Cold Spell Discussion cont: Tuesday, Wednesday - more heavy snow risk

jasperok

i have been checking yr.no daily since christmas.
its always been excellent up to 72 hours and a bit hit and miss on anything further out.
snow has always been 5-7 days away for the last few weeks and never makes it into the 72hour or less forecasts.
tonight however it is forecasting snow in 48hours. only 1cm mind but its nice to see it make its way into the more imenent forecasts for a change!

munsterlegend

jasperok wrote: »

i have been checking yr.no daily since christmas.
its always been excellent up to 72 hours and a bit hit and miss on anything further out.
snow has always been 5-7 days away for the last few weeks and never makes it into the 72hour or less forecasts.
tonight however it is forecasting snow in 48hours. only 1cm mind but its nice to see it make its way into the more imenent forecasts for a change!

yeah i always use it too. shows a lot of sleet down here for tuesday/wednesday for the first time since january in the short range. will be an interesting week ahead as the experts have pointed out.

nacho libre

jasperok wrote: »

i have been checking yr.no daily since christmas.
its always been excellent up to 72 hours and a bit hit and miss on anything further out.
snow has always been 5-7 days away for the last few weeks and never makes it into the 72hour or less forecasts.
tonight however it is forecasting snow in 48hours. only 1cm mind but its nice to see it make its way into the more imenent forecasts for a change!

yes i agree about yr.no. it seems good in the short term but further out it tends to be inaccurate. it is showing snow for me as well on Tuesday.

although, what the bbc precipitation charts, on the countryfile forceast, showed is snow being confined to the border counties and Ulster.
while things can change, especially in such a complicated setup, i've found these charts to be fairly accurate. so fingers crossed, while pangea, and others in the north, look to be the favourites to see snow on Wednesday, those of us further south get snow.

Deep Easterly

nacho libre wrote: »

yes i agree about yr.no. it seems good in the short term but further out it tends to be inaccurate. it is showing snow for me as well on Tuesday.

You shouldn't take anything passed 24hrs as gospel. yr.no data reflects what the latest ECMWF model run shows. We all know any model will become less accurate beyond 48hrs.

yr.no is excellent for spotting trends in the medium term and is a good way to see how the ECMWF run looks on a local level.

Deep Easterly

I haven't looked yet at the latest runs, but I like that fax chart DM posted above. Won't happen exactly like that of course. Some of the heaviest, most prolonged rain I have seen here come from set ups like that with an occlusion stationary over the center of the country with a low to the south. Rain or snow, I don't care, but it will be nice to see some active weather for a change. (if it happens)

Deep Easterly

Deleted User wrote: »

Darkman2.. in january 1982,temperatures in Britain especially most of wales off which we were getting a fast gale force surface feed were sub zero.

We don't have that this week.
It's a crucial difference.
What we do have is a circulation that runs up through rain in southern Britain,runs through snow in colder central Britain and then gets remodified whilst crossing the irish sea.

Eveylyn did mention away from coasts and she's said that to be realistic.

Heres the air temps over Britain today before the irish sea gets to work on them

http://www.wunderground.com/cgi-bin/findweather/getForecast?query=united%20kingdom&wuSelect=WEATHER

Cardiff is 7c which is a hell of a difference from the daytime surface feed of january 1982.

Like should be compared with like.

I seen the 'Farming Forecast' earlier, and she did say that any rain could turn to snow 'further inland' if those systems did effect us. She was right in pointing this out this risk. If her charts verified, then there could be the odd sleety mix thrown in on exposed coasts but snow risk would be greater inland.

Edit: I would just like to ask people why they feel the need to bash met eireann on boards.ie weather. Why? is there an actually point to it?

WolfeIRE

Tomorrow's charts will obviously tell all.

However, at the moment the highest risk areas for snow are North Connaught, Northern midlands and Ulster. The primary reason for this is that a quasi stationary front will position itself from North Mayo to Louth, trapping colder air to the north and preventing the warmer behind from tracking north. The uppers to the south of this line are in the -1 to -4c region which will support sleet on lower levels at best. Of course, the potential for snow below the line exists as the front moves north but it will readily turn back to rain/sleet.

Tomorrow will paint a clearer picture.

Vudgie

Unbelievable to see a couple of people slag off met eireann a bit sad really. Nice day in Dublin today. Serious drop in temps this evening prob goin to get foggy later. Will be an interesting week the grand finale!

thetonynator

much colder tonight than last night everywhere, especially the M2 buoy, its at 2.2/ -0.6, which seems very cold to me???

unless its a mistake . . .

arctictree

GFS 18z seems much better for snow in Southern/Eastern areas. Looks much colder than the 12z when the precip arrives.

Su Campu

Deep Easterly wrote: »

Edit: I would just like to ask people why they feel the need to bash met eireann on boards.ie weather. Why? is there an actually point to it?

I think some people think they're the Charles Doswells of these here parts and will try any means to try to convince people of it.

Yeah ME get things wrong the odd time, what met service doesn't, but they get it right most of the time....which goes conveniently unnoticed by certain people.

arctictree

OK, a bit off topic but do RTE always HAVE to get their weather forecasting services from Met Eireann? What if another forecasting company came along with a cheaper quote for a similar service? Do RTE even request tenders for this?

WolfeIRE

thetonynator wrote: »

much colder tonight than last night everywhere, especially the M2 buoy, its at 2.2/ -0.6, which seems very cold to me???

unless its a mistake . . .

sounds like the line from that professor in the scottish observatory in The Day After Tomorrow:D

Ps....Have great respect for the meteorologists at ME. Meteorology in this country is not an exact science and would challenge the world's leading meteorologists in this regard.

nacho libre

it seems met eireann and and MI5 have one thing in common - in that no one remembers the vast majority of times they get it right, they are only remembered for their screw-ups. which is not the case for people on here. if, which does happen often enough, people here get it wrong there is no scrutiny of them. i think it's really bad form to downplay the service qualified meteorologists provide. Also, you'd swear by some of the talk it was as simple as collecting a certain number of crisp tokens to become a qualified meteorologist;)

WolfeIRE

nacho libre wrote: »

you'd swear by some of the talk it was as simple as collecting a certain number of crisp tokens to become a qualified meteorologist;)

DAMN...*empties his USA biscuit tin full of tayto tokens into the bin*

darkman2

18z GFS Tuesday night

ninebeanrows

Temperature dropping like a stone here.

-5c at the airport.

WolfeIRE

that gfs throws up some very exciting scenarios for much of the country. Looking forward to tomorrow's runs

Su Campu

The GFS forms a dipole low by Wednesday, with one low dragging its heels over the Irish Sea. The other models don't have this, though the ECMWF has some troughing in this direction. I put this down to the different way the GFS treats the evolution of the 500hPa low connected with the surface low, keeping it deeper than the other solutions and forming an elongation of the low pressure centre. Could be one to watch....

doccy

Jeez there sure is a lot of met eireann love going down tonight.

Danno

Cork could get a dumping Friday morning 6am to midday according to tonights charts, slightly less chance for Waterford though as a secondary low throws in milder air there, which sends colder air over to Cork!

Note: This is based on tonights GFS output, and is subject to change during the week without warning or refund.

Redsunset

Don't know if this was already posted so just sticking it in here.

Horizontal resolution increase

On Tuesday 26 January, ECMWF upgraded the horizontal resolutions of its deterministic forecast and data assimilation systems and the Ensemble Prediction System (EPS), including the weekly extension to 32 days.

A new cycle of the IFS model has been introduced to implement the higher resolution upgrade. This cycle is labelled 36r1. The resolution of the deterministic model is increased from T799 (25 km grid) to T1279 (16 km); the EPS resolution changes from T399 (50 km) to T639 (32 km) for the first 10 days of the forecast and from T255 (80 km) to T319 (65 km) for day 10 onwards. The higher resolution results in a better representation of features such as tropical storms, fronts, heavy rainfall and land/sea transitions. The impact of the new cycle on the performance of the deterministic forecast system has been tested on more than 500 cases. Objective verification shows significant improvements for 1000 and 500 hPa height, 850 hPa temperature and wind at most levels. The location and intensity of synoptic features are improved in many cases. The frequency of occurrence of intense rainfall events has increased resulting in better agreement with observations.

The new high-resolution model (right) captured the exceptional snowfall event that affected southern England on 5/6 January this year very well. Panels show precipitation totals (mm liquid water equivalent) forecast by the old (T799) and the new (T1279) model versions in the period 00 UTC 5 January 2010 (T+0h) to 09 UTC 6 January (T+33h). The cross marks ECMWF, where 27 cm of fresh snow was measured. This melted down to about 20 mm of rainfall equivalent, which is much closer to the T1279 forecast (~18 mm).

The higher resolution wind fields are better at representing features such as tropical storms, fronts and land/sea transitions which translates into better wave forecasts. Tropical cyclone track and intensity forecasts are generally improved in the higher-resolution system, based on the relatively small sample available.
The overall benefit of the T639 EPS is reflected in the results for the probability scores which are consistently improved for 500 hPa height anomalies and 850 hPa temperature anomalies. EPS spread is in general unchanged. The EPS ensemble-mean errors are consistently lower, resulting in some overestimation of spread in terms of 500 hPa height and a better tuned spread in terms of 850 hPa temperature.

delw

redsunset wrote: »

Don't know if this was already posted so just sticking it in here.

Horizontal resolution increase

On Tuesday 26 January, ECMWF upgraded the horizontal resolutions of its deterministic forecast and data assimilation systems and the Ensemble Prediction System (EPS), including the weekly extension to 32 days.

A new cycle of the IFS model has been introduced to implement the higher resolution upgrade. This cycle is labelled 36r1. The resolution of the deterministic model is increased from T799 (25 km grid) to T1279 (16 km); the EPS resolution changes from T399 (50 km) to T639 (32 km) for the first 10 days of the forecast and from T255 (80 km) to T319 (65 km) for day 10 onwards. The higher resolution results in a better representation of features such as tropical storms, fronts, heavy rainfall and land/sea transitions. The impact of the new cycle on the performance of the deterministic forecast system has been tested on more than 500 cases. Objective verification shows significant improvements for 1000 and 500 hPa height, 850 hPa temperature and wind at most levels. The location and intensity of synoptic features are improved in many cases. The frequency of occurrence of intense rainfall events has increased resulting in better agreement with observations.

The new high-resolution model (right) captured the exceptional snowfall event that affected southern England on 5/6 January this year very well. Panels show precipitation totals (mm liquid water equivalent) forecast by the old (T799) and the new (T1279) model versions in the period 00 UTC 5 January 2010 (T+0h) to 09 UTC 6 January (T+33h). The cross marks ECMWF, where 27 cm of fresh snow was measured. This melted down to about 20 mm of rainfall equivalent, which is much closer to the T1279 forecast (~18 mm).

The higher resolution wind fields are better at representing features such as tropical storms, fronts and land/sea transitions which translates into better wave forecasts. Tropical cyclone track and intensity forecasts are generally improved in the higher-resolution system, based on the relatively small sample available.
The overall benefit of the T639 EPS is reflected in the results for the probability scores which are consistently improved for 500 hPa height anomalies and 850 hPa temperature anomalies. EPS spread is in general unchanged. The EPS ensemble-mean errors are consistently lower, resulting in some overestimation of spread in terms of 500 hPa height and a better tuned spread in terms of 850 hPa temperature.

Woosh,way over the head,redsunset any chance in laymans,cheers

Redsunset

It is in laymans.

The ECM model has upgraded to higher resolution to get more precise measurements of precip and so on.Explained well using the images before and after upgrade to the UK snow event in jan.
MY PREDICTION
I'll make a prediction for tuesday/wednesday.

Rain pushing up from south on tuesday evening could give initial snow on leading edge then sleet as it hits our shores and about 5 to 10 miles inland can deliver continous snow for a time.

Waterford,wexford,cork and kerry may eventually become wet rather quickly because as it slowly pushes further north over land,somewhat milder air enters into the equation so the snow line retreats to above 150m in southern parts before eventually giving rain to all in this region except the mountains which should hold onto the snow.

Now counties like laois, north kilkenny,kildare, offaly,northern carlow,tipperary should hold on to snow much longer down to 50m,possibly allowing a few hours of sneachta to fall leading to some accumulations before that dreaded warm sector puts a damper on things and rises the snowline to above 200m.

Highlands of wicklow and dublin should do well too however those on lower eastern sides could be in for a disappointment.

The fun i feel may be that if i draw a line from galway city to dublin city and say all to the north of this line could possibily see significant snow fall for many hours and lead to severe disruption.

Naturally the further north you are here and in sustained precip the better for this to come to your home.

So thats my early prediction folks and i could be way off the mark here as models will continue to change the whole situation,so a nowcast can be the outcome if it remains on a knife edge.

However i feel dewpoints and upper air may eventually rise too much over southern half of country to allow continued snow to fall.

I wish all the best of luck,including myself in all of this,so get charging those camera batteries and maybe someone will get to build the biggest snowman.

Ps Remember this is a marginal situation for alot of us and may not deliver anything but rain for many so don't be disappointed,just remain optimistic because friday could be the real dark horse this week:)

snaps

-5.3c here, very dry frost, no white like usual and no fog this morning.

Shows how cold this winter has been as parts of my garden that dont see any sun until about this time of the year have been frozen since 2nd week of december. In about 2 weeks time these parts of the garden will start to see sun as its getting higher now!

The cold spell before Christmas really froze deep into the sheltered parts of the garden and all these cold nights have topped the frozen ground up.

Ive no daffodills/flowers out yet this year (Even in the south facing parts of the garden that see sun all the year), they seem really late this year as i can remember in previous years daffs flowering the end of January?

DOCARCH

snaps wrote: »

Ive no daffodills/flowers out yet this year (Even in the south facing parts of the garden that see sun all the year), they seem really late this year as i can remember in previous years daffs flowering the end of January?

Was just thinking the same thing yesterday. Spring has definitely been delayed!

Min

redsunset wrote: »

It is in laymans.

The ECM model has upgraded to higher resolution to get more precise measurements of precip and so on.Explained well using the images before and after upgrade to the UK snow event in jan.
MY PREDICTION
I'll make a prediction for tuesday/wednesday.

Rain pushing up from south on tuesday evening could give initial snow on leading edge then sleet as it hits our shores and about 5 to 10 miles inland can deliver continous snow for a time.

Waterford,wexford,cork and kerry may eventually become wet rather quickly because as it slowly pushes further north over land,somewhat milder air enters into the equation so the snow line retreats to above 150m in southern parts before eventually giving rain to all in this region except the mountains which should hold onto the snow.

Now counties like laois, north kilkenny,kildare, offaly,northern carlow,tipperary should hold on to snow much longer down to 50m,possibly allowing a few hours of sneachta to fall leading to some accumulations before that dreaded warm sector puts a damper on things and rises the snowline to above 200m.

Highlands of wicklow and dublin should do well too however those on lower eastern sides could be in for a disappointment.

The fun i feel may be that if i draw a line from galway city to dublin city and say all to the north of this line could possibily see significant snow fall for many hours and lead to severe disruption.

Naturally the further north you are here and in sustained precip the better for this to come to your home.

So thats my early prediction folks and i could be way off the mark here as models will continue to change the whole situation,so a nowcast can be the outcome if it remains on a knife edge.

However i feel dewpoints and upper air may eventually rise too much over southern half of country to allow continued snow to fall.

I wish all the best of luck,including myself in all of this,so get charging those camera batteries and maybe someone will get to build the biggest snowman.

Ps Remember this is a marginal situation for alot of us and may not deliver anything but rain for many so don't be disappointed,just remain optimistic because friday could be the real dark horse this week:)

Fairly similar to the Met Eireann forecast, they giving a lot of snow unfortunately.

redsteveireland

Going by yr.no it looks more probable to be rain for me all the way:mad:

But rain is better than nothing.

Su Campu

In this morning's 07:55 bulletin, Vincent O'Shea said rain moving northwards through munster and Leinster during the day will change to snow inland, giving sizeable accumulations over higher ground, and possibly leading to disruption in the north and west tomorrow night.

redsteveireland

Su Campu wrote: »

In this morning's 07:55 bulletin, Vincent O'Shea said rain moving northwards through munster and Leinster during the day will change to snow inland, giving sizeable accumulations over higher ground, and possibly leading to disruption in the north and west tomorrow night.

Fingers crossed and ticket purchased!