Model Discussion And Chat 19th Feb.2012

[phil nw.]

The American`s state that they have good confidence in the forecasted zonal outlook and a +NAO pattern into week 2.

http://www.cpc.ncep....day/fxus06.html

As expected really as in recent days the ongoing outputs from their days 8-14 hts. anomol. forecasts have consistently shown low heights over the Arctic and High pressure just to our south west trending to build further north and east with time.

Tonights NAEF`s heights anomolies also paints the same picture.

http://176.31.229.22...-0-0-240.png?12

Mid- latitude heights could well be a persistent feature on 500hPa outputs well into March and with MJO forecasted to move into Phase 3 with the new month the composite is a decent match for high pressure around the UK.

http://raleighwx.ame...Phase3500mb.gif

The only uncertainty is where the core of the High pressure will be but any ridging further north and east looks limited by the continuing presence of lower northern heights and fairly flat jet pattern.

[J10]

The American`s state that they have good confidence in the forecasted zonal outlook and a +NAO pattern into week 2.

http://www.cpc.ncep....day/fxus06.html

As expected really as in recent days the ongoing outputs from their days 8-14 hts. anomol. forecasts have consistently shown low heights over the Arctic and High pressure just to our south west trending to build further north and east with time.

Tonights NAEF`s heights anomolies also paints the same picture.

http://176.31.229.22...-0-0-240.png?12

Mid- latitude heights could well be a persistent feature on 500hPa outputs well into March and with MJO forecasted to move into Phase 3 with the new month the composite is a decent match for high pressure around the UK.

http://raleighwx.ame...Phase3500mb.gif

The only uncertainty is where the core of the High pressure will be but any ridging further north and east looks limited by the continuing presence of lower northern heights and fairly flat jet pattern.

I'd say fairly flat is a understatement.

[phil nw.]

I'd say fairly flat is a understatement.

Lol.yes i think a few of us could think of more colourfull ways to describe the flow Jackone.It`s a very disappointing end to official Winter for us coldies with little of interest in this solid looking westerly type pattern.

[Don]

Lol.yes i think a few of us could think of more colourfull ways to describe the flow Jackone.It`s a very disappointing end to official Winter for us coldies with little of interest in this solid looking westerly type pattern.

With the current pattern it seems like we have as much chance of cold/snowy weather developing as we would in July or August! OK, a bit of an exaggeration but lets face it we're pretty stuck at the moment.

[johnholmes]

It will be interesting to see how the Fax chart starts to look in 4-5 days time, T+120 will put it into the time frame where the anomaly charts are suggesting the upper ridge to be about ENE of the UK. Just where its surface partner will be is not clear but I'd think if the anomaly charts are correct then a touch ENE or NE of the UK, so a blocked pattern for most of the UK as opposed to only for more southern areas at the moment.

[damianslaw]

Reliable timeframe - staying mild for many - nearer average in the north over the weekend as we see a westerly airstream take hold. Dry for the south with further rain in the north.

Into next week all the models suggest azores high will ridge NE into the country with signs of central heights developing over the country through the week - meaning lots of dry settled weather but not sure whether it will be a cloudy affair or a sunny affair.

There is a signal for cold air to be building out to our east once again as we enter the new month and it wouldn't take much for this to be advected our way once again if we maintain strong heights over and just to our NE- not as extreme as early in feb but cold all the same.

[Cheese Rice]

If and thats a pretty big if we manage to get the cold advocated to the UK the lack of sever cold uppers should make up for the stronger sun.

It would be really quite interesting to see an easterly this late into the season, a mixture of a stronger sun and uppers 10 or below would result in heavier showers, homegrown convection would occur too.

I would say height rises over the UK/NE as we head into March. During the first week of March heights established with a chunk of PV spreading south advocating cold air into eastern Europe. Cold air advocated west into the second week with a chance of it spreading into Western Europe. At the moment I don't see cold air over the UK. Eastern Europe has a good shot at something significant, whether the high can position itself favorably to affect the UK remains to be seen.

Edited February 22, 2012 by Cheese Rice

[Cheese Rice]

Well I'm carefully watching the models, as I expect a severe cold spell to effect Eastern Europe with a chance of the cold air advocated towards the UK.

[johnholmes]

The ECMWF-GFS 500mb anomaly issue this morning shows quite a difference between the two. The ECMWF is quite similar to that put out by NOAA on their 8-14 day outlook last evening=upper ridge building east or NE of the UK. GFS shows almost no sign of any 500mb +ve anomaly and a much flatter westerly flow, also less strong than the SW pattern ECMWF suggests over and west of the UK.

Differences as marked as this lead me to have considerably less trust in what the actual 500mb pattern may look like 2 weeks on from here.

[IDO]

GFS 06z:

March 1st 2m temps:

http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120223;time=06;ext=177;file=ukmaxtemp;sess=d5ab142fb1ae7a1b2cfdfe29b0ce2c5a;

March 9th (end FI) 2m temps:

http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120223;time=06;ext=372;file=ukmaxtemp;sess=d5ab142fb1ae7a1b2cfdfe29b0ce2c5a;

Average in between so looking good for a nice Springlike March.

[Frosty.]

The latest models are showing another spell of very mild (warm) weather during much of next week with temps easily into the 14-16c range, around 60f and locally warmer than that. The current warm spell is peaking today with 17 and possibly 18c for lincs and widely at 15-16c with similar values for the south tomorrow but cooler/fresher air filtering into the north and northwest with temps falling back to around average which is only 8c, the weekend looks cooler everywhere under high pressure or at least a strong ridge with slight overnight frosts but sunny periods and then turning much milder through next monday as another strong pulse of Tropical maritime air races towards and swamps the uk in very springlike weather next week but also very breezy and with some rain in the northwest as lows pass to the nw of scotland. The further outlook on the gfs suggests a very blocked anticyclonic pattern for the whole of the BI with possibly a cold surge from the east with some wintry flurries and sharp frosts but then probably warming up later as winds become southerly but high pressure looks dominant for the next few weeks.

[nick sussex]

The GFS operational runs seem much more bullish regarding more amplified mid Atlantic troughing which helps to ridge high pressure further ne.

They certainly seem more inline with the NOAA maps, the ECM has a flatter pattern and keeps wanting to place troughing much nearer the UK in FI, so this disagreement makes it difficult to decide whether the outlook will trend colder or remain average to above average.

[bluearmy]

The GFS operational runs seem much more bullish regarding more amplified mid Atlantic troughing which helps to ridge high pressure further ne.

They certainly seem more inline with the NOAA maps, the ECM has a flatter pattern and keeps wanting to place troughing much nearer the UK in FI, so this disagreement makes it difficult to decide whether the outlook will trend colder or remain average to above average.

probably because those maps are far more representitive of ens data than op data nick. tbh, the ecm spreads are showing the atlantic trending towards troughing to our sw and although only half hearted, just seeing a spread which doesnt point the azores ridge at us is a novelty.

[johnholmes]

Is this a flatter pattern-I don't think so, ECMWF is the left hand one?

[Pixel]

does any one know the yellow member in this:

as I'd like to buy them a drink for being soo brave :lol:

[picog]

does any one know the yellow member in this:

as I'd like to buy them a drink for being soo brave :lol:

Control run almost as brave!

[johnholmes]

Control run almost as brave!

or as daft-sorry-but they are both so far away from what is most likely to happen-but then again egg on face is nothing new to any forecaster!

[Cheese Rice]

GFS having another wobble, after the 0Z been Atlantic dominated the 6Z reverted to height rises over the UK. Now the 12Z has gone loco. Don't think I've ever seen that many mini lows spinning around in all directions.

[Cheshire Freeze]

Interestingly the GFS 12z ensembles show hints of some amplification up to 180 hrs with a ridge being thrown north, this is one to watch IMO as I don't think the March pattern will be one of a flat pattern and anomalous warmth. In fact quite the reverse- especially later on.

More immediately, it looks like another chance is comig up to get the jet going south with hints from the GFS suite of pressure falling to the SW

This should become incresingly likely throughout March as the vortex begins to disrupt as it warms. I'd target 15th-22nd March as key dates for something more akin to winter than spring/summer.

Edited February 23, 2012 by CreweCold

[nick sussex]

Perhaps a few hints this evening of some changes in the NH pattern as we head into March, signs of the jet tracking a little further south and a stretching and eventually fragmenting of the PV.

The ECM looks to develop a more amplified troughing to the west of the UK at 192hrs, the more digging south of this trough the better chance that as this pivots it ejects some energy se'wards towards Iberia allowing some pressure rises to the ne.

Any interest doesn't really appear till the post FI timeframe and the ECM has pulled out the odd interesting run over the last week which its dropped after a day so we'll just have to see whether this is just a one off.

Edited February 23, 2012 by nick sussex

[mcweather]

Perhaps a few hints this evening of some changes in the NH pattern as we head into March, signs of the jet tracking a little further south and a stretching and eventually fragmenting of the PV.

The ECM looks to develop a more amplified troughing to the west of the UK at 192hrs, the more digging south of this trough the better chance that as this pivots it ejects some energy se'wards towards Iberia allowing some pressure rises to the ne.

Any interest doesn't really appear till the post FI timeframe and the ECM has pulled out the odd interesting run over the last week which its dropped after a day so we'll just have to see whether this is just a one off.

Yes Nick it did this a few nights back didn't it and then dropped it like a stone. It will be interesting to see whether it does it again or whether this might , just might be the signs of a pattern change that could give us a surprise or two later in March. I won't be holding my breath though.

[Frosty.]

wow it's so busy in here tonight.

The models are showing another very mild spell for the first half of next week with temps into the mid teens celsius, basically it's a rinse and repeat of this week but then perhaps a little colder from the northwest later next week but still high pressure dominated, however, both the gfs and ecm 12z show the atlantic becoming much more active from around T+240 hours with a sequence of deep depressions rushing towards the uk with a mix of mild and cool zonal, no sign of anything cold for the uk in the next few weeks, quite the reverse really..spring has sprung, well actually it's been sprung for 80% of this winter.

[nick sussex]

Yes Nick it did this a few nights back didn't it and then dropped it like a stone. It will be interesting to see whether it does it again or whether this might , just might be the signs of a pattern change that could give us a surprise or two later in March. I won't be holding my breath though.

The last FI ECM tease was a few days back with the suggestion of a possible easterly, that imploded after two runs, tonights doesn't deliver anything within 240hrs but holds a little interest as to where the pattern could go after that.

[Jason T]

Interesting current output actually has similar displays to feb and march 1976.????

[Cheshire Freeze]

Interesting current output actually has similar displays to feb and march 1976.????

I don't know what you may trying to imply about 1976 but, hemispherically, those two charts are very different