Model Output Discussion - 8th - 14th January

[WhiteFox]

Must admit even im shocked by how the models are saying NO to the upstream and forecast atmospheric patterns being projected by the experts.

1. SSW events which are trying to break the PV

2. Arctic High doesnt seem to want to play ball

3. AO & NAO thought were going negative/neutral...Surely that would allow Northern blocking to some extent?

4. Ensemble mean heights showing more mid atlantic blocking or heights to the North North East

5. Jet doesnt want to dive south to quickly?

What you end up with is a halfway house and I think we are still to see things pan out yet......ECM seems to be the model to choose but that goes against what some were saying last night.......and I really didnt see the ECM verifying.......

That PV just doesnt want to move!

Still many scenarios to play out i feel

Regards

Surely the forecasts of negative AO/NAO are also based on forecasting models? Therefore they are just as prone to variation as the synoptic output (in fact, they are simply differences in pressure between two points are they not? If the synoptic forecasts are wrong then by definition the AO/NAO forecasts are out).

Anyway, all this is simply due to the fact that the route to the Easterly shown by the GFS yesterday is exceptionally difficult to pull off. It was have been a classic, but the reason we have so few of these classics is because the timings all have to be just right. Put up against a strong jet, it is not impossible to get the cold air over the UK, but you're really threading a needle. Looking at Steve M's post on timing yesterday sums it up perfectly. If the shortwave aligns correctly, and the Arctic high can link up and the flow is on the correct path.... etc.

Not the first time we've seen such outbreaks forecast only for them to break down before they begin.

[SMU]

Surely the forecasts of negative AO/NAO are also based on forecasting models? Therefore they are just as prone to variation as the synoptic output (in fact, they are simply differences in pressure between two points are they not? If the synoptic forecasts are wrong then by definition the AO/NAO forecasts are out).

Anyway, all this is simply due to the fact that the route to the Easterly shown by the GFS yesterday is exceptionally difficult to pull off. It was have been a classic, but the reason we have so few of these classics is because the timings all have to be just right. Put up against a strong jet, it is not impossible to get the cold air over the UK, but you're really threading a needle. Looking at Steve M's post on timing yesterday sums it up perfectly. If the shortwave aligns correctly, and the Arctic high can link up and the flow is on the correct path.... etc.

Not the first time we've seen such outbreaks forecast only for them to break down before they begin.

thanks- yes timing & a slight change in jet orientation topples the projected cold like a string of dominoes...

Looks pretty much game set & match ECM tonight-

Hopefully more opportunities down the line towards day 11 ish

S

[ukpaul]

Surely the forecasts of negative AO/NAO are also based on forecasting models? Therefore they are just as prone to variation as the synoptic output (in fact, they are simply differences in pressure between two points are they not? If the synoptic forecasts are wrong then by definition the AO/NAO forecasts are out).

Anyway, all this is simply due to the fact that the route to the Easterly shown by the GFS yesterday is exceptionally difficult to pull off. It was have been a classic, but the reason we have so few of these classics is because the timings all have to be just right. Put up against a strong jet, it is not impossible to get the cold air over the UK, but you're really threading a needle. Looking at Steve M's post on timing yesterday sums it up perfectly. If the shortwave aligns correctly, and the Arctic high can link up and the flow is on the correct path.... etc.

Not the first time we've seen such outbreaks forecast only for them to break down before they begin.

The Ensembles are, in that case, being surprisingly bullish about an easterly, only a couple with the same oomph as yesterday's 18z but seven or eight members, and that's just the ones that hit us for a few days, a number also go further south into France instead.

Edited January 10, 2012 by ukpaul

[Cheshire Freeze]

If we look into FI, it can be seen that even with a zonal flow, uppers of -7 are brought in from the west and thicknesses are well down.....yes it's FI and th GFS sometimes does this to an extent, but I think it sums up how much cold air is potentially knocking around the mid latitudes come day 10......even for FI an Atlantic westerly flow with -7/-8 uppers is really quite impressive.

[Frosty.]

been out all day can someone update me resembling the charts please? any potential?

It looks like the gfs is continuing to signal cold zonal for all of the uk beyond T+240 hours but for northern britain and mainly scotland, there should be cold zonal well before then with a lot of hill and mountain snow. This ties in with the latest thoughts of the met office with a colder and more unsettled trend towards the end of the month.

[snowray]

I do think if we walk away from this and the last act is not a truely cold one, then we do have to admit, that forecasting is beyond anyone, at least in this forum. To their credit the Met-office, if it turns out the way is projected have called this one fairly correctly but whether that's down to their genuine knowledge or a pot luck pick in a difficult scenario, we won't know. Ill be very happy if we haven't gone down the route of the cold occurring, not because I'm a killjoy or anything like that, but because it shows how complex the synoptic situations are, and it doesn't show us up to be clueless, because it is so complex.

Quote of the day for me there SP.

It's like everyone saying don't look at at every individual run, just follow the trend, yer, yer, what trend, todays, yesterdays, GFS's, ECM's? Sometimes I wish the models all just went out to just T144 maybe T180. If they can't get close at T144, the rest is pretty pointless much of the time creating a complete waise of time and much waffle.

See GEM now running with UKMO, oh the joy, guess expect the unexpevted with the ECM thats coming out now.

[nick sussex]

It's funny in this game of model chopping and changing, the outputs which looked good for a while then go onto produce the worst outcomes when they backtrack.

The ECM/GEM a few days back and now the GFS which went from Hollywood movie star to an extra on Eastenders at 120hrs!

The ECM between 96hrs and 144hrs looks quite cold for the UK with that continental flow, could be some hard frosts if that verifies.

Strange looking 168hrs chart from the ECM, down here in sw France theres an easterly flow from here into the Atlantic which starts about 3000 miles to the east!

Edited January 10, 2012 by nick sussex

[I remember Atlantic 252]

unlucky no 13, (because wont come off) is an absolute snowfest in FI, around 192 hours

[ChartViewer]

It's funny in this game of model chopping and changing, the outputs which looked good for a while then go onto reproduce the worst outcomes when they backtrack.

The ECM/GEM a few days back and now the GFS which went from Hollywood movie star to an extra on Eastenders at 120hrs!

The ECM between 96hrs and 144hrs looks quite cold for the UK with that continental flow, could be some hard frosts if that verifies.

Got to agree re ECM T12Z 120 Nick looks colder and some frost and better than 00z....but then along comes T168 to spoil it lol!!!

Edited January 10, 2012 by ChartViewer

[Snowmadsam]

Got to agree re ECM T12Z 120 Nick looks colder and some frost and better than 00z

Better to have dry cold first then introduce precipitation ECM looks ok tonight

[Tim Bland]

More akin th the Meto outlook with a cool se breeze helping to keep dew points low. Hopefully some transient snow as the PV pushes SE ?

Much prefer GFS scenario ECM looks boring and average under high pressure. PV still raging to the north west

Edited January 10, 2012 by Tim Bland

[stewfox]

Quote of the day for me there SP.

It's like everyone saying don't look at at every individual run, just follow the trend, yer, yer, what trend, todays, yesterdays, GFS's, ECM's? Sometimes I wish the models all just went out to just T144 maybe T180. If they can't get close at T144, the rest is pretty pointless much of the time creating a complete waise of time and much waffle.

See GEM now running with UKMO, oh the joy, guess expect the unexpevted with the ECM thats coming out now.

This is unfair to the majority of posters on here.

The UK is a tiny tiny Island re the global scene and IMBY is a tiny tiny part of the UK.

Its not a waste of time or waffle to try and learn and its been very informative for me. Its not like its going to hit 70f in Moscow on friday is it ?.

A few minor changes re tilt /jet have implications down stream.

[nick sussex]

Got to agree re ECM T12Z 120 Nick looks colder and some frost and better than 00z....but then along comes T168 to spoil it lol!!!

Yes that 168hrs chart is bizarre, look how far east that flow is sourced from for southern Europe.

http://www.meteociel.fr/modeles/ecmwf.php?ech=168&mode=1&map=1&archive=0

I think it starts off in China!

I agree though could be shock of all shocks some air frosts !

I think COBRA are calling an emergency meeting as we speak!

[The PIT]

Good pooling over Europe in the ECM pity it's getting pushed away. Not looking like any major change from the ECM so colder this weekend and then slowly warming up as warmer air is gradually brought up from the south west. Dry as well. Not a good run.

[Snowmadsam]

Good pooling over Europe in the ECM pity it's getting pushed away. Not looking like any major change from the ECM so colder this weekend and then slowly warming up as warmer air is gradually brought up from the south west. Dry as well. Not a good run.

Still got the ECM ensembles to come out

[snowray]

My worst fear confirmed, UK high links up with Azores high at T192, all the cold heads into the South Eastern Med. Uk balmy mild, no cool zonality. What next ECM?

[ukpaul]

ECM looking much better in the reliable timeframe (about 96h at the moment it appears). After that then it could go anywhere (see GEFS ensembles!). Equally likely to bring in an easterly or a Bartlett high and each as likely to verify!

EDIT: Can't get post 120h to load, bugger.

EDIT: EDIT: Got it, hah, well that's yet one more wildly different solution to add to the pot.

Edited January 10, 2012 by ukpaul

[Tim Bland]

Awfull run! 8c uppers under high pressure. North Africa is colder than us! It would be tragic if we ended up back at square 1 with all the background signals and the recent Synoptics we have seen

[igloo]

not bad this evening from the ECM it has the HP hanging around for a wee bit longer than the rest of the models so a spell of clear skys and frost before it starts to turn slowly more unsetted and milder from the SW cant help but think we may end up with a mid atlantic HP before the month is out

[SP1986]

The ECM is broadly similar to the GFS in the near time run, into the later stages is seems to have thing a bit more further north than the GFS, subduing a potential cool/cold zonality situation. The PV is still very strong, and as yet isn't going anywhere.

[snow drift]

If you read through the previous three or so posts you will see why sooooooooo many people are confused to what the models are showing. So its good but its awful!!!!!!!!!! Some really need to analyise before they post. Its not a race!!!!!!!!!!!!!

Not including sp 1986

Edited January 10, 2012 by snow drift

[Paul]

I also think some people comment without actually having looked at the charts - maybe the highlight of their day to get a reaction in the model thread?!

[nick sussex]

I think we have to face the reality of the situation, if the PV stays where it is theres little chance of a decent cold spell.

If it edges west to Baffin then a cold spell is likely given the Arctic high and high pressure further east.

Thats it, we can have all the positive factors going but it comes down to the PV. If that doesn't move then we can watch as people throw snowballs on the beaches of Sicily!

Just one small thing to note, the ECM although reluctant to sink the high which delays that possible cooler zonality maybe about to go into tease mode again!

Please no more........!

[Jayces]

If you read through the previous three or so posts you will see why sooooooooo many people are confused to what the models are showing. So its good but its awful!!!!!!!!!! Some really need to analyise before they post. Its not a race!!!!!!!!!!!!!

Not including sp 1986

I complain about this every year but I don't know what the solution is.

I wish the people posting would consider that hundreds if not thousands of people come here during the winter especially just to read what may be happening and then get 3 consecutive posts giving 3 viewpoints of the models in 3 word sentences but no backing up what they are saying with examples.

Maybe this forum needs an ignore feature which hides posts from unhelpful people or does that already exist?

[snowmadchrisuk]

Just a quick one from me tonight , but of note is the arctic high isn't there yet , it is forecast to start building in around +48 hours. When it does form both the GFS and the ECMWF have it remaining until the end of there outputs . Extending South all the time . My point is when it has actually formed and is in the models starting data , I think we will then start to see some much more exciting model output . I am calling a country wide Cold spell before the end of the month , I might be wrong but the output and background signals all lean towards Cold eventually reaching our shores more than they do not .

Chris