Snow and Ice Warning : Saturday(PM)/Sunday 9th/10th December - SEE MOD NOTE POST #1

Danno

The main rain band is showing up off the coast of Kerry now.

Dermondo

Rain in south west Wexford currently ....

icesnowfrost

Dew point in Louth is -1 to -2 did u see the midlands however, dew point is -4

dfx-

I'm around the Birmingham/Coventry area and forecast is for snow for nearly 12 hours supposedly from 5am at about 3cm/hr...

Is there really that sort of potential in this or more likely turning to rain? :eek:

BLIZZARD7

dfx- wrote: »

I'm around the Birmingham/Coventry area and forecast is for snow for nearly 12 hours supposedly from 5am at about 3cm/hr...

Is there really that sort of potential in this or more likely turning to rain? :eek:

Definitely the potential for that in certain areas Midlands UK.

dzer2

nagdefy wrote: »

I know it well. We'd be around the same height. You know where the highest windmills are, that would be opposite us.

We get dumped alright! I went to school in Ardough with a lot of the Cruttenclough lads. My grandmother on my dad's side was from where you're from!

Yeah know them wind mills well.

If there is snow about we get it.:o:o:o:o:D

BorneTobyWilde

Temp predicted to gradually rise almost every where, could be some nice rain.

sryanbruen

nagdefy wrote: »

That cold December led into the January 8th 1982 snowfall. It was a raw month that December.

Sryan would confirm but it was a 'frontloaded' winter. I'd say your parents were worrying about getting to the hospital:)

I have access to archival newspapers lately and they're brilliant for confirming what's in my memory, some dates are correct and then some fixed in my mind are off. But that 13 December 1981 stuck in my mind and just the similarities with now.

Indeed it was a front loaded Winter.

December 1981 was the coldest December of the century with an IMT of only 1.1c, -4.5c below the average. December 2010 had an IMT of -0.7c in comparison, -6.3c below the average.

Here's what Met Éireann say about the month:

The period from the 1st to 4th was cloudy and mild with extensive fog and patches of drizzle. A wave depression affected the southwest on the 5th after which a northwesterly airflow set in. Squally showers occurred, some heavy especially in northern areas on the 7th. Weak troughs of low pressure affected the country between the 8th and 10th and high pressure dominated the 11th and 12th. There was extensive freezing fog during these spells Strong winds and widespread heavy falls of snow or rain occurred in all areas on the 13th, associated with a depression centred over southern areas.

A ridge of high pressure developed on the 14th and the period to the 19th was very cold and dry with general air frost and sharp to severe ground frost.
Mild air in a complex frontal trough affected the country during the 19th and there was widespread heavy rain, especially in southern regions. The period from the 20th to the 22nd was foggy with spells of drizzle and there was light frost at night in some places. Subsequently, a cold easterly airflow was established and widespread frost became severe between the 23rd and 25th.

A strong south to southeast airflow set in during the 25th. The weather became mild with extensive rain and drizzle. Winds backed easterly on the 28th and there was widespread heavy rain on the 28th and 29th. Rain became scattered on the 30th and 31st and some frost occurred at night.

Looking at this information, with the IMT, December 1981 does not seem like a particularly amazing month does it? Well the thing was that the majority of the severe cold was associated with extensive fog which in Winter often leads to a lot of frost. Mullingar had the minimum for December with -12.4c on the 12th, the night before the depression that brought widespread snow on the 13th as you mentioned.

January 1982 started off rather mild in a southwesterly air stream bringing heavy rain. However, a very cold (extremely so) spell set in on the 6th up to the 14th. This severe cold gave temperatures as low as -27c in Scotland, equaling the UK's all-time lowest temperature (equaled with February 1895 and December 1995). See this graphic here showing the daily mean temperatures (red = above average, blue = below average) for Phoenix Park in Winter 1981/82. Look at the extremes of the cold near the beginning to mid January 1982. The lowest Ireland got down to during this spell was -14.6c at Birr on the 12th. Along with these extremely low temperatures, there was a lot of snow. Snow drifts of 2-5m were recorded including extensive blizzards on the 8th and 9th. However, from the 15th onwards, this became a distant memory and the rest of January was mild to very mild as you can see from the graphic. As a result, the IMT was 5.2c for the month, only -0.3c below the average so the devil really is in the detail!

February 1982 was mild generally with just a few cold intervals toward the latter half of the month.

Danno

Coldest spot in the country here tomorrow night according to the latest ECM.

A bone chilling -9c! :eek:

KingBobby

according to my maplin weather station temp is +1.7c and dewpoint is -6.6c
does that sound a bit wrong? like could it be faulty? I thought the figures would be a bit closer together or something. Absolutely no idea what dewpoint really is, in case that wasnt obvious already from my post

BLIZZARD7

KingBobby wrote: »

according to my maplin weather station temp is +1.7c and dewpoint is -6.6c
does that sound a bit wrong? like could it be faulty? I thought the figures would be a bit closer together or something. Absolutely no idea what dewpoint really is, in case that wasnt obvious already from my post

I'd be surprised if the DP is that low given the air coming in is very much saturated.

nagdefy

dzer2 wrote: »

Yeah know them wind mills well.

If there is snow about we get it.:o:o:o:o:D

One on the farm at home. Do you know what i must do sometime, there's an elevator up to the top. Go up and take pics!

There's a hardy oul wind blows over from The Lots alright!

nagdefy

Danno wrote: »

Coldest spot in the country here tomorrow night according to the latest ECM.

A bone chilling -9c! :eek:

Hopefully with lying snow Danno that would be very realistic. I always find Durrow to be a frost hollow too..

amadangomor

natashaob6 wrote: »

Well Offaly was mentioned by Gerry Murphy's as one of the counties to get some decent snowfall so depending on what time the low pressure reaches your part of the County and the time you plan to leave I would say just keep an eye on the forecast.

Maybe get a cheap hotel near the airport, just in case. Or could go before the front arrives and hot whiskeys in the airport bar to keep you going

Nettle Soup

What effects do large freshwater lakes have on temperatures and snow?
I heard before that Lough Corrib and Mask can act as a snow shield. Is that true?

sryanbruen

snowstorm445 wrote: »

Rain here in Cork for the past few hours now, far too warm for snow. Hoping to see some on the way back up to tomorrow.

You have to feel sorry for the poor Dubs, they’ve had no real snow of note since late 2010. Looks like it’ll miss out on this one as well. Hopefully there’ll be a decent easterly at some point this winter to fix that.

At least somebody cares . Thanks :pac:.

giveitholly

Have a look at mt's update on his daily forecast for anyone living in the south

Danno

The black line will be the rough path of the triple-point.

Slashermcguirk

How many times have met eireann changed their forecast today!!?? You would really think within 12-24 hours they could have nailed it down better. I mean changing forecast about 5 hours before the so called event is pretty bad. I know there are variables at play but they surely have access to a lot of weather models, you would expect a met service to be able to predict better within 24 hours. We will see what happens from here but it’s been like musical chairs today moving warning from one county to another. You would most certainly expect it 2 or more days out but not within 12-24 hours

Danno

A big 1c jump in temperatures in the last few minutes. Now 2.9c. Interestingly, the dewpoint is still sub-zero just at -0.1c.

John.Icy

Slashermcguirk wrote: »

How many times have met eireann changed their forecast today!!?? You would really think within 12-24 hours they could have nailed it down better. I mean changing forecast about 5 hours before the so called event is pretty bad. I know there are variables at play but they surely have access to a lot of weather models, you would expect a met service to be able to predict better within 24 hours. We will see what happens from here but it’s been like musical chairs today moving warning from one county to another. You would most certainly expect it 2 or more days out but not within 12-24 hours

It's a ridiculously volatile situation. The whole concept of a 'nowcast' is that anything can happen in certain areas no matter the forecast. Until it starts falling from the sky anything could happen for parts.

In fact I commend ME for regularly updating the forecast in such a dynamic situation. Could have easily sat on a generic safe forecast and hoped for the best.

JCX BXC

Slashermcguirk wrote: »

How many times have met eireann changed their forecast today!!?? You would really think within 12-24 hours they could have nailed it down better. I mean changing forecast about 5 hours before the so called event is pretty bad. I know there are variables at play but they surely have access to a lot of weather models, you would expect a met service to be able to predict better within 24 hours. We will see what happens from here but it’s been like musical chairs today moving warning from one county to another. You would most certainly expect it 2 or more days out but not within 12-24 hours

Completely disagree, frontal snow where conditions are so marginal, a difference of 0.5c could put several counties in or out of the mix, I think ME are Infact doing a very good job.

sryanbruen

Slashermcguirk wrote: »

How many times have met eireann changed their forecast today!!?? You would really think within 12-24 hours they could have nailed it down better. I mean changing forecast about 5 hours before the so called event is pretty bad. I know there are variables at play but they surely have access to a lot of weather models, you would expect a met service to be able to predict better within 24 hours. We will see what happens from here but it’s been like musical chairs today moving warning from one county to another. You would most certainly expect it 2 or more days out but not within 12-24 hours

You seriously don't understand the difficulty of things like this - or weather in general, do you?

rahmalec

Need to get from Cork to Dublin Monday morning. Should I book a train or a bus?

Gaoth Laidir

Nettle Soup wrote: »

Can someone tell me what the ideal dew point is for snow?

Wet-bulb temperature is more important. It's just above half way between dew point and temperature (closer to temperature). A wbt of less than zero is needed, though snow can survive up to around +0.5 °C.

If temperature is 4 and then dewpoint needs to be around -5 for the wbt to be around 0.

Danno

Here is a good map to the highly regarded Davis Weather Stations - quite a few across Ireland when you zoom in: http://www.weatherlink.com/map.php

Slashermcguirk

sryanbruen wrote: »

You seriously don't understand the difficulty of things like this - or weather in general, do you?

This is hardly the first time we have encountered a snow event. I do understand there are variables at play but they have decades of experience doing this. I am not saying met eireann are poor in general, they are often very reliable but today has been all over the shop.

Danno

Gaoth Laidir wrote: »

Wet-bulb temperature is more important. It's just above half way between dew point and temperature (closer to temperature). A wbt of less than zero is needed, though snow can survive up to around +0.5 °C.

If temperature is 4 and then dewpoint needs to be around -5 for the wbt to be around 0.

And here is a good calculator for getting the wetbulb from your humidity, temperature and air pressure: http://www.srh.noaa.gov/epz/?n=wxcalc_rh

George Sunsnow

Currently 0.9c in Arklow co Wicklow
Dew point is -2c
100% cloud cover
Flat calm

CeilingFly

Slashermcguirk wrote: »

How many times have met eireann changed their forecast today!!?? You would really think within 12-24 hours they could have nailed it down better. I mean changing forecast about 5 hours before the so called event is pretty bad. I know there are variables at play but they surely have access to a lot of weather models, you would expect a met service to be able to predict better within 24 hours. We will see what happens from here but it’s been like musical chairs today moving warning from one county to another. You would most certainly expect it 2 or more days out but not within 12-24 hours

Can you state your expertise in metrology that gives you such a standing that you can question experts?

I've very little knowledge, but I do know that Ireland has some of the most changeable weather in the world. Atmosphere is constantly moving, the Atlantic and the coastal mountains can mean last minute changes especially in volatile systems such as this.

Its also why its called a "forecast" not a "certainty"