Further Cold Spell In February? 0-180 Charts Only

Redsunset

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

Alot clustered south

Elmer Blooker

This could be the 12 ECM !! almost identical.
(sorry , wrong thread , should be the reload thread, haven't posted in a while.)

lucernarian

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

More southerly than easterly flow in the 18z GFS.

ninebeanrows

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

derekon

Just had a look at the North Atlantic pressure charts - its now very likely that high pressure will build gradually over Ireland from the middle of the week onwards with HP sitting right over us next weekend.

In other words, we will be sitting right between two weather systems - the mild Atlantic to our west and the brutal Siberian air just off to our east.

Put simply, we will be in weather's version of no mans land. And this will bring us right up to the middle of February so again the window is now closing on any decent snow for Ireland

D

ninebeanrows

It looks a case of, cold all around us again today.

Again signs are that Greenland may not allow heights to rise sufficiently, and the halfway house that may prevail as a result will lead us to miss out on a possible easterly shot as a result.

ECM has some very cold air off England at T96hrs

If things could just prop themselves another 200 miles further north and get some undercutter to appear in Biscay things could be oh so different.

But again a non-descript outlook today. But with increasing night frosts and cool generally, compared to the winter as a whole, a cold outlook for the next week.

ninebeanrows

Although a glance at upper may make you sceptical.

The ECM 144hr chart would result in snow for eastern Ireland

Tom Cruises Left Nut

168 also ?

darkman2

Possible sleet/snow event on the ECM @ 144hrs. Small undercutting low pressure and fronts coming up against cold Easterly winds. Suspect this may go to an Easterly briefly.

ninebeanrows

t|nt|n wrote: »

168 also ?

Yes, cold dry air from the east, 850hpas around -4 to -6c, would wish to be lower but as flowing from a cold continent and with further supplies of cold appearing in eastern Europe, i would suggest snow showers for eastern and southeastern areas.

Musicman2000

The one thing im not getting, How come the HLB has being dropped so quick? when the teleconnections are saying different?

Kippure

It will be back next run

pistolpetes11

FIND THE CORRECT THREADS TO BE POSTING IN PLEASE, WARNING'S & INFRACTIONS FROM NOW ON

Sponge Bob

18z GFS Rolling out now.

Looks like the Atlantic influence over us will last into Thursday in this one.

The previously modelled Siberian Pushback is shown as being delayed somewhat. Compare these two.






Then compare these Two.