Cold Spell - Snow & Ice Possible Thursday 8th / Friday 9th

JCX BXC

I'm looking forward to my 1:1 ratio tomorrow

Periscal

latest EURO4 is still kind to west wicklow,but I will be surprised to see more then 2cm of lying snow

squarecircles

JCX BXC wrote: »

I'm looking forward to my 1:1 ratio tomorrow

I'm looking forward to the
Dublin postcode rosary mantra.

Gets rosary beeds.*

pjohnson

Why are some people mentioning Snow Friday? This isnt a week long thing is it?

sryanbruen

pjohnson wrote: »

Why are some people mentioning Snow Friday? This isnt a week long thing is it?

This was a cold spell thread before the yellow warning for tomorrow night and Tuesday morning was issued. It's going to be quite an extended cold spell, according to the outlooks.

highdef

pjohnson wrote: »

Why are some people mentioning Snow Friday? This isnt a week long thing is it?

The first event is Monday night. There might be another event on Thursday night but that's still very much up in the air. In any case, that's 3 days between two separate events so unsure where you are getting any idea of something lasting a week.

typhoony

sryanbruen wrote: »

Why would you be writing off the Winter at this time of the year? February is far more favourable for snow than November or December.

maybe in the last 50 years but not in the modern winters of the last 20 years.

sryanbruen

typhoony wrote: »

maybe in the last 50 years but not in the modern winters of the last 20 years.

Let me give several examples of February over riding said months in terms of winter weather in the last 20 years - that includes frosty conditions, snow, easterly winds, northerly winds etc.

2015-16, 2014-15, 2012-13, 2008-09, 2007-08, 2006-07, 2004-05, 2003-04, 2002-03.

From a statistical point of view, you're factually wrong. Maybe you had 2010-11 too focused on your mind?

February certainly hasn't been extremely cold in the last 20 years but it has delivered more "Winter weather" than November or December in terms of years - see the above ones I've named.

If you'd want to know on any of the above on how and what Winter weather those Februaries had, well then come to the Irish Weather Statistics thread and ask me - so that the discussion here can focus on tomorrow night and Tuesday morning's little event.

https://www.boards.ie/vbulletin/showthread.php?t=2057714322&page=15

Gonzo

I am not expecting a whole lot here, maybe somewhere between 1 and 3 cm of snow. I got really lucky a few weeks ago and got a decent 8 or 9 cm from a north-westerly, sadly it was very mild the following day and it washed away.

dacogawa

The HIRLAM is looking quite good, snow starting in Dublin around 10pm tomorrow

highdef

Gonzo wrote: »

I am not expecting a whole lot here, maybe somewhere between 1 and 3 cm of snow. I got really lucky a few weeks ago and got a decent 8 or 9 cm from a north-westerly, sadly it was very mild the following day and it washed away.

Whilst I'm not expecting a huge amount either, it'll be nice to see constant falling snow for several hours. I would imagine that locally, some areas will receive higher accumulations, just as is the case with any Atlantic based weather front.

Your snowfall totals a few weeks ago demonstrate that as I only for a couple of cm, despite not being too far from you. 400% more than me is quite a difference, you were just lucky with precipitation distribution.

Oneiric 3

Td temp around the time the front is lying over the east of Ireland:



Not sure how this equates to the idea of 'dry snow'? Good chance of snow, yes, but I thought 'dry' snow needed dew points of at least -4.0c?

Meteorite58

WRF -NMM 2 km only runs to 01.00 at this stage. Looks light .

Cantona's Collars

BBC forecast on Countryfile giving snow mainly for Eastern Ireland as the front moves in and hits the cold. A very slight rise in temperature on Wednesday into Thursday with another front moving in and back to cold weather again.

Meteorite58

Watch the roads Tues morning!

Periscal

Ok here we go, charts for midnight tomorrow

1.Arpege



2.Hirlam



3.Arome



4. ICON



5. GFS

Gaoth Laidir

highdef wrote: »

So how dry do you reckon the snow will be? I'm reckoning dry, especially in areas with a little bit of height and also away from urban areas but still not really really dry snow. Should I multiply the expected liquid precipitation totals by about 10 or so, for this event? So 5mm of precipitation would give in our around 5cm of even snow?

I'd say in initially it should be more dry than wet, so probably 20 or 30, but I'd say anything that does fall from Tuesday onwards will be more like 5-10ish.

JCX BXC

GFS is a bit all over the place there isn't it?

Gaoth Laidir

Oneiric 3 wrote: »

Td temp around the time the front is lying over the east of Ireland:



Not sure how this equates to the idea of 'dry snow'? Good chance of snow, yes, but I thought 'dry' snow needed dew points of at least -4.0c?

That's what I mean. Dewpoints on the rise, so what will start off initially as dry snow will probably turn a lot more mixed later on. The dewpoint required depends on the dry-bulb temperature (which determines what the all-important wet-bulb temp will be). As a guide, for the following dry-bulb temperatures we need these dewpoints to keep the wbt at 0 °C:

Dry-bulb.....Dewpoint
+4 ................. -8
+3 ................. -5
+2 ................. -3
+1 ................. -2

PS. Is that the GFS? I don't think we'll be getting -3 dewpoints from a northwesterly.

BLIZZARD7

hmmm a good few of those charts have a snow shield around Dublin, are we looking at another onshore wind scenario or are the models overplaying the UHI effect? I would have thought a light onshore breeze wouldn't necessarily scupper our chances given any air to our east should be of dry continental origin.

ninebeanrows

BLIZZARD7 wrote: »

hmmm a good few of those charts have a snow shield around Dublin, are we looking at another onshore wind scenario or are the models overplaying the UHI effect? I would have thought a light onshore breeze wouldn't necessarily scupper our chances given any air to our east should be of dry continental origin.

I do think the models over playing the UHI, that added to Dublin bay probably tips the balance. Eg.. half grid square in the sea and half grid square ultra UHI bias.

Oneiric 3

Gaoth Laidir wrote: »

PS. Is that the GFS? I don't think we'll be getting -3 dewpoints from a northwesterly.

I agree, and HIRLAM, strangely enough, shows similar, if not more enhanced dew point readings for around the same time. Forecast for my town for Tuesday morn from YR.

redsteveireland

km79 wrote: »

Looks wonderfully dry alright

Dry, except when it rains ?

Oneiric 3

redsteveireland wrote: »

Dry, except when it rains ?

We need an easterly, and one that is sourced somewhere deep in Mother Russia.

redsteveireland

Oneiric 3 wrote: »

We need an easterly, and one that is sourced somewhere deep in Mother Russia.

I've a good 35 years left in me so you never know.

Rebelbrowser

havent watched closely today but from charts just posted what stands out to me is that the front is arriving about 4 hours earlier than progged last night. I dont think that is in anyones interests and completely gooses any chance for my area anyway. I thought this would be more of an overnight affair.

Rodar08

Rebelbrowser wrote: »

havent watched closely today but from charts just posted what stands out to me is that the front is arriving about 4 hours earlier than progged last night. I dont think that is in anyones interests and completely gooses any chance for my area anyway. I thought this would be more of an overnight affair.

Would this mean it will touchdown more to the west and northwest rather than passing over there and touching down in the midlands and east as before? Or have I got that all wrong

JCX BXC

Rodar08 wrote: »

Would this mean it will touchdown more to the west and northwest rather than passing over there and touching down in the midlands and east as before? Or have I got that all wrong

Not like that at all sadly, just means temperatures could be higher meaning less snow and more mixed precipitation/rain

mickger844posts

The front coming in earlier than previously modeled which isn’t a good thing for anyone really. All looking that bit more marginal now. Like always it’s never easy for us to get snow and even harder to forecast it. As usual it will be a now cast.

pad199207

mickger844posts wrote: »

The front coming in earlier than previously modeled which isn’t a good thing for anyone really. All looking that bit more marginal now. Like always it’s never easy for us to get snow and even harder to forecast it. As usual it will be a now cast.

The east still pretty much in the game