Model Discussion And Chat 19th Feb.2012

[Summer Sun]

Well ECM is very easy to sum up tonight, High pressure dominates every day expect 144h in the north. Expect some very settled and dry weather for the foreseeable future if ECM turns out to be correct.

Edited February 20, 2012 by Gavin D

[cooling climate]

ZZZZZZZ! Thats my thoughts regarding the ECM upto 192hrs, the amplified eastern USA trough flattens out and delivers a level of boredom in tune with most of the winter so far!

The GFS continues to make an effort at trying to spur my cognitive function into life but fails as the northern arm of the jet flattens the high out, the UKMO looks similar to the ECM although it takes longer to develop that eastern USA low.

Either way it looks a very mundane picture with limpet high to the south and weak low pressure to the north, drab uneventful apart from highish temps this week, hopefully the ECM ensembles have some options that don't induce sleep!

A sudden burst of excitement at 216hrs as that troughing digs further south into the Atlantic!

At 240hrs the ECM finally decides to bring some interest with the classic pre easterly signature of digging trough in the mid Atlantic and pressure would rise to the east , shame its at 240hrs, no doubt that will implode by tomorrow!

Yes as you say all the classical signs are there with the PV held back over to west of Greenland and heights starting to

fall in the med. Lets hope it is there tomorrow otherwise the borefest we have had to endure for three months will

continue. It will be interesting to see if the GFS picks up the baton again in its FI range on tonights 18z.

[nick sussex]

Lol Nick,i think you need to phone the net-weather helpline. :lol:

Lol! I can't I'm the one that answers the calls normally!

Apologies for my rather sarcastic attitude to the models this evening, putting aside much of the operational output theres one very good chart at 240hrs from the ECM, I'd like to see the troughing at least neutrally or preferably negatively tilted, if that was the case you'd have a very good chance of seeing an easterly or ne flow a few days after.

If that was shown within 144hrs I'd be quite positive as it is its at the far reaches of the ECM and hence could well just be a charitable effort by the ECM this evening!

Edited February 20, 2012 by nick sussex

[phil nw.]

The 12z outputs continue the Westerly pattern through this week with the Azores High reluctant to move from it`s home near the south of the UK.

Fronts will straddle the UK at times and the north,particularly Scotland will see brief spells of less milder air at times but generally stubborn low heights to the north will continue to dominate into the medium term keeping things mainly mild and breezy with rain at times in particular for the north and west.

A look at the hemisphere view at T144hrs tells the story.

Thurs into Friday continue to promise some fine and very mild temperatures for more southern and eastern districts.

as a broad warm sector between the frontal systems straddles the UK.

Further on into week 2 both GFS and ECM show some build north of the Azores High to be centred over the UK by day 10.

This fits in well with the MJO forecasted into Phase 3 by the new month.

So March may well come in like a lamb with quiet anticyclonic conditions and near normal temperatures.

[TEITS]

Blimey Nick S is even more miserable than I am. :lol:

I can't say im surprised because my word is been pretty rubbish following the models for cold spells this winter. Im now focussing on rainfall rather than snowfall and considering i've only recorded 11mm this month some of us need it. The last thing I want the models to show is HP centred over the UK but thats exactly what the models are showing for the start of March.

[nick sussex]

Blimey Nick S is even more miserable than I am. :lol:

I can't say im surprised because my word is been pretty rubbish following the models for cold spells this winter. Im now focussing on rainfall rather than snowfall and considering i've only recorded 11mm this month some of us need it. The last thing I want the models to show is HP centred over the UK but thats exactly what the models are showing for the start of March.

Dave have you seen the JMA this evening?

That will put a smile on your face!

I agree the lack of rainfall is a concern but I'm sure the Azores high will leave just in time for summer!

[mcweather]

Lol! I can't I'm the one that answers the calls normally!

Apologies for my rather sarcastic attitude to the models this evening, putting aside much of the operational output theres one very good chart at 240hrs from the ECM, I'd like to see the troughing at least neutrally or preferably negatively tilted, if that was the case you'd have a very good chance of seeing an easterly or ne flow a few days after.

If that was shown within 144hrs I'd be quite positive as it is its at the far reaches of the ECM and hence could well just be a charitable effort by the ECM this evening!

Hi Nick quite agree if that 240 chart was at 144. There could be some excitement to be had.

However under the caveat that all of this is in FI. There is clearly something in the data input that made the gfs start showing either an eaterly or northerly in its long term output. The interesting thing now is that perhaps for the first time this winter the ECM has actually moved towards the GFS ( allbeit in FI).

As you say the the troughing digging south in the atlantic is a classic pre-easterly pre-requisite. All a long way off and as you say may all be gone tomorrow morning,but if it isn't then at least it has livened up the borefest that has marked out most of this winter.

[nick sussex]

Hi Nick quite agree if that 240 chart was at 144. There could be some excitement to be had.

However under the caveat that all of this is in FI. There is clearly something in the data input that made the gfs start showing either an eaterly or northerly in its long term output. The interesting thing now is that perhaps for the first time this winter the ECM has actually moved towards the GFS ( allbeit in FI).

As you say the the troughing digging south in the atlantic is a classic pre-easterly pre-requisite. All a long way off and as you say may all be gone tomorrow morning,but if it isn't then at least it has livened up the borefest that has marked out most of this winter.

If by some miracle the ECM had the right trend and continued with this over the next few days we'd need to be able to tap into a decent cold pool for it to deliver.

Generally I'd prefer to see a more ne flow at this time of year sourced in the Arctic rather than eastern Europe unless that is we can get a piece of the PV to drop south into western Russia.

[Frosty.]

Well it's officially a drought like 1976 and 1995 and the models are showing very little rain for the areas that need it but the areas that have had more than enough water this winter (nw uk) will continue to get soaked this week, especially nw and n scotland where it rains almost every day.

[Cecil Hogmanay Melchett]

Dave have you seen the JMA this evening?

That will put a smile on your face!

I agree the lack of rainfall is a concern but I'm sure the Azores high will leave just in time for summer!

lack of rainfall????? LOL.

I think i can count the number of sunny days here since june on two hands,its been utterly awful.Just been to the shop and its raning oderately.

On the news i saw talk of a drought in the SE,the divide in conditions between the SE and the NW is getting more pronounced imo,posibly due to the almost persistant westerly airmass for goodness knows how long.

[phil nw.]

Well it's officially a drought like 1976 and 1995 and the models are showing very little rain for the areas that need it but the areas that have had more than enough water this winter (nw uk) will continue to get soaked this week, especially nw and n scotland where it rains almost every day.

Tonights GEFs clusterings show 50% of it`s members go for a High over the UK by week 2.

http://expert-images...100_2012_01.gif

so no meaningfull rain in the medium term looks likely for those areas in the south and east that need it.

Edited February 20, 2012 by phil n.warks.

[Cloud 10]

Tonights GEFs clusterings show 50% of it`s members go for a High over the UK by week 2.

http://expert-images...100_2012_01.gif

so no meaningfull rain in the medium term looks likely for those areas in the south and east that need it.

Tonight's 8-14 day cpc goes for the high over the UK scenario as well.

Pattern change to come as we enter march?

[nick sussex]

Tonights NOAA maps suggest high pressure is likely to become the main feature in the medium term:

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610day.03.gif

http://www.cpc.ncep.noaa.gov/products/predictions/814day/814day.03.gif

You can see there the trend to edge this further north with lower heights developing in the mid Atlantic.

The uncertainty is more in relation to how far north any high ridges and whether troughing in the Atlantic will amplify sufficiently to go that next step in allowing a colder east to ne flow to become established across the UK.

[bluearmy]

Nick, the dropping of heights in the atlantic to our sw in fi was a gefs theme from yesterday. Since then, the gfs ops seem to have got a little progressive with it and tried to bring it forward. However, ECM today at day 10 seems to be a good fit with yesterdays theme from gefs. I note the 8/14 day cpc chart looks a good fit also with the high anomaly stretching across the pole. I fancy we could go anywhere from that set up.

[nick sussex]

Nick, the dropping of heights in the atlantic to our sw in fi was a gefs theme from yesterday. Since then, the gfs ops seem to have got a little progressive with it and tried to bring it forward. However, ECM today at day 10 seems to be a good fit with yesterdays theme from gefs. I note the 8/14 day cpc chart looks a good fit also with the high anomaly stretching across the pole. I fancy we could go anywhere from that set up.

Yes that CPC chart is certainly giving some support to the ECM operational run tonight, what do you make of the ECM spreads, the 240hrs looks to me to suggest a strongish signal for troughing to the west and a weaker signal for higher pressure to the east.

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&type=2

Edited February 20, 2012 by nick sussex

[bluearmy]

Yes that CPC chart is certainly giving some support to the ECM operational run tonight, what do you make of the ECM spreads, the 240hrs looks to me to suggest a strongish signal for troughing to the west and a weaker signal for higher pressure to the east.

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&type=2

The troughing mid Atlantic is definite and continues from the past two ECM runs. Not sure about the higher heights to the east. Currently at day 10 the block is centred southern uk. Its after this that we need to get sight of. I notice a split in the extended ECM ens with a chunk of colder runs now showing up, along with some pretty mild ones.

[nick sussex]

The troughing mid Atlantic is definite and continues from the past two ECM runs. Not sure about the higher heights to the east. Currently at day 10 the block is centred southern uk. Its after this that we need to get sight of. I notice a split in the extended ECM ens with a chunk of colder runs now showing up, along with some pretty mild ones.

I think we can see where those two diverging opinions are coming from, one the troughing is probably too close and positively tilted driving a mild southerly flow up and the other probably a more amplified neutral/negatively tilted trough further west allowing the ridge to extend far enough north to advect some colder air west on the southern flank.

[phil nw.]

I think we can see where those two diverging opinions are coming from, one the troughing is probably too close and positively tilted driving a mild southerly flow up and the other probably a more amplified neutral/negatively tilted trough further west allowing the ridge to extend far enough north to advect some colder air west on the southern flank.

The MJO composite i posted earlier Nick suggests that we could get the High further north eventually.The uncertainty is in the orientation of the flow as to whether we can get cold air from it.

It does seem though we are likely to get a pattern change as BA suggests with a low heights anomol. to show up near the Azores.

[nick sussex]

Big differences on the GFS 18hrs run from very early on between the handling of the eastern USA low, the earlier 12hrs run developed this into a much deeper feature much further upstream.

[Zakos]

Not much hope in the output for an end to the drought, infact quite the opposite. Quite remarkable the lack of rain, my county has experienced the driest 16 months on record.

It is now safely "game over" for this winter in terms of cold weather. However just because it says March on the calender doesn't mean we cant experience cold and snow, especially in the first week.

Once again I think we should look E/NE for cold, were not going to get a sustained Greenland High. Definite trend from the GFS to build pressure over Scandinavia, However no consitentcy on its orientation or longevity

The 00z would do fine -

The 12z not so much

For an unsettled convective easterly we really need to see the low heights to our SW. The Azores high has been a persistent and rather bullish feature this winter. Hopefully it has run its course.

[Jason M]

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=174&mode=0

Flat as a pancake which has been further flattened by a large steamroller!!

Still no rain of note for the SE and now that the temperature is going to move from 'mild' to 'tropical' this will simply worsen the problem.

At this rate my 5.9C CET guess won't be far off despite a sub zero first week.

Absolutely no prospect of any meaningful rain in the SE anywhere in model land.

Jason

[bluearmy]

It does seem though we are likely to get a pattern change as BA suggests with a low heights anomol. to show up near the Azores.

thats a brave statement so far out, given how persistent the AH has been this winter Phil. at the moment its clues and sniffs at a 10 day range. would love to see it verify, especially as i suspect most of mainland europe to our east is likely to still be cold with snow cover.

[phil nw.]

thats a brave statement so far out, given how persistent the AH has been this winter Phil. at the moment its clues and sniffs at a 10 day range. would love to see it verify, especially as i suspect most of mainland europe to our east is likely to still be cold with snow cover.

Just asuggestion on 18z of this at around day 10.

maybe a temporary Eastern Atlantic trough before the renewed burst of energy from our north west .

That`s a mighty piece of low heights modelled up there.

[Zakos]

http://www.meteociel...&ech=174&mode=0

Flat as a pancake which has been further flattened by a large steamroller!!

Still no rain of note for the SE and now that the temperature is going to move from 'mild' to 'tropical' this will simply worsen the problem.

At this rate my 5.9C CET guess won't be far off despite a sub zero first week.

Absolutely no prospect of any meaningful rain in the SE anywhere in model land.

Jason

worrying isn't it? the 18z is nothing like the 12z at 192 hours, but still no rain to speak of at all throughout both runs.

And then, after completely flattening the pattern at 192 hours, the GFS actually manages to build a stronger Scandi High than the 12z did

There is genuinely more consistency at 348 hours then at 192 hours. Doesn't make much sense to me. Unless perhaps GFS is implying that whatever happens at 192 hours the outcome would still be a pressure build over Scandinavia. Interesting.

Also, is it me, or does the PV look ridiculously strong in FI? GFS reverting to default?...

[Jason M]

worrying isn't it? the 18z is nothing like the 12z at 192 hours, but still no rain to speak of at all throughout both runs.

And then, after completely flattening the pattern at 192 hours, the GFS actually manages to build a stronger Scandi High than the 12z did

There is genuinely more consistency at 348 hours then at 192 hours. Doesn't make much sense to me. Unless perhaps GFS is implying that whatever happens at 192 hours the outcome would still be a pressure build over Scandinavia. Interesting.

Also, is it me, or does the PV look ridiculously strong in FI? GFS reverting to default?...

Yes, i've never seen anything like this. In Jan 2011 pressure rose suddenly over Iberia and that killed off last winter and kept us dry, and ever since we have had relentless high pressure to our south. The pattern will break eventually, but after nearly 14 months no reason to think it will be anytime soon.