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Cold prospects Late Jan/Early Feb
Topic Started: January 20 2012, 04:22 PM (1,804 Views)
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Weather and Climate Through The Eyes of Mark Vogan Via his facebook page.

LONG RANGE THOUGHTS: Next 2 wks, core of cold has eastern Europe bias but the trough will slowly migrate westwards and by Feb wk 2, core of cold will be over w. mainland from Germany to Ireland, warmer in east.Weather and Climate Through The Eyes of Mark Vogan

While an area from Norway through Russia down to Bulgaria may be cold just now... this is nothing compared to the period starting Sat-Sun through at least mid next week where a wall of intense Siberian air roars in. First Russia, then Poland then Germany eventually knocking on the door of France, low countries, UL, Ireland by end of next week. Hope these governments are aware of what's coming.


zzzzzzzz zzzzzzzz zzzzzzzz zzzzzzzz zzzzzzzz zzzzzzzz c-raz-y c-raz-y -n-o- -n-o-
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Wouldn't pay any attention to Mark Vogan, he doesn't seem to have any more knowledge than someone like myself but the fact he posts videos about his thoughts seems to give his opinion more weight than a lot of genuinely knowledgeable people. He's been forecasting extreme cold just around the corner every time I've seen one of his forecasts going back to November!
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I guess the Express have been following Mark Vogans weather forecasts updates h-e-h-e


BIG FREEZE TO LAST A MONTH
Friday January 27,2012
By Nathan Rao


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Britain's big freeze could last for up to four weeks, weathermen warned last night


THE first big freeze of the winter could last for up to four weeks, weathermen warned last night.

Snow is expected to hit parts of the North today with the whole country set to shiver over the next few days as temperatures plunge below zero.

The cold spell, which comes at the end of one of the mildest winters on record, is the result of a blast of icy air from Siberia.

Forecasters say the UK will be “put in the freezer” with weeks of snow, ice and freezing temperatures set to cause chaos on the roads.

The AA yesterday warned motorists lulled into a false sense of security by the mild weather to take extra care as wet roads freeze over, making driving conditions treacherous.

The Met Office has severe weather warnings in place today for ice, with snow turning to slush leading to traffic disruption.
ì
We have had a very mild winter so far and motorists need to get into their winter mindset from today
î

AA spokesman Luke Bosdet


Forecaster Helen Chivers said: “We have got cold air coming in from the East, an Atlantic system from the West and the UK is the battleground. It is going to turn cold with the risk of snow cover in the North.” Black ice could turn roads into skating rinks and drivers were warned to be prepared for delays and to check road conditions before setting off.

AA spokesman Luke Bosdet said: “We have had a very mild winter so far and motorists need to get into their winter mindset from today.

“It is going to be important not to charge around in the way they may have been used to and be prepared for the unexpected.”

Around two inches of snow could fall by the end of today with Cumbria, the Midlands and parts of Wales likely to get a dusting. Heavier snow is possible across much of northern England with up to four inches settling on higher ground.

Temperatures will plunge to -3C (27F) overnight, bringing widespread frost, while daytime temperatures are not expected to rise above 3C (37F).

Although milder air could bring brief periods of respite, the bitter spell is not expected to let up until the end of next month.

Ms Chivers said: “The Midlands and northwards are most at risk of snow but exactly where and how much is still in the balance. Colder weather is most likely to dominate into next week. We had cold snaps in December and earlier this month, but it would be fair to say this period has the potential to be the first cold spell this winter and the longest lasting.

“Cold weather is winning the battle for dominance and people will notice the chill carrying on for more than a few days.”

Forecaster Brian Gaze, of The Weather Outlook, said: “This has been a very mild winter so far but that should change as high pressure to the North and East blocks mild Atlantic weather and pushes bitterly cold air westwards from Siberia.

“The cold block to our east shifting a few hundred miles west is the diff­erence between Britain being in the freezer or the recent run of mild south-westerly winds.”

This week has already seen the first real taste of winter with sub-zero temperatures and snow bringing parts of the UK to a standstill. Up to four inches fell on higher ground in northern England and Scotland, with Wales and even Devon on alert.

Eastern parts of the country are expected to be worst hit by the ­coming cold snap with councils warned to have gritters on standby.

Last year Britain ground to a halt as one of the coldest winters on record caused transport chaos. Parts of the country were buried under up to a foot of snow for days as temperatures plunged to -20C.

But a spokesman for the Local Government Association said yesterday: “Councils are better prepared this ­winter than they have ever been. Town halls have stockpiled 1.4 million tons of grit, more than was used throughout all of last winter.

“They have also invested in dozens of new gritters, thousands of extra salt bins and better communications to keep residents informed.”

s-ho-cked- s-ho-cked- -n-o- -n-o- -n-o- -n-o-

Link ..... http://www.express.co.uk/posts/view/298249/Big-freeze-to-last-a-month
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Met Eireann has switched to a colder outlook again.

The week ahead looks like it will become much colder again.

Monday next looks cloudy and wet with the risk of some wintry falls in the East.

Tuesday and Wednesday look like they will bring some rain at times mainly to Western areas with drier but much colder weather in the East. Nights will be cold with frost in many places and the risk of icy patches.

Thursday looks mainly dry at the moment with rain moving down across the country on Friday followed by a cold and frosty night Friday night.
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Some latest observations. ECM computer model still favours cold building west into Britain in the short term and eventually into the east coast of Ireland by Monday. Beyond 96hrs, which is unreliable territory at present due to massive swings from model run to model run, cold eventually reaches the west coast of Ireland.

Here is an animation of the 850hpas (temps at approx 1500m). Snow generally will not fall when the uppers are milder than -5 to -8c, the latter being preferable. Of course, dew point, theta values and other criteria must also be favourable for snow to fall.

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ECM Northern Hemisphere z500
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Meanwhile, the GEFS is very different from the ECM showing the cool zonal pattern with milder interludes continuing. The GEFS believes that the high ridging west from Russia will sink quickly this weekend, therefore preventing any cold air from the continent from pushing west toward Ireland and the UK. It has the jetstream continuing to be directed at and over Ireland bringing occasional rain and average temps for the time of year.

The UKMO model lies somewhere in between but ultimately favours colder weather extending into at least eastern England and Scotland with the Atlantic maintaining its influence over the western half of the British Isles. This presents a battleground situation for eastern parts of england where cold air meets up when warmer Atalntic air. Some heavy snowfall is possible by later Sunday or Monday but details remain sketchy. Of course, there is some potential for this frontal situation to track further west in the meantime.

The JAM Model is very similar to the ECM and UKMO out to 96hrs before it has the Russian high sinking south with a more zonal pattern redeveloping across western Europe. Here is the 850hpa chart for Sunday

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Cold lovers will prefer the GEM model which has a gradual cool to severe cold outlook from 27 Jan through 6 February. It's one model that paints a more familair picture of how a easterly develops in this neck of the world i.e. slow buildup of cold to our east (i.e. cold becomes entrenched) and it's gradual progression westwards as blocking to our west keeps atlantic fronts at bay.

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Who is saying what?

Met Eireann appear to be discounting the GEFS completely.
Outlook

The week ahead looks like it will become much colder again.

Monday next looks cloudy and wet with the risk of some wintry falls in the East.

Tuesday and Wednesday look like they will bring some rain at times mainly to Western areas with drier but much colder weather in the East. Nights will be cold with frost in many places and the risk of icy patches.

Thursday looks mainly dry at the moment with rain moving down across the country on Friday followed by a cold and frosty night Friday night.


The UK Met Office are saying there is a one in 3 chance that milder weather will prevail into the second week of February but that it is much more likely that eastern Britain will be hit by much colder and wintry weather, with this cold extending west fully by the second week of February. The UKMO has held this line for the past 4 days.

IWO's Peter O'Donnell also things the GEFS output is unlikely to materialise.

SUNDAY ... Mostly cloudy, occasional light rain, may mix with wet snow or sleet in parts of eastern Ulster and inland north Leinster, and on higher parts of Dublin and Wicklow mountains. Cold across the east, winds backing to SE at 10-20 mph, highs 3-6 C. Variable cloud, some showers possible, milder further west, highs 7-10 C.

OUTLOOK for NEXT WEEK ... Much of the time, there will be a marked temperature contrast from east to west as a rather diffuse front will settle in over the Irish Sea and eastern Ireland. This will lead to outbreaks of sleet, with snow possible at times especially higher elevations, but largely confined to eastern Ulster and northeast Leinster. Dublin will remain very close to this frontal boundary, and further west it will tend to stay mild except for brief intervals when the front drifts further west. Temperatures to the east of the front will be as low as -2 C at times, and generally in the range of 1-4 C. To the west, it will stay considerably milder, around 6-9 C on average, and 10 or 11 C on outer west coastal margins. This pattern could persist for several days or even the entire week. Confidence is rather low concerning details, watch for updates because as we get closer to the time, the forecast models may begin to pick up on the details which will help us with the timing. I still consider it quite plausible that a snowfall event could develop eventually, as things are in a rather fine balance between a weak Atlantic flow trying to hold its position, and a very wide-ranging cold blocking high which could at some point begin to push west more vigorously.


REVIEW

It will be interesting to watch the GEFS throughout the day and see if it falls into line with what the UKMO, GEM and ECM are trending towards. The JMA and GEFS may also be out on their own for very good reason in forecasting a continuation of the zonal conditions that have so far defined winter 2011-12. Both sides of the fence have been consistent in their output in recent days but one side has to falter eventually. The AO and NAO indices do offer some clues that side somewhat with the GEFS and JMA output.

The Arctic Oscillation (AO) remains in negative territory and is forecast to remain negative for the coming 10 days or more meaning that some warming of the stratosphere over the Articic is continuing. This ensures further spillages of cold Arctic air south over parts of the Northern Hemisphere. The NAO (North Atlantic Oscillation), meanwhile, looks like it will remain low positive for the same period. This suggests a less active Atlantic than what we have seen in recent weeks but one which is likely not to give up its grip on our weather without a fight.

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Changes afoot on the GEFS 06z run.

The 06z GFS significantly upgrades cold potential for that same period bringing cold further west than shown in the 0z. Here is a comparison of the two charts at midnight Sunday (0z run first and 06z run second). The GEFS seems to have followed the lead of the ECM, GEM and UKMO.

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Temps at midday on Monday with cold pushing west all the time.
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The changes to the jetstream are very interesting.


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We are in a slack easterly by Wednesday with some severe overnight frosts by the end of the week. Details regarding potential snowfall remain very sketchy but the current charts would suggest occasional wintry showers in east and southeast. A potential battleground situation between cold and the warmer Atlantic does present itself, which could be interesting. See previous post.

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Cold is entrenched over Europe on Wednesday
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Max temps at 6am on Thursday (0z first and 06z second). Big differences between the last two GEFS runs.
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Very encouraging GFS 06Z. Well summed up Mark.Could this actually happen after a boring Winter so far?? Lets hope so.
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Simon Keeling of weatheronline.co.uk rightly dismissing the Daily Express trash article

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GFS ensembles of 2m temp (close to surface temps)

Comparing 0z (second) to 06z (first). GEFS upgrade for cold is evident.

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Latest from UKMO

UK Outlook for Wednesday 1 Feb 2012 to Friday 10 Feb 2012:

Although there is a lot of uncertainty, eastern and central areas will most likely see clear or sunny spells, and scattered light wintry showers. Westernmost areas will probably see more cloud, with occasional rain and some hill snow. Temperatures will probably be below average, the cold accentuated further by fresh winds from the east. Towards the end of the week and through the rest of the period, a general continuation of the cold weather type seems most likely, but it is by no means certain. There is a risk of snow, ice and sharp frosts, with easternmost parts being most prone. However we certainly cannot discount the possibility that mild west/southwesterly winds will return instead, bringing rain at times.

Updated: 1200 on Fri 27 Jan 2012
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Huge upgrades for next week in the 12z GFS.

Comparisons of last two runs below (most recent run is top image in each pair)

The featured day is Thursday

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The UKMO also trending cold


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By Friday, minimum temperatures at midday are well below freezing away from the coast. This upgrade in favour of cold from the GEFS is so extreme that one would be better off waiting another run to see if it backtracks.

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MAX TEMPS
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GEFS on steroids

Next Saturday

850hpas (temp at 1500m asl) around 15-18c in parts of England c-raz-y
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Latest from Paul Hudson, formerly of the UK Met Office

For the first time this winter, after a relentless spell of westerly winds, many areas are expected to see a general change to colder conditions as we head through the weekend and into next week.

As the colder air becomes established it will be competing with milder air from the Atlantic. Where the two meet, snow is likely, with western areas most at risk.

Here in Yorkshire there is a risk of some patchy snow later in the weekend and into monday mainly in western areas - although it is unlikely to be heavy. At the same time wintry showers may affect coastal areas.

But the exact location of this battle between cold air from the east and milder air from the west is still a source of uncertainty, and getting the detail right will cause problems.

Much of the country will then have a period of quiet, settled & cold weather as we head through next week, with sharp overnight frosts developing.

After that, the outlook remains a major headache for forecasters, as it has for some time. In fact I can't remember the last time there has been so much disagreement between the major forecasting models.

As I've explained before, each computer model runs many times, and each time the initial starting conditions of the atmosphere are changed by a very small amount, in order to see what happens.

An example of this can be seen below, from the American GFS model, from midnight.

It clearly shows that after a few days, when all the model runs are in broad agreement, each separate run of the model thereafter yields different results - with some solutions showing a 15 Celsius difference in temperature at 5000ft.

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In fact model solutions from yesterday summed up the dilemma forecasters have had for days now, in that 50% had a milder south-westerly in the further outlook period; the other 50% had a colder east or south-easterly.

The latest information gathered so far today shows a shift away from the milder south-westerly scenario described above - but such run to run changes have been common this week and until there's more consistency it's impossible with any degree of confidence to determine which scenario will ultimately win.

That said, a cold early February is the more likely scenario.

Finally, since my blog has featured articles in the past about the merits of different private forecasting companies before, and how some newspapers often use their long range forecasts for front page headlines, I thought you might be interested in this article about Positive Weather Solutions which appeared in the Guardianyesterday.

Follow me on twitter @Hudsonweather.
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12Z ECM holds its own up to 96hrs and then there is a slight regression on the 0z in terms of bringing the cold from the continent westwards. The cold airmass more or less just dances around the east coast of England and the North Sea all of next week. Things are kept cool here with frosty nights.

Sunday
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Monday
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Thursday
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The UKMO also is the same as the 00z keeping us in a slack northeasterly from Monday, turning easterly on Tuesday. The battleground situation referred to earlier certainly comes into play here (see bottom fax chart). Exciting weekend of model watching.
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By the way, handy site here for viewing the models
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Death toll warning with freezing weather set to stay for a month
The government issued a nationwide big freeze health warning as a bitter ‘beast from the east’ weather system hits this weekend amid death toll fears from sub-zero temperatures lasting up to a month.



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A walker battles through the snow at Nenthead, Cumbria, as the country braced itself for a spell of cold weather (Picture: PA)

Forecasters said the vast pool of cold air from Russia is expected to affect Britain for up to four weeks due to easterly winds - raising fears about the cold weather death toll.

The Department of Health issued a rare England-wide level 2 cold weather health warning running from 6pm Sunday night until 9am Tuesday - which is expected to be extended as the cold is due to persist through next week. Wales, Scotland and Northern Ireland do not have the warning system.

The alert was issued as there is a 60-70 per chance temperatures will remain below a bitter 2C for 48 hours or more.

A Met Office spokespeerson said: 'There is a 70 per cent probability of severe cold weather between 6pm on Sunday and 9am Tuesday, which could increase health risks to vulnerable patients and disrupt the delivery of services.

'There is a good chance this alert will be extended beyond 0900 Tuesday over the coming days.'

The warning instructs NHS Trusts, hospitals and health and social care workers to expect to be busier than usual.

The cold weather health watch system, launched this winter, is aimed at slashing the total of 25,700 more people who died last winter than in similar periods in other months of the year, described as 'shocking' by pensioners’ groups.

The cold particularly affects the elderly, babies and the ill.

Experts say people most likely to die during cold weather are those in fuel poverty or living in cold and damp accommodation, the elderly and anyone with underlying health conditions.

Doctors say cold weather can cause thicker blood, increased blood pressure and tightened airways, increasing deaths from heart attacks and respiratory illnesses.

Forecasters urged people to keep up to date with health and weather warnings and follow their advice.

Age UK’s charity director Michelle Mitchell said: 'Winter deaths figures are shocking. Around 3.5million older people live in fuel poverty and one in three over-60s live in houses which fail the decent-home standard.'

The Met Office said more than two inches of snow was understood to have fallen today over the Pennines and Cumbria, while Twitter users reported snow in the Peak District, Derbyshire, and Exmoor, in Somerset and Devon.

Nigel Hester tweeted: 'Sharp snow showers on Exmoor but quickly melting - brilliant weather for a walk.'

Next week will see biting daytime temperatures at 2C or lower and nights below -5C.

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A car struggles up the hill in the snow at Killhope, County Durham, as the country braced itself for a spell of cooler weather that has brought snow to some regions. 27/01/2012



By Simon Garner - 27th January, 2012 ...... http://www.metro.co.uk/news/888682-death-toll-warning-with-freezing-weather-set-to-stay-for-a-month


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This is also a handy site .


Link ............... http://policlimate.com/weather/
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MARK VOGAN'S EUROPEAN LONG RANGE: Friday 27, Jan 2012.



Video ...................... http://youtu.be/V2VJSpj3bqk
Edited by Audi-Tek, January 28 2012, 04:54 AM.
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The best way of describing the way the various computer models have been handling the weather prospects for the next 7 days or more is to compare it to trench warfare. If you take the warmer Atlantic and colder Continental airmasses as opposing armies and take where they meet as the front line, you have a setup where advances are made by one side before they are pushed back only to begin advancing forward once again.

The western side of this frontline will bring much milder and often wet conditions. The eastern side will bring very cold but mostly dry conditions (wintry showers likely along east coast of England). All the action takes place on the frontline where cold air brushing up against an Atlantic frontal system presents a typical battleground situation. This front will deliver snowfall to all but the western flank. So, the question people have been asking here and elsewhere is where Ireland will be in the context of the “front line”.

The models have been trending cold for Britain since last weekend with Ireland remaining on the periphery of this cold for the last few days of January and the first couple of days of February. However, the past 48 hours have seen models bring much colder but largely drier weather west over the country by the middle to the end of the first week of February. While England, Wales and all but Western Scotland appear to be certain of experiencing severe cold by the middle of next week, things are not so clear for Ireland.

Forecasts from Peter O’Donnell, Met Eireann, UKweatheronline and the UK Met Office all agree that battleground between cold and warmer air will roughly be over the Wales or possibly the eastern half of the Irish Sea, at least. This line looks like pushing east again after midweek which is different to what the met agencies have been saying all week.

Peter O’Donnell: MONDAY ... The east-west divide may continue with sleety rain or wet snow at times in east Ulster and coastal Leinster, while further west most places remain a bit milder with fog, rain or drizzle at times, highs 3-6 C east, but about 7-10 C west. TUESDAY-WEDNESDAY ... Little change as fronts remain near the east coast of Ireland, any clearing at night could lead to sharp frost and icy patches on roads, but in general, this mid-week period will be cloudy with patchy light rain or sleet, milder to the west, highs in the range 3-8 C. THURSDAY-SATURDAY ... This period could turn considerably colder, but guidance continues to be less than unanimous ... with very cold air likely to be present as close as southeast England and northeast France (-10 C or so) a sharp front will be trying to push west and could succeed in bringing sub-freezing temperatures and some outbreaks of snow to eastern counties. This may never get much further west than about Athlone to Waterford, and with mixed precipitation in that zone, milder and rain or drizzle to the west. However, at some stage, the very cold air and snow could make a push even further west. The chances are assessed at about 70% possible for cold and snow in eastern counties, to 30% in west coastal counties, during this period.

Met Eireann:
Monday will be wet with heavy and persistent rain for much of the country. Highest temperatures of 4 to 9 degrees with the colder weather in the north. Winds will be moderate and from the southeast. The rain will continue into Tuesday with some heavy falls in the south. However the rain will tend to ease off towards evening. It will feel cold in the east of the country with highs of 3 to 5 degrees, while in the west temperatures will range from 7 to 10 degrees. It will be cold overnight on Tuesday with lows of 1 to 4 degrees. There will be a lot of dry weather on Wednesday and Thursday with highs of 4 to 9 degrees, once again it will be cold in eastern areas. There is also the risk of frost on both nights.

Ukweatheronline: Wednesday 01/02/12 - Generally a cloudy day with outbreaks of rain across Northern Ireland. Cold but dry across the rest of the country with long spells of sunshine. Another sharp, widespread frost across England tonight. Highs of 1 to 3C. Thursday 02/02/12 - A very cold day and there is a risk of heavy snow showers around North Sea coasts. The bulk of the country looks dry with good sunny spells. A widespread and penetrating hard frost by night. Expect highs of -1 to 2C. Friday 03/02/12 - A bitterly cold day across the country. Snow showers around eastern coasts may penetrate a bit further inland today with wintry showers also around western coasts. Central areas generally keeping dry, sunny conditions. A hard to locally severe frost is possible tonight. Expect highs of -2 to 0C. Saturday 04/02/12 - As rain moves in off the Atlantic, we may see heavy snow across Northern Ireland today. Further snow showers to come along North Sea coasts and windier today. Continued bitterly cold with inland areas fair and dry. Another severe frost develops tonight. Highs of -2 to 0C.

UKMO
Outlook for Monday to Wednesday: Occasional rain, sleet and snow across western areas, easing somewhat through Tuesday and Wednesday, especially across England and Wales. Drier and brighter further east, but some wintry showers. Feeling cold. UK Outlook for Thursday 2 Feb 2012 to Saturday 11 Feb 2012: Mostly settled and cold leading up to the first weekend, especially towards the southeast of England, with widespread overnight frost and some wintry coastal showers towards the east. However, northwestern parts will soon become cloudier, more unsettled, but milder with spells of rain and some snow, the snow mainly on hills. Although there is considerable uncertainty, the bright, cold conditions will probably continue for a time into the second week in the east. However, the unsettled but milder conditions in the west will probably spread erratically further east with time, introducing spells of rain and some snow, again mainly on hills. This progression may be coupled with strong winds and possibly gales in northwestern parts. Updated: 1237 on Sat 28 Jan 2012

REVIEW

I do believe that all models, with the exception of the GEM (has cold pushing furthest west), have backtracked on previous interpretations of the coming week’s weather prospects. The fact that the majority of them have done so suggests a trend is being picked up on. I mentioned yesterday that I did not believe the Atlantic would give in so quickly after maintaining control of our weather for the past few months. This does appear to be the case but at the same time throws up a classic major snowfall situation as mentioned above (front line).

Presently, Ireland is not on the front line up to Wednesday but the east coast will be very close to same by Thur/Fri according to all models (below). Peter O’Donnell refers to this in his forecast too.

GEFS
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ECM
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UKMO
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GEM
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The GEFS on steroids that we saw yesterday is a far cry from the overnight runs. The ECM also has backtracked. The main cause of this has been the weakening of the HP over Russia into Scandinavia and the failure of any significant blocking to occur to the west/southwest, therefore allowing the jetstream to dominate proceedings.

GEFS will roll out at 3.30pm followed by the ECM/UKMO at 6pm. “It's getting tickly now - squeaky-bum time, I call it”.
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Sunday's snow and the week ahead 28/1/12
From: Weather School Channel Jan 28, 2012.


Link ................. http://youtu.be/l_9Otw8wm8Q
Edited by Audi-Tek, January 28 2012, 06:24 PM.
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One of the three main models. the GEFS has upgraded the prospects for colder weather to affect Ireland next week following two successive downgraded runs overnight and this morning. The ECM model rolls out after 6pm this evening. The UKMO is rolling it out now. Update will be posted shortly.

The GEFS is more or less the same as its previous run up to Tuesday. Thereafter, there is a noticeable progression west of colder air as the Russian High ridges west, and blocking is reestablished to our west/southwest diverting the jetstream and Low Pressure systems north away from us.

The below charts for 3pm next Thursday (5 days from now and on the fringes of FI territory) feature the latest run (12z) and the previous run (0z), placed top and bottom respectively.
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AO & NAO

The Arctic Oscillation remains strongly negative meaning cold air from the Arctic is set to continue spilling south across various parts of the Northern Hemisphere i.e. the tap of cold air remains turned on into early Feb.

Next we look at the North Atlantic Oscillation. We preferably want a negative index here to indicate a less potent SW/W flow i.e. jetstream diverted away from us. Below you will see it remains positive with subtle signs of a dip toward the end. Like all models, the AO and NAO indices are only as reliable as their last run. In this case, zonal conditions to our west and most likely over us do not look like breaking down over the next week, hence the very slow progress of any cold airmass beyond England.

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Mark (IWO)
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UKMO is an upgrade on previous run, like the GEFS (see previous post in this thread)

Wednesday on the UKMO. The aforementioned front line (see previous post) reaches east coast of Ireland.
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Winds direct from the east compared to the southeast in previous run (see below)
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Fergal (IWO)
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Here's an excellent analysis of the synoptic evolution over the next week or so by Paul Blight over on UKWW.

http://www.ukweatherworld.co.uk/forum/index.php?/topic/89194-synoptic-detail-and-discussion/page__pid__785239#entry785239

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Synoptic Analysis and Discussion - Jan 29th to Feb 4th

Marked buckling of the Atlantic Jet is now underway, however the 300mb flow over Europe is extremely complex which explains in part the discrepancies and model variances in the upcoming evolution.

At the Surface and extending up to 500mb an intense Russian Cold High is located over NW Russia (central pressure around 1055-1060mbs). A separate high is located over the SW Approaches and the Atlantic Jet has been forced to surge Northward. (see below)

However at 200/300mb the flow is somewhat different with a marked Atlantic Ridge and sharp disrupting trough over the North Sea. The RUssian High is not well defined yet at this level although that changes over the coming 48hrs as high pressure develops and moves towards Novoya Zemlya. The evolution is complex but should simplify over the coming 72hrs. The North Sea trough sinks south into Europe and rotates and brings an element of PVA into Eastern England before warming out and moving into the Nr COntinent. However a breakaway warm front wave moving NE in the flow ahead of the Mid Atlantic RIdge gets caught in the NW'ly Flow on the east side of the ridge in the coming 48hrs and sends rain / sleet and some snow over High Ground SE between now and Monday 12Z. COld Advection from the east undercutting the upper level developments, though this cold advection largely doesnt make much inroads into the more western parts.

Further east the developing intense high aloft over Novoya Zemyla has the effect of sucking an extremely cold pool of air west into Western Russia and Eastern Europe where some very cold temperatures are likely through the coming week. (ECMWF has lows of -25 to -30C over Poland, and into Western Russia by the end of the week and -12 to -20C over parts of Germany. Daytime Temps staying well below freezing)

The Models have been struggling with this evolution - though as usual the Ensemble Guidance has provided a reasonable steer, but with varied solutions offered, it is not a surprise that the Op Run has varied between cold and less cold. There is now good agreement on the period to around Thurs. After that there is considerable variation in the developments. The runs of Friday had extended the marked cold pool over Eastern EUrope west on the broad easterly flow with the intense high anchored over Finland and extending well aloft. However the Runs today have introduced mmuch more variability. This is seen within the EPS from the ECMWF which has gone from 2 clusters at T+168 last night to 6 Clusters at 00Z today. Again there appears to be a desire from some of the OP runs to introduce mobility from the Atlantic and a reurgent amount of Jet Energy which seems to squash the extending RUssian High and assoc cold pool exdtending west across Continental Europe. Models do not handle these types of block very well. The "natural" progression is from west to east and thus big blocking highs and their assoc to marked stratosheric warming is not well understood. Deep layer cold blocks of air and their assoc huge high pressure zones also do not break down easily and need very marked jet energy to do do. The Jet leaving the east coast of the US is varying within the model guidance for the end of the week and thus the spread west (or not) is linked to this energy. A Jet nr 200Knts or greater is very powerful and is strong enough to weaken and erode the cold continentla block, however Jet Speeds less than this will likely not be sufficient to weaken a well established and deep layer cold block which models tend to underrepresent.

The UKMO GM generally does quite well in these types of Scenario whereas the ECMWF does not generally perform as well with continental easterly blocks and tends to throw up some quite oscillating solutions. Its EPS however and the Ensemble Mean is generally more consistent.

There is good agreement for colder air to move west into many Eastern, SE and Central PArts through Mon -Weds. However fronts stay closer to Scotland and N Ireland and these complex fronts have the ability to bring some rain /snow at times to Western Parts. Temps will fall and overnight Frosts will become more widespread after the weekend with daytime temps 1-4C generally. The coldest temps over the high ground. SST are quite well up around the UK so expect coastal areas to remain with temps somewhat higher than one would expect from thickness values. The lowest layers strongly modified from the Sea. Wintry showers developing around some Eastern and SE coasts at times, largely sleet or rain but snow inland. However the amount of Showers depends on the wind direct Tues - Fri. The UKMO 00Z and GFS 00Z were both keen on this.

Warm front wave on Sunday and Monday is complex. The 00Z ECMWF gave a very strong snow signal. However the 00Z Hirlam did not. The 00Z and 06Z NAE had a muted snow signal and the 00Z UKMO GM had a stronger snow signal. The 00Z and 06Z GFS again targetted parts of Wales, NW England and Wessex.
Therefore the conclusion to draw is that the Global Models have a stronger snow signal than their Hi Res COunterparts. The NAE has a bias to produce too much snow in its model fields - and therefore the fact it doesnt have much is interesting. This may be more linked to the fact it has generally light precip = whereas the indications are for some sharp bursts of precip at times. However rising pressure, daytime and not a very cold airmass in place generally do not favour a widespread snow event at this stage. I think therefore the areas most at risk are inland and upland parts of NW England, Wales and perhaps parts of the Cotswolds etc. (over 200M) Elsewhere a cold rain/sleet slowly moving SE through Sunday and Sunday N into Monday. The forcing for the wave is largely thermal based (marked warm advection aloft with a cold undercut - however there is some evidence of some Vorticity forcing overriding into Monday Morning which needs watching. This whole element of the forecast is extremely uncertain.

Through Tues -Fri - The Russian BLock builds at the surface and aloft and extends west. Question is how much and how much the cold pool elongates and extends west. As i said models do not well here so it will need careful watching as to how the deep and quickly the cold pool extends west and how persistent the deep layer Russian BLock becomes in conjunction with Jet Energy leaving the Eastern Seaboard. The 06Z GFS depicted a battle zone developing over The UK next week. This type of solution appeared in a number of solutions of the ECMWF 00Z EPS and represented one of the 6 clusters. However at this stage its no more or less likely the the 00z SOln and indicates what considerable variability exists in the current forecast.

TOI 14.06
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Mark (IWO)
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The ECM this evening will be a big one. It will follow the GEFS's repeat of yesterday's very cold 12z today following a downgrade overnight.

the UKMO and GEFS are more or less in sync up to 96hrs, which in itself is a time where confidence in the charts actually materialising remains low.

The UKMO beyond 96hrs does suggest that milder air will win through over most of Ireland. If the ECM follows suit then the GEFS play of very cold weather dominating into next weekend will be questioned, despite the fact that its outlook is being backed up by the GEM and NOGAPS (NoWHO?) t-on--gu-e
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Upgrade from the ECM regarding cold potential beyond midweek. It falls very much into line with the GEFS up to 120hrs.

850hpa (temp at circa 1500m asl) on Thursday (top = latest run, bottom = previous run)
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Massive upgrade at 144hrs, though this is a bit too far out to be associated with anything other than low confidence
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Trend is your friend, however, and the models are edging toward a colder outlook.
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Wicklow Weather
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Do we have a similar historical event that developed into anything like a snow event with similar patterns as to whats been happening with the recent threat of cold or should I say the upcoming cold event? 47?
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Fergal (IWO)
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I'm not sure about that, maybe Patrick will be able to answer that for you, he's a bit of a database when it comes to stuff like that!!
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Latest UK Met Office Fax forecast chart for 120hrs showing a much modified continental air stream over Ireland. Should bring some very pleasant dry weather but if I could also warn people not to get too excited about any prospects thereafter. Models are all over the place but the general overall trend is for the real cold to stay to our east with non-descript, Atlantic ridge/Col type weather for Ireland. Hopefully I am wrong but best to remain cautious anyway.

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The ECM 00z is less aggressive with moving the cold west, compared to the 12z. However, it is continuing to trend cold from midweek. The GEFS and UKMO also indicate cold weather from midweek. Sleet/snow showers are likely in parts of the SE and E
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The rollercoaster continues as the GFS 6z shortens the lifespan of any potential countrywide cold spell from 4-5 days to 2-3 days. The east coast will see the coldest conditions from Thursday with 24-48hr incursion of -8c 850hpas westwards.

The Atlantic again proving that it will not be a pushover.

It should be noted that the 00z ECM and 00/06 GFS on Saturuday and Friday all downgraded the runs of the previous day. On that basis, an upgrade is likely in the 12 ECM (due out from around 6pm) and the 12 GEFS (due out from around 3.30pm).

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On that previous point about specifics beyond 72-96hrs, here is a comparison between the 06z on Thursday and the 06z today. Both maps refer to this coming Thursday. Poles apart.


TODAY'S RUN
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THURSDAY'S RUN
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The below GEFS ensembles chart shows that there is considerable divergence in output from Wednesday on.
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The longevity and severity of this potential cold spell is therefore far from certain. It will turn colder for the eastern half of the country at least. Questions still remain over how cold it will get further west. As for saying which parts of Ireland and the UK will be on the front line where cold air meets Atlantic fronts later next week is pure guess work. We may waiting up to 24 hours before the event before we know.

As for the ECM, it looks like the western half of the country will remain much milder than the eastern half. Overall, the ECM downgrades the long term outlook.
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I'm still fairly sure that this week will turn out less cold than the models are showing (still cold enough for some snow though), and that in the longer term we will see the warm-cold battleground shift east over Europe, keeping us on the warrm side. This is something I've been saying for almost two weeks now and I think the stratospheric outlook is hinting that too. There is an attempt at a 100 hPa vortex split at around 1 week but it is shifted well to the east, and translating that down to the troposphere would mean the cold will be shifted well to the east, over eastern Europe, and will stay there. Upstream over North America we should see the pattern redevelop a positive NAO and set things up similar to the way they've been so far this winter. The difference this time will be the large cold pool to our east, which has been lacking so far, so there will always be the chance of tapping into that further down the road (after mid-month).

Below is the 5 day ECMWF 100 hPa forecast, showing a return of the polar trough over Greenland and the northwest Atlantic, with cold over eastern Europe.

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The highest pressure so far this winter was recorded along the Russian-Finnish border this morning, with both Reboly (Russia, 181 m) and Suomussalmi Pesio (Finland, 223 m) recording sea level-corrected pressure of 1061.3 hPa. The chart below shows pressure at 09Z this morning, with the 3 digits representing the final three digits of the pressure (eg. 61.3 = 1061.3 hPa)

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gefs brings cold largely dry days to all but extreme west by Thursday. Atlantic starts making inroads thereafter. fergal, you may not be far off.
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gefs horror show for cold lovers. cold snap over by sat night. would suggest that it has overcooked the rapid progression east of Atlantic front

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UKMO is no better, also taming the Beast from the East

Positive NAO lends support to the latest call from the GEFS/UKMO. ECM rolls out from 6pm

Expect may more ups and downs between now and Tuesday when models will be a little more dependable fro the timescale mentioned above.
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ecmwf also calling for a return to a milder sw/w flow by sat/sun. cold spell at present, according to main models, begins for all but west and south munster on Wednesday and ends Saturday. little if any snow. severe nighttime frosts for many. dry and cool. beats the mild Atlantic muck any day
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Fergal (IWO)
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Yes, start checking the oil levels in your heating tanks as this week could be the coldest of the winter so far. I reckon I'm around €500 up on last year's heating bill so I won'y mind a cold week at this stage! :)
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Not quite as good as it could have been but looking like a taste of winter at least, haven't really looked beyond 96h all week so no big let downs as of yet with proper cold never being shown to push any further than the east coast. With deep cold entrenched over most of Europe February should be far more interesting than January as well.

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Strong negative AO (first attachment) i.e. cold air spillages south continuing

Low positive NAO (second attachment) i.e. Atlantic sw-w flow still packing some punch

End result, East versus West = The Cold War (does a shot even get fired over Ireland?) -scar-ed[

A negative or even neutral NAO would greatly improve the prospects of the cold pushing further west and digging in. Any strengthening of the Russian High coupled with ridging toward eastern canada will increase the prospects of more penetrating cold next week. Models will chop and change between now and Tuesday so keep an eye out for small upgrades and downgrades of cold potential.

As it stands, models indicate that the eastern half of the country will see the coolest temps from Wed into Saturday. After that it is back to the same zonal setup we have had since October.

Meanwhile, the UKMO has the following: "As we go into February there is still considerable uncertainty in the forecast, although at the moment we expect the cold weather to persist with occasional wintry showers near to the east coast and sharp overnight frosts. Although temperatures will be below average, it is not expected to be exceptionally cold. Alternatively by the middle of February we could see a return to milder and more unsettled conditions with showers or longer spells of rain."

Met Eireann, in their 7pm update, stick with very cold conditions for next weekend even though the "computer models say no"
"Any lingering rain will clear to the west early on Tuesday night. It will be a very cold with lowest temperatures of -2 to +2 degrees and a sharp frost and icy patches developing. Wednesday, Thursday and Friday will each be very cold a largely dry days with sunny spells. Temperatures will only range from 3 to 6 degrees by day and will fall as low as -5 degrees in places at night. Winds will be mostly light to moderate and east to southeast in direction. Current indication suggest that next weekend will continue very cold with a risk of wintry showers on east and south coasts."

Damn this model watching rollercoaster.....
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I am not too concerned about how cold any easterly flow will be by the time it reaches Ireland, but I am looking forward to any drier weather it will bring to this side of the country. Although it hasn't made all that much rain over the month whole it seems to be constantly drizzling since the start of the winter and the ground is saturated. Even when it isn't actually raining everything is still dripping. A good, solid week of easterlies should sort this out!

PS, good analysis above guys. Nothing I can add really. The latest ECMWF op run seems to be a bit of an 'outlier' in the FI reaches though the actual ensembles continue to keep the Scandinavian block in place right up to 240hrs which is never a bad thing. Ups and downs on the model front for some time to come me thinks.

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Edited by Patrick (IWO), January 29 2012, 11:16 PM.
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