Freezing Weather Discussion - Widespread Snow Tonight/Tuesday

Shires · 04-01-2010 10:59am

owenc wrote: »

hopefully that happens then people do not have to go back to work etc till next week another week off would be brill!:eek: Hopefully we get alot more than last night we can still see grass its really slim snow..

School yes, work no! When people cannot get to work it jepordises businesses, jobs and lives.

owenc · 04-01-2010 11:00am

maquiladora wrote: »

I don't think the country will be brought to a standstill by "scattered wintry showers".

There is good potential for a dusting of snow in a lot of places and some decent snowfall in other places, on high ground for sure, but I wouldn't expect more than that. These events have an unfortunate habit of being frustrating half or non events at the last minute.

isnt this a trough laarger than the one last night which was just showers?

owenc · 04-01-2010 11:02am

Shires wrote: »

School yes, work no! When people cannot get to work it jepordises businesses, jobs and lives.

Don't worry my place wont shut we had 20cm one time and it was still open so this trough would need to get a hell of alot larger for snow larger than that if it even comes here considering its going se...

200motels · 04-01-2010 11:03am

Snowaddict wrote: »

Morning Everyone

Introduction

Firstly, a few points. The overnight outputs, especially that of ECMWF is much better in the medium term with a more sustained Easterly flow. A rewned, fairly potent due Easterly flow, is now likely to be developing into the weekend. Also, the overnight ECMWF shows no sign of a breakdown again until T+240! UKMO 00Z is another excellent run, with a shortwave feature moving down across the country between T+96 T+120, undercutting, with a strong Easterly flow developing. Into the medium term there is, at present, no sign of a let up in these conditions, with renewed blocking quite likely from Scandinavia to Greenland, Ireland being under an Easterly flow.

Snowfall Distribution & Potential

What I find a bit perlexing about the latest Met Eireann update is that the overnight ECMWF 00Z Guidance is once again holiding firm about the snowfall threat, in Eastern and Southeastern areas in particular. With the risk as mentioned last evening for Western Atlantic Seaboard areas into Thursday, when a Shortwave feature will run down the country, hitting into the cold air in place, as a Blocking High builds over Scandinavia.

Here are some of the overnight ECMWF Precip Charts:

Tuesday Night

Wednesday Morning

Wednesday Afternoon

UKMO 00Z

Also holds constant regarding the snowfall risk. The main risk periods include the period from 01.00 to 07.00 tomorrow, when it models the cold front moving down across the country. In models this as remaining intact, all the way down, even strengthening in Eastern areas:

It also models a further risk of snowfall quite widely in the East and Southeast, later on Tuesday and into Wednesday, very much in line with the latest ECMWF guidance. Again, that's not to say that these are entirely correct but these latest runs are almost even better than the ones of last evening & do clearly suggest the potential for snowfall in the risk areas that were mentioned last night. Also, most model guidance now prolongs the Northeasterly flow into Thursday.

GFS 00Z is not as good into the medium term but I suspect it's picking up on a signal initially picked up upon by the other models and subsequently dropped, as overnight, all other NWP Guidance supports a renewed, potent Easterly flow developing towards Friday onwards.

Summary

In summary, the snowfall potential, as discussed last night largely holds firm on the vast majority of guidance. Again, there are no certainties in this setup, the evolution is complex and snowfall is very difficult to predict and model. From all of the available NWP Guidance, the risk of the overnight GFS 00Z evolution with much slacker conditions, is about 35%, with a solid 65% support for a renewed Easterly flow. Equally, it would be positive to see a fairly rapid reversion from GFS, preferably by later today. Some of the other Guidance has modelled this GFS evolution before, bus has subsequently dropped it. UKMO appears to be, by far, the most consistent at the moment.

SA

Going by your excellent analysis, we here in the city of no snow, could possibly get a dusting.

WolfeIRE · 04-01-2010 11:05am

The UKMO and GFS are a big upgrade on last evening's runs.

There is no doubt that the potential for snowfall along the E and SE coast over the on Tuesday, wed and Thurs (at least) is significant. I am also surprsied at why ME have more or less ignored this potential in their latest report. They obviously have a hunch that it will not happen. Would love to know what they are basing their forecast on as the UKMO, in particular, shows widespread heavy and often prolonged wintry showers for the E and SE, stretching inland to Meath, Carlow, Kilkenny, Kildare, and Waterford.

Meanwhile, tonight also puts most of the country in line to receive at least a dusting. The UKMO shows an upgrade on last evening's run. Most of the country is in line for snow. I think inland parts of Connaught, Ulster and North Leinster will see the heaviest precipitation. Western and Northern Munster will also see heavy precip early tomorrow morn.

I reckon that the most serious potential for significant snow along the W and SW comes from the Thursday front that will at the very least affect western coastal areas. If this moves further inland then we could see some serious disruption there by the end of the week.

GavinH · 04-01-2010 11:05am

Temp in Cork is -4.4 and rising. This band that will move down from the north, will it push too far east for it to affect Cork?

jambofc · 04-01-2010 11:06am

a lite dusting of hail here overnight,-1/-3 at the mo and gone cloudy

my reading of this "event" tonight is that there will be some snow around but also a bit of rain/sleet,as this passes temp will drop more and then the north-north/east and then the east will see some more snow tomorrow.

200motels · 04-01-2010 11:10am

WolfeIRE wrote: »

The UKMO and GFS are a big upgrade on last evening's runs.

There is no doubt that the potential for snowfall along the E and SE coast over the on Tuesday, wed and Thurs (at least) is significant. I am also surprsied at why ME have more or less ignored this potential in their latest report. They obviously have a hunch that it will not happen. Would love to know what they are basing their forecast on as the UKMO, in particular, shows widespread heavy and often prolonged wintry showers for the E and SE, stretching inland to Meath, Carlow, Kilkenny, Kildare, and Waterford.

Meanwhile, tonight also puts most of the country in line to receive at least a dusting. The UKMO shows an upgrade on last evening's run. Most of the country is in line for snow. I think inland parts of Connaught, Ulster and North Leinster will see the heaviest precipitation. Western and Northern Munster will also see heavy precip early tomorrow morn.

I reckon that the most serious potential for significant snow along the W and SW comes from the Thursday front that will at the very least affect western coastal areas. If this moves further inland then we could see some serious disruption there by the end of the week.

This is the Met Office chart for midnight.

ninebeanrows · 04-01-2010 11:13am

200motels wrote: »

This is the Met Office chart for midnight.

See the triple point,

Warm front joining the cold front, just east of Dublin?

You want to be under that for the heaviest precip!

Cul a cnoic · 04-01-2010 11:17am

Annagry in West Donegal had rain this morning, roads are very dangerous, a few miles down the road in Gweedore had a light dusting of snow. very cold.

billy the squid · 04-01-2010 11:20am

johnstown castle reporting -12 at 10 am

that can't be right.

Elmer Blooker · 04-01-2010 11:28am

billy the squid wrote: »

johnstown castle reporting -12 at 10 am

that can't be right.

Johnston Castle is in Wexford, isn't it?.... cos if it is really -12 then that amounts to a lot of frozen pipes in those vacant holiday homes!

Slidey · 04-01-2010 11:29am

Currently snowing in Sligo.

Dry flakes, sticking immediately on the frozen ground.

Very very slippy now

F-Stop · 04-01-2010 11:31am

Slidey wrote: »

Currently snowing in Sligo.

Dry flakes, sticking immediately on the frozen ground.

Very very slippy now

Slidey says it's slippy in Sligo.

spadder · 04-01-2010 11:35am

F-Stop wrote: »

Slidey says it's slippy in Sligo.

Slippy snow makes Sligo a no-go

peasant · 04-01-2010 11:38am

Slidey wrote: »

Currently snowing in Sligo.

Dry flakes, sticking immediately on the frozen ground.

Very very slippy now

Yet at the airport it's still raining (with the odd snowflake mixed in) and the ground is wet, not freezing over.

amazing the difference a few kilometers make

Elmer Blooker · 04-01-2010 11:40am

jambofc wrote: »

a lite dusting of hail here overnight,-1/-3 at the mo and gone cloudy

my reading of this "event" tonight is that there will be some snow around but also a bit of rain/sleet,as this passes temp will drop more and then the north-north/east and then the east will see some more snow tomorrow.

A dose of reality if I may say so myself. These fronts that approach from the north always have a bubble of warm air embedded (aka warm sector)
It happened as recently as this Saturday night when it rained here in Dublin thawing some of the lying snow. I cannot see why this wont happen tonight!

Snowaddict · 04-01-2010 11:42am

We are seeing another different evolution from GFS 06Z Operational - marked lack of consistency from GFS in the past 12+ Hours.

For the moment, I would be happy to side with the ECMWF 00Z and UKMO 00Z Evolutions. It's very rare that ECMWF has the general pattern wrong at T+120. Indeed, at the moment, it's still verifying the best in the Northern Hemisphere as far out as Day 6:

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

Also, GEM is doing very well at the moment and had shown the trend as displayed by GFS 06Z, but has now reverted to a very potent Easterly by T+120.

Again, the exact positioning of the High is instrumental for a continuing snow risk & for those reasons it would be better to see UKMO/ECMWF being correct. In fact, if UKMO was correct as T+120, many areas would be at risk of snowfall.

Expect the UKMO Long Range later to mention bitterly cold weather in the first week, with further snowfall in Eastern areas, but perhaps slightly less cold in the second week, with a reduced risk of wintry showers for a time.

Hopefully we will have the evolution resolved by this afternoon's 12Z runs. Also interesting to see GFS now modelling more widespread snowfall potential in Eastern and Southeastern areas into tomorrow.

SA

ninebeanrows · 04-01-2010 11:44am

UK Meso still progging this polar low type feature tomorrow morning off West Scotland pushing south across the country.

Where the precip falls is uncertain.

18z last night had it to the west, 0z to the east, 6z down the middle!

Su Campu · 04-01-2010 11:45am

The 00Z NAE has mostly rainfall for Ireland until tomorrow morning, then the snow starts in earnest.

The GFS is a snowier outlook overall. It will be interesting to see which wins out. Don't forget there will be a slight warm front before the cold front, so don't be surprised to see the NAE scenario become reality.

cian1500ww · 04-01-2010 11:46am

Light snow falling here atm.

WolfeIRE · 04-01-2010 11:46am

Looks like Sligo, North Roscommon, Northern half of Leitrim and parts of Mayo will see a dusting between now and midday. I have noticed that dew points have started to rise in the Donegal Bay area (namely Manor Hamilton and Finner Camp). They are now at +1c unlike the Collooney Bypass at -3c

force eleven · 04-01-2010 11:46am

billy the squid wrote: »

johnstown castle reporting -12 at 10 am

that can't be right.

No, it can't. Johnstown is automated isn't it? Maybe it is reading the ground temperature. Should be around -2 I would of thought - could be a typo as well.

pistolpetes11 · 04-01-2010 11:46am

Morning all from Newbridge,

Well its our 4th day of lying snow from the NYE event !

Temp -3.3

DP -4.5

The M2 buoy is reporting a temp of 4.1 with a dp of -3.2 and a sea temp of 9.5

EDIT: Any one heading southbound on the M50 towards Sandyford be careful as its reporting as Icy.

rhonin · 04-01-2010 11:49am

Slidey wrote: »

Currently snowing in Sligo.

Dry flakes, sticking immediately on the frozen ground.

Very very slippy now

Fairly heavy snowfall too.

maquiladora · 04-01-2010 11:49am

http://news.bbc.co.uk/weather/forecast/10209

Shows snow/rain showers in Ulster overnight but then turning just to rain as it moves down the country early Tuesday morning.

jambofc · 04-01-2010 11:50am

Elmer Blooker wrote: »

A dose of reality if I may say so myself. These fronts that approach from the north always have a bubble of warm air embedded (aka warm sector)
It happened as recently as this Saturday night when it rained here in Dublin thawing some of the lying snow. I cannot see why this wont happen tonight!

have to read chart's with the head an not the heart,i think there will be snow around however,it's is going to be very localised.
it is amazing how localised it has been in the last couple of weeks,one lad getting 3-4cm and only a few mile's down the rd nothing,or rain in one part of dublin(just an example) and snow in another say.
have to say though im getting more excited by tonight and the rest of the week as it get's nearer.

im a 40 year old child and lovin it

embee · 04-01-2010 11:52am

I'm very confused, a lot of those pics look like I'll miss out on the snow once more.... seems to be all the east and southeast.... I'm on the Louth/Monaghan border, up on high ground. We haven't had a scrap of snow, it sucks

Su Campu · 04-01-2010 11:52am

force eleven wrote: »

No, it can't. Johnstown is automated isn't it? Maybe it is reading the ground temperature. Should be around -2 I would of thought - could be a typo as well.

Oak Park in carlow is only at -3 at 10am, so it must be instrument error, and the lack of reported dewpoint in the PsMETAR below would hint at that.

PsMETAR JOHN 041000Z AUTO 34006KT 9999NDV OVC048/// M12/// 1023 MSL=

PsMETAR OKPK 041000Z AUTO 35004KT 9999NDV NCD M03/M03 1024 MSL=

Figuramatyi · 04-01-2010 11:53am

Me likey:

Given that it really covers Galway too

Mind you, it gives 90% of snow on Thursday night, not tonight!

ffarrell · 04-01-2010 11:56am

Still as white as ever in Castleknock, Dublin,:) with no thaw and ice and snow everywhere except main routes. A little bit of snow last night as well. currently -1.

Tom Cruises Left Nut · 04-01-2010 11:57am

pistolpetes11 wrote: »

Morning all from Newbridge,

Well its our 4th day of lying snow from the NYE event !

Temp -3.3

DP -4.5

The M2 buoy is reporting a temp of 4.1 with a dp of -3.2 and a sea temp of 9.5

EDIT: Any one heading southbound on the M50 towards Sandyford be careful as its reporting as Icy.

I have retreated from Kildare to my daytime lair in Clontarf !!

Big window beside me looking out onto the sea... hope I see something lovely heading our way !

ninebeanrows · 04-01-2010 11:57am

The situation is:

Tonight
Band of sleet and snow pushing south between midnight and 6am, band will fall as sleet or rain in the northwest but should be snow elsewhere.

Widespread accumulations of 3cm's, upto 10cm's in places.

Tuesday Morning
Trough feature/ Polar Low(?)

Moving into Northern Ireland around 6am tomorrow pushing south through the morning, early afternoon. Exact track uncertain, likely to give around 10cm's of snow where it hits.

Tuesday Afternoon --> Wednesday Evening
Heavy snow showers will affect coastal areas of the north and northwest, East and southeast. Accumulations of another 5-10cms widely with upto 20cm's where a streamer sets in.

So some places could have 20cm's on the turf come Wednesday night, perhaps more.

Snowaddict · 04-01-2010 12:03pm

Here is the latest UKMO Fax chart, showing this feature moving down onto the North Coast. This is very much in line with the overnight UKMO Precipitation Guidance, so very noteworthy:

http://www.meteociel.fr/modeles/ukmo2.php?ech=24&carte=2000

SA

owenc · 04-01-2010 12:05pm

Weathercheck wrote: »

The situation is:

Tonight
Band of sleet and snow pushing south between midnight and 6am, band will fall as sleet or rain in the northwest but should be snow elsewhere.

Widespread accumulations of 3cm's, upto 10cm's in places.

Tuesday Morning
Trough feature/ Polar Low(?)

Moving into Northern Ireland around 6am tomorrow pushing south through the morning, early afternoon. Exact track uncertain, likely to give around 10cm's of snow where it hits.

Tuesday Afternoon --> Wednesday Evening
Heavy snow showers will affect coastal areas of the north and northwest, East and southeast. Accumulations of another 5-10cms widely with upto 20cm's where a streamer sets in.

So some places could have 20cm's on the turf come Wednesday night, perhaps more.

so in total if the snow is heavy tonight e could end up with 20cm if the snow is heavy tonight? now that would be good!

Su Campu · 04-01-2010 12:07pm

Weathercheck wrote: »

The situation is:

Tonight
Band of sleet and snow pushing south between midnight and 6am, band will fall as sleet or rain in the northwest but should be snow elsewhere.

Widespread accumulations of 3cm's, upto 10cm's in places.

Tuesday Morning
Trough feature/ Polar Low(?)

Moving into Northern Ireland around 6am tomorrow pushing south through the morning, early afternoon. Exact track uncertain, likely to give around 10cm's of snow where it hits.

Tuesday Afternoon --> Wednesday Evening
Heavy snow showers will affect coastal areas of the north and northwest, East and southeast. Accumulations of another 5-10cms widely with upto 20cm's where a streamer sets in.

So some places could have 20cm's on the turf come Wednesday night, perhaps more.

I think there'll be less snow than you forecast tonight. It's a marginal situation until tomorrow morning, according to the GFS forecast sounding for Belfast and the NAE snow predictions. From tomorrow morning on though I would expect snow to be getting well into the north, spreading southwards, especially if a polar low does form off Scotland. Tough one to call at this stage though, as it may hit land before maturing. Watch the satellite animations today for signs

Scubadevils · 04-01-2010 12:08pm

Snowaddict wrote: »

Here is the latest UKMO Fax chart, showing this feature moving down onto the North Coast. This is very much in line with the overnight UKMO Precipitation Guidance, so very noteworthy:

http://www.meteociel.fr/modeles/ukmo2.php?ech=24&carte=2000

SA

Does the triangle/semi circle indicate being both a cold & warm front?

Figuramatyi · 04-01-2010 12:09pm

It's overcast now in Galway, with temp well around -2 (in a higher elevation part of the town, in Ballybrit). No thaw is likely since there is no direct sunlight.
We're looking to be in a position just as good for snow as any other part of the country, so can't wait to see what the week brings

force eleven · 04-01-2010 12:12pm

Weathercheck wrote: »

The situation is:

Tonight
Band of sleet and snow pushing south between midnight and 6am, band will fall as sleet or rain in the northwest but should be snow elsewhere.

Widespread accumulations of 3cm's, upto 10cm's in places.

Tuesday Morning
Trough feature/ Polar Low(?)

Moving into Northern Ireland around 6am tomorrow pushing south through the morning, early afternoon. Exact track uncertain, likely to give around 10cm's of snow where it hits.

Tuesday Afternoon --> Wednesday Evening
Heavy snow showers will affect coastal areas of the north and northwest, East and southeast. Accumulations of another 5-10cms widely with upto 20cm's where a streamer sets in.

So some places could have 20cm's on the turf come Wednesday night, perhaps more.

We've been here before, so I am not holding out hope. BBC have very little snowfall on the first feature for Ireland, mostly rain/sleet and that lovely phrase - hill snow. They have been quite accurate so far. Anything that has drifted south since this cold spell began has been a disappointment so far - picking up that milder maritime air as it comes south towards us.

As for the second feature - interesting. Polar lows are notorious difficult to track, so you may be onto something on that one.

I'm playing bad cop on this one, in the hope of jinxing my rain prediction.....

Snowaddict · 04-01-2010 12:12pm

Felixdhc wrote: »

Does the triangle/semi circle indicate being both a cold & warm front?

Not sure exactly on that particular chart, but to me it looks like a quasi-stationery front, meaning that it is fairly slow moving, however those symbols combined are meant to indicate an Occlusion - that is when a cold front catches up with a warm front. Behind this feature there is even progressively colder and more unstable air.

SA

maquiladora · 04-01-2010 12:13pm

Felixdhc wrote: »

Does the triangle/semi circle indicate being both a cold & warm front?

Thats an occluded front.

Elmo5 · 04-01-2010 12:16pm

Had a look at sky's long term forecast. They do forecast that band crossing the country tonight, starting off as rain but snow as it moves inland.
For rest of week until Friday, just the showers skirting the coast but on Friday, their map showed snow showers over the eastern half on Ireland.

maquiladora · 04-01-2010 12:17pm

Countrywide Orange alert on Meteoalarm for snow/ice :

http://www.meteoalarm.eu/countryIE.asp?Country=IE&lang=EN&ShowDate=today

"Very cold and frosty today with ice lingering in places. Scattered wintry showers also."

cherryghost · 04-01-2010 12:21pm

heavy snow in longford atm

EDIT: holy crap. its sticking to the gritted roads and footpaths with ease. am not looking forward to my trip home to work tonight if it continues

maquiladora · 04-01-2010 12:22pm

Yr.no forecast for Waterford City, this uses the ECM output I think?

I hope it's right, would be nice to see some snow here, though I don't think a couple of mm would cause too much disruption. :pac:

tucker1971 · 04-01-2010 12:26pm

Just saw some sat pictures and it looks like coleraine is in for some severe flooding over the next 5 days.
Possibly the only place in the country that wont see any snow.;)

Tom Cruises Left Nut · 04-01-2010 12:31pm

IS anyone seeing any flakes in Kildare / Dublin at all ?

That raintoday intermittent radar is very very annoying !

Redsunset · 04-01-2010 12:31pm

Above image is our situation today and im wondering is there a similarity with any of the developing polar lows imaged below??
Answers on a postcard please:D

Here you can identify a Polar Low approaching Scotland's north east shores.

pistolpetes11 · 04-01-2010 12:35pm

t|nt|n wrote: »

IS anyone seeing any flakes in Kildare / Dublin at all ?

That raintoday intermittent radar is very very annoying !

Not a thing in Newbridge , although it is cloudy .

Johnny1999 · 04-01-2010 12:36pm

Nothing but Blue clear skies in Kilkenny its freezing cold!! although there looks to be some cloud coming in from my north, which I would guess would be from castlecomer direction.

Freezing Weather Discussion - Widespread Snow Tonight/Tuesday

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