Snow Ice Warning for Ireland 29 Jan to 03 Feb 2019 *See Mod Note in OP *

Danno

AWS Air -3.8c, Screen Air -4.1c, Grass minimum -8.6c. Five centimetre soil 0.9c, Ten centimetre soil 2.2c.

If it snows here, she'll stick and build.

South Laois, 89m ASL.

Kermit.de.frog

It does feel like one of those classic prep nights for the following day

JanuarySnowstor

Things have swung back in favour of snow tonight. Both gfs and parallel are both upping the wintry ppn. Indeed the parallel would bring things very close to red. Sweet spot tomorrow for me Cahir/Clonmel

sdanseo

Parallel moving the precip slightly further south. Any decent stuff stopping around the Dublin/Wicklow border.

In any event, for Dublin at least, will be schnizzle, not snow.

Gaoth Laidir

JanuarySnowstor wrote: »

Things have swung back in favour of snow tonight. Both gfs and parallel are both upping the wintry ppn. Indeed the parallel would bring things very close to red. Sweet spot tomorrow for me Cahir/Clonmel

The GFS are not worth a shïte for low levels when it comes to the precipitation type. I've shown two examples of that over the past few days. It's still as you were earlier. Marginal at lowest levels, good higher up. The ARPEGE soundings are surprisingly on board too. It tends to have a slight warm bias at times but it seems consistent with the others on this occasion.

Kermit.de.frog

First echos coming in to Shannon range

sdanseo

GL, am I reading it wrong (very possible) or is this showing for 2200UTC this evening an air temp of around 3.5°, wet bulb 2.5° and DP 1.5° or so at 1013hPa?

http://www.meteociel.fr/modeles/sondagewrf/sondagearpegefr_-6.3_53.4_3_0.png

If so, it's very wrong. Current Temp 0° at Dublin and DP -3°
(edit: 1°/-3° at 2230, temp has actually now risen 2 degrees since 6pm) ?

Villain

I’m thinking Baunreagh on border of Carlow and Kilkenny could be a sweet spot, 300m ASL

Marengo

Villain wrote: »

I’m thinking Baunreagh on border of Carlow and Kilkenny could be a sweet spot, 300m ASL

Good oul 1798 rebel camp with nice views

squarecircles

Virgin Media news reporting that met eireann are contemplating upgrading the snow ice warning.

RobertKK

Villain wrote: »

I’m thinking Baunreagh on border of Carlow and Kilkenny could be a sweet spot, 300m ASL

Not a million miles away from where I live.

Captain Snow

squarecircles wrote: »

tv3 news reporting that met eireann are contemplating upgrading the snow ice warning.

I still think this is a 95/96 event.

Mortelaro

Arklow bypass and baltinglass co Wicklow are joint 2nd coldest of the traffic infrastructure Ireland road weather stations at the moment at -4,1c
My own Davis station near Arklow is at -3.2c

squarecircles

Captain Snow wrote: »

I still think this is a 95/96 event.

what did that entail?

Captain Snow

squarecircles wrote: »

what did that entail?

An lp going astray and hammering the east coast with snow. It was a classic.

Mortelaro

Baltinglass co Wicklow TII station down to -5,8c now

pauldry

Think bitter chill will ease now and temps will start moving up to 0c

Oscar Bravo

A messy TAF for Knock tomorrow.One things for sure there will be a nasty wind chill. Sleet becoming light snow for most of the day


EIKN 302300Z 3100/3124 20006KT 9999 FEW018
PROB40
TEMPO 3100/3102 0500 FZFG BKN002
BECMG 3101/3104 12012KT
BECMG 3106/3109 10017G27KT 6000 -RASN SCT002 BKN007
TEMPO 3108/3119 09020G34KT 1500 -SN BKN002 SCT018CB
BECMG 3119/3122 06016G26KT 9999 NSW FEW007 SCT020

RobertKK

Mean temperature for my location in Kilkenny for today is currently at -0.2C.

Itssoeasy

Can I ask what to the weather eagles here is a stupid question. From looking at the things posted here, it looks like a weather system will move up over Ireland tomorrow. Is the uncertainty what it will produce rain or snow or a mixture or both ?

Rebelbrowser

Is this level of cold tonight unexpected? I'm in Cork suburb near the coast and it's -3.2 here? Really thought from reading the knowledgeable posters here today that this far west we wouldn't get a cold layer anything like this deep in advance of the front. Does this change things? I note a similar query re the accuracy of the Dublin airport forecast.

Danno

WEATHER WATCH - RISK OF SNOW - THURSDAY WILL BE A NOWCAST: The two charts attached are from the highly respected ECMWF computer model which are used by both the Irish and UK Met Office. The ECMWF is used amongst other models by forecasters, coupled with their experience to produce a weather forecast.
Out of all the forecast models, the ECMWF is "out on it's own" in predicting widespread, substantial snowfall. The American GFS supports widespread snowfall, but not as substantial. Other models such as the Pan-European HIRLAM predict snowfall for hills and mountains, with some isolated lowland areas away from the coasts getting a few centimetres worth. Meanwhile, the British UKMO are predicting alternating waves of sleet and snow across the region tomorrow.
Taking all the above on board it really is impossible to say with any great confidence how tomorrow's weather front will behave. We attach the two images to show the *worst* possible outcome with regards to disruption. So, it would be wise to advise people to keep close attention to weather updates from early morning as reports begin to come in about how the weather front is behaving in its trek up from the southwest - hence "NowCast"
FORECAST FOR THURSDAY: Bitterly cold to begin with temperatures hovering between -4c and -1c, with a light southeast breeze. Clouding over rapidly. Rain and sleet arriving by mid-morning at the latest and continuing to get heavier through lunchtime, becoming more sleet and wet snow at lower levels, heavy settling snow above 250m. Highest temperatures of 1c to 3c at this stage in fresh east winds. Before darkfall, temperatures will drop and winds will shift to the northeast, remaining fresh. Precipitation will turn more to snow at lower levels and begin to settle. Snow continuing past darkfall before clearing later. Temperatures dropping back below 0c. ***This forecast is likely to be revised***
[Apologies that we cannot be more precise, this really is a very difficult situation to forecast]

---

The above went out on https://www.facebook.com/LaoisWeather/

It's probably the best way of summarising the current situation.

Meanwhile, it's gone to -4.3c here on the AWS, screen probably nudging below -4.5c at this stage.

SleetAndSnow

Rebelbrowser wrote: »

Is this level of cold tonight unexpected? I'm in Cork suburb near the coast and it's -3.2 here? Really thought from reading the knowledgeable posters here today that this far west we wouldn't get a cold layer anything like this deep in advance of the front. Does this change things? I note a similar query re the accuracy of the Dublin airport forecast.

Only about -1.4 here in bishopstown area (mostly basing off what cork airport is reading and a basic thermo.in my garden, when combined are usually accurate enough but maybe not tonight), though the cars aren't fully frozen just the roofs of them and the owns with remaining snow, the others not yet. Slightly foggy too.

Mortelaro

Itssoeasy wrote: »

Can I ask what to the weather eagles here is a stupid question. From looking at the things posted here, it looks like a weather system will move up over Ireland tomorrow. Is the uncertainty what it will produce rain or snow or a mixture or both ?

Yeah the air will mix as it heads up making it borderline for rain or snow in most places
Hence the either it will or it wont

pad199207

-6.3c reported in Co Down

SleetAndSnow

Cork airport has winds coming from the east and temp has risen to 1 degrees up there.

aisling86

Rebelbrowser wrote: »

Is this level of cold tonight unexpected? I'm in Cork suburb near the coast and it's -3.2 here? Really thought from reading the knowledgeable posters here today that this far west we wouldn't get a cold layer anything like this deep in advance of the front. Does this change things? I note a similar query re the accuracy of the Dublin airport forecast.

Also makes me wonder why are all the school's in cork city not opening until 10.30/11 tomorrow morning. Are they expecting the rain to freeze as it falls if ground temps don't rise as quickly as air temp is expected to.

sdanseo

Temperature back down again to -1° at Dublin 2300Z. Dewpoint -5°
Has been up and down. -1 at 1800, 0 for a couple of hours, +1 at 2230, now back to -1.

Gaoth Laidir

sdanseo wrote: »

GL, am I reading it wrong (very possible) or is this showing for 2200UTC this evening an air temp of around 3.5°, wet bulb 2.5° and DP 1.5° or so at 1013hPa?

http://www.meteociel.fr/modeles/sondagewrf/sondagearpegefr_-6.3_53.4_3_0.png

If so, it's very wrong. Current Temp 0° at Dublin and DP -3°
(edit: 1°/-3° at 2230, temp has actually now risen 2 degrees since 6pm) ?

Not quite. These soundings only go to 1000 hPa (look at the righthand axis). The top of the faint grey horizontal band just above 1000 hPa shows where the local station level is. In this case it's around 975 hPa (station pressure). So those curves intersect the 975 hPa surface at around 3.0, 2.0 and 0.0, respectively.

When the local pressure is above 1000 hPa there is no grey band. The sounding still stops at 1000 hPa so we don't get to see the rest of it down to the surface. That can be a problem in very strong surface heating or cooling setups, but a bit of local knowledge or filling in the gaps with station observations can fix it.

PS. The time of that chart is 2200 French time (2100 our time). Actual station reports at that time were temp -0.8, dp -2.6, wbt -1.5ish. The sounding does seem to have a cloud layer at around 400 hPa, so it would have had less surface cooling because of that.

Danno

Hard to believe that in December 2010, this would have been a rather "mild" night!