Cold Spell - Feb 7th to 13th 2021 - Chat

typhoony

Looking at temps over in the UK this morning I would suggest it will not be cold enough in Dublin until late this evening

gerrybhoy

ffarrell7 wrote: »

Freezing cold in West Dublin now... I can smell the snow at this stage.... I imagine we will start having hail and snow showers by late this evening in parts of Dublin and lots more tomortow and Tuesday...

Said the same to the wife there her reply

Eff off and get back to sleep

Elmer Blooker

Its taking its time getting here. 4.5c when I went to bed and 3.8c now so hardly dramatic. I was expecting it to be a LOT colder than that this morning.
The lamb from the east?

TheMilkyPirate

Thursday going to be a fun day snow wise. Hopefully the cold air can hang on in the east at least and allow the snow to stick around on the ground.

celt262

gerrybhoy wrote: »

Said the same to the wife there her reply

Eff off and get back to sleep

Well for some lying in on a Sunday I'd take that over snow !

gerrybhoy

celt262 wrote: »

Well for some lying in on a Sunday I'd take that over snow !

its the only day we get anything that resembles a lay in,2 of us up at 6.30 most the week

Gaoth Laidir

TheMilkyPirate wrote: »

What location is that for GL? Have you a link that would explain how to interpret these soundings for an amateur

That was somewhere in the midlands, probably near Laois, I think. I just clicked on the map to generate it. The latitude and longitude are stated on it. Here is the link

https://meteologix.com/ie/model-charts/euro

Change the map time to whenever you want. Click on the balloon icon on the map to convert to sounding mode and then just click on the location on the map to generate a forecast soundings for that location.

It's a vertical image of the atmosphere, with the horizontal white lines showing pressure levels as you go up. The slanting white lines from bottom left to top right are isotherms, labelled every 10 degrees along the bottom axis. If you look at the 0-isotherm, anything to the left of that line is below 0 and to the right of it is above 0.

The two white curves are the temperature (right curve) and dewpoint (left curve). Both are plotted for every pressure level and joined up to form the line.

For snow we want these curves to be to the left of the 0-degree isotherm, which they both are in that sounding I posted. Also, at the lowest levels they are on top of eachother, meaning the air is fully saturated. They both are around -5 °C for a good depth of the lower levels, which would form small snizzle or single snow crystals. They are also together below -10 °C, which is the start of the Dendritic-growth Zone, the optimum temperature for forming dendrite snow crystals. With saturation occuring at these temperatures and not lower it means that there is a lot of moisture in the air and therefore snowfall intensity would be enhanced.

At the very lowest level (bottom of the curve) we want the temperature curve to be near or below zero for snow to fall at the surface. Even if temperature is slightly above 0 snow could still fall of the dewpoint is far enough below zero (to the left), as this would keep the wet-bulb temperature below the critical 0.5 °C. WBT is between the temperature and dewpoint curve, around 40% from the temperature.

DellyBelly

DOCARCH wrote: »

Agreed. Would have liked a few decent air/ground frosts before this easterly set in. Not too excited about prospects for the coming days.

I think we may right on the prospects alright. Hopefully we get away with altogether here on the East Coast...

Davaeo09

Great Post GL thanks very much for the level of detail and explanation you always deliver.
Can we pin this some where so it doesn't get lost in this fast moving thread lol.

esposito

Gaoth Laidir wrote: »

https://meteologix.com/ie/model-charts/euro

.

Do you know if there is an app we can download for meteologix?

Gaoth Laidir

esposito wrote: »

Do you know if there is an app we can download for meteologix?

They do the Pflotsh ECMWF app, which I downloaded and paid subscription for, but I don't use it anymore and prefer the site.

Comhrá

Gaoth Laidir wrote: »

That was somewhere in the midlands, probably near Laois, I think. I just clicked on the map to generate it. The latitude and longitude are stated on it. Here is the link

https://meteologix.com/ie/model-charts/euro

Change the map time to whenever you want. Click on the balloon icon on the map to convert to sounding mode and then just click on the location on the map to generate a forecast soundings for that location.

It's a vertical image of the atmosphere, with the horizontal white lines showing pressure levels as you go up. The slanting white lines from bottom left to top right are isotherms, labelled every 10 degrees along the bottom axis. If you look at the 0-isotherm, anything to the left of that line is below 0 and to the right of it is above 0.

The two white curves are the temperature (right curve) and dewpoint (left curve). Both are plotted for every pressure level and joined up to form the line.

For snow we want these curves to be to the left of the 0-degree isotherm, which they both are in that sounding I posted. Also, at the lowest levels they are on top of eachother, meaning the air is fully saturated. They both are around -5 °C for a good depth of the lower levels, which would form small snizzle or single snow crystals. They are also together below -10 °C, which is the start of the Dendritic-growth Zone, the optimum temperature for forming dendrite snow crystals. With saturation occuring at these temperatures and not lower it means that there is a lot of moisture in the air and therefore snowfall intensity would be enhanced.

At the very lowest level (bottom of the curve) we want the temperature curve to be near or below zero for snow to fall at the surface. Even if temperature is slightly above 0 snow could still fall of the dewpoint is far enough below zero (to the left), as this would keep the wet-bulb temperature below the critical 0.5 °C. WBT is between the temperature and dewpoint curve, around 40% from the temperature.

Excellent post. I needed such an explanation to make it easier to understand those soundings. This makes things clearer for us amateur enthusiasts.

Thank you Gaoth Laidir!

TheMilkyPirate

Gaoth Laidir wrote: »

That was somewhere in the midlands, probably near Laois, I think. I just clicked on the map to generate it. The latitude and longitude are stated on it. Here is the link

https://meteologix.com/ie/model-charts/euro

Change the map time to whenever you want. Click on the balloon icon on the map to convert to sounding mode and then just click on the location on the map to generate a forecast soundings for that location.

It's a vertical image of the atmosphere, with the horizontal white lines showing pressure levels as you go up. The slanting white lines from bottom left to top right are isotherms, labelled every 10 degrees along the bottom axis. If you look at the 0-isotherm, anything to the left of that line is below 0 and to the right of it is above 0.

The two white curves are the temperature (right curve) and dewpoint (left curve). Both are plotted for every pressure level and joined up to form the line.

For snow we want these curves to be to the left of the 0-degree isotherm, which they both are in that sounding I posted. Also, at the lowest levels they are on top of eachother, meaning the air is fully saturated. They both are around -5 °C for a good depth of the lower levels, which would form small snizzle or single snow crystals. They are also together below -10 °C, which is the start of the Dendritic-growth Zone, the optimum temperature for forming dendrite snow crystals. With saturation occuring at these temperatures and not lower it means that there is a lot of moisture in the air and therefore snowfall intensity would be enhanced.

At the very lowest level (bottom of the curve) we want the temperature curve to be near or below zero for snow to fall at the surface. Even if temperature is slightly above 0 snow could still fall of the dewpoint is far enough below zero (to the left), as this would keep the wet-bulb temperature below the critical 0.5 °C. WBT is between the temperature and dewpoint curve, around 40% from the temperature.

Brilliant, thanks

Slashermcguirk

Not sticking though, very wet over in London

DOCARCH wrote: »

Much colder air filtering into SE UK now and earlier rain turning to snow.

JanuarySnowstor

https://modeles.meteociel.fr/modeles/gfs/runs/2021020706/gfs-1-198.png?6
Wow!!! An extraordinary level of cold out East in 7/8 days time. Would smash records if it came our way

SEPT 23 1989

Snowing heavily and sticking in Kent according to a live report on BBC 4

monty_python

Have we been downgraded lads?
I've a feeling we will won't get much out of this, hopefully im wrong

West Dublin

Slashermcguirk

Was just talking to a friend in London who said it’s very wet there and not sticking yet anyway. They had a lot of rain

SEPT 23 1989 wrote: »

Snowing heavily and sticking in Kent according to a live report on BBC 4

AndyBoBandy

JanuarySnowstor wrote: »

https://modeles.meteociel.fr/modeles/gfs/runs/2021020706/gfs-1-198.png?6
Wow!!! An extraordinary level of cold out East in 7/8 days time. Would smash records if it came our way

I spent 2 winters in Lithuania, and was not disappointed.....



Arrived there on Jan 5th, and didn't see the grass outside my apartment until April...

redsteveireland

SEPT 23 1989 wrote: »

Snowing heavily and sticking in Kent according to a live report on BBC 4

My sister is in Kent and just accused me of lieing about the arrival of snow, as she has none yet

Slashermcguirk

Met Éireann website saying moderate accumulations in the east by Tuesday

Mimon

monty_python wrote: »

Have we been downgraded lads?
I've a feeling we will won't get much out of this, hopefully im wrong

West Dublin

Have a look at MT's forecast. Still all to play for.

SleetAndSnow

Raining in cork city, if this wind kept up and the temperatures dropped I think we'd be lucky!

hatrickpatrick

What exactly are we looking for model-wise when it comes to streamers? They've always been a bit of a mystery to me! Would they show up as spontaneously appearing bands of snow originating in the Irish Sea on a model like HARMONIE for instance?

YanSno

Cold air rolling in, 10am DP 0c @ M2 Buoy. Any precipitation will be of a wintry nature

Reversal

Slashermcguirk wrote: »

Met Éireann website saying moderate accumulations in the east by Tuesday

Yeah more variability in wind direction on this morning's runs. More ENE direction at times should give a wider coverage of showers.

Rebelbrowser

hatrickpatrick wrote: »

What exactly are we looking for model-wise when it comes to streamers? They've always been a bit of a mystery to me! Would they show up as spontaneously appearing bands of snow originating in the Irish Sea on a model like HARMONIE for instance?

In 2018 the rainfall forecast interactive map thing on the met.ie app was pretty good for them and think that is Harmoine so, yes, I think..... but I think they only start to show when they are a few hours away.

Little snowy old me

A cold fresh morning here in south Donegal. Even a few peeks of blue sky from between the clouds. Bitingly cold in the breeze. Had a big walk and it was wonderful to feel the cold against your face. While I'm disappointed that there appears to be a downgrade concerning later in the week, I'll take 2 or 3 days of this current weather anyday over Atlantic mild muck.

Zogabomb

Little snowy old me wrote: »

A cold fresh morning here in south Donegal. Even a few peeks of blue sky from between the clouds. Bitingly cold in the breeze. Had a big walk and it was wonderful to feel the cold against your face. While I'm disappointed that there appears to be a downgrade concerning later in the week, I'll take 2 or 3 days of this current weather anyday over Atlantic mild muck.

What's the downgrade later in the week? ME's forecast is firming up on a snow day Thursday before milder air pushes through for the weekend. That was always the general theme

coconnellz

Currently Sleet shower and nice big chunky flakes falling here South Cavan 100 meters