Monday onward, frost, ice returns - snow later

darkman2

Looks like that extra salt will come in handy. Our weather will increasingly come from the East through the early days of next week, then it is likely a Northeasterly will set in and then a Northerly. So the best of three different worlds. Turning increasingly cold and later in the week snow is likely especially in Eastern parts but this is likely to transfer to more Northern areas by the weekend. The models agree on a gradual retrogression of High Pressure into Greenland. There is also a risk of more substantial snow in the Southern half of the country at some stage through the week as the Atlantic energy may put up a fight. But that is just a risk. The next week looks exceptionally cold with snow at times, the East most at risk as Easterly winds resume. Cold everywhere. Very cold later next week.


Discuss the prospects....

ShoulderChip

I think we will have some scattered showers on tuesday evening to wednesday morning but mostly a muggy balmy introduction to spring week

darkman2

ShoulderChip wrote: »

I think we will have some scattered showers on tuesday evening to wednesday morning but mostly a muggy balmy introduction to spring week

Will you have the deck chairs ready?;)

mickger844posts

darkman2 wrote: »

Looks like that extra salt will come in handy. Our weather will increasingly come from the East through the early days of next week, then it is likely a Northeasterly will set in and then a Northerly. So the best of three different worlds. Turning increasingly cold and later in the week snow is likely especially in Eastern parts but this is likely to transfer to more Northern areas by the weekend. The models agree on a gradual retrogression of High Pressure into Greenland. There is also a risk of more substantial snow in the Southern half of the country at some stage through the week as the Atlantic energy may put up a fight. But that is just a risk.


Discuss the prospects....

Are we officially in ramp mode???? Didn't honestly think we would see another cold spell of note this winter but it looks like next week it will happen. Bring it on i say

Deep Easterly

met.ie morning update:

"OUTLOOK FOR THE WHOLE COUNTRY: (as opposed to what?? )

The outlook is for cold weather with predominately easterly winds. Most places will have a good deal of dry bright weather, but frosty nights with icy patches and also some fog at times.

SUNDAY NIGHT: There will be a fresh East to southeast breeze across Munster on Sunday night, keeping frost to a minimum and where there may be some cloudy wet weather in places also. Dry and clear with somewhat slacker winds elsewhere with some frost.

MONDAY: Still probably cloudy in some parts of the south and west on Monday with some rain at times mainly near coasts but even these areas will be dry much of the time and the fresh easterly winds will fall off light. Largely dry and bright for the rest of the country, with some sunny periods, but cold and there may be some light wintry showers near the east coast. Sub zero temperatures with hard frost Monday night with some fog possibly also.

TUESDAY AND WEDNESDAY:Cold bright and mainly dry days with sunny spells and afternoon temperatures of just 3 to 6 degrees, some light wintry showers are possible on exposed eastern and northern coasts. Very cold at night , with sub zero temperatures and as low as -5 or -6 degrees in places with very severe frosts and icy conditions with some freezing fog possible in places also."

http://www.met.ie/forecasts/


Meanwhile, on this morning's ECM, looks pretty much as expected over the next 6 or 7 days. Slack & anticyclonic:


Nothing to get me excited at least.

The best charts reserved in the far out stages as usual. This is what I want to see:



Ridge from main anticyclone over Iceland extending into central/east Europe, cutting off cool maritime Arctic air and ensure a more deeply continental feed. Temps may not be all that spectacular, but if that chart was to verify, humidity levels would drop off significantly and it would be very very dry. Oddly, there has been very little rain here in the west all winter, yet the roads have been constantly wet and mank (when they were not frozen). A dry continental is what is needed. Some beautiful colour's in the sky as well should the above chart come to pass.

Please, please let it be so.

jambofc

nothing on the charts getting me to excited
now way out in FI,next saterday on,did you see the charts :eek:
would be lovely but way out as i said,seems to be the norm this winter,it always seems to be a week away
anyway just to wet our appetite even further....














all the way out to tuesday :eek:











sure what do i no,but im a dreamer

Snowaddict

Good morning everyone

General Outlook

We have seen some Exceptionally consistent overnight Multi-Model Guidance with excellent Medium Term agreement - something not seen in quite some time. At the moment, it appears that ECMWF is leading the way on the general evolution, but a blend of ECMWF/UKMO/GFS/UKMO is likely into the Medium Term.

It should be noted that from T+132 - T+144 onwards now, quite exceptional Northern Blocking is indicated. The tend at the moment appears to be to take the main core of blocking even further North with each and every evolution.

Winds eminate from an Easterly/Northeasterly direction throughout. For the coming week as a whole, conditions are likely to remain cold to very cold at times, with signs of even deeper cold arriving towards Day 5/6.

While there will be a risk a light sleet & snow flurries/showers in Eastern areas during later on Monday & Tuesday, the pattern will generally be Anticyclonic Easterly, with limited snowfall potential in general.



During the midweek period, conditions may become somewhat even more slack, but with winds still generally Northeasterly, as the main core of blocking becomes situated to the immediate North. In addition, at this point, even more extensive Northward Warm Air Advection is indicated, setting up a prolonged blocking pattern all across the variable North.



Towards Friday onwards, there are some continuing indications that a more cyclonic Easterly pattern may well become established, with an enhanced threat of snow showers in Eastern areas in particular. Rather more deep cold is advected across the country at this point also, with main blocking centres over Scandinavia and Iceland.



Day 7 - Day 10

NWP Guidance also remains very consistent for this period, with a marked signal for extreme Northern Blocking to develop & a solid retrogression phase of the main blocking centres towards Greenland. As a result, an even more unstable Northeasterly to Easterly flow becomes established across the UK & Ireland, with an enhanced threat of snowfall once again. Conditions remain very cold throughout with a deep continental sourced airflow.

In addition to the recent warming event at the 30mb level, a renewed phase of warming is now taking place, which provides even further support for potential Northern Blocking towads Day 10 - Day 15:

30mb Temperatre Trend



Between Day 10 & Day 15, we are likely to see a more West Based -NAO evolution become established, with the main core of blocking transferring into Western Greenland & the Canadian Arctic. This also allows for a more cyclonic cold pattern to become established & is something to monitor over the next several days.

Summary

In summary then, there are solid indications of a cold spell lasting through to Day 5 at least this morning. There is the risk of light wintry showers in Eastern areas on Monday & Tuesday, but nothing significant is expected at present. The midweek period will see conditions falling even slacker, with light Northeasterly to Easterly winds & further overnight sharp to severe frosts. Towards Day 5/6 onwards, a somewhat more cyclonic Easterly/Northeasterly pattern is indicated, with exceptional Northern Blocking throughout, as indicated by the 6-10 Day CPC 500mb Height Anomoly Chart:

CPC 500mb Height Anomoly - Through to Day 10

http://www.cpc.noaa.gov/products/predictions/610day/610day.03.gif

SA

Deep Easterly

Mark, can I just say that your analysis continues to be just fantastic. Very scientific and rooted firmly in objectivity and logic, yet at the same time, easy to absorb and enjoyable when read.

Your calm confidence, often set against childish hysteria and tantrums (often from myself ) is just a pleasure to injest intellectually. Nice one!

I suspect SA will be getting a fix before this spell is out...that is to say I'm quietly more confident than I was.
I'm reserving full judgment until later though given recent flip flops.

I'd be reasonably confident of some snow flurries in the East by midweek though.
I'm not so sure at sea level where most people live that any light stuff that comes in off the sea in the flow in the early part of the week will be more than drizzle though.It's not going to be cold enough.

For historic examples of what can fall though in very cold anticyclonic easterly air,look back at the '85 charts posted last night.
That was very cold air though at 850 level which is not what we will see monday/Tuesday.
In '85 by the way,that low of the south iirc came up north and did fall as snow in Dublin before dying out into a rain/sleet mix but stayed entirely snow just inland and a bit higher eg rain sleet at ucd while snow continued at the top of mt Anville at Goatstown [mt anville might be just a 100 metres higher than ucd and only a mile away]

Anyhow I digress..

derekon

Hello folks,

After the disappointment of the non-cold spell last week, it looks like something from the east might be finally brewing up.

I would not be too versed in how to read the met charts you guys post here (although they look very pretty!), however my confidence has increased this morning having read our fellow poster MT Cranium's forecast for the week ahead.

I found his posts to be very accurate during the recent freezing weather and in general his forecasts are quite on the money.

Here is what MT has to say about weather later in the week:

TUESDAY to THURSDAY, Ireland will remain in this "transitional" cold air mass near a ridge of high pressure, and this will result in cold but not exceptional temperatures near -3 C overnight and near +4 C in the daytimes, with variable skies, some sunshine and some cloudy periods. There could be local snow flurries in parts of Ulster and the Dublin and Wicklow coastal areas, as winds will generally be NE 10-25 mph.

FRIDAY and next weekend, the colder air from further east will finally be released and flow out over Ireland to bring even colder weather and some risk of accumulating snows.


I would say the coming week to ten days might be interesting

Derek

nacho libre

Deep Easterly wrote: »

Mark, can I just say that your analysis continues to be just fantastic. Very scientific and rooted firmly in objectivity and logic, yet at the same time, easy to absorb and enjoyable when read.

Your calm confidence, often set against childish hysteria and tantrums (often from myself ) is just a pleasure to injest intellectually. Nice one!

very well put paddy1. Also given he is emotionally invested in the outcome it's all the more impressive the way he can remain calm and objective. Quite a contrast to what you see over on netweather;)

InKonspikuou2

nacho libre wrote: »

very well put paddy1. Also given he is emotionally invested in the outcome it's all the more impressive the way he can remain calm and objective. Quite a contrast to what you see over on netweather;)

For all you know he could be dancing on his keyboard and typing with his feet.

greysides

In addition to the recent warming event at the 30mb level, a renewed phase of warming is now taking place, which provides even further support for potential Northern Blocking towads Day 10 - Day 15:

Could someone explain this please.

I understand that the 30mb level is the height where the air is at that pressure but it seems counter-intuitive that warm air up there is a pointer to cold air down here.:o

Redsunset

greysides wrote: »

Could someone explain this please.

I understand that the 30mb level is the height where the air is at that pressure but it seems counter-intuitive that warm air up there is a pointer to cold air down here.:o

Look here

http://www.boards.ie/vbulletin/showthread.php?t=2055728070

lucernarian

Firstly I want to also praise Snowaddict's analysis of what can be realistically be expected for the week - Some cold days ahead for the next 5 days, with the outlook pointing to more cold weather. Albeit still rather dry:(

The amount of warm air feeding into the Greenland region is impressive and that 30mb chart is going to look remarkable as the week progresses. But the pattern of the blocking is a bit confusing for me. On GFS, That significant Siberian High seems to do nothing to help our cold-loving cause except to link up enough to drag the cold air brought down by the european cyclone over to here. See that attached file.

And despite the significant WAA, the ECM and GFS seem to have very similar views on height rises over Greenland. Nothing significant until hints inside FI. The northern arm of the jet stream still won't play ball over the medium term on GFS or on ECMWF too, given by how similar they portray the evolution.

Redsunset

Yep signals are definately on for a strong retrogression.

Then allowing cyclonic systems to approach from our south west that could cause blizzard conditions if angle of attack was correct and we were still in a very cold airmass.

Very far away but could be interesting to see if it materialises to give a last hurrah of extensive snowfall to end our winter.The end.:D

nacho libre

InKonspikuou2 wrote: »

For all you know he could be dancing on his keyboard and typing with his feet.

It wouldn't surprise me if he was in fact doing this.
Is there no end to his talents.

anyway, it'll be interesting to see how far to the northwest the high moves and what will be its pressure reading.

could it all fall into place, with repeated frontal snow ensuing, or will it all go horribly wrong??

irishdub14

nacho libre wrote: »

It wouldn't surprise me if he was in fact doing this.
Is there no end to his talents.

anyway, it'll be interesting to see how far to the northwest the high moves and what will be its pressure reading.

could it all fall into place, with repeated frontal snow ensuing, or will it all go horribly wrong??

Ermmm, i'll go with horribly wrong......... :P

Snowaddict

Thanks for all the comments everyone

It's very difficult not to get over-excited when looking at some of the charts on display, but it's always best to downplay any potential until being at least moderately confident - Greater than 60% confidence in the risk of an event.

Another very solid GFS 12Z Operational evolution, which has 850mb temperatures of -8 across many parts from later on Monday and during Tuesday - with the threat of some light sleet or snow showers moving in off the Irish Sea.

It's also noteworthy that towards Day 5, a deep cold pool is advected across the country, with 850mb temperatures of -9 to -11 moving in from the East. With pressure falling slightly, such developments would offer more potential for snow showers into Eastern areas, which fits in with threat of a slightly more cyclonic Easterly pattern developing later in the week.

However it must be stressed that this is currently at Day 5.

Overall however, a solid, increasingly cold spell lasting for a minimum of 6 Days is indicated on this latest evolution, with an increasing threat of snow showers towards Day 5, especially in the East.

Rather extensive Northern Blocking is also in evidence between Day 5 & Day 6.

SA

snaps

I'd better go and check to make sure the Ballinrobe & Tuam snow shields are still working as they had a hard December and early Jan, But worked fantastically well!!!!!!!!!!!!!!!!!!!!!

Su Campu

greysides wrote: »

Could someone explain this please.

I understand that the 30mb level is the height where the air is at that pressure but it seems counter-intuitive that warm air up there is a pointer to cold air down here.:o

It's easier to picture it if you think of the middle atmosphere like water swirling anticlockwise around in a bucket.

In wintertime, there is a largescale westerly (zonal) flow around the middle latitudes, called the Polar Vortex. It is caused by the extremely cold polar airmass, which causes low geopotential heights over the high latitudes, similar to the low level of the water in the centre of the bucket. Around the sides of the bucket the water level is higher. As this water is allowed to swirl, this pattern continues, as we would expect. It's the same with the atmosphere - the difference in geopotential heights (due to different airmass temperatures) causes these westerly winds to continue throughout the winter.

Now imagine what would happen if you stuck your hand down into one edge of the swirling water. The pattern will be disrupted, with the water being deflected inwards towards the centre of the bucket, causing the water level there to rise. Behind your hand, the water will flow backwards towards the edge, and then continue on as before. So there's an omega-shaped blocking in the water, with part of it now flowing in the opposite direction to the mean flow. It's the same with the atmosphere, except this time instead of your hand we have warm air being advected northwards and upwards into the high latitudes and lower stratosphere, forming this omega blocking situation. Behind the blocking the winds are more northeasterly or easterly, and after a few days, these winds extend down to the troposphere too, dragging cold polar airmasses to lower latitudes, like we saw in early January.

We keep an eye on the temperatures of the stratosphere to see if warming is occuring, cos if it is then it may lead to the blocking pattern above, and a cold spell for someone a week or two down the road.

Note though that around April all bets are off, as the polar stratosphere is now warming anyway due to increased solar radiation, which is why there is no polar vortex in the summer.

Su Campu

Again we look to be several hundred miles too far west for anything to happen in the first half of the week. Anticyclone bang right over us, so even with the cold lower levels, upper level capping will limit or totally stamp out any precipitive convection up to Wednesday.
Not so for the North Sea though, as conditions look ripe for a polar low (there he goes again with his Polar Lows!! :rolleyes: ), with a cold pool of -40°C H500 moving southwards from Norway late Tuesday. Polar Low or not, eastern parts of Britain look set for some real disruption again, with some major showers looking definite.



I like this next chart for Thursday though , with the upper levels finally destabilising enough for some decent convection to develop over the Irish Sea.

snow ghost

Something is definitely going down with the weather... I was up all night last night and there were birds singing and making strange noises throughout the night, very strange... they were also acting crazy all day today.

After noticing the bizarre animal behaviour last night, and just coming here reading this, I'm beginning to wonder if there is actually something in this animal forecast model, that Donegal Postman could be on to something, there appears to be a definite correlation.

Bring on the snow!

200motels

Snowaddict wrote: »

Thanks for all the comments everyone

It's very difficult not to get over-excited when looking at some of the charts on display, but it's always best to downplay any potential until being at least moderately confident - Greater than 60% confidence in the risk of an event.

Another very solid GFS 12Z Operational evolution, which has 850mb temperatures of -8 across many parts from later on Monday and during Tuesday - with the threat of some light sleet or snow showers moving in off the Irish Sea.

It's also noteworthy that towards Day 5, a deep cold pool is advected across the country, with 850mb temperatures of -9 to -11 moving in from the East. With pressure falling slightly, such developments would offer more potential for snow showers into Eastern areas, which fits in with threat of a slightly more cyclonic Easterly pattern developing later in the week.

However it must be stressed that this is currently at Day 5.

Overall however, a solid, increasingly cold spell lasting for a minimum of 6 Days is indicated on this latest evolution, with an increasing threat of snow showers towards Day 5, especially in the East.

Rather extensive Northern Blocking is also in evidence between Day 5 & Day 6.

SA

Excellent as usual, any ideas of how long this cold spell will last?

dbyrne

If only there was a chance of the 71cm of snow they have just had in the US...

http://news.bbc.co.uk/2/hi/americas/8501246.stm

quick question, why dont any of these big storms that hit the us travel across and hit us on a regular basis?

http://content.usatoday.com/weather/CityForecast.htm?LocationID=USNJ0552&ps=L1

Musicman2000

Down to the Jetstream and a warm atlantic, if they did hit us would be as rain

dbyrne

but even when they hit the USA as heavy rain, storms etc they do not travel with the currents and remain strong

arctictree

dbyrne wrote: »

If only there was a chance of the 71cm of snow they have just had in the US...

http://news.bbc.co.uk/2/hi/americas/8501246.stm

quick question, why dont any of these big storms that hit the us travel across and hit us on a regular basis?

http://content.usatoday.com/weather/CityForecast.htm?LocationID=USNJ0552&ps=L1

I'd say that amount is possible here but we would need a heavy Atlantic storm stalling over us for 24 - 48 hrs with cold air in place, a very rare event. A few weeks ago we had 14 inches of snow here in Wicklow in a 12 hr period. Probably much more at higher elevations (I'm at 250M).

A

Pangea

Big freeze: Northern Ireland to miss out

By Clare Weir
Saturday, 6 February 2010





Ulster householders can express a sigh of relief as it emerges that Northern Ireland will escape the worst of a new big freeze and more snow showers expected to sweep into the UK next week. However, a cold snap is still on the way for some.

A spokesman for the Met Office says that while this weekend will be warmer than usual for February, temperatures will drop below freezing overnight.

“It’s not going to be too bad, with temperatures over the weekend actually quite warm for this time of year,” he said.

“It is at night times that temperatures will slide towards the middle of the week, things will get colder after Wednesday, dropping to -2 or -3 at night, even in inland areas and Belfast — so there will be freezing temperatures but no big freeze for Northern Ireland as such, compared to what we have already experienced.

“Towards the end of the week there will be some sleet and snow but the worst of this will be in southern and eastern areas of the UK. Southern, central and eastern areas will get more of this type of weather pattern but it will not be as bad as the weather seen in December and January and there are no severe weather warnings in place so far for the next fortnight in Northern Ireland.”

For many across Northern Ireland, the clean-up after the big freeze continues after frozen and burst pipes cause misery for hundreds of residents.

Read more: http://www.belfasttelegraph.co.uk/weather/big-freeze-northern-ireland-to-miss-out-14670241.html#ixzz0enMWwl64


Hmm belfast telegraph are talking a bit too soon, I dont think we will miss out.

lucernarian

I really can't see how donegal will experience much wintry weather from a not very cold continental easterly. The Met Office are making a safe call at least up to the beginning of Thursday.

thetonynator

i can't wait forthe next super thread on the snow, with 500 people on the weather forum at 1 in the morning!!! good times . . .

Pangea

To_be_confirmed wrote: »

I really can't see how donegal will experience much wintry weather from a not very cold continental easterly. The Met Office are making a safe call at least up to the beginning of Thursday.

Well it was v bad up here during the big freeze easterly.

Has the eastern being downgraded? I notice u said not very cold

mike65

*sighs* Bring on the Spring.

Pangea

Pangea wrote: »

Well it was v bad up here during the big freeze easterly.

Has the eastern being downgraded? I notice u said not very cold

It's actually like an election thats too close to call.
Next week will be colder.
That we are sure of-say daytime -with the ecm being least wintry to the end of the week.
4's and 5's max or a little lower.
Pressure will be high initially limiting precip to coastal drizzle or sleety flurries.
Current indications vary Towards the weekend,most including ecm make it colder and more wintry with more precip that if it verified would by then be mostly snow.

Thats the question,will it verify as the end of the week is definitely fi,the models are so flakey lately and also,the block is in fairness weak but trending stronger,it's just whether they will verify.
Most guidance says they probably will.

So it's not a good call at this stage to discount easterly winds especially a few days in to them as being "not so cold".
Also bear in mind that areas not in line for irish sea convection if and when the colder cold arrives later next week are usually areas best placed or at least first placed to feel the wintry mix of any attempted atlantic incursion up against the easterly.

lucernarian

My "not very cold" easterly is what is being forecast up to Thursday. I don't want to comment beyond that, so that's why I agreed with the Met Office up to Thursday.

Beyond the likes of Thursday can only be taken as a hint of what's to be expected. It does seem to be saying "colder" but the manner and duration of it are still yet to be nailed down.

I think SnowAddict's analysis is top notch on the upcoming week and he rightly points out that some of the nicer charts are at 5 days and further out, and simply points to the northern blocking beyond that.

And my 2 cents: I've seen a few -6 or -7 850hPa air masses dragged over Ireland in an easterly Scandi High on my time using this forum which delivered a few dry cold days with the odd flurry, as often as they have given 1-4 inches of snow train showers. Basically, the ramper within is saying that the first half of the week will be more of a starter than a main course:)

irish1967

I'm watching this thread quietly and smiling.

To_be_confirmed

To_be_confirmed wrote: »

the ramper within is saying that the first half of the week will be more of a starter than a main course:)

A hungry one at that.

bray man

I am too^^^:D

Deep Easterly

To_be_confirmed wrote: »

I really can't see how donegal will experience much wintry weather from a not very cold continental easterly. The Met Office are making a safe call at least up to the beginning of Thursday.

During a continental easterly in winter, Donegal, and indeed much of the western half of Ireland, may not see much snow (but it can happen), but be assured that it will feel wintry. Temps are usually lowest in the west during such spells being furthest away from the maritime influence of the Irish Sea. By contrast, the highest temps in summer and the most fantastic weather are more likely to occur in the west under a continental easterly.

Hence my choice of user name. :P

snaps

snow ghost wrote: »

Something is definitely going down with the weather... I was up all night last night and there were birds singing and making strange noises throughout the night, very strange... they were also acting crazy all day today.

After noticing the bizarre animal behaviour last night, and just coming here reading this, I'm beginning to wonder if there is actually something in this animal forecast model, that Donegal Postman could be on to something, there appears to be a definite correlation.

Bring on the snow!

Birds singing at 4am this morning, never heard anything like it, especially while dawn is still 4hrs away! Its either the weather or the birds were out on the lash last night and were just getting all loved up!!!!!!!

Deep Easterly

snaps wrote: »

Birds singing at 4am this morning, never heard anything like it, especially while dawn is still 4hrs away! Its either the weather or the birds were out on the lash last night and were just getting all loved up!!!!!!!

Ditto here Snaps. Birds were singing away very late last night which was kind of spooky and are still at it now. It is quite a balmy feeling, if gloomy, morning so that probably explains it. 4.4c currently. Some sharp bursts of wind at times to, which only happen on occasion; very strange morning weatherwise overall!

Snowaddict

Good Morning everyone

General Outlook

There is now quite importantly strong consensus for the deep upper cold pool to our immediate East to back westwards through Day 5, signalling a retrogression phase. It is worth noting also that ECMWF 12Z Yesterday was over-progressive with the entire pattern, as indicated on the much better defined and consistent ECMWF 00Z Operational output this morning.

From Day 1 (Monday) - Day 5, an Anticyclonic Northeasterly/Easterly influence is likely, with very hard frosts and fog developing widely at night time, along with rather cold days. There is the outside risk of some light sleet or possibly snow flurries/showers in Eastern areas at times, but conditions will generally remain dry throughout.

ECMWF 00Z T+96 - Day 4



As mentioned above, there is general consensus on the overnight ECMWF/UKMO & GFS Guidance for the upper cold pool to back westwards, with winds turnning into a more Easterly direction once more at T+120. With deeper cold being advected Westwards and pressure falling to an extent, the threat of sleet or even snow showers increases towards Day 5 onwards. Rather widespread High Latitude Blocking is now indicated at Day 5, with further Warm Air Advection progressing Northwestwards into Greenland, facilitating further Medium - Long Term Height Rises.

ECMWF 00Z T+120 - Day 5



Medium Term

Beyond Day 5, ECMWF & other Multi-Model Guidance is very keen to indicate a long term cold pattern, with multiple High Pressure centres all across the variable North. Winds generally eminate from the East/Northeast throughout.

ECMWF 00Z T+144 - Day 6



Towards Day 7, Retrogression of the main core of positive Height anomolies has taken place, now centred firmly towards Greenland. Easterly/Northeasterly winds persist across the country.

ECMWF 00Z T+168 - Day 7



After the retrogression phase to Greenland has taken place, it is increasingly likely that a very cold but much more cyclonic pattern will then develop. Areas of low pressure may well approach from the Southwest, along with the potential for a renewed Northerly/Northeasterly incursion.

Summary

In summary then, a prolonged and quite likely increasingly cold spell is indicated on overnight NWP Guidance. Northern Blocking is likely to become the dominant feature driving our overall Weather Pattern through to Day 10. From Day 5 onwards in particular, it does appear that the threat of sleet/snow showers will begin to increase, as the Upper Cold pool from the continent backs Westwards. Overnight frosts, sharp to severe are likely, with fog persisting in some areas throughout the day.

This pattern, out to Day 10 & possibly beyond is indicated very well on the latest CPC 10/14 Day 500mb Height anomoly chart, with a mean, increasingly unsettled, Northeasterly to Easterly airflow:

http://www.cpc.noaa.gov/products/predictions/814day/814day.03.gif

SA

I must say I like the 120 to 168 charts above as long as they don't stay out there.

Deep Easterly

Indeed Mark. The ECMWF freebie today suggests (unfortunately :pac:) that the possible cold snap next week will remain polar maritime sourced rather than continental:

216hrs Chart: (500's/850's)



Cold never-the-less, with always the risk of wintry type shower near coasts, but probably remaining mediocre further inland unless a sharp trough develops.

I ask however, what does it take to get a polar continental these days? they just don't seem to happen anymore. Same in summer, true continental feeds just can't seem to get going the way they used too. The last half decent one was in May 2008. Only very brief encounter's since.

Deep Easterly

Deep Easterly wrote: »

I ask however, what does it take to get a polar continental these days? they just don't seem to happen anymore. Same in summer, true continental feeds just can't seem to get going the way they used too. The last half decent one was in May 2008. Only very brief encounter's since.

We need to move the island ... not to the south pacific though :pac:

As for the models...the Katy perry rule applies more than ever I'm afraid...

https://www.youtube.com/watch?v=y-LhyAVzDBI

Deep Easterly

Deleted User wrote: »

We need to move the island ... not to the south pacific though :pac:

As for the models...the Katy perry rule applies more than ever I'm afraid...

https://www.youtube.com/watch?v=y-LhyAVzDBI

Ha ha! "the Katy Perry rule" Sounds good to me! Great tune by the way. Annoyingly catchy. :pac:

lucernarian

Considering the signals that were pointing towards retrogression happening, I'm relieved that the models do seem to be taming the northern part of the jet stream by t+144 onwards.

But with healthy retrogression towards Greenland and not exactly the most significant of cold air pools over scandanavia, there may be a period where it gets warmer before it gets colder. On the other hand, there's no doubt that northern areas would receive plenty of snowfall sooner or later over the week starting 15/2 if that evolution even vaguely materialises. By materialises, that the HP actually does go to Greenland instead of travelling halfway:p

The coldest air seems to be over Ireland by Friday going on the ECM and GFS charts. But because the cold air pool is not massive and is being "dragged" away from the continent. Small enough changes in how the situation develops would have big enough consequences for us, so I'm definitely not going to call that until Tuesday at the earliest:eek:

To_be_confirmed

To_be_confirmed wrote: »

The coldest air seems to be over Ireland by Friday going on the ECM and GFS charts. But because the cold air pool is not massive and is being "dragged" away from the continent. Small enough changes in how the situation develops would have big enough consequences for us, so I'm definitely not going to call that until Tuesday at the earliest:eek:

Yes but at that stage ,you have to factor in cold surface air advection towards Ireland from the East.
Theres lots of that and while the really cold uppers are transitory,if you have sub or close to zero air moving from 0 to 1000ft-you can let 850 temps rise to -6 or -7c and still have snow even at the coast.
You mightn't have the normal super cold over warm sea convection but as the flow is to go more cyclonic,you will have more instability due to that.
Thats what we need to see happening after next weekend.
Surface air takes longer to travel here than the uppers and it's also more easily modified so we do need it to snow in Britain to disable the modification.
Colder sst due to the january cold spell will help.

Heres a good indication of how cold Europe is at surface level at the moment,the 0c isotherm is at sea level currently as far as Holland which at worst means the athmosphere is such that air temps won't go above freezing there.
In reality with snow cover etc,they are well below zero at times.
Thats the surface air we need and should be advecting in by next weekend as the easterly/NE persists



~Thats assuming everything goes to plan...

I'm off now to watch the country tracks forecast which I've recorded,I'll comment on it in a bit.
Expect a bad Gerry Murphy one by the way with the usual Wintry showers mentioned towards the end of the week.
It will be exclusively ecm as usual.

I hope they are the same type of wintry showers that they had on the farming forecasts in early january... as we all know snow was what came.

yay \o/
It's Tomaz if you don't like snow look away now shafanaker

Rakes of snow everywhere on his map including us lot come thursday friday despite the high pressure

Tom Cruises Left Nut

Farming weather on RTE One now

Redsunset

HA she commented on the jumper over the VT on rte news now.

And not the forecast but heres Tomaz havin a strop.
http://www.youtube.com/watch?v=2HtEmhMfz7M