Big Change Monday Onward, much colder, ice and snow later

13-12-2009 04:14PM

Looks like there will be no snow this week

John Eagleton didn't even mention it - "a bit wintry"

How can the folks on here be so certain?
Have Met Eireann got it wrong?

maquiladora · 13-12-2009 04:26PM

12Z out as far as next weekend now and delivers and bit of a snowfest Saturday/Sunday to the northern half of the country. Shame that the good snow always seems to be outside the reliable timeframe with the GFS....

JanuarySnowstor · 13-12-2009 04:33PM

12z is a huge upgrade
Snow can and will occur anywhere from wed on
Bitterly cold aswell with ice days very likely

maquiladora · 13-12-2009 04:44PM

JanuarySnowstor wrote: »

12z is a huge upgrade
Snow can and will occur anywhere from wed on
Bitterly cold aswell with ice days very likely

Precip looked very light on the 12Z to me until Saturday, look lighter than the 06Z.

Gonzo · 13-12-2009 04:54PM

hmm the snow seems to be consistently delayed a day as each day go's on? a few days ago it was looking like we mite get the first flurries tonight and 2moro, now its nearly another week away?

13-12-2009 05:12PM

JanuarySnowstor wrote: »

12z is a huge upgrade
Snow can and will occur anywhere from wed on
Bitterly cold aswell with ice days very likely

But will it stick, temps are above 0c during the day, a good bit above

Jesus Wept · 13-12-2009 05:13PM

It's too cold to snow.

Supercell · 13-12-2009 05:16PM

I dont see any delay in the 12z, looks like Tuesday onwards has snow potential (here), nothing has changed that opinion for days now. I fully expect to have a white covering outside by Friday , only question in my mind is to what depth it will be!

Pangea · 13-12-2009 05:19PM

The-Rigger wrote: »

It's too cold to snow.

humbug :P

cinnamon · 13-12-2009 05:22PM

Ireland NEEDS snow.

Floods, Recession, Raging Unemployment, Thwarted World Cup attempt, not to mention the bloody Budget.

I don't know of a country more in need of a snowman-making-snowball-fighting-childhood-reawakening-going-back-to-the-simpler-things-magical-winter-wonderland than this one!

TheGreenGiant · 13-12-2009 05:38PM

look at this chart 160 hours out! Looking pretty good I must say. :cool:

gfs-0-162.png?12

Elmo5 · 13-12-2009 05:38PM

I know, this is FI... BUT.. if you want some of the good stuff have a look at this...

Elmo5 · 13-12-2009 05:40PM

LOL, snap GreenGiant!

Su Campu · 13-12-2009 05:47PM

The models are swinging back around to a northerly flow over the country next weekend, with little synoptic activity. Main precipitation with that setup would be marine instability generating wintry showers in the north and northwest, which is what the GFS has in abundance (below).

The rest of the country would get the odd shower making it south, and depending on the exact wind vectors, maybe a convergence line forming north-south down the Irish Sea. But to be honest, I see the whole thing turning out to be a damp squid (pun intended) - raw, yes, but not widespread snow as shown below. Too much of a sea track will modify the Arctic airmass too much...

Su Campu · 13-12-2009 05:50PM

Elmo5 wrote: »

I know, this is FI... BUT.. if you want some of the good stuff have a look at this...

Excuse the ignorance, but what does FI stand for??!

maquiladora · 13-12-2009 05:52PM

Something which should not be overlooked is how cold its going to get, regardless of snow.

For example, Met Eireann is predicting lowest temps of -5 overnight tonight. If you look at the current GFS chart for tonight the lowest you can see over Ireland is -1 which shows that the GFS struggles to nail temps in detail.

Now thats just tonight, let's use that as a guide and say that you could subtract 3 or 4 degrees from a GFS chart to get something closer to reality.

With that in mind lets look ahead to Sunday, and if we use that guide then we could see temps getting down to -9 at night and the midlands could even have max daytime temps of -5. Crazy cold compared to what were used to. And thats 2m temps, not 850s!

Brrr...

maquiladora · 13-12-2009 05:55PM

Su Campu wrote: »

Excuse the ignorance, but what does FI stand for??!

Anything beyond about 100 to 120 hours is subject to big changes and isnt reliable so its nicknamed Fantasy Island.

Supercell · 13-12-2009 05:56PM

Su Campu wrote: »

The models are swinging back around to a northerly flow over the country next weekend, with little synoptic activity. Main precipitation with that setup would be marine instability generating wintry showers in the north and northwest, which is what the GFS has in abundance (below).

The rest of the country would get the odd shower making it south, and depending on the exact wind vectors, maybe a convergence line forming north-south down the Irish Sea. But to be honest, I see the whole thing turning out to be a damp squid (pun intended) - raw, yes, but not widespread snow as shown below. Too much of a sea track will modify the Arctic airmass too much...

Su Campu, I refer you to the last post by maquiladora...

pauldry · 13-12-2009 05:59PM

My FI forecast is for cold weather until 23rd Dec. Some snow next weekendin North, East and maybe North Connaught . After this wet and windy weather moving up from the South preceded by sleet in places for Xmas day.Prob unsettled cold (but not v cold) until end of December.

FI but quite likely id think.:D

Su Campu · 13-12-2009 06:11PM

maquiladora wrote: »

Something which should not be overlooked is how cold its going to get, regardless of snow.

For example, Met Eireann is predicting lowest temps of -5 overnight tonight. If you look at the current GFS chart for tonight the lowest you can see over Ireland is -1 which shows that the GFS struggles to nail temps in detail.

Now thats just tonight, let's use that as a guide and say that you could subtract 3 or 4 degrees from a GFS chart to get something closer to reality.

With that in mind lets look ahead to Sunday, and if we use that guide then we could see temps getting down to -9 at night and the midlands could even have max daytime temps of -5. Crazy cold compared to what were used to. And thats 2m temps, not 850s!

Brrr...

Met Éireann don't use the GFS so that's why one should look at several models together, look for agreements/differences, and use your meteorological knowledge to put the meat on the bones. I believe they use the HIRLAM, UKMET and ECMWF, but stand to be corrected on that.

Predicting minimum temperatures in slack conditions like today's can be tricky, as a coupled vs decoupled boundary layer can make several degrees of a difference. I would always go with a human forecast for the short term, as local nuances can be missed in global models.

PS Thanks for the FI explanation Maquiladora!

maquiladora · 13-12-2009 06:23PM

Su Campu wrote: »

Met Éireann don't use the GFS so that's why one should look at several models together, look for agreements/differences, and use your meteorological knowledge to put the meat on the bones. I believe they use the HIRLAM, UKMET and ECMWF, but stand to be corrected on that.

Predicting minimum temperatures in slack conditions like today's can be tricky, as a coupled vs decoupled boundary layer can make several degrees of a difference. I would always go with a human forecast for the short term, as local nuances can be missed in global models.

PS Thanks for the FI explanation Maquiladora!

Thats right, Met Eireann use HIRLAM out to 48 hours I think and ECM beyond that (?). The point I was making was that the GFS being a global model rather than a regional one isnt so good with smaller scale places like our little Island :P and temps could be easily out by 3 or 4 degrees.

Weather coming up on TV now after the news...

rc28 · 13-12-2009 06:30PM

Wow, if anything that 6 weather forecast was even more dissappointing than the farming forecast - not even a mention of 'wintriness' this time.

maquiladora · 13-12-2009 06:31PM

Not even a mention of "wintery" let alone the s word on that forecast!

Oh well...

maquiladora · 13-12-2009 06:31PM

rc28 wrote: »

Wow, if anything that 6 weather forecast was even more dissappointing than the farming forecast - not even a mention of 'wintriness' this time.

Snap!

Edit...the latest ECM run might be the reason why....

snow plow · 13-12-2009 06:39PM

maquiladora wrote: »

Not even a mention of "wintery" let alone the s word on that forecast! Oh well...

Yes but he did say there was alot of uncertainty mid-week with instability building up on a cold north-easterly wind and showers will affect Eastern and northern coasts.

Met eireann are playing it very safe IMO but seriously they could have said wintry showers!

Dan

Trogdor · 13-12-2009 06:54PM

maquiladora wrote: »

Something which should not be overlooked is how cold its going to get, regardless of snow.

For example, Met Eireann is predicting lowest temps of -5 overnight tonight. If you look at the current GFS chart for tonight the lowest you can see over Ireland is -1 which shows that the GFS struggles to nail temps in detail.

Now thats just tonight, let's use that as a guide and say that you could subtract 3 or 4 degrees from a GFS chart to get something closer to reality.

With that in mind lets look ahead to Sunday, and if we use that guide then we could see temps getting down to -9 at night and the midlands could even have max daytime temps of -5. Crazy cold compared to what were used to. And thats 2m temps, not 850s!

Brrr...

I don't think daytime maxes of -5C are quite on offer, but i hope i'm proven wrong:p:D

owenc · 13-12-2009 07:00PM

trogdor wrote: »

I don't think daytime maxes of -5C are quite on offer, but i hope i'm proven wrong:p:D

well we had a max of 1c here today and that was in sunshine and we arnt even in the cold air yet. id say mins of -10c are on offer but id say for most maxes of -3c are possible its england were their will be -6c maxes!

Elmer Blooker · 13-12-2009 07:07PM

maquiladora wrote: »

Not even a mention of "wintery" let alone the s word on that forecast! Oh well...

I can only describe the Eagle Eagleton's forecast as hilarious, talk about "the elephant in the room" He kept mentioning "instability" which probably means "disruption"

Elmo5 · 13-12-2009 07:23PM

The Eagle did also say that the high was going to move up north and the easterly flow was going to move in... that our weather would be coming from the east and the north...

Pangea · 13-12-2009 07:40PM

Eageltons forecast from this evening Forecast.mpg - 51.24MB#
I found it a bit dissapointing aswell.

Heres the latest from met uk, they seem to think that it will turn warmer after christmas

oh well , still a fantastic week ahead

UK Outlook for Friday 18 Dec 2009 to Sunday 27 Dec 2009:

"Initially it looks likely to be cold with sleet and snow showers, most of which will fall in northern and eastern areas, giving accumulations of snow in places. There is also the risk of some more persistent sleet or snow at times in northern parts whereas the driest conditions are most likely to occur in the south and west. There is also a risk of freezing fog patches. Many parts windy with a significant wind chill making it feel very cold. As we move into the following week we are likely to see a period of sleet and snow moving northwards across the UK, turning to rain in the south. Then, over the Christmas period we currently expect unsettled and occasionally windy conditions, and perhaps turning less cold at times"

Big Change Monday Onward, much colder, ice and snow later

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