Model Output Discussion

[cooling climate]

I refer to my earlier post re look no further for certainty than the ECM chart I posted. Like for cold forecast, any backslapping re mild outcome now nailed should hold on. 06z perfect example of what hasn't happened yet. With the ECM arctic ridge there is no clear sign on how far NE energy will get...and I still say as I did a few days ago the UKMO sends a way to far NE......lets see what develops tomorrow shall we. Look N and NW...that is where the block will build.

I suspect that next 36hrs will be fascinating model watching...and I'll hint at some sudden changes too.

BFTP

Good post which I agree with although I definetely would still argue for a east of north airflow

but as you say more changes to come definetely.

The ECM ensembles this morning tell me something is not right. A sudden flip like they are

showing to warm is very unconvincing in my opinion.

I have taken this from paragraph from American met Larry Cosgroves latest weather American

newsletter, which if correct would mean big changes to what is being modeled in the Atlantic at

the moment I think.

There are still some question marks concerning the track and character of a large storm forecast by most of the numerical models to form over northern Mexico around February 2 - 3. But for the most part, track and precipitation estimates among the various schemes have shown some consistency with one particular scenario. And that is for the subtropical jet stream to initiate cyclogenesis over Chihuahua state in Mexico late Tuesday, with the resultant surface cyclone to move through the Gulf Coast and up along the Eastern Seaboard. A concern has emerged

recently that the distrubance may become a vortex over New England and the maritime provinces, perhaps ushering in a long period of cold weather over the eastern half of the nation.(see more on this topic below in the EXTENDED PERIOD OUTLOOK).

[The Eagle]

Whilst I remain disappointed about how things have panned out it has to said that the ECM is not that far from a colder spell after 168hrs so there is a little bit of hope, but not much. It is not even Febuary yet so we have time to get something mid Febuary. Hopefully.

[remymartin]

Yes thats right, Feb 1969 was very cold and snowy with a polar low around the 7/8th Feb and a big easterly afterwards.

I'm not saying that exactly the same is going to happen but like in a +AO set up you can get a cold inversion high in what is otherwise a westerly zonal pattern with a northerly jet stream, you can also get the sort of west based -NAO/-AO set up that brings in mild atlantic air in what is traditionally a cold pattern. These interchange within the same regime of pressure at the north pole that either bottles up cold (+AO) or sends cold to mid latitudes (-AO). With the latter, not everwhere in mid latitudes get lucky all the time. For every northerly or easterly in one place, somewhere else there is a southerly or a westerly

Thanks for your reply. i remember it well now.

[Snowyowl9]

I`m surprised at this week what`ll the real outcome will actually be,ECM giving SE-lys UKMO giving mild wet SW-lys and now GFS giving an undercutter snowfest.

http://www.wzkarten.de/pics/Recm1201.gif

http://www.wzkarten.de/pics/Rukm1201.gif

http://www.wzkarten.de/pics/Rtavn1201.png

[Methuselah]

I've now seen the updated (12z issue) UKMO 6-10 day briefing based on 00z runs and the 10-15 day guidance remains identical (to that cited above). I'm not going to abstract it here but instead offer just a key section, as follows: "....at this stage the continuity of the EC ensemble is compelling and a cold spell is indicated here, especially by the middle of next week.... Hence few changes are made here to the (midnight briefing) until greater confidence is shown by the operational models and their ensembles."

All sounds simply like prudent science to me, rather than 'back-tracking'.....!

Agreed Ian. As others have said, a battleground between mild air off the Atlantic and cold air off the near Contininent is hardly unusual at this time of year? What's more, I remember the 1960s - which definitely wasn't a 'little Ice-Age.' IMO, mild weather is as much a part of our winter (perhaps more so?) than are the blizzards of old???

Ever since December, I've recognized (imagined?) some of the knife-edge situations of yesteryear...And, how difficult they were to predict??

1969 Tamara... :lol:

[Guest North Sea Snow Convection]

Agreed Ian. As others have said, a battleground between mild air off the Atlantic and cold air off the near Contininent is hardly unusual at this time of year? What's more, I remember the 1960s - which definitely wasn't a 'little Ice-Age.' IMO, mild weather is as much a part of our winter (perhaps more so?) than are the blizzards of old???

Ever since December, I've recognized (imagined?) some of the knife-edge situations of yesteryear...And, how difficult they were to predict??

1969 Tamara...

Hello Pete

I know! Great weather (and great music!)

We should all be delighted that after all this time we are seeing weather patterns modelled that mimic those great times

[TEITS]

I've now seen the updated (12z issue) UKMO 6-10 day briefing based on 00z runs and the 10-15 day guidance remains identical (to that cited above). I'm not going to abstract it here but instead offer just a key section, as follows: "....at this stage the continuity of the EC ensemble is compelling and a cold spell is indicated here, especially by the middle of next week.... Hence few changes are made here to the (midnight briefing) until greater confidence is shown by the operational models and their ensembles."

All sounds simply like prudent science to me, rather than 'back-tracking'.....!

I have followed the ECM ensembles on a daily basis and this morning I did find the trend in these rather concerning. Seems to me that using the ensembles can be a waste of time as they tend to follow the operationals like a herd of sheep. Whats worrying about the ensembles is how the control run follows the Op. So what im saying is if the ECM 12Z continues with the same trend I fear the ECM mean will rise even further.

Still having said all of this if the ECM Ops suddenly trend towards a colder pattern then the herd will follow suit. My whole point im getting at is I find the focus should always be on the operationals rather than the ensembles especially within the +144 range.

[Frosty.]

I've now seen the updated (12z issue) UKMO 6-10 day briefing based on 00z runs and the 10-15 day guidance remains identical (to that cited above). I'm not going to abstract it here but instead offer just a key section, as follows: "....at this stage the continuity of the EC ensemble is compelling and a cold spell is indicated here, especially by the middle of next week.... Hence few changes are made here to the (midnight briefing) until greater confidence is shown by the operational models and their ensembles."

All sounds simply like prudent science to me, rather than 'back-tracking'.....!

Hi Ian,

It's great to have your professional view, especially since JH is away skiing right now, or maybe he has returned already. It sounds like a mild pattern is far from likely to become established for any length of time and still a good chance of colder continental air poised during the following week. I liked the meto update today, could have been better for cold lovers but it offers hope for us. :lol:

Also, I enjoy reading paul hudson's blog although I havent emailed him yet, do you have a blog?

Edited January 31, 2010 by Frosty039

[MP-R]

Hi Ian,

It's great to have your professional view, especially since JH is away skiing right now, or maybe he has returned already. It sounds like a mild pattern is far from likely to become established for any length of time and still a good chance of colder continental air poised during the following week. I liked the meto update today, could have been better for cold lovers but it offers hope for us. :lol:

Also, I enjoy reading paul hudson's blog although I havent emailed him yet.

I was wondering if an evolution similar to March 2006 is ahead of us. The month started with a northerly lasting for over 4 days, then the Atlantic pushed in briefly but quite potently with strong winds then it became colder again by the 10th and that set up two weeks of cold easterly winds. Just a thought, of course it will be a lot colder now than it would have been in 2006.

[Harsh Climate]

Despicable charts this morning!... .

If theres any consolation, the AO + NAO forecasts are still very promising

Nao -1 around the 10th februrary:

http://www.cpc.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

AO between -4 and -6 around the 10th februrary:

http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif .

Taking these factors into consideration and in a El Nina year.. I cant see februrary being mild and zonal at all . I think as the charts are suggesting things should turn milder around the 4th of februrary http://www.wetterzentrale.de/pics/Rtavn1081.png http://www.wetterzentrale.de/pics/Rukm961.gif perhaps this will last 5-6 days? I think that will be the duration of any mild zonal weather.

After that I would expect a weakening jetstream as a ridge from Eastern USA edges into the atlantic, with pressure building further north and east. I would then look east for our future weather

[full_frontal_occlusion]

Models huh?....a graphical representation of the solution for an immensely complex set of partial-differential equations. The thing is, there is always more than one solution.

Ensembles? As a previous poster suggested, sheep in wolves clothing - 'ya cannay change the laws of physics captain.'

Continuity between runs is also no guarantee of a correct solution especially in a blocked synoptic where the entrance and track of dynamic features can significantly alter an outcome with even minor deviations between runs. For instance, ECM suggest 15-30% of the kinetic energy of transient eddies on all scales are underestimated with a tendency to zonality.

The recent heavy snowfall over the last few days in central and eastern Europe may also play into reinvigorating the blocking pattern and extending the uncertainty of this period.

Teleconnection indexes are but statistial representations of semi-permanent pressure patterns - retropspectively accurate but constrained by the same limitations that govern synoptic evolution models. As such they are are also sheep taking their lead from the potentially flawed ensemble members.

In this situation experimental (and the traditional old school seagull) techniques may offer the only path for guidance.

Methinks more upgrades, downgrades and also ran grades will be on offer before the week os out.

ffO.

Edited January 31, 2010 by full_frontal_occlusion

[Methuselah]

Hello Pete

I know! Great weather (and great music!)

We should all be delighted that after all this time we are seeing weather patterns modelled that mimic those great times

It was, wasn't it!! Did you get the Polar Low in Feb?? What a stonker!! I still remember going to the 1st Year disco and being taught to dance to Hey Jude and The Israelites!!!

Not all memorable snowfalls come from the East, do they? Even though the models have backed-off from that megablast, there's still plenty of cold air around. Very different from the rubbish we've all shared for the last few years!!

[nick sussex]

As much as it maybe disappointing to see the easterly vanish at least the background teleconnections offer some hope, although a negative NAO and AO don't guarantee colder weather they at least give you a chance, for this reason I hope people don't think winter is over.

[andymusic]

As much as it maybe disappointing to see the easterly vanish at least the background teleconnections offer some hope, although a negative NAO and AO don't guarantee colder weather they at least give you a chance, for this reason I hope people don't think winter is over.

winter ain't over yet - the models just can't decide which direction to go in next

[PubliusEnigma]

Just had a look at the UKMO, ECM and GFS. And all point to a spell of two weeks of unsetlled weather

with some large rainfall totals, very low sunshine totals, very damp at times, winds generally SW or S,

and indeed somewhat breezy at times. Yet again the MO 6-15 dayer remains out of kilter with the big3.

It is a noticeable downgrade on yesterdays 6-15 but not as much as I had expected. Expect this trend

to continue tomorrow with and sleet or wintryness limited to the mountains of NE Scotland out till around

14th Feb.

[Jason T]

I take it the 30 mins silence is because noboddy wants to talk models anymore. Must say that feelings towards a mild spell are on most forums on diff sites, But disagreements are still the same.

Come on people think positive thoughts its no way near over yet alot can change.The models will shine soon.

[Cheese Rice]

Just had a look at the UKMO, ECM and GFS. And all point to a spell of two weeks of unsetlled weather

with some large rainfall totals, very low sunshine totals, very damp at times, winds generally SW or S,

and indeed somewhat breezy at times. Yet again the MO 6-15 dayer remains out of kilter with the big3.

It is a noticeable downgrade on yesterdays 6-15 but not as much as I had expected. Expect this trend

to continue tomorrow with and sleet or wintryness limited to the mountains of NE Scotland out till around

14th Feb.

You can be so sure because? No one really knows what will happen at the end of this week, yes SW's may be what we end up with but the outlook is still uncertain.

[PubliusEnigma]

I take it the 30 mins silence is because noboddy wants to talk models anymore. Must say that feelings towards a mild spell are on most forums on diff sites, But disagreements are still the same.

Come on people think positive thoughts its no way near over yet alot can change.The models will shine soon.

Although there is technically only another month left of winter, I have a nagging feeling that sooner or later

it will turn very cold again towards the end of February, and the first few weeks of Spring will actually bring

a return to winter ! Its happened before and can happen again.

[andymusic]

The models aren't sure what's gonna happen totally mid week and beyond right now - they will get a better idea once this atlantic low has figured out where it's going and how much the block will affect it

[PubliusEnigma]

You can be so sure because? No one really knows what will happen at the end of this week, yes SW's may be what we end up with but the outlook is still uncertain.

Even if it did "flip" in 8 -10 days time, there is no cold pools left anywhere the continent will have warmed up as the

SW'lys are not limited to UK but most of NW Europe and Scandi will see a massive increase in temps in the coming week. Its -15 to -20 in some parts currently, with temps expected to rocket to -3 to 0oC by this time next week. So an easterly if it did occur would probably bring overcast leaden skies, damp 3oC and light very cold drizzle, which to my mind is even worse than rain and milder SW's.

[andymusic]

Even if it did "flip" in 8 -10 days time, there is no cold pools left anywhere the continent will have warmed up as the

SW'lys are not limited to UK but most of NW Europe and Scandi will see a massive increase in temps in the coming week. Its -15 to -20 in some parts currently, with temps expected to rocket to -3 to 0oC by this time next week. So an easterly if it did occur would probably bring overcast leaden skies, damp 3oC and light very cold drizzle, which to my mind is even worse than rain and milder SW's.

models aren't doing too well past mid week so how can you know what the temp is gonna be next week for definite!

[La Bise]

That's a fair point the Enigman chap, I've checked the Swiss met forecaste for next week and they indicate a big warming in the mountains thanks to gale force SW winds. In fact it warms up a lot more up there than at lower altitude.

[Mark Bayley]

Just had a look at the UKMO, ECM and GFS. And all point to a spell of two weeks of unsetlled weather

with some large rainfall totals, very low sunshine totals, very damp at times, winds generally SW or S,

and indeed somewhat breezy at times. Yet again the MO 6-15 dayer remains out of kilter with the big3.

It is a noticeable downgrade on yesterdays 6-15 but not as much as I had expected. Expect this trend

to continue tomorrow with and sleet or wintryness limited to the mountains of NE Scotland out till around

14th Feb.

Its perhaps out of kilter with the ECM and UKMO. I wouldn't say its out of kilter with the GFS though. The second week of Feb looks pretty cool and showery with the risk of frosts on the GFS 6z (don't know what the 0z was like) which is similar to the 6-15 days forecast. As ever it will change in that time frame. Any movement towards the GFS by the ECM (which is big ask ) would probably result in the forecast not being far off. Its all speculation of course. The main focus should be this weeks potential snow events! Expecially to higher ground in the North and East.

[Bobby]

I've got a feeling we'll get one really good run from one of the big models tonight which will throw a spanner in the works and start the confusion again.

[andymusic]

I've got a feeling we'll get one really good run from one of the big models tonight which will throw a spanner in the works and start the confusion again.

it's all gonna be about what the atlantic low is gonna do when it meets the blocking cold! - no one seems to have an idea including the models!