Monday onward, frost, ice returns - snow later

Deep Easterly

jambofc wrote: »

2.8/-0.7

cloudy,nothing to report except more dreary rubbish and the charts make me feel like crying for the immediate future

Yep, that is a good weather outlook alright going by the latest charts. Same ole pointless ****e for the foreseeable. Didn't even manage a frost here last night. "Cold spell" getting off to a good start then....

DOCARCH

Light hail/graupe shower here now. 3.8c DP -0.2c At least the air is drying out a little!

Light dusting of snow visible on the Dublin Mountains.

munsterlegend

Deep Easterly wrote: »

Yep, that is a good weather outlook alright going by the latest charts. Same ole pointless ****e for the foreseeable. Didn't even manage a frost here last night. "Cold spell" getting off to a good start then....

i always find that website yr no a good indicator of weather and they are showing sleet/snow showers in my area(north cork) for next tuesday and wednesday.

it was spot on the last time we got snow from the east in january- heres hoping again!

Deep Easterly

munsterlegend wrote: »

i always find that website yr no a good indicator of weather and they are showing sleet/snow showers in my area(north cork) for next tuesday and wednesday.

it was spot on the last time we got snow from the east in january- heres hoping again!

Yes, on the whole they are usually spot on, but they did not pick up on the amount of cloud coming in from the east. yr.no forecast temps of -3c for here last night, cloud and breeze kept the temp above 1c.

lucernarian

Hold on, I don't remember northwesterly Polar Maratime weather systems ever affecting much of Leinster or Munster, certainly not anywhere near the east and south coasts. There was the inch or so of snow from 4th January coming from the north which did reach towards Dublin and the midlands. And Christmas 04 had some efforts at snow where I lived.

I don't think they deliver serious amounts of snow anymore than easterly situations do. Both give decent but localised falls of snow. Organised snow which falls over much of the country seems to happen more from Atlantic vs Easterly situations with polar lows hitting Ireland head-on being pretty rare.


Back to the forecasting, I do feel that the signals for this week should result in more northerly blocking developing. The Polar Frontal Jet looks overplayed to the north in the face of the significant WAA that's heading into Greenland and it's clear from the charts that the southern arm of the Jet is strong too. They can't have it both ways with negative NAO prevailing.

On the same hand as me feeling people were talking up the prospect of very cold snowy weather in Fantasy Island forecasts, there's no reason to take the current model output beyond t+120 except with a very big pinch of salt. As I said already, the HP alignment doesn't have to change much in these scenarios to make a big difference to us.

I do think that this week can be written off up to Friday though. Yucky cloudy wet cold rain type weather outside.

patneve2

To_be_confirmed wrote: »

Hold on, I don't remember northwesterly Polar Maratime weather systems ever affecting much of Leinster or Munster, certainly not anywhere near the east and south coasts. There was the inch or so of snow from 4th January coming from the north which did reach towards Dublin and the midlands. And Christmas 04 had some efforts at snow where I lived.

I don't think they deliver serious amounts of snow anymore than easterly situations do. Both give decent but localised falls of snow. Organised snow which falls over much of the country seems to happen more from Atlantic vs Easterly situations with polar lows hitting Ireland head-on being pretty rare.


Back to the forecasting, I do feel that the signals for this week should result in more northerly blocking developing. The Polar Frontal Jet looks overplayed to the north in the face of the significant WAA that's heading into Greenland and it's clear from the charts that the southern arm of the Jet is strong too. They can't have it both ways with negative NAO prevailing.

On the same hand as me feeling people were talking up the prospect of very cold snowy weather in Fantasy Island forecasts, there's no reason to take the current model output beyond t+120 except with a very big pinch of salt. As I said already, the HP alignment doesn't have to change much in these scenarios to make a big difference to us.

I do think that this week can be written off up to Friday though. Yucky cloudy wet cold rain type weather outside.

I disagree about the polar maritime air not delivering. I got a few inches back in late December 2000 (here in SE co. dublin) with a strong NW/N flow..Polar maritime air can deliver well if it is unstable!

Yes ,thats happened a few times-that was the year leopardstown was called off due to snow cover.
It can often go the other way though with too much maratime mixing.

This current high is acting like a cóck block with respect to the real cold to the east.
I suspect that because it's never going to be a total atlantic block that *if* the winds turn exclusively northerly for a time,that an invasion by a low pressure system will win out and sweep away the cold.
I suspect that it will continue to be a cóck block.

DOCARCH

Deleted User wrote: »

cóck block.

That's a new one?

nacho libre

i have little doubt that if the wind turns northerly it will eventually turn to the south west after two-three days. If that's the case a strong northerly airflow, albeit brief, would be much better than this present rubbish. So bring it on.:cool: Who knows it could even lead to a bump of the Polar Low thread

Rebelbrowser

The long term forecast for Cork on yr.no shows the wind coming from the South / South West next week but with temps as low if not lower than this. For example for Wednesday 17 it shows mid morning temps of -3 and snow showers. Forgetting for a moment that it won't happen, could someone explain how that could even conceiveably come about? Ta.

nacho libre

Rebelbrowser wrote: »

The long term forecast for Cork on yr.no shows the wind coming from the South / South West next week but with temps as low if not lower than this. For example for Wednesday 17 it shows mid morning temps of -3 and snow showers. Forgetting for a moment that it won't happen, could someone explain how that could even conceiveably come about? Ta.

the colder airmass keeps the milder air at bay and eventually sees it off.

Pangea

DOCARCH wrote: »

That's a new one?

Youve obviously never been cóck blocked then :pac:

ninebeanrows

In the past years if we had this type of Ensembles output we'd be loving it, yet now we almost discount this type of cold!

ninebeanrows

Here comes a clearance from the east. The muck is exiting the east coast now, but for how long?

Pangea

The weather seems very boring and cloudy, its better than rain anyday ,and this is what one would call good weather.
But I dont see any signs of a good cold spell yet ,no real frost or anything.

DOCARCH

DOCARCH wrote: »

That's a new one?

Think of the cold as shex with a beautifull woman and the high pressure as a well... a cóck block

DOCARCH

Deleted User wrote: »

Think of the cold as shex with a beautifull woman and the high pressure as a well... a cóck block

nacho libre

1.) At the club, Sal was was about to get Lisa's phone number, when Nathan came up cock-blocked him by asking him if he found a job yet. He made it even worse when he reminded Sal that they had to hurry up and catch the last bus home. Lisa rolled her eyes and walked away.

:pac:

DOCARCH

Weathercheck2 wrote: »

Here comes a clearance from the east. The muck is exiting the east coast now, but for how long?

Wonder will anything develop from that clearance? *wishful thinking* But looking at the latest sat, there are a couple of clumps of cloud devlopining on the back edge and I see Dublin AP is now reporting CBs???

pistolpetes11

Lads the temp here in Newbridge is 4.4C but the DP is -1.0 , what cause's such a low DP with a high enough temp ?

EDIT make that temp 3.9 and DP -1.4 !

danni2

patneve2 wrote: »

I disagree about the polar maritime air not delivering. I got a few inches back in late December 2000 (here in SE co. dublin) with a strong NW/N flow..Polar maritime air can deliver well if it is unstable!

Totally agree, polar maritime air has delivered very well in the past especially the one in Dec 2000.

Also here's polar maritime in Jan 2005
http://www.boards.ie/vbulletin/showthread.php?t=218140

And one in March 2008
http://www.boards.ie/vbulletin/showthread.php?t=2055245965

As you can see only the extreme east and SE escape most of the snow during these times, but the majority of of Ireland enjoyed a nice dumping of snow on those days.

owenc

I wonder if I could get a -6c tonight considering that Its so clear would love that... I'll know by 6pm if it's -2c by then then I'm sure to get it!!!

patneve2

I smell a polar low for next week...:P

DOCARCH

pistolpetes11 wrote: »

Lads the temp here in Newbridge is 4.4C but the DP is -1.0 , what cause's such a low DP with a high enough temp ?

EDIT make that temp 3.9 and DP -1.4 !

Just dry (or drier) polar and/or continental air. Nothing too unusual. We're just so used to having higher humidities with are usual Atlantic (sub-tropical) air.

Speak Now

owenc wrote: »

I wonder if I could get a -6c tonight considering that Its so clear would love that... I'll know by 6pm if it's -2c by then then I'm sure to get it!!!

There no "I" in weather

Supercell

Had a nice dusting here driving home this morning.
Off to China tomorrow for new years festival, hope you all get 10 feet of snow when I'm gone, I had enough of it already.

lucernarian

danni2 wrote: »

Totally agree, polar maritime air has delivered very well in the past especially the one in Dec 2000.

Also here's polar maritime in Jan 2005
http://www.boards.ie/vbulletin/showthread.php?t=218140

And one in March 2008
http://www.boards.ie/vbulletin/showthread.php?t=2055245965

As you can see only the extreme east and SE escape most of the snow during these times, but the majority of of Ireland enjoyed a nice dumping of snow on those days.

My post didn't say that they don't deliver anything but it did say that Polar Maratime rarely gives widespread accumulations unless there was a Polar Low. I don't see how highlighting a weather event 10 years ago means that Polar Maratime situations deliver regularly. The 00/01 winter was an exceptional one and mainly Polar Maratime based.

Those two threads you highlighted are very minor events? One or two inches around Ireland by the looks of it. That is absolutely nothing compared to 00/01 or a whole lot of seasons before it. Or even this season, where the combined easterly/northerlies so far have collectively given quite a lot of places 3 or 4 inches.

I'm leaving it at that.

I see the charts really don't want the HP to leave our shores... I'm frankly amazed, but at least the cold burst from the north is still predicted to happen (in 6 days if you call it a prediction:))

Snowaddict

Without a doubt, we have seen a sharp southeastward correction in the overall pattern over the past 48 - 72 hours, this has continued on each evolution. Whilst these are only smallscale changes in the overall largescale pattern, they do have a serious effect upon the resultant conditions for Ireland & result in inhibiting potential snowfall through to Day 5.

To date, this cold spell has all the hallmarks of the December 2009 Cold Spell, except the main centre of HP continues to be further southeast, resulting in a greatly reduced Easterly flow. Therefore, in terms of the first phase of this cold spell, we have certainly missed out on opportunity for snowfall & rather more deep cold.

However, the general pattern is still following the synopsis that was outlined some days ago, albeit with HP centred several hundred miles further south than was initially indicated.

Overall, it appears that NWP Guidance has a an over-rapid proponseity to Retrograde the main core of any positive height anomilies, as has been seen in the past 48 Hours.

The above aside however, the pattern does remain on course. Within the next 5 Days, the main core of the HP cell will gradually Retrograde to the West/Northeast. Indeed, the main centre of the HP cell (indicated by the warmer core of air) is now to the West of Ireland at T+96, which is a relief to see:



Turning towards Day 5 & beyond, the Southeastward correction continues. What was initially modelled as being a West Based -NAO is now a pattern that is centred much further & more importantly more favourably East.

Towards Day 5, a fairly major Polar Outbreak will begin to progress Southwards from the High Arctic.

Could this well be a case of ''short term pain for long term gain''? If the pattern as modelled towards Day 6 is generally correct, then the above could potentially turn out to be the case. This is because with a slower Retrogression phased evolution, the trough bringing the deep cold Southwards is forced much further Eastwards. In the past 36 Hours, we have seen at least a 500 Mile Eastward correction in the positioning of this trough. If we are to continue to see even a continuous slight Eastward correction with each NWP evolution, then this deep pool of cold air could well target Ireland & the UK directly towards Day 6 onwards. Present indications on the very latest 12Z Guidance suggest sufficient Eastward positioning for Ireland, but it would be preferable to see the main trough some 300 Miles further East/Southeast.

The cold and increasingly cyclonic pattern that was previously discussed is still modelled to arrive within the expected timeframe, as indicated on the latest ECMWF Evolution for Day 6:



30mb Temperature

The 30mb Temperature continues to remain in a warming pattern & we are likely to have seen, by technical definition, a major Midwinter Warming event today at the 30mb level. With this in mind, Northern Blocking is likely to continue for some time, with a negatively phased North Atlantic Oscillation & Arctic Oscillation.



Summary

In summary then, remaining rather cold to cold for the next several days, with a persistent Anticyclonic influence & sharp to severe frosts at night time. Winds generally light to moderate, Easterly to Northeasterly in direction. The main core of HP should begin to Retrograde Northwestwards within the 3 - 5 Day period, and conditions should turn even somewhat colder as the main HP influence pulls away to the Northwest.

With the latest developments in mind however, this Retrogression phase could be even somewhat slower and more prolonged than is currently modelled. As the main core of HP Retogrades Northwestwards towards Greenland, this allows for a cold & cyclonic pattern to become established. This is the most likely outcome towards Day 7 - Day 10. The exact extent of Retrogression will have a significant bearing on the amount of renewed cold air that is advected across the country. However, there is clearly an increasing cyclonic signal towards Day 6 onwards, which does lead to the potential for snowfall, at least for a time.

Remember that trend towards Southeastward correction though, that could well be the case in subsequent evolutions & we would like to see this continued at least to an extent for the medium term positioning of the largescale synoptic features.

SA

bray man

Snowaddict wrote: »

In summary then, remaining rather cold to cold for the next several days, with a persistent Anticyclonic influence & sharp to severe frosts at night time. Winds generally light to moderate, Easterly to Northeasterly in direction. The main core of HP should begin to Retrograde Northwestwards within the 3 - 5 Day period, and conditions should turn even somewhat colder as the main HP influence pulls away to the Northwest.


SA

with every day I smile more and more watching this froum

pauldry

why do people WANT snow. I hope those charts on www.wetterzentrale.de for next week are FI. I recall being so pi$$ed off with the schno in December n January n wanted a thaw. The charts for next week look like snow at present.

On the next run they might show milder but it looks like a cold cold spell. Is there anyone out there who hates snow? Or am I the only weather lover who thinks of it as a nuisance. Let the US n Russia keep it is what I say. Its pretty, yes - pretty awful.

SNOW RANT OVER