Further Cold Spell In February? 0-180 Charts Only

Redsunset · 04-02-2012 12:43am #1

There are some signs of below average temps to return to our shores and we shall watch and discuss Model Outputs here up to 180 hours only.

I will also add that if I see silly off topic posts you will now be met with an Infraction,I have given several yellow cards already and Pistolpetes11 has been moving several posts over to Chat thread. May I ask that you simply spend a moment to think about where your post is most suitable
Thank you.

Please continue your quest......................:D

200motels · 04-02-2012 1:45am

Looking at the GFS 18Z run there's a fair difference to the previous run, I know it's the pub run but a difference from next wed to fri, I think they'll chop and change through the weekend.

Redsunset · 04-02-2012 1:46am

Here's the 50 members of the 12z ECM for 168 hrs (10th Feb) showing good support for a block to be sitting over or just near us. As echoed already in previous thread,this may or may not lead to blocking in a more favourable position for much colder feed of air around mid month with Greenland heights looking more favourable by then.
We shall see.

http://www.ecmwf.int/samples/d/getchart/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2012020312!!chart.gif

Harps · 04-02-2012 2:26am

No real consistency on what the high does next week, ECMWF and GFS have it sitting right over us at the moment but there's been numerous different solutions including a return to an easterly airflow as early as midweek. GEFS runs all over the place after Tuesday

GEFS mean at 144h hinting at heights over Scandi' which is roughly what the Canadian model is going for giving us a second shot at an easterly

Basically they haven't got a clue yet :P

nilhg · 04-02-2012 10:22am

ECMWF operational run

and ensemble mean

seem quite consistent this morning, and the same applies even well out into FI, it looks the likeliest solution to me.

GFS builds HP to our NE eventually in its run but the operational run has poor enough support there even in what might usually be regarded as a reliable time frame so I'm not too keen on that.

Tom Cruises Left Nut · 04-02-2012 12:01pm

Thanks for letting the rollercoaster stay lads !!!

Looking good this morning on GFS !

Musicman2000 · 04-02-2012 1:41pm

We were here this time last week and we all know what happend:D The GFS has some great charts this morning, But the ECM is having none of it which is a slight worry, and UKMO is not so bad today. Going to be another fun few days model watching.

derekon · 04-02-2012 1:49pm

Musicman2000 wrote: »

We were here this time last week and we all know what happend:D The GFS has some great charts this morning, But the ECM is having none of it which is a slight worry, and UKMO is not so bad today. Going to be another fun few days model watching.

Excellent point Musicman - those GFS charts should carry a major health warning

:D

To avoid heartbreak folks, best rule of thumb is not to trust anything outside T+48 hours. I have followed this rule myself and it shows Ireland having mild and wet weather for the next 2 days. Not great, but at least I ain't deceiving myself!!

:D

D

Sponge Bob · 04-02-2012 2:03pm

ECM 00z Is still showing an atlantic winning the battle of the upper temps and the next interesting data form them is due just after 6pm.

Met Iceland shows the current prognostication very well when you yank the slider across.

http://en.vedur.is/weather/forecasts/atlantic/#type=temp

Be Interesting to see whether that blue stain widens on the right!!

Su Campu · 04-02-2012 3:16pm

Sponge Bob wrote: »

ECM 00z Is still showing an atlantic winning the battle of the upper temps and the next interesting data form them is due just after 6pm.

Met Iceland shows the current prognostication very well when you yank the slider across.

http://en.vedur.is/weather/forecasts/atlantic/#type=temp

Be Interesting to see whether that blue stain widens on the right!!

It doesn't! This is at 240 hours!

But we are seeing the high building over Greenland, which I thought might happen.

Sponge Bob · 04-02-2012 3:29pm

I don't think the GFS has been simply dire at around 180 hours. On Thursday the 26th of Jan this was the 180hr 850 hpa temp forecast.

Anyone remember what yesterday actually turned out like. ??

gfs-2012012612-1-180.png?6

Now I know the GFS can flip flop ....a lot

But overall the GFS is betting across a few recent runs on a Siberian Push against the Atlantic starting midweek. I reckon that much is correct. Whether it gets here and runs into moist air is another question..the last Siberian blasteen was a very dry event.

darkman2 · 04-02-2012 4:37pm

The 00z and 06z GFS building on the possible very cold Easterly for next week. The 00z UKMO moving that direction aswell. The 00z GEM is a case of almost whilst the 00z ECM is more toward what we want to see but not quite there yet. Signs are good that the Jet Stream might take take a dive south allowing low pressure from the Atlantic to undercut the Scandinavian high. Also increasingly note that gradually the models are lessening the dispersion of cold air on the Continent and maintaining a feed from a Siberian source so we should have a decent pool of cold air to tap IF the Easterly comes off. My forecast is an Easterly followed by a Northerly some days later with frost and ice becoming widespread severe again and snow for some.

12z's rolling now. Let's see if they build on this further.

DWD 12z 72hrs- not bad at all.

gme-0-72.png?12

Tom Cruises Left Nut · 04-02-2012 5:01pm

Cold in Europe a bit further west on this run.

Lets see what this means when we get to the reload timeframe

TheMilkyPirate · 04-02-2012 5:09pm

GFS pretty much identical to the GEM at 72h.

Tom Cruises Left Nut · 04-02-2012 5:24pm

Here come the colder uppers

Tom Cruises Left Nut · 04-02-2012 5:27pm

-8 over us now !

Tom Cruises Left Nut · 04-02-2012 5:32pm

And boom

Tom Cruises Left Nut · 04-02-2012 5:49pm

UKMO wants to join the party now too !

GFS at same time frame

Harps · 04-02-2012 5:54pm

GFS keeping consistent with its recent theme, reasonably mild and wet up until Wednesday before a cool easterly returns and eventually the high shifting to Greenland ushering in a north easterly

GEM is even more progressive with the cold air holding on, a potential snowfest over Eastern Ireland on Wednesday but it seems to overdo the cold air compared to the rest

UKMO also has the easterly winning out after Wednesday

All eyes on the ECMWF at 6pm then

jimmynippy · 04-02-2012 6:08pm

GFS 12Z AND UKMO 12Z are very similar at 1300 on Friday,this must be a very positive sign?

BEASTERLY · 04-02-2012 6:14pm

Well the the UKMO nailed the week just past, hopefully another good performance this time.

darkman2 · 04-02-2012 6:22pm

Much more confident now about this with the UKMO more or less on board. It looks like turning much colder again from Wednesday with the surface cold arriving first and reintroducing very cold frosty nights and low daytime maxima. Then the increasing possibility of very cold weather extending west over Ireland with more instability and snow particularly in the East. ECM the odd one out now.

Su Campu · 04-02-2012 6:39pm

Guys I must again warn you against getting too excited about such a setup if it were to materialise as it would be very similar to this week's one, which delivered absolutely nowt. High pressure near us with strong inversion, very dry airmass and cold air advection at low-mid levels, all pointing towards surpressed cloudiness and hence little chance of snow. All depends on whether the wind could back a bit more from a east-northeasterly direction to increase the fetch over the North Sea and hence get the boundary layer working a bit. There could also be a disturbance over the continent which would give things a boost but without that we would be peeing against the easterly.

I'm still not convinced it will work out the way these models are showing, though obviously the nearer we get to the time the wronger I may get! I would have been more inclined to agree with the ECMWF, which is the odd man out at the moment. We'll see what happens, but I don't think snow is a given in a setup like that shown.

Tom Cruises Left Nut · 04-02-2012 7:02pm

ECM looks to have jumped west in the first 2 frames

TheMilkyPirate · 04-02-2012 7:40pm

ECM looks to be taking a trip to Greenland at 168h, High is farther south than the other model runs before this.

Redsunset · 04-02-2012 7:49pm

Looking at the bigger picture we see heights push across the pole promoting negative AO conditions and wanting to link up with Atlantic block over Greenland.

Su Campu · 04-02-2012 7:52pm

redsunset wrote: »

Looking at the bigger picture we see heights push across the pole promoting negative AO conditions and wanting to link up with Atlantic block over Greenland.

That's how I was thinking things would pan out. The low off New Foundland cuts off and heads north, allowing the high over Ireland to back off westwards, allowing the attack from the north.

TheMilkyPirate · 04-02-2012 7:53pm

Have a feeling the path to this next cold shot will be a lot smoother than what we just experienced.

darkman2 · 04-02-2012 8:01pm

High pressure is going to build in Greenland inevitably. Easterly then Northerly is what i'm going for. The ECM has come more in line with the GFS\UKMO but it has the high pressure centered closer to us between 96 and 144hrs. It could be right about that but given the other models (GFS\NOGAPS\UKMO\GEM) I suspect it will shift more toward them on the 00z tomorrow. The Easterly I see over us is part of the process of building heights over Greenland. The high pressure is going West it's just a case of will it deliver cold and snow before the Northerly sets in and the PV moves over Scandinavia.

ECM 144hrs

UKMO 144hrs

Redsunset · 04-02-2012 8:03pm

Yes Su that would be a very good scenario for us and could very well play out as shown. A Greenland block is what I crave, much better probability of producing the goods.

Models are certainly showing a strongly negative AO for the mid month period.

We shall see.

BEASTERLY · 04-02-2012 8:26pm

redsunset wrote: »

Yes Su that would be a very good scenario for us and could very well play out as shown. A Greenland block is what I crave, much better probability of producing the goods.

Models are certainly showing a strongly negative AO for the mid month period.

We shall see.

Is it reasonable to expect a third episode of this in 3 years? If it comes off the ECM deserves a lot of praise, and Su deserves even more!

Redsunset · 04-02-2012 8:29pm

Looking at GFS current ensembles I would say chance is fairly high, I don't do percentages:D

Alot clustered south

Elmer Blooker · 04-02-2012 8:37pm

This could be the 12 ECM !!

almost identical.
(sorry , wrong thread , should be the reload thread, haven't posted in a while.)

lucernarian · 04-02-2012 10:18pm

If we do see some ridging towards Greenland, there's still the issue of the kind of airmass that could be brought down over Ireland. There really won't be the kind of cold air that there might have been if it wasn't dragged over half of western europe! And unless there's a more significant shift in height rises to the north of what's been suggested by the models, it'll be more a case of cold and frosty nights. Whether the ECM or the rest are right, pressure would be too high and the air mass too stable for decent organised bands of showers or troughs.

I really want to be proved wrong but nothing in those charts suggest widespread snow for all of Ireland:eek:

K_1 · 04-02-2012 11:15pm

More southerly than easterly flow in the 18z GFS.

ninebeanrows · 04-02-2012 11:30pm

Some classic signs of Northerly development on the 18z.

Will Greenland at last allow High pressure form over her for the first time this winter??

Cold to our east, cold to our north. Us in no-mans land, although a chilly one at this stage.

ninebeanrows · 04-02-2012 11:37pm

It looks like the whole pattern shift is going to take place and from there it will just be a matter of luck for us to get in the right place, eventually we should as some very good signs for cold weather in the next 3 weeks.

lucernarian · 05-02-2012 12:02am

Something like the above could end up in an Atlantic showdown way off in FI. All that would take is for some real cold air to be shoved over Ireland from an easterly direction.

I don't fancy a northerly, even if it wasn't a regular toppler (and the models suggest that's not really on the cards anyway). I just can't see where sufficiently cold air will come from for widespread snow. And northerlys just won't deliver for The Pale:p

Best outcome I can see is some mother and father of a greenland high or perhaps some lucky break with the nearby cold air coming into contact with a tepid atlantic LP.

Su Campu · 05-02-2012 12:25am

SLP and 500 hPa multimodel chart of GFS/GEFS/ECMWF/BOM at 240 hrs shows the retrogressing cold troughing setting in over Scandinavia and height rises over Greenland, yielding the northerly. This is what I had in mind.

Source: http://www.meteogiornale.it/mappe-modelli-meteo/multimodel?map=hgtmean500&click=li-10

T850 on the way down. This would be much more productive snow-wise than an easterly.

lucernarian · 05-02-2012 12:30am

That 850hPa temperature chart shows the -14 isotherm as not even reaching Svalbard. I'm not sure that situation could deliver on snow in more coastal or low-lying parts of Ireland.

Su Campu · 05-02-2012 12:49am

To_be_confirmed wrote: »

That 850hPa temperature chart shows the -14 isotherm as not even reaching Svalbard. I'm not sure that situation could deliver on snow in more coastal or low-lying parts of Ireland.

No, but what would follow after those charts is a strengthening northerly gradient which would advect at least -8 °C T850s, which would be enough.

lucernarian · 05-02-2012 1:30am

What would follow would be even more in Fantasy Island. But taking the chart at face value, the parts of the Arctic to the north of Scandinavia and Russia will have little more in the way of cold air to offer then. Given how the HP dominating western europe for the next week will have done a thoroughly good job of cutting off colder air from futher beyond.

In my experience, -8 850hPa temps are still going to be touch and go for coastal locations and might lack the extent of cold needed to encourage more convection. The kind that would let showers be carried more than 80km inland.

But the synoptics and the overall look of those charts encourage me. They all point to the formation of a proper Greenland High and we know what that can bring:) Maybe with a little patience and luck we'll get a "northerly" with a northeasterly aspect and this would allow for a path over colder parts of the Atlantic and also Scandinavia. There's still that and many other variations where it could deliver snow for lots of Ireland. The Greenland High is key however.

darkman2 · 05-02-2012 5:38am

Hi all,

I have read all the posts since I last posted. I think Su Campu is partially wrong. He is correct that a Northerly is coming. However where he is incorrect is wrt the Eastlery before hand. That is also coming.The 18z GFS was a joke run fit for the bin. Completely unrealistic to anyone with experience and knowledge of these situations.Yes a Greenland high is going to build (does not need support from the Azores, it's going to happen anyway). But I stick to my point a very cold Easterly will become established before hand. Now it could be a few days prior to the Northerly but I think the driver of heights that direction will be coming through these Islands. This will drive instability probably off the continent. So the flow will be likely Southeasterly. But that does not mean no snow. That is an error to think that. Geopotential heights will fall in a South Easterly and the differential in temperature from upper to sea level would drive convection over the Irish Sea (and possibly onto the South coast aswell) so we could end up with beefy enough snow showers (thunder and lightning aswell) on windward coasts. That may well not happen but I think it's fairly likely. And I am going to stick by that forecast I made earlier. Like I say I could well be wrong and Su Campu completely right but I am fairly confident.

Eastcoastryan · 05-02-2012 5:44am

darkman2 wrote: »

Hi all,

I have read all the posts since I last posted. I think Su Campu is partially wrong. He is correct that a Northerly is coming. However where he is incorrect is wrt the Eastlery before hand. That is also coming.The 18z GFS was a joke run fit for the bin. Completely unrealistic to anyone with experience and knowledge of these situations.Yes a Greenland high is going to build (does not need support from the Azores, it's going to happen anyway). But I stick to my point a very cold Easterly will become established before hand. Now it could be a few days prior to the Northerly but I think the driver of heights that direction will be coming through these Islands. This will drive instability probably off the continent. So the flow will be likely Southeasterly. But that does not mean no snow. That is an error to think that. Geopotential heights will fall in a South Easterly and the differential in temperature from upper to sea level would drive convection over the Irish Sea (and possibly onto the South coast aswell) so we could end up with beefy enough snow showers (thunder and lightning aswell) on windward coasts. That may well not happen but I think it's fairly likely. And I am going to stick by that forecast I made earlier. Like I say I could well be wrong and Su Campu completely right but I am fairly confident.

Hey DM, Sounds positive!! isn't the 0z due out around this time? have you had a look? Does it keep the trend going?

Deep Easterly · 05-02-2012 12:55pm

This morning's ECMWF is no great shakes but as said above a lot of uncertainty with the models at the moment though one consistent theme is that high pressure will remain close to or over Ireland over the next 5 to 8 days.

ECMWF 144hrs geopotential and 850hPa temperature:

Ireland remaining in the middle with the occasional overlap of both Atlantic and Continental influences but neither taking any real firm hold. Reasonable weather for some with average days and maybe a few frosty nights (contingent on cloud cover).

Two of the more extreme EPS members at 144hs this morning which shows how much uncertainty is in the models this morning:

I'll take member 43 please. Too much member 44 going on the last year.

Su Campu · 05-02-2012 1:28pm

darkman2 wrote: »

Hi all,

I have read all the posts since I last posted. I think Su Campu is partially wrong. He is correct that a Northerly is coming. However where he is incorrect is wrt the Eastlery before hand. That is also coming.The 18z GFS was a joke run fit for the bin. Completely unrealistic to anyone with experience and knowledge of these situations.Yes a Greenland high is going to build (does not need support from the Azores, it's going to happen anyway). But I stick to my point a very cold Easterly will become established before hand. Now it could be a few days prior to the Northerly but I think the driver of heights that direction will be coming through these Islands. This will drive instability probably off the continent. So the flow will be likely Southeasterly. But that does not mean no snow. That is an error to think that. Geopotential heights will fall in a South Easterly and the differential in temperature from upper to sea level would drive convection over the Irish Sea (and possibly onto the South coast aswell) so we could end up with beefy enough snow showers (thunder and lightning aswell) on windward coasts. That may well not happen but I think it's fairly likely. And I am going to stick by that forecast I made earlier. Like I say I could well be wrong and Su Campu completely right but I am fairly confident.

I was just highlighting to people that an easterly does not always mean snow, but of course sometimes it does. I didn't rule out snow, I said that the actual setup posted yesterday was very similar to last week's, which produced nothing, but that if things were to change slightly, such as a disturbance over the continent, then we could get some. The same as what you said above.

I have not been using the models beyond 48 hours over the past 2 weeks and I'm very happy with the way things have worked out. As I've been saying, I am not basing any of my longer term ideas on model output as to do so is totally useless, and in any case my timescale was well outside the range of all but the GFS. I posted the multimodel charts above purely to illustrate what sort of setup I was talking about. I wasn't claiming that the models were reliable, because they're not. As it happens there is no real model support this morning for a very cold easterly becoming established over Ireland, but of course I would take that too with a pinch of salt.

Basically, don't put any focus on the models beyond 48-72 hours.

mickger844posts · 05-02-2012 1:42pm

Su Campu wrote: »

I was just highlighting to people that an easterly does not always mean snow, but of course sometimes it does. I didn't rule out snow, I said that the actual setup posted yesterday was very similar to last week's, which produced nothing, but that if things were to change slightly, such as a disturbance over the continent, then we could get some. The same as what you said above.

I have not been using the models beyond 48 hours over the past 2 weeks and I'm very happy with the way things have worked out. As I've been saying, I am not basing any of my longer term ideas on model output as to do so is totally useless, and in any case my timescale was well outside the range of all but the GFS. I posted the multimodel charts above purely to illustrate what sort of setup I was talking about. I wasn't claiming that the models were reliable, because they're not. As it happens there is no real model support this morning for a very cold easterly becoming established over Ireland, but of course I would take that too with a pinch of salt.

Basically, don't put any focus on the models beyond 48-72 hours.

I agree 100% with your comments Su. The models have been a mess the last number of weeks and can't be relied on past 72hrs. In fairness you have been spot on with your forecasts and i will continue to give them the up most of respect.

blackius · 05-02-2012 1:55pm

To give darkman2 his due.
It is much much easier to forecast milder weather for Ireland and be right than it is to forecast colder and especially severe cold and be right.

At the moment the cold is lurking just 250 miles to the south east.
Thats is perilously close.
There have been several winters when it's done the same and stayed there for similar reasons as to why it would this time round and that is put very simply,systems thrive over water and we are at the edge of a very big warm pond.

Redsunset · 05-02-2012 3:55pm

Looking at the Ecm and GFS comparison, we see that high pressure will be dominant close to our shore and also some key slight difference with height rises trying to push across the pole from pacific side. Very uncertain.

http://policlimate.com/weather/ecmwf/2012020500/ec_gfs_z_panel.html#picture

Deep Easterly · 05-02-2012 6:00pm

You'd be hard pressed to find anything inspiring on the GFS 12z. Weather going into hibernation mode for a while me thinks.

Hopefully ECMWF 12z run has something better to offer - easterly or storm, I don't care, just something.

darkman2 · 05-02-2012 6:33pm

blackius wrote: »

To give darkman2 his due.
It is much much easier to forecast milder weather for Ireland and be right than it is to forecast colder and especially severe cold and be right.

At the moment the cold is lurking just 250 miles to the south east.
Thats is perilously close.
There have been several winters when it's done the same and stayed there for similar reasons as to why it would this time round and that is put very simply,systems thrive over water and we are at the edge of a very big warm pond.

Su Campu could well be right. In fact it's kind of increasingly going that direction more quickly.

It's irritating at the moment particularly when charts like this are still appearing. And even when we get a Greenland high and all that it could still miss us to the East.

Easterly, no Easterly? Northerly, no Northerly? If anything the outlook for the end of the coming week is more uncertain now then it was yesterday.

Further Cold Spell In February? 0-180 Charts Only

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