Model Discussion And Chat 19th Feb.2012

[Frosty.]

Spring is the most common time of the year for Northerly outbreaks statistic wise.

The beginning of march 2006 is a classic example of this, a northerly which caused snowdrifts to stop trains in aberdeenshire during a ferocious northerly outbreak which dumped over 24 inches of level snow in shetland. The latest models are hinting at a colder spell after the warm spell next week...but nothing on that scale sadly.

Edited February 25, 2012 by Frosty039

[ukpaul]

For down here, recent charts have been suggesting that we are heading towards a nightmare scenario of a warm and dry spring which, coming after a very rainless autumn, would be another nail in the coffin.

I've been a little more relieved today that a chink of light may be on the horizon though looking at the charts, FI I know, but the direction may well be becoming more favourable once we've got through the next week. Vague suggestions of more rain and colder weather may not be enough, but at least it might mean that I don't have to travel north in order to have a shower!

Seriously, it's that bad down here, my folks up on the Lancashire coast seem to have been drowned whilst we keep getting dry, dry and more dry. It rained slightly on Thursday and I just stayed out there getting wet, I'd almost forgotten what it feels like.

[karyo]

By the way, if anyone considers our mild winter is anything to do with Global Warming, UAH Global average temps have recently dropped to the lowest ever on the satellite record!

hi there,

can you please provide us with a link? I find your statement very interesting for obvious reasons!

Karyo

[Frosty.]

Well I love this chart from the gfs 06z even though it probably has a snowballs chance in hell of actually verifying.

[Timmytour]

Not much change from 6z to 12z on the GFS to T60.....slight rise in pressure over Greenland

[Summer Sun]

Looking very mild and dry for a time this week, lets hope the sun get's out more this coming week to make it feel more like spring,

http://www.wetterzen...s/Rtavn7817.png

http://www.wetterzen...cs/Rtavn784.png -Rain

http://www.wetterzen.../Rtavn10217.png

http://www.wetterzen...s/Rtavn1024.png - Rain

Becomes more unsettled for the weekend but still mild for some

http://www.wetterzen...s/Rtavn1742.png

http://www.wetterzen...s/Rtavn1922.png

Into FI it becomes chilly for a time

http://www.wetterzen...s/Rtavn2162.png

http://www.wetterzen...s/Rtavn2641.png

http://www.wetterzen...s/Rtavn3361.png

[Ruzzi]

The beginning of march 2006 is a classic example of this, a northerly which caused snowdrifts to stop trains in aberdeenshire during a ferocious northerly outbreak which dumped over 24 inches of level snow in shetland. The latest models are hinting at a colder spell after the warm spell next week...but nothing on that scale sadly.

http://www.wiseweather.co.uk/id110.html

[Timmytour]

looking at GFS 12z it's deep FI but a continuing trend now of bringing in a northerly, though not sure how potent that will proved to be away from northern areas in terms of delivering snow. Azores high definitely pushed out a little further west on the latest run.

[Nick F]

All this talk of northerlies, but it's all way in FI and we need to see where the ridge building in across western Europe goes next week first. 12z GFS quite progressive in blasting the ridge away eastwards by the end of the week, while 12z UKMO pulls the ridge north across the UK (t+144) which could lead on to height rises across Scandi - which is not really conducive to a northerly further down the line, rather a E/NE'er instead.

I suppose 12z GFS progressiveness in bringing in Atlantic mobility would at least bring some much needed rain for the drought stricken areas of England.

[cooling climate]

Despite what the GFS is showing in its extended output I can not see any chance of a northerly.

If we are to see any colder and perhaps wintry weather it will surely come from the east or

northeast.

[Polar Continental]

The ECM is beginning to become slightly more interesting in it outer reaches. Low-pressure tracking further south as heights tentatively build to the north, will be worth keeping a desperate eye on if the trend continues.

http://www.wetterzentrale.de/pics/Recm1921.gif

http://www.wetterzentrale.de/pics/Recm2401.gif

Edited February 25, 2012 by Polar Continental

[Milhouse]

Increasing signs that the Atlantic will be fighting back in about a weeks time with the jet showing signs of sinking south. Although how much rain would result for southern areas is still questionable. A fairly mobile pattern does look likely to resume though with HP being shoved southeast. ECM beings LP quite far south at 240h, perhaps far enough to bring a bit of wintriness to Scotland. Will be interesting to see where it fits alongside the ensemble mean.

[bluearmy]

The period post 7th march has been a consistent 10% London snow chance on the gefs for many days now. the odd 15 and more commonly 5 thrown in. Not a surprise to see ECM toying with colder scenarios as the period comes within it's op range. Currently, gfs suites seem quite buoyant on firing up the Atlantic again in low res. Some eye candy to look at as we end winter though a final cold hurrah may well be on the agenda.

[Milhouse]

However the GEFS mean shows heights remaining fairly strong in the south well on into the following week.

http://www.wetterzentrale.de/pics/Rz500m10.html

[phil nw.]

All this talk of northerlies, but it's all way in FI and we need to see where the ridge building in across western Europe goes next week first. 12z GFS quite progressive in blasting the ridge away eastwards by the end of the week, while 12z UKMO pulls the ridge north across the UK (t+144) which could lead on to height rises across Scandi - which is not really conducive to a northerly further down the line, rather a E/NE'er instead.

I suppose 12z GFS progressiveness in bringing in Atlantic mobility would at least bring some much needed rain for the drought stricken areas of England.

There does look a tendency to drop low heights towards the UK from the North West towards the end of next week.

Any ridge looks shortlived to me Nick.

If you look at the energy spilling across towards Scandinavia it would seem to prevent any high pressure to our north east at that stage.

http://www.meteociel...44-21.GIF?25-17

Viewing the ECM which looks similar at T144hrs.ie.some ridging but like on the GFS it`s pushed away by the energy from the North west.

There seems to be a theme on the 12z mean ht. ens. ie. the jet coming south and things cooling off and becoming more cyclonic by week 2.

http://www.meteo.psu...F_12z/test8.gif

I wouldn`t rule out a polar outbreak from the north or north west after that.Looking at those mean heights modelled around mid-latitudes it is a more viable solution than an easterly.

There doesn`t seem to be any appetite to remove the Azores high from the scene so you would think any chance of a colder spell has to be from Atlantic ridging and Scandi. troughing.

Edited February 25, 2012 by phil n.warks.

[Alex95]

The trend seems to be for some pretty cool westerlies as we head into March - I fancy some heavy snow over the hills in Cumbria and Scotland

With stronger contrasts in temperature at this time of year we could be also looking at a pretty stormy spell, and a strongish Azores high which stays out west can often set ESE tracking lows across the UK which I have known to give many inches of snow over northern higher ground, and plenty of gales everywhere. I know its still FI, but I see little reason to assume March will be boring, especially if you like hill walking.

Edited February 25, 2012 by Alza 2

[Milhouse]

The trend seems to be for some pretty cool westerlies as we head into March - I fancy some heavy snow over the hills in Cumbria and Scotland

With stronger contrasts in temperature at this time of year we could be also looking at a pretty stormy spell, and a strongish Azores high which stays out west can often set ESE tracking lows across the UK which I have known to give many inches of snow over northern higher ground, and plenty of gales everywhere. I know its still FI, but I see little reason to assume March will be boring, especially if you like hill walking.

Indications from the ECM mean of a much more NW-SE tilt to the jet as we go into March

http://www.wetterzentrale.de/pics/Reem2161.html

http://www.wetterzentrale.de/pics/Reem2401.html

[nick sussex]

At last some signs of a change in the pattern but still too far out to assume the Azores high will be displaced into the mid Atlantic.

The ECM does follow its morning trend, the UKMO again wants to bring a stronger ridge into play but you suspect this won't last long as troughing to the west edges east, the GFS is less bullish regarding the removal of the limpet high.

Looking at the ECM ensemble maps these are supportive of troughing near the UK at 168hrs, this is likely to verify but its the orientation of this and what happens to high pressure to the south thats still undecided.

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009112700!!/

It's clear to see from those ensemble maps which members could go on to provide a change to more unsettled and colder conditions and which suggest a flatter upstream pattern with the limpet high still proving a difficult obstacle to overcome.

[Alex95]

Even if the Azores high doesn't play ball it would still be possible for a vigorous low to give some heavy rain / gales in the North though, but obviously a displaced Azores high would be the most 'interesting' situation in the eyes of most on here.

[nick sussex]

Even if the Azores high doesn't play ball it would still be possible for a vigorous low to give some heavy rain / gales in the North though, but obviously a displaced Azores high would be the most 'interesting' situation in the eyes of most on here.

Really to alleviate the drought conditions in southern areas we need to see the Azores high displaced, aswell as this for those looking for some late season snow and cold that needs to take a hike!

Certainly the longer range ECM De Bilt ensembles have improved regarding colder prospects:

http://www.weerplaza.nl/15daagseverwachting/default.asp?type=eps_pluim

Bearing in mind that troughing sinking into Europe would likely provide especially northern areas of the UK with colder temps than Holland which may take longer to get on the cold side of any troughing.

[bluearmy]

big difference at day 10 between naefs and ecm mean. i suspect the ecm 12z suite to be a 'rogue' run wrt the troughing over our lattitude. would be nice if it were to verify but methinks the mid lat high ridging to our ne from our sw will be more likely come tomorrows ens runs from ecm.

[cooling climate]

It looks to me as if the 18z is now siding with what the ECM has been showing for the last two

runs. This could be very entertaining in FI.

[karyo]

It looks to me as if the 18z is now siding with what the ECM has been showing for the last two

runs. This could be very entertaining in FI.

Yes, an interesting FI from a cold perspective although most people are fed up of waiting and have left the building!

The operational is colder than the mean but overall a turn towards colder weather on the ensembles: http://www.netweather.tv/index.cgi?action=ensviewer;sess=

Karyo

[Timmytour]

If I didn't know better I would have said the GFS has been wating for the Daily Express to do a front page on how mild and springlike March is going to be before starting to show us that it could in fact have quite a wintry punch within it! Do Daily Express headlines get input into the models

[Frosty.]

The latest models are agreed on unsettled weather arriving by T+144 hours and the ecm is more bullish about a rather cold unsettled spell persisting beyond t+144 whereas the gfs 00z, after a brief burst of polar maritime, quickly buckles the jet as a ridge builds north into next weekend but it's only temporary as lows then sweep east into the following week with a mix of mild and cool zonal, occasionally colder further north. Most of the coming week looks dominated by high pressure which should cover most of the uk apart from the far northwest and north and it also looks like becoming very mild or warm, especially towards the southeastern half of the uk as pressure remains high until next friday but the warmth will be mixed out by then and the weather becoming windier and more unsettled by next saturday across the uk with the southeast last to see the change but some much needed rain eventually for the southeast.