Your daily forecasts from Boards.ie weather forum (NO CHAT)

Tae laidir · 08-12-2010 7:49pm

Hi MT,
on 3rd December you mentioned the possibility of a 'significant storm' around 20-21 December.
Any updates?

M.T. Cranium · 08-12-2010 7:58pm

Thanks, I find this a very friendly "home base" among four places that I frequent in the weather-internet universe, and you can't beat the Irish weather community for wit, enthusiasm, and (finally) snow !!! :eek:

Well maybe some place near Lake Huron has the upper hand on snow, but they won't have the wit to describe it properly, beyond saying "guess it snowed eh?"

But anyway, remember the law of averages is bound to catch up to old MTC on the long-range in particular, I don't claim those hyper-inflated percentages of accuracy that you sometimes hear in this game. Actually, I don't claim anything, I am just riding the wave and hoping to make it to shore. :cool:

muirsheen · 08-12-2010 8:09pm

Tae laidir wrote: »

Hi MT,
on 3rd December you mentioned the possibility of a 'significant storm' around 20-21 December.
Any updates?

I'd like to know too please

smokin ace · 08-12-2010 8:28pm

yes i would also like to know what way is the winter storm looking now is it still possible or has the possibility faded

DFS UTD · 08-12-2010 9:09pm

Winter Storm?

or

Will we be warm!!

M.T. Cranium · 08-12-2010 9:42pm

The conventional weather models may pick up on trends 10-15 days in advance but details are often very hazy on them because the energy cycle of storms is really confined to 5-10 day periods. This is why as long as the general scenario remains cold in that time period, I have no reason to change my outlook until we get into reliable time frames like 4-6 days, then I can start to fine-tune or even abandon a specific forecast like the winter storm potential for 20-21 Dec.

It remains the case that there's an energy peak available there, cold air in abundance, and the details will sort themselves out as we get closer to the time. The only time that energy peaks fail to deliver some kind of event are those rare occasions when blocking high pressure is right over the region and then the jet stream has to split to get around the block. In this case, the block is shown retreating west rather rapidly to around 30-40 W and the arctic portion of the jet stream will be dropping south (to the west of Ireland) and meeting up with the subtropical portion that takes the southern way around the block. My research model strongly suggests that in a setup like this, with a strong energy peak, you can expect low pressure somewhere just to the south or southwest of Ireland, and possibly a larger area of unsettled (which would have to be snowy) weather over the U.K. and Ireland from upper level low pressure.

Anyway, I don't claim to be psychic, any of these forecasts are based on probability from research, and so I'm basically saying the odds favour a snowy pattern developing around that time. Do you really want more snow? Might be better to recycle what's already there. :cool:

fizzycyst · 08-12-2010 9:50pm

Do you really want more snow? Might be better to recycle what's already there.

oh yes! I want the 1982 type snow that everyone is talking about

M.T. Cranium · 09-12-2010 7:56am

Thursday, 9 December, 2010
______________________________

TODAY ... The gradual thaw sets in ... but will be very slow to impact the deeper snow in central to southeast counties, and inland Ulster ... expect fog to blanket the snow fields in many places with highs of 3-5 C (possibly even lower in valleys) ... further west, a good chance of mild sunshine breaking through low clouds, with highs 8-10 C ... places like Dublin and coastal Wexford could be somewhere in between these extremes with partly cloudy skies and mist, highs of 6-8 C, but around higher parts of Dublin fog could remain fairly thick. Now these boundaries won't be too distinct, if you have snow off to your east a few miles, the fog from there could drift over your way although any organized wind is likely to be more NW'ly near coasts.

TONIGHT ... Trading cold air mass for higher pressure, the overnight lows over the snowy areas could still drop down quite low, to -6 C or lower, but many places will have dense freezing fog and lows near -2 C. A few western coastal areas may stay above freezing in partly cloudy skies. There could also be some patchy drizzle on the Donegal and Mayo coasts.

FRIDAY ... Much the same as today, hazy and mild around the west and south coasts, highs 8-11 C ... foggy inland over snow, some thawing as highs reach 3-5 C there, and partly cloudy, 6-8 C east coast. The wind will slacken near the northwest coasts as high pressure comes almost directly overhead.

SATURDAY ... The overnight conditions about the same as tonight, then another hazy, mild day, possibly with the fog somewhat less extensive as some of the peripheral snow will have melted away ... but some dense fog nevertheless ... highs in a similar range, 8-12 C coastal, 3-6 C central.

SUNDAY ... Now a slight change begins again, with cooler air returning from the southeast, perhaps leading to extensive low cloud and trapping the fog ... expect fairly cold overnight lows of -2 to -7 C followed by chilly highs in the 4-7 C range mostly.

MONDAY-TUESDAY ... Cold with some sunshine, risk of flurries in the southeast, winds E-SE 15-30 mph adding some chill, very cold nights ... lows around -7 to -10 C inland, -3 to -5 C coastal, and highs of about 2-4 C on average but possibly near -1 C over remaining snow.

OUTLOOK ... Models suggest a bit of milder air returning as the high collapses and a northerly flow sets in ahead of much colder air in the far north. So, it may reach 7-8 C again mid-week before plunging back to near freezing late in the week. This would begin to set up the winter wonderland scenario that some hope to see and others would prefer not to see (again).

Drive with extreme caution in foggy areas as there may be a lot of black ice and very reduced visibility.

Today (Wed 8th) here was cloudy with rain returning this afternoon, not too heavy, and quite mild at about 10 C. I mentioned in another thread that London (Ontario) got hammered by snow squalls off Lake Huron in the past two days and reports of 75-150 cms of snow have been verified. There was some wind with this but it seems to have fallen in a level blanket about as high as the average vehicle, so road travel has been greatly reduced in that region. Toronto, meanwhile, only got about 3 cms.

TURRICAN · 09-12-2010 10:25am

150 cms.... Nice

jenningso · 09-12-2010 10:39am

Why do Met Éireann give such a short-term forecast? I mean they never even give an estimation about how the weather will be in a weeks time. So, for example, I hear in the news this morning that Met Éireann are saying that the cold spell is now over and it's back to normal December weather and temperatures from now on. Serious credit to you MT, you should have your own show on RTÉ; would be a massive improvement on their dumbed-down coverage.:rolleyes:

munsterlegend · 09-12-2010 11:00am

jenningso wrote: »

Why do Met Éireann give such a short-term forecast? I mean they never even give an estimation about how the weather will be in a weeks time. So, for example, I hear in the news this morning that Met Éireann are saying that the cold spell is now over and it's back to normal December weather and temperatures from now on. Serious credit to you MT, you should have your own show on RTÉ; would be a massive improvement on their dumbed-down coverage.:rolleyes:

To be fair even to MT nothing is written in stone yet and things can change as even MT would admit. Met Eireann have a duty not to create unnecessary panic unless certain that it will arise which no one can positively say at present.

Bigcheeze · 09-12-2010 11:04am

jenningso wrote: »

Why do Met Éireann give such a short-term forecast? I mean they never even give an estimation about how the weather will be in a weeks time.

Because most people don't have much attention span when listening to the forecast and don't take in subtleties such as probability of something happening a week from now. If they mention the S word, the news spreads around the country that we'll have more of the same weather next week and there'll be no mention that it's maybe a 30-40% chance. When it doesn't happen,Met E get criticised for giving rubbish forecasts. People will be bulk buying in the supermarket at the weekend, farmers taking action, people cancelling events.

Met eireann have to be a responsible when forecasting, they're not just another guy on the internet. I witnessed short term predictions (i.e. in the next few hours) ranging from snowmageddon to non-event change by the hour on here last week. Met E don't have that luxury! They get one maybe two shots per day at communicating the weather to most people.

If they did offer long term forecasts what would the general population do with this information ? Reality is people want to know what it's going to be like for the next few days.

alfalad · 09-12-2010 11:33am

They give a 6 or 7 day forecast on a Sunday, it's called the farming forecast, think it's on around 12 or 1 in the day.

jenningso · 09-12-2010 11:42am

Bigcheeze wrote: »

Because most people don't have much attention span when listening to the forecast and don't take in subtleties such as probability of something happening a week from now. If they mention the S word, the news spreads around the country that we'll have more of the same weather next week and there'll be no mention that it's maybe a 30-40% chance. When it doesn't happen,Met E get criticised for giving rubbish forecasts. People will be bulk buying in the supermarket at the weekend, farmers taking action, people cancelling events.

Met eireann have to be a responsible when forecasting, they're not just another guy on the internet. I witnessed short term predictions (i.e. in the next few hours) ranging from snowmageddon to non-event change by the hour on here last week. Met E don't have that luxury! They get one maybe two shots per day at communicating the weather to most people.

If they did offer long term forecasts what would the general population do with this information ? Reality is people want to know what it's going to be like for the next few days.

Yeah, you do make sense alright. I suppose Met Éireann do have a responsibilty to not create any histeria out there. It's just sad that we're not provided with a little more detail. Except for the Farmer's Weather Forecast once a week, the level of detail is quite low. But, as you say, most people only really want to know what's happening over a three day timeline. Although, maybe this is the reason why everybody is so 'shocked' when the weather does turn bad; i.e. Met Éireann said it was back to normal weather, how come it's snowing again? (will we hear this next week?)

Anyway, I'm glad to have a forecasting resource such as this thread. Keeps ME in the know at least!!:cool:

eoinbergin · 09-12-2010 11:58am

hey guys that winter storm that MT is talking about looks like its on the card as there is storm force winds coming down from Scandinavia from next thursday

little bess · 09-12-2010 12:08pm

From The Independent :

"We expect the severe cold of Wednesday to be the last," said forecaster Gerard Fleming.

"We're confident the weather will get less cold from Thursday to Sunday. Daytime temperatures will reach 6C to 8C, and it should be 1C or 2C at night. This less cold weather will last into Monday and Tuesday, then it's back to standard winter weather. We don't expect snow in the coming days."

Back to standard winter weather

Not according to reports on here !

Joe Public · 09-12-2010 1:05pm

The only thing standard about weather is the science used to understand and measure it.
Forecasters can only stand over four or five day forecasts and even at that there can be surprises.
Keep an eye on the "big freeze bites back...." thread where a lot of the longer range forecasting is happening.

ongarboy · 09-12-2010 2:41pm

little bess wrote: »

From The Independent :

"We expect the severe cold of Wednesday to be the last," said forecaster Gerard Fleming.
"We're confident the weather will get less cold from Thursday to Sunday. Daytime temperatures will reach 6C to 8C, and it should be 1C or 2C at night. This less cold weather will last into Monday and Tuesday, then it's back to standard winter weather. We don't expect snow in the coming days."

Back to standard winter weather Not according to reports on here !

Gerald Fleming said on Monday that the heavy snow front that came down across the country that day from the north west would not generate snow in Dublin...we got 4 hours and about 2 inches of it in west Dublin! I would take what he says regarding 6-7 days time with a pinch of salt. This is not a criticism of Met Eireann's forecasting ability as I acknowledge long range forecasting is notoriously difficult for Ireland and snow is often a nowcast event however MT Cranium has had the most precise long range forecasts for these winter events and has not been wrong once as far as I can see so I am paying closer attention to his forecasts

Welsh Wizard · 09-12-2010 3:23pm

Folks this is a forecasting thread.
Open a new thread if there isn't already one..

The weather section on here has become very busy recently so all efforts are needed to keep each thread bound to the headline of each thread.

I for one find the weather section on here fascinating and credit to all that go out there way to give us their expert advice.

Thanks

M.T. Cranium · 10-12-2010 7:17am

Friday, 10 December, 2010
____________________________

TODAY ... Cloudy and mild with drizzle, mist and some fog, thicker over any snow well inland. Some sunny breaks possible in the southwest and south. Light winds. Highs reaching 7-11 C except closer to 4-6 C over inland snow where fog may remain rather persistent.

TONIGHT ... Misty or foggy and rather mild, except where any clear patches develop over the snow, then fog may become freezing fog with lows near -2 C, but for most other districts, lows 3-6 C. Calm winds.

SATURDAY ... Hazy and mild, fog tending to disperse slowly inland, slow thaw continuing for the deeper snow ... highs 8-12 C in general, possibly as low as about 5-7 C over snow.

SUNDAY ... Cloudy with some brighter intervals, drizzle near south and east facing coasts, some fog inland, winds picking up to SE 10-20 mph, cooler feeling with highs about 6-9 C.

MONDAY ... Cloudy with sunny intervals, rather cold again, with milder air moving off the west coast in a SE flow, highs 4-7 C generally but 7-10 C west.

TUESDAY ... Partly cloudy, cold, flurries may develop in east, as winds start to come in from an easterly direction, highs near 5 C.

WEDNESDAY-THURSDAY ... Staying moderately mild but winds increasing from the north to 20-30 mph, passing showers turning to flurries over higher ground, highs near 6 C.

LATE THURSDAY or FRIDAY, another cold spell is likely to develop on very gusty northerly winds, and rapidly falling temperatures, with snow returning to the picture ... we'll wait until closer to the time to speculate about how much, where and when, but at first it's likely to be the northern half of the country seeing more conducive conditions, then later all over the country in play for snow as a stormy period may develop (this about 19-22 Dec).

Temperatures during this cold spell may well be about as cold as what we've just seen, as the air coming out of the arctic will have quite a cold start, but we will have to bear in mind a fairly long sea passage at least for a while, before possibly seeing more of a home-grown chill from air masses over Britain and Ireland with snow cover.

Meanwhile, here today (Thurs 9th) it was cloudy and mild with showers, but a cooler air mass is developing with gradual clearing here at present. A snowstorm is developing in stages for the Great Lakes region -- this will be fairly widespread over the weekend, not just local snow squalls as they had in a few parts earlier this week. The east coast will get slightly milder with this shift in storm track.

Please note, arrangements are underway to lock this thread but comments and questions can be placed in a parallel "comments" thread that will open. For the time being, please direct comments, observations etc to the appropriate threads as readers of the forecasts are having trouble finding them in all the other posts. Thanks very much -- MTC

tbh · 10-12-2010 11:22am

off-topic posts deleted. I appreciate a bit of banter as much as the next man, but on these threads it annoys a lot of people - so try to resist the urge, thanks

M.T. Cranium · 11-12-2010 5:42am

Saturday, 11 December, 2010
_____________________________

TODAY ... The thaw continues ... mild and hazy with some brief sunny intervals possible for west and south coast, but most places under a rather low overcast with fog somewhat thicker over some central counties, especially hilly areas ... snow should continue to melt slowly where deepest, as highs reach 6-8 C over snow and 9-12 C elsewhere.

TONIGHT ... Partly cloudy with extensive mist or fog, but somewhat colder again after midnight, lows -2 to +4 C, some patchy freezing fog and ice on outlying roads.

SUNDAY ... Partly cloudy, not quite as mild, winds SE 10-20 mph, some patchy drizzle in south and east, highs 6-8 C.

MONDAY ... Sunny intervals, but some low cloud near south and east coasts, cooler ... lows -4 to -1 C and highs 4-7 C. Winds E-SE 15-25 mph.

TUESDAY and WEDNESDAY ... Partly cloudy, cold, some flurries or wintry showers developing near southeast coast, winds E-NE 15-25 mph. Lows near -5 C and highs in the range of 3 to 6 C.

THURSDAY ... Becoming windy, passing mixed wintry showers in a moderate to strong NE to N wind, lows near -2 C and highs near 6 C (possibly a bit milder in west but feeling quite cold in the strong winds).

Then winter bites back, as they say ...

FRIDAY ... Windy and cold with scattered snow flurries or heavier squalls, in strong northerly winds, temperatures steady near -1 C on average (some inland counties colder).

WEEKEND 18th-19th ... Likely to be very cold with further snow, possibly significant amounts, temperatures in the range of -6 to -1 C for most.

OUTLOOK ... This cold spell will probably dig in and stay for a while, whatever the models may show at this early stage ... which makes a white Christmas rather likely. There may indeed be a long spell of severe wintry weather.

WEATHER FOR MY LOCATION ... Cloudy and mild with highs of about 8 C, mostly dry, just spits of rain this evening (Friday 10th that is). Great Lakes and Midwest U.S. gearing up for mixed precip turning to heavy snow over the weekend and into Monday. Turning milder on the east coast where it has been chilly, highs may reach 10-15 C by Sunday there.

I may be away from the forum all day Saturday due to a combination of computer troubles and plans for the day ... hoping to update this forecast at the usual time Sunday morning.

M.T. Cranium · 12-12-2010 7:04am

Sunday, 12 December, 2010
____________________________

Winter is making a comeback, in stages. At first, it will be a trend to colder nights and longer morning frosts. But by Thursday, a more severe arctic chill will descend from up around the polar regions between Greenland and Norway. Snow is likely to accompany this much colder air mass.

TODAY ... cloudy with some hazy sunshine, although far southwest could see showers from a weak trough ... fog lingering over remaining snow in southeast and east central to north central counties ... highs generally 5-8 C.

TONIGHT ... clear intervals, quite cold again, freezing fog becoming widespread inland ... lows -6 to -3 C.

MONDAY ... cloudy with some sunny intervals, although fog may linger most of the day in the usual places ... highs only 3 to 6 C.

TUESDAY ... partly cloudy, cold, possible brief flurries near east coast, as winds become more E to NE at 10-15 mph. Lows near -6 C and highs near 3 or 4 C. Fog may linger most of the day in some inland areas.

WEDNESDAY ... mostly cloudy, drizzle or sleet at times in moderate NE winds, 15-25 mph ... cold ... lows near -4 C and highs near 4 C.

THURSDAY ... windy and turning much colder, any showers quickly turning to hail then snow flurries or squalls, some accumulations inland north ... winds becoming N 30-50 mph ... temperatures steady near 2 C then falling below freezing.

FRIDAY ... windy and very cold, intervals of snow likely, winds northerly at about 30-50 mph may become more NE'ly, lows near -5 C and highs near -1 C in most areas, some snow accumulations likely.

WEEKEND ... expect it to remain very cold with additional snow in some areas. As we get closer to this time, I will post some estimates on snowfall amounts, for now, I would say prepare for possibly scattered 5-10 cm amounts mainly in the north and east. But this could change.

The cold spell could continue to Christmas, and possibly beyond, as a large-scale blocking pattern is setting up over the Atlantic.

Meanwhile, (back at the ranch) in western Canada, we have had a cloudy, mild and increasingly wet day as a strong wave is moving in from the Pacific, about 7 C at 10 p.m. here now, and expecting 12-15 C locally on Sunday as we get into a warm sector briefly. There is a major winter storm brewing over the western Great Lakes that has drawn up somewhat milder air on the east coast, but threatens to drop 15-30 cms of snow across parts of the Great Lakes region tomorrow, with freezing rain in places too. :eek:

Lots of other opinions on the cold spell can be found in the discussion threads. Let's hope it won't be too bad, but would plan around some disruption if you can ... it may become difficult to travel in some places again by Thursday or so.

M.T. Cranium · 13-12-2010 7:18am

Monday, 13 December, 2010
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TODAY ... Widespread low cloud and fog with some sunny intervals around mid-day ... rather chilly inland and in north, still rather mild near south coast and in parts of the west, but with light winds in all areas ... highs near 4 C inland and north, to 8 C south and west coasts, about 7 C in Dublin. A few light showers near the Kerry coast.

TONIGHT ... Clear intervals, very cold inland, fog and frost forming, some icy roads ... lows -5 to -2 C on average, some coastal locations +2 C.

TUESDAY ... Sunny with some lingering fog or low cloud, cool ... highs generally about 4-6 C, could stay colder in a few central locations, light winds for most with a slight easterly component. A passing flurry is possible in the southeast, nothing very substantial.

WEDNESDAY ... Partly cloudy, winds becoming NE 10-20 mph, some coastal fog or drizzle near east coast, lows in -5 to -2 C range, highs 4-7 C.

THURSDAY ... Windy and turning much colder, quite early in the day in the north, mid-day in the south. Any showers in the morning (mostly south) would change rapidly to flurries or snow squalls. Heavy snow at times in parts of Ulster and Connacht, with mixed wintry showers near west coast, as winds rise to NNW 30-50 mph. Temperatures may be slightly above freezing for the morning, then will fall to about -2 or -3 C in many areas by afternoon.

FRIDAY ... Very cold, strong winds diminishing slowly from NNW 40 mph to about 20 mph, snow streamers likely in many parts of the north, some wintry sunshine further south and temperatures in the range of -5 to -1 C from morning to afternoon. Snow accumulations of 3-7 cms likely (from Thursday on) in parts of Ulster and inland Connacht.

WEEKEND ... Very cold, local snow streamers possible almost anywhere within 25-50 kms of the coasts, as winds respond to various weak pressure systems embedded in a large upper level disturbance. Showers may become mixed at times near coasts but snow accumulations are possible almost anywhere, especially a short distance inland and on higher ground. Also some sunshine in the mix, and overnight lows of -10 C to -5 C while daytime highs remain in the range of -3 to +2 C. Severe frost, local freezing fog, icy roads in some areas. Conditions appear likely to be locally severe but quite variable place to place. We will of course be refining all this as we get closer, but basically it looks like a case of many local scale weather events in a generally cold pattern.

OUTLOOK ... I am growing more confident that this cold will dig in and stay, with any effort to return mild air likely to lead to snowfalls that could even be heavy at times and may not avoid the south as the storm track seems likely to be south of Ireland into northern France by early next week. A snowstorm is quite possible at any time from about Sunday 19th to Wednesday 22nd. No guarantee is possible at this stage. Longer range model output is now leaning more towards continued cold, only very weak warming if any at all, and even the prospect of a renewed push of bitterly cold air from either the far north or Scandinavia and before that Siberia, later in the month (between Christmas and New Years).

Much, much more will be available in the discussion threads, including some expanded commentary from me. I can't stress enough the uncertainty but also the potential for severe disruption in this pattern, which is really quite remarkable to behold on the charts in terms of how much of the North Atlantic is soon to be covered in cold, arctic air with a generally northeast flow pattern over much of the ocean and surrounding land masses.

Meanwhile, it has to be mild somewhere, and that somewhere is right here. We had a high of 12 C, fog, a few breaks to reveal the sun, and earlier quite a bit of rain. It has now become very foggy but it's still 8 degrees at 10 p.m. here. A winter storm is pushing through the Great Lakes region, and it has turned briefly mild in the northeast U.S. -- that won't last very long as arctic air moves back in, and the mild air heads up towards northern Quebec and Baffin Island. This is all related to the development of the Greenland high.

More when I can make it up. :cool:

M.T. Cranium · 14-12-2010 8:10am

Tuesday, 0700 ... forecast is coming, no major changes from the previous.

M.T. Cranium · 14-12-2010 8:26am

Tuesday, 14 December, 2010
_______________________________

TODAY ... Cloudy with some lingering fog, possibly a few sunny breaks later, and temperatures about the same as yesterday for most regions, highs in the range of 5 to 8 C. Light winds with a slight easterly component.

TONIGHT ... Some clearing but still quite cloudy on average, cold, lows in the range of -2 to +2 C, extensive mist and some fog, icy roads.

WEDNESDAY ... Partly cloudy, a bit milder as the air mixes more in a northwest breeze backing to west later, some drizzle possible in the north towards late afternoon. Highs reaching 7-10 C west, 4-7 C east and southeast. Winds increasing somewhat to 20-25 mph at times by late in the day.

WEDNESDAY NIGHT ... Cloudy, outbreaks of light rain in a moderate westerly wind, some wet snow on higher terrain, lows generally 2-3 C, could stay near 5 C in coastal Connacht and north Ulster.

THURSDAY ... Becoming windy during the morning, mild in the south until mid-day (highs 7-10 C), turning much colder in the north about sunrise to mid-morning, sleet turning to snow or hail, some accumulations in Ulster and inland Connacht. Rain showers on the west coast turning to hail. Very strong NW winds developing, 40-60 mph. The east and south will see the early mildness come to a sudden end with squally showers turning to sleet, hail and then snow, before some clearing sets in. Temperatures will remain steady near 2 C for a while, then drop to -2 C late in the day. Wind chills near -10 C at that point, with squally snow showers possible but more likely in Ulster and Connacht with 3-7 cms accumulating in places by midnight.

FRIDAY ... Overnight squalls of hail and snow in gusty winds, some further accumulations, then some cold wintry sunshine in the south and east while the squally weather continues in the north and west. The strongest winds will be in the early morning hours but it will stay windy most of the day near the north and west coasts, winds becoming more moderate (W-NW) in the east and south. Very cold in most places, highs struggling to reach even the freezing point and possibly -2 C inland over snow.

FRIDAY NIGHT to SUNDAY NIGHT ... Overnight temperatures on the weekend could drop very low if any clearing persists, with potential for readings of about -12 C in some inland northern and central locations. Probably closer to -4 C on average around coastal regions, as winds rapidly drop off then become somewhat easterly on average. Days will feature some outbreaks of snow, and some sunny intervals, with very cold conditions. At any point there could be some moderate or even heavy snow in streamers coming inland from the south or east, but snow is possible near the other coasts as well, as winds rotate around low pressure that may be right over Ireland at times. Much more specific snowfall forecasts can be made closer to the time, but for now, would say expect an average of 5 cms and potential for 10-20, with some sleet and coastal rain in the mix due to somewhat marginal temperatures (highs will generally be -2 to +1 C, could be lower in a few spots, and higher in a few coastal locations, so you can see there is some risk of mixing to rain and in the usual places, you know your own location's tendencies). We'll have to keep a very close eye on developments with the potential for snowstorm or even local blizzard conditions given these patterns of slow-moving low pressure nearby.

OUTLOOK ... Not much change, as cold air remains in the general vicinity, and further outbreaks of snow quite possible, with temperatures staying near or below freezing with potential for very cold nights wherever it clears. Any organized milder trend may have to wait quite a while whatever the models may depict today, we can't totally trust these warming indications given the past history. And the large-scale pattern favours renewed cold outbreaks at frequent intervals even if one or two days do turn a bit milder.

Here, we have continued to see mild weather on Monday (13th) with a high of about 11 C, and only a few spits of rain this evening. It has become very cold and windy across most of the east except in Atlantic Canada where it was mild and rainy.

More updates may follow, and please check in with the discussion threads for all the latest opinions of the weather forum crew.

Wine Goddess · 14-12-2010 4:52pm

Thanks so much again we really appreciate it.
BTW can someone tell me how to just say thanks as part of the list rather than posting a reply? I did look for it in the newbie section but could not find....thanks so much (know it's off=topic sorry):(

smashey · 14-12-2010 4:58pm

Wine Goddess wrote: »

Thanks so much again we really appreciate it.
BTW can someone tell me how to just say thanks as part of the list rather than posting a reply? I did look for it in the newbie section but could not find....thanks so much (know it's off=topic sorry):(

Click on the little thumbs up icon

at the bottom right hand corner of a post

skipz · 14-12-2010 5:05pm

Wine Goddess wrote: »

Thanks so much again we really appreciate it.
BTW can someone tell me how to just say thanks as part of the list rather than posting a reply? I did look for it in the newbie section but could not find....thanks so much (know it's off=topic sorry):(

Press the thumbs up icon at the bottem right hand corner or the post.

Steve · 14-12-2010 5:08pm

smashey wrote: »

Click on the little thumbs up icon at the bottom right hand corner of a post

skipz wrote: »

Press the thumbs up icon at the bottem right hand corner or the post.

The thanks feature isn't enabled until you've made 10 posts - 2 more to go.

smashey · 14-12-2010 5:23pm

Steve wrote: »

The thanks feature isn't enabled until you've made 10 posts - 2 more to go.

Ah ffs.

I give up.

M.T. Cranium · 14-12-2010 6:19pm

UPDATE _ Tuesday, 1700h
_______________________

The main thing to focus on at this point is the rapid onset of the cold spell and the sudden nature (not the sodden nature) of the frontal passage on Thursday. This is likely to set off some very squally mixed showers turning rapidly from rain to hail then sleet and snow as it moves south at a very fast pace. I will make an effort to time that for readers on Wednesday afternoon or evening, but at present, it looks like this front will hit Ulster between 0600 north to 0900 south, then should move through Connacht and north Leinster between 0900 and noon, and be clearing the south coast around 1500h.

If you have travel plans that place you and this front in the same place at the same time, expect some slow going or perhaps the need for a well-timed meal break while it blows through. The further north you are, the more likely it will be that instead of just blowing through and clearing afterwards, the front will be followed fairly quickly by further snow (except along the immediate west coast, everything behind this front should be snow or hail).

There are some good snowfall estimate maps on the discussion thread now, showing potential for 10-20 cms in some parts of the northwest into Ulster, from Thursday to Friday. This would be in advance of any more widespread snow that could develop with low pressure systems circling around on the weekend into Monday. I don't want to be too specific yet on that period as the details will be all-important, but could say that the current maps show potential for several inches of snow in many areas over that later time period.

I've noticed an expected tendency for the longer-term maps now available to begin a delaying process for any potential warming trends mid-week. I guess it's almost inevitable that one or two days between the weekend and New Years will be milder than most, although there is some chance of a complete "locking in" of a cold northeast flow pattern too.

The thing everyone should keep in mind here, I would conclude, is that even today's relatively reliable weather models are being challenged here by the very large-scale changes underway, bringing the polar vortex which usually stays up around Svalbard or Greenland, right down across Britain and Ireland by Friday night. Analogues for this are scarce, so the models are working off a very limited data base in terms of modelling how the atmosphere will respond with this frigid air spilling out over the 10-12 deg North Atlantic where storms will then develop along a boundary. Just slight changes in the track or intensity of those features still 4-6 days away, would mean large differences in snowfall forecasts for any part of Ireland or the U.K. ... but in the more general sense, I think we can say that snow is likely on a fairly widespread basis given this pattern development. The fact that my research energy peak for 20-21 December is right in that time frame has me concerned that a major snowfall event is very possible, and of course it could begin as soon as the event starts to take shape rather than waiting until those dates.

M.T. Cranium · 15-12-2010 7:53am

Wednesday, 15 December, 2010
_________________________________

Advance ALERT ... Rapid freeze likely on Thursday morning in north, by afternoon in south; rain showers will turn to sleet, hail and then snow in many places with a sharp drop in temperatures. Roads and pavements will become icy and in some northern counties, also snow-covered, in a matter of an hour or less, leading to dangerous travel conditions. See forecasts for more details on that. Also, 5-15 cms of snow possible in west and north on Thursday and Friday. Further significant snowfalls more widely over the weekend. Details in forecasts.

TODAY ... The calm before the storm, with partly to mostly cloudy skies, slowly strengthening WNW winds at 15-25 mph, and eventually, a few light showers mainly northwest of the Midlands. Rather mild again, with highs in the range of 7-10 C (mildest in coastal Connacht and west Munster).

TONIGHT ... For all but the far north, a mild and cloudy night with periods of rain, not likely to be very heavy (2-4 mms), moderate westerly winds at 20-30 mph, and lows of about 3-5 C. In the far north, these conditions will suddenly change to cold, windy and squally as rain changes to hail and snow. This change will be felt throughout Ulster by about sunrise.

THURSDAY ... The main feature of the day's weather will be a sudden change to much colder, wintry weather. The timing of that change will vary from morning in the mid-north, to late afternoon in the south coastal counties. Before the change, it will continue mild, breezy and showery with temperatures steady 5-8 C. The changeover will involve squally showers, some thunder, turning quickly to hail, sleet and then snow, with roads becoming very icy. Temperatures will fall to -3 C in the north and -1 C in the south. Winds will increase to NW 30-50 mph (gusts to 60 near west, north coasts). Snow may break out over large parts of Connacht and Ulster, spreading at times to West Munster, inland Leinster, with flurries further south and east. The heavier snow could accumulate to 5-10 cms by Thursday night.

THURSDAY NIGHT ... Very cold and windy with temperatures falling to a range of -6 to -3 C inland and east, and near zero C west coast, -2 C south coast. Widespread snow and icy roads, 3-7 cms of snow in all but a few coastal districts where sleety hail or rain showers may mix in. Winds continuing strong, NW 30-50 mph with some higher gusts. Some thunder-snow especially around Mayo, Donegal, Galway, Clare nearby parts of other counties.

FRIDAY ... Windy and very cold, with passing flurries or heavier snow squalls, mixing near west coast at times with hail and sleet. Winds WNW 30-50 mph except NNW 30-50 mph in eastern Ulster. Highs only -2 to +2 C (except possibly 4-5 C in coastal Kerry). Some further snow accumulations mainly north and west to 10 cms, but some snow possible further east and south. Risk of thunder-snow, icy roads widespread, also intervals of blinding sun between showers combining with bright surfaces at this low-sun time of year can be a real hazard.

SATURDAY ... The early morning may be bitterly cold due to some clearing and much lighter winds, but coastal Ulster may see heavy snow, and west coast may see mixed wintry showers. Lows inland, east and south in the range of -4 to -10 C. Around the coasts especially west and north, lows about -2 C. ... During the day, outbreaks of heavy snow, mixing near sea level with sleet, inland accumulations of 5-10 cms likely, winds generally from a westerly direction across the south and from the north or east elsewhere. Highs -3 to +1 C for most.

SUNDAY ... Risk of some moderate or heavy snow with greater accumulations inland from south coast, on higher ground especially, and through the inland southeast, on the east coast and in parts of Ulster (10-15 cms potential in these zones) ... more showery in Connacht, snow amounts 2-5 cms. Very cold with lows near -5 C or lower in some areas, although -2 C south coast, and highs in range -2 to +1 C.

MONDAY ... Further snow likely, 5-15 cms in some areas, may mix with sleet near coasts. Winds becoming rather strong northeast, heavy streamers for Dublin and Wicklow may develop. Very cold with lows near -5 C and highs near -1 C.

TUESDAY ... Snow may end gradually with some wintry sunshine especially in north. Lows -6 C on average, could reach -12 C in parts of Ulster ... highs around -3 C inland to +2 C coasts.

WEDNESDAY ... Wintry sunshine at times, very cold. The morning lows here may be the coldest of this spell (-15 to -10 C potential inland). Highs may not reach freezing in many areas.

OUTLOOK ... Some chance of another wintry storm by Thursday 23rd into Friday 24th (Christmas Eve). A lower chance that this may turn to a milder rain event. Continuing to assess this, models seem challenged at this range. Would count on further cold and snow in the weeks to follow.

Meanwhile, over here, the day on Tuesday was showery and a bit cooler, with sleet mixing in at times, temps 5-6 C. There was a massive lake effect snowstorm west of London, Ontario from Lake Huron that dumped incredible amounts (100-150 cms) in narrow bands. This is slowly dying out now. But those snowfalls are quite limited and many areas have had cold, dry weather in the east today.

Updates will be posted here rather than in discussion threads first. So if you're looking for updates, they will appear here first.

jarvis · 15-12-2010 9:50am

Silly uestion here MT but Shen you mention daily accumulations are the adding up or are they accumulations for those particular day which you think may fall and rest on top of an earlier accumulation???
Thanks.

squonk · 15-12-2010 11:34am

Don't want to drag the thread OT but in fairness, I'm sure if each of us wrote down our fantasy winter spell it'd probably not be far off MT's forecast this morning! I'm starting to get really excited about this!

Tom Cruises Left Nut · 15-12-2010 11:39am

Hi All

Can we direct any questions / comments to the regional / national forecasting thread.

MT is doing a great job here but this thread is for his forecasts only.

Cheers

cabot · 15-12-2010 12:59pm

There isnt a regional thread for all of us, I'm in the UK.

Speak Now · 15-12-2010 1:33pm

cabot wrote: »

There isnt a regional thread for all of us, I'm in the UK.

But it's a weather forecast for ireland

cabot · 15-12-2010 1:36pm

Some of the forecasts have mentioned the UK too, plus we ARE going to get snow!

Tom Cruises Left Nut · 15-12-2010 1:44pm

t|nt|n wrote: »

Hi All

Can we direct any questions / comments to the regional / national forecasting thread.

MT is doing a great job here but this thread is for his forecasts only.

Cheers

All

Not wanting to sound moany here but can we please just stop any discussion in this thread from this point on.

Lets leave this for MT to post his forecasts and updates and discuss any other issues in the other threads that WC opened.

If you want to discuss any of MTs posts I suggest you quote them in the relevant thread and go from there.

It is going to get very busy here from tonight on so lets keep everything in its right place !

Cheers

M.T. Cranium · 15-12-2010 8:23pm

May update around 9 to 10 p.m. but forecasts seem to be generally on track.

Re the UK forecasts, if by that you happen to mean any part of Northern Ireland, my approach is to include the six counties within the forecasts as a general rule. Otherwise, would refer interested parties to such sources as

http://metoffice.gov.uk

http://net-weather.co.uk

and a smaller UK forum where I issue some of the daily forecasts and alerts,
Weatherchat Plus

http://s2.excoboard.com/Weatherchatplus

As I think is widely known in the Irish weather community, while M.T. Cranium is a very apt name for one with this much space between the ears, I have such meat world names as Peter O'Donnell (my birth name) and Roger (J) Smith (my assumed name) and in Canada I am sometimes known as Amazing Negative Stereotype Man, the first citizen to acquire every possible negative stereotype and therefore win an award as First to Walk to the North Pole.

If you happen to go for a look-see at Weatherchat Plus, that's a fairly small membership forum but we do have about four members from Ireland there, and the bulk of the membership is Midlands-based as the forum was started by folks from that part of England (where coincidentally I was born before being tossed on a boat to Canada as a mere infant).

As boards members have been extraordinarily kind to this citizen of no particular country, I tend to identify more and more as a cyber-resident of Ireland even if physically far removed, and indeed when I read accounts of being a "Canadian" I think that notion has been disproved on almost a daily basis over half a century, a fact now pretty much confined to my passport. Quite true the saying that no prophet is without honour except in his own country. :cool:

sdanseo · 15-12-2010 8:30pm

M.T. Cranium wrote: »

I tend to identify more and more as a cyber-resident of Ireland even if physically far removed, and indeed when I read accounts of being a "Canadian" I think that notion has been disproved on almost a daily basis over half a century, a fact now pretty much confined to my passport. Quite true the saying that no prophet is without honour except in his own country. :cool:

Well if you didn't have an Irish passport, I reckon you'd get an honorary citizenship for services to meteorology!

As it stands, you have one, you're stuck being Irish whether you like it or not!

M.T. Cranium · 15-12-2010 9:19pm

Forecast update ... Wed 15 Dec 2010 ... 8 p.m.
_______________________________________________

In general, the morning forecast remains valid, but I am updating more to emphasize that some of the potential events now appear more likely to verify near top of ranges suggested.

TONIGHT ... Cloudy and relatively mild with scattered outbreaks of light rain mostly after midnight, winds picking up gradually from a westerly direction to reach 20-30 mph, temperatures steady 2-4 C for most. Late tonight, turning very windy and much colder in north coast Ulster, with hail and snow showers spreading rapidly south to cover most of Ulster by sunrise, and some parts of north Connacht and north Leinster by 0800h. Snowfalls in this zone only 3-7 cms. Temperatures falling to -3 C inland, +1 C near coasts, in the north only.

THURSDAY ... Very windy and turning much colder from north to south. The milder air will remain in place for the morning in central counties and to mid-afternoon in the south. In all areas, a rapid change to much colder weather as winds shift from W 25-40 mph to NW 30-50 mph with higher gusts in Connacht. Earlier rain showers will change to hail, sleet and snow in a squally fashion with some thunder and lightning. Earlier snow in the north may intensify to heavy snow at times giving 10-15 cms locally there, while further south amounts will average 1-3 cms and a few spots may escape snow but nowhere is likely to escape icy roads by evening.

THURSDAY NIGHT, FRIDAY ... Continuing windy and very cold with frequent squally showers of hail and snow, considerable accumulations possible but mostly in Ulster and Connacht, west Munster, parts of north, west Leinster where amounts will average 5-10 cms and reach 15 cms locally. Highs for the day only -3 to -1 C in north (inland) and 2-4 C in southwest, 0-2 C in southeast and east. Some intervals of bright sun will also be hazardous because of glare off snow and ice at low sun angles. Roads becoming very treacherous in many counties but with highly variable conditions too, travel with care if you can't avoid travel.

WEEKEND ... Bitterly cold to start with some clearing late Friday night and lows generally -7 to -4 C but as low as -10 C in any northern valley locations under clear spots in the general overcast. Ice fog likely over central counties. Then snow likely to spread in or break out locally, heavier in the northeast at first, then becoming rather heavy in many areas, local accumulations of 5-15 cms both days, potential for near-blizzard or blizzard conditions with Dublin possibly near the higher snowfall zone that is likely to extend from about Meath to Laois and Tipps, but should emphasize that heavy snow could develop quite widely outside that zone too. Maximum snow accumulations could reach 20-30 cms. Some thunder-snow likely. Winds will increase at times to NE 20-40 mph blowing this snow around, in temperatures in the range of -2 to +1 C (could stay colder than that in parts of Ulster and inland Connacht).

MONDAY ... The above snowstorm to blizzard conditions may continue or may ease slowly, but in any case, there will be a lot of snow on the ground and temperatures near -1 C with potentially strong E to NE winds at times.

TUESDAY to THURSDAY ... Some snow could continue in the south, and flurries or freezing drizzle will keep roads icy in many areas, but this could be a somewhat drier period with breaks in the overcast and very cold temperatures at night as a result, lows may fall to -8 C or lower, highs will remain in the range of -2 to +2 C.

OUTLOOK ... I tend to discount any suggested warmings but there is a chance of milder weather around Christmas, however, I think there is an equal chance of a further period of snow with the mild air held back to the southwest.

For those with an interest in weather in the U.K. or northern France for their travel plans, it seems quite possible that the snow in Ireland will break out over large parts of the U.K. as well, and may extend at times into northern France. Parts of central England are likely to see the worst of the snow there, 20-40 cms potential. Eastern Scotland may see some snow, but central Scotland and northern England could see bitterly cold overnight lows during the period, as low as -20 C in some places, but generally -10 C or lower.

Further updates as required ...

M.T. Cranium · 15-12-2010 10:49pm

UPDATE to yesterday's posted regional snowfall predictions:

issued 2145h Dec 15th, 2010 -- amounts in cms -- expected regional averages -- more may fall on higher ground in each region, less near shores and urban centres.

REGION .............. THURS .... FRI ..... SAT ..... SUN ..... MON
____________________________________________________

Ulster ..................... 08 ...... 07 ...... 10 ..... 10 ...... 03

Connacht ................ 05 ...... 10 ...... 05 ..... 05 ...... 02

West Munster, Clare .. 03 ..... 03 ...... 07 ..... 12 ...... 10

East Munster ............ 01 ..... 02 ...... 10 ..... 10 ...... 08

inland southeast ....... 02 ..... 03 ...... 12 ..... 18 ...... 10

Dublin/Wicklow/Meath. 01 ..... 02 ...... 15 ..... 15 ...... 10

rest of Leinster ........ 03 ..... 04 ...... 12 ..... 12 ...... 07

Notes
_______

Snow Thursday-Friday mostly in passing squally snow showers that may merge into longer periods of snow in counties such as Mayo, Roscommon, Sligo, Donegal, Derry, Tyrone, Fermanagh, parts of Galway and Clare, and that may apply to adjacent parts of other counties at times

Snow Saturday-Monday mostly from organized areas of snow that may sweep in from east or northeast, heavy bands likely from about Meath southwest to Laois and Tipps, also in Dublin, Wicklow, Wexford, Waterford, Carlow, Kilkenny, Kildare, but this could spread further north and west in other bands crossing Ulster and moving southwest.

If you got heavy snow in the last round, you'll probably get heavy snow in this round, but, if you escaped snow in the last round, you may get at least some snow in this round, and parts of Mayo to Fermanagh could start off this round with heavy snow.

MilanPan!c · 16-12-2010 12:38am

Those totals are in inches I hope

Irish Steve · 16-12-2010 1:53am

M.T. Cranium wrote: »

UPDATE to yesterday's posted regional snowfall predictions:

issued 2145h Dec 15th, 2010 -- amounts in cms -- expected regional averages -- more may fall on higher ground in each region, less near shores and urban centres.

Hope that makes it clear

M.T. Cranium · 16-12-2010 8:14am

Thursday, 16 December, 2010
________________________________

ALERT for snow and blowing snow in northern, northwestern and some western counties today, with some local accumulations of 10-15 cms. ALERT for icy roads developing from north to south after a frontal passage (see forecasts for timing). ADVANCE ALERT for further snow, icy roads, bitterly cold temperatures Friday to Monday and possibly beyond.

Brief situational update -- all guidance continues much as yesterday, with some range between models, requiring a blend and some intuition to come up with your forecast, but of more immediate interest, a small "polar low" may be forming upstream south of Iceland heading for Connacht and Donegal later, and this may necessitate a slight upgrade of snow potential -- will be tracking this closely. Meanwhile, the arctic front is about to sweep through Ulster, and I'm expecting it to reach Dublin to Galway by 1230 to 1300h, then about Shannon to Waterford about 1500h, finally Cork about 1630h. Winds will veer to NW before this front arrives, as there is a pre-frontal trough. But temperatures only drop after the main front goes past, and based on reports from northern Scotland, they drop very quickly to below freezing. Thus the urgency of the alert for icy roads and sudden reductions in visibility due to heavy snow.

TODAY ... Very windy and turning much colder from north to south. The milder air will remain in place for the morning in central counties and to mid-afternoon in the south. In all areas, a rapid change to much colder weather as winds shift from W 25-45 mph to NW 35-55 mph with higher gusts possible especially in Connacht. Morning rain showers will change to hail, sleet and snow in a squally fashion with some thunder and lightning. In the north morning sleet or hail may intensify to heavy snow at times giving 10-15 cms locally there, while further south amounts will average 1-3 cms and a few spots may escape snow but nowhere is likely to escape icy roads by evening. A few sunny breaks may develop behind the front in the south and east but passing flurries may suddenly reduce visibility even there. Finally, an interval of heavier snow may develop in the northwest towards evening.

Morning to mid-day highs of 8-10 C will contrast sharply with later temperatures falling below zero to about -3 C. At this stage, wind chills may reach -10 C.

TONIGHT ... Windy and very cold with snow at times, heavier in north and west, further accumulations of 10-15 cms possible there, 2-5 cms south and east. Winds NW 30-50 mph, lows reaching -4 to -6 C except -2 to zero in west coastal locations. Wind chills -10 to -15 C. Very icy roads.

FRIDAY ... Continuing windy and very cold with frequent squally showers of hail and snow, considerable accumulations possible but mostly in Ulster and Connacht, west Munster, parts of north, west Leinster where amounts will average 5-10 cms and reach 15 cms locally. Showers may mix with sleet near the outer Kerry coast. Highs for the day only -3 to -1 C in north (inland) and 2-4 C in southwest, 0-2 C in southeast and east. Some intervals of bright sun will also be hazardous because of glare off snow and ice at low sun angles. Winds WNW 20-40 mph with some higher gusts. Roads becoming very treacherous in many counties but with highly variable conditions too, travel with care if you can't avoid travel.

WEEKEND ... Bitterly cold to start with some clearing in the north late Friday night and lows generally -7 to -4 C but as low as -10 C in any northern valley locations under clear spots in the general overcast. Ice fog likely over central counties. Periods of snow may continue Friday night in some southern and eastern counties. Then on Saturday, snow likely to spread in or break out locally, heavier in the northeast at first, then becoming rather heavy in many areas, local accumulations of 5-15 cms both days, potential for near-blizzard or blizzard conditions with Dublin possibly near the higher snowfall zone that is likely to extend from about Meath to Laois and Tipps, but should emphasize that heavy snow could develop quite widely outside that zone too. Saturday night could clear in some northern and central counties with frigid temperatures possible (lows -12 C or lower in cold spots).

Sunday may also produce periods of snow in a northeast wind flow, and eventually, maximum snow accumulations could reach 20-30 cms. Some thunder-snow likely. Winds will increase at times to NE 15-25 mph blowing this snow around, in temperatures in the range of -2 to +1 C (could stay colder than that in parts of Ulster and inland Connacht).

MONDAY ... The above snowstorm to blizzard conditions may continue or may ease slowly, but in any case, there will be a lot of snow on the ground and temperatures near -1 C with potentially strong E to NE winds at times.

TUESDAY to THURSDAY ... Some snow could continue in the south, and flurries or freezing drizzle will keep roads icy in many areas, but this could be a somewhat drier period with breaks in the overcast and very cold temperatures at night as a result, lows may fall to -8 C or lower, highs will remain in the range of -2 to +2 C. It could become just slightly milder by Thursday, 2-4 C.

OUTLOOK ... I tend to discount any major suggested warmings but there is a chance of milder weather around Christmas, however, I think there is an equal chance of a further period of snow with the mild air held back to the southwest.

For those with an interest in weather in the U.K. or northern France for their travel plans, it seems quite possible that the snow in Ireland will break out over large parts of the U.K. as well, and may extend at times into northern France. Parts of central England are likely to see the worst of the snow there, 20-40 cms potential. Eastern Scotland may see some snow, but central Scotland and northern England could see bitterly cold overnight lows during the period, as low as -20 C in some places, but generally -10 C or lower.

Weather here today was cloudy with light rain and a high near 6 C (Wed 15th).

I may update the snowfall table later, but will maintain it for now.

M.T. Cranium · 16-12-2010 7:53pm

UPDATE _ Thursday, 16 December, 2010 _ 1845h
_________________________________________

The models are (as anticipated) showing greater potential for snowfall through the weekend now. This forecast update is followed by a revised table of snowfall predictions but generally this forecast is a continuation of the earlier one.

TONIGHT ... Rather windy and very cold with frequent snow showers in Connacht, Ulster and some parts of West Munster, accumulations of 5-15 cms possible, with Mayo to Fermanagh favoured for the heavier amounts. A few flurries could show up further south and east. Any remnant showers in the southwest should turn to hail or snow soon. Winds generally NW 20-40 mph with some higher gusts in exposed areas, falling off inland to 10-20 mph. Overnight lows near -3 C in the heavier snowfall areas, -6 C further inland where partly cloudy, but -3 C south coast and central Dublin. Feeling closer to -10 C in the wind. Very icy on some roads, and reduced visibility due to snow or ice fog in some places.

FRIDAY ... Continued windy and very cold with heavy snow showers in parts of Connacht, Ulster, West Munster, inland north Leinster, and flurries elsewhere, amounts 5-10 cms heavier once again from about Mayo to Antrim.

Further east and south, some sunny intervals with passing flurries or hail showers. Winds in general WNW 20-35 mph, backing to SW late afternoon, mixed showers likely in Kerry and Cork at this point, with outbreaks of heavy snow further north spreading across the country during the evening. Widespread icy road conditions.

Highest temperatures -3 to +1 C, except 2-4 in Kerry and Cork.

FRIDAY NIGHT ... Snow becoming rather heavy at times and spreading into the eastern counties while becoming more intermittent in the west, amounts of about 5-10 cms likely with heavier amounts this time in eastern counties and also across much of Ulster. Winds turning more northerly after midnight, with lows of about -3 C east to -7 C central and -4 C west. Widespread icy road conditions.

SATURDAY ... Periods of snow may become intermittent, with 5-8 cms further, very cold with light to moderate northeast to northwest winds, some sunny intervals could develop in the north and west, but highs only -3 to near zero C.

SATURDAY NIGHT & SUNDAY ... Renewed periods of snow becoming heavy across most of the country, with winds NE 15-25 mph in northern counties, somewhat variable and lighter across the south. Snow could mix with sleet near east or south coasts. Amounts likely to be 10-20 cms but could reach 30 cms in some inland southeast counties. Morning lows of about -4 to -7 C with daytime highs -3 to -1 C for most.

MONDAY ... There could be an extension of the snowfall period although becoming lighter, well into Monday with a gradual tapering off to drizzly light snow grains or freezing drizzle. Then it seems likely to clear late Monday with bitterly cold temperatures over the fresh snow. Temperatures on Monday similar to Sunday, -5 to -1 C.

TUESDAY ... With any clearing, Tuesday morning lows could be downright frigid inland, -12 C or even lower in parts of the inland southeast and Midlands, Ulster. Elsewhere, closer to -7 C ... afternoon highs in the range of about -5 to zero C, with some sunshine and some lingering ice fog or low cloud.

OUTLOOK ... Possible sleet or freezing rain is entering the mix for the period Wednesday 22nd to Friday Christmas Eve, as well as some chance of further snow, and there could be a thaw with some rain in the far south. This will all depend on the track of an Atlantic storm that seems likely to try to push the cold air back north to some extent. With that could come strong SE winds. Watch for updates on this period.

Now, here's the updated snowfall chart, snowfall in cms.
Tonight refers to the period now to 0800h Friday, which may be one reason why Friday (0800-2400h) amounts appear reduced.

REGION ............ TONIGHT .... FRI ..... SAT ..... SUN ..... MON
____________________________________________________

Ulster ..................... 05 ...... 05 ...... 10 ..... 10 ...... 03

Connacht ................ 05 ...... 08 ...... 07 ..... 08 ...... 02

West Munster, Clare .. 03 ..... 03 ...... 05 ..... 12 ...... 07

East Munster ............ 01 ..... 04 ...... 10 ..... 12 ...... 08

inland southeast ....... 01 ..... 04 ...... 12 ..... 18 ...... 10

Dublin/Wicklow/Meath. 01 ..... 03 ...... 12 ..... 20 ...... 10

rest of Leinster ........ 03 ..... 04 ...... 12 ..... 15 ...... 07

The weekend snowfalls may appear blizzard-like in some cases, whether they are technically a blizzard or not may depend on wind speeds which may not be excessive. Snowfalls on some higher terrain may be even higher than estimated here. But coastal parts of the east and south could see some mixing so that while it may snow the same amount, not all of the snow will cover the ground to same depths.

next possible update time would be 2200h depending on changes in guidance by then. -- MTC

M.T. Cranium · 17-12-2010 12:17am

Have looked at the available new guidance, mainly the 18z GFS, and while there are suggestions of a stronger storm system for late Saturday into Sunday, that could also bring in mixed types of precipitation for the southeast coast, I am not currently going to amend the forecast because I believe there is too much uncertainty about the details presented, and continue to think the actual evolution of this storm will be a bit further south and therefore with less tendency to mix precipitation over Ireland (this will be an issue across southern England perhaps).

As a result, no amendment to the current forecast is the call, and I await the verdict of the 00z models where I can compare any changes that four or five reliable players are picking up ... the situation is no doubt fluid and readers are cautioned that these are forecasts, not timetables (of course, timetables are forecasts too, perhaps I should say tide tables which tend to be virtually 100% reliable unless very strong winds interact with the ocean tides).

pauldry · 17-12-2010 1:07am

The BBC weather hinted at the Saturday storm bringing 25cm of snow to the UK I think, (sorry I was hypnotised by snow outside at the time:rolleyes:)

Your daily forecasts from Boards.ie weather forum (NO CHAT)

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