with the trough dropping from the northwest than this weekend. Any MJO update today? I know the Met Office is going for the return of the positive NAO and nothing of interest but if they are underplaying the MJO they may end up being wrong.

I think theres a strike at NCEP. The MJO discussions haven't updated. In terms of the UKMO Ian F said a few days back that they expected a low amplitude signal and didn't expect it to be a factor. Theres a divergence at the moment between the outputs, the GEFS are now more amplified, the ECM less so and the ECM monthly has a large spread. The UKMO disagrees with the ECM so its really hard to say what will happen. I think we'll have a better idea by the weekend.

[karyo]

Thank you both                                                                                                                                                                                                                                        By the way Nick, is the NCEP really on strike or are you joking?

[The Enforcer]

2 hours ago, Alexis said:

12z high res precipitation showing all rain for Friday, unless you're on a Welsh mountain. Afterwards it's looking dry and frosty for most before a toppler bring back more average conditions.

 

I'm struggling to see where any upgrade would come from now that 850s are 4 degrees higher than they were 36 hours ago.

That Arpege run is currently showing the mildest option of all models judging by how close the 0C isotherm is at midnight on Sunday.

[nick sussex]

2 minutes ago, karyo said:

Thank you both                                                                                                                                                                                                                                        By the way Nick, is the NCEP really on strike or are you joking?

Lol! I was joking, perhaps they're all glued to the New Hampshire primary vote! Hopefully the updates will happen later.

[stratty]

4 minutes ago, The Enforcer said:

That Arpege run is currently showing the mildest option of all models judging by how close the 0C isotherm is at midnight on Sunday.

...with some nice results close by....

[Faronstream]

5 minutes ago, karyo said:

Thank you both                                                                                                                                                                                                                                        By the way Nick, is the NCEP really on strike or are you joking?

If the AAO value goes negative phase, will the low pressures over N Atlantic slow down and decrease the westerlies for W Europé? If yes then it's better looking at AAO value than the NAO which just tells the difference between Azore high and Icelandic low?

 

[karyo]

2 minutes ago, Faronstream said:

If the AAO value goes negative phase, will the low pressures over N Atlantic slow down and decrease the westerlies for W Europé? If yes then it's better looking at AAO value than the NAO which just tells the difference between Azore high and Icelandic low?

 

I am not very familiar with the AAO to be honest.

[Faronstream]

Just now, karyo said:

I am not very familiar with the AAO to be honest.

Okey i was just curious, since so many people just talk about the NAO value