FI Charts (T120+ onwards) Winter 2018 **READ MOD NOTE IN FIRST POST**

Gonzo

these charts are showing alot of work is needed before we are even ready for snow to hit our eastern coastline, we still have a 6 week window for something decent, lets hope it happens!.

Kermit.de.frog

It's getting closer

Kermit.de.frog

rbelmc

both Danish and Swedish weather services are going for a decent period of high pressure weather with signs it may get colder towards the end of this week.The temps forecast are not cold though-just around freezing or a little bit below so we may have to wait a bit longer for any Siberian cold to come our way
www.smhi.se
www.dmi.dk

BLIZZARD7

At +192hrs ECM we are very close to a very cold and snowy scenario, the slider lows back on the menu it seems. This time with a robust high to our north east though. With some luck we could be looking at an improved version of the early December event. Any correction South West from this and we're in business.



UKMO is very similar to the ECM up to +144hrs, if not better. GFS not as good looking east but has improved hugely in the +120 to +144 hrs timeframe from what it was showing just a day or two ago. The block is putting up a fight, if and it's a big IF the jet dives South east then we might be in luck this time. I am however taking the models with a big pinch of salt til we have cross model agreement at +96-120hrs as they have all performed quite badly recently in my opinion, with the exception of the UKMO.

George Sunsnow

Bad performances from the models seems to be par for the course in recent years if they are in any way taxed with complications
It would make you wonder about science and computing
We’re extra sensitive to it here because we know a tweak here or a tweak there does to the feed of air and consequently whether we’re mild or cold

That high hopefully will cool down Europe,the colder it gets,the more surface continental cold feeds come into play rather than 850 temps if you get even a South easterly feed but you’d prefer an easterly
You’ll see it in the rh,the negative dew points,the thickness’s
In short a continental feed in the right circumstances can do what an Atlantic feed can never do and that is deliver a feed of air that’s zero or below completely from cloud base to ground
In some of the 80’s easterlys we had washing on the line freezing in the day time with a wind off the sea
That’s what you get when your surface air feed is also blowing off a totally snow covered Britain and coming via Denmark and the Baltic
I don’t see my favored northeasterly with that high about south scandy
But I don’t see any uninteresting model watching either but will it pay off?
Now there’s the question

Rebelbrowser

Em,, er, the Cork snowshield is down? (of course 20cm of snow is nothing down here....)

JCX BXC

Snow shield pfft

No more snow shield than the vast majority of southern Ireland!

patneve2

The GFS ensembles are actually decent enough. Possibility of a strong polar maritime flow in the long term

Rebelbrowser

I know Atlantic based snow is not highly regarded in these parts but the GFS continues to suggest we've got plenty of it coming on several different days next week. Tomorrow week is the pick of the bunch - see below...

:):)

average_runner

Rebelbrowser wrote: »

I know Atlantic based snow is not highly regarded in these parts but the GFS continues to suggest we've got plenty of it coming on several different days next week. Tomorrow week is the pick of the bunch - see below...

:):)

When ever it comes from the West, it rarely reaches us in Dublin. Hope ye get a load though.

giveitholly

Rebelbrowser wrote: »

I know Atlantic based snow is not highly regarded in these parts but the GFS continues to suggest we've got plenty of it coming on several different days next week. Tomorrow week is the pick of the bunch - see below...

:):)

That'll do

munsterlegend

Rebelbrowser wrote: »

I know Atlantic based snow is not highly regarded in these parts but the GFS continues to suggest we've got plenty of it coming on several different days next week. Tomorrow week is the pick of the bunch - see below...

:):)

Hopefully the experts can throw light on it but unfortunately usually the air gets modified by the Atlantic and only high ground benefits from any snow.

Rebelbrowser

munsterlegend wrote: »

Hopefully the experts can throw light on it but unfortunately usually the air gets modified by the Atlantic and only high ground benefits from any snow.

Agreed but the Atlantic does cool down to some extent throughout the winter so I think a westerly sourced cold feed has at least a better chance of making it here as snow in late January than earlier in the winter. Perhaps the record cold in the U.S. is of assistance in that regard in terms of cooling the gulf stream?

Gonzo

average_runner wrote: »

When ever it comes from the West, it rarely reaches us in Dublin. Hope ye get a load though.

I think it will be the usual story for greater Dublin region. The cold spells so far this winter were mild enough that the precipitation made it all the way across, however several factors including a wind off the Irish sea at one stage turned the snow to cold rain over Leinster. If this cold spell is colder then the December spells, then the shower precipitation will have a much tougher time making it past the river Shannon unless an organised band of precipitation is involved. That chart is showing a mostly dry east, also much of eastern UK is dry too. This is a great chart for those along the west, north-west, Northern Ireland and perhaps Cavan/Monaghan.

Now back to the FI Charts...

George Sunsnow

Nothing inspiring on the 17th
First attachment is the ecm for that day
I’d have said maybe Ulster based on that

3rd is gfs for 1pm 17th RAIN

2nd is gfs the following day- looks like a slush fest inland away from Munster to me-Ulster says yes maybe

All deep FI from nwps that can’t decide 96hrs properly at the moment
So it’s a NO from me

squarecircles

average_runner wrote: »

When ever it comes from the West, it rarely reaches us in Dublin. Hope ye get a load though.

Ohh, exciting,looks good for the west,hope this time the snow sticks around for a while longer.

Shedbebreezy

Rebelbrowser wrote: »

I know Atlantic based snow is not highly regarded in these parts but the GFS continues to suggest we've got plenty of it coming on several different days next week. Tomorrow week is the pick of the bunch - see below...

:):)

I got 1 foot of snow from a South Westerly, 3 years ago I think, Snow showers just streamed all day, the air was of Canadian Arctic origin. Also the timid NW earlier in December me 5 days of lying snow in Donegal. We can do well out of them, nothing beats a straight northerly for us from a greenie high but if you have snow lying, falling and its not melting you couldn't give a ___ what direction its coming from.

nacho libre

Rebelbrowser wrote: »

munsterlegend wrote: »

Hopefully the experts can throw light on it but unfortunately usually the air gets modified by the Atlantic and only high ground benefits from any snow.

Agreed but the Atlantic does cool down to some extent throughout the winter so I think a westerly sourced cold feed has at least a better chance of making it here as snow in late January than earlier in the winter.  Perhaps the record cold in the U.S. is of assistance in that regard in terms of cooling the gulf stream?

Yes these two factors combined increase the chances of snow in the optimum period for snow, which are January  and February, in Ireland. It might not be to some peoples liking, but i think a bit of netweather imbyism is perhaps creeping into some posts because the models are not showing a convective shower train for the east. The charts as depicted by the GFS won't  lead to ice days with a foot of snow in the east, but, even allowing for the fact they do tend to over egg the the 850 temps and dam thickness, quite a few places might see snow and it may accumulate on lower ground.

Neddyusa

nacho libre wrote: »

Yes these two factors combined increase the chances of snow in the optimum period for snow, which are January  and February, in Ireland It might not be to some peoples liking, but i think a bit of netweather imbyism is perhaps creeping into some posts because the models are not showing a convective shower train for the east. The charts as depicted by the GFS won't  lead to ice days with a foot of snow in the east, but, even allowing for the fact they do tend to over egg the the 850 temps and dam thickness, quite a few places might see snow and it may accumulate on lower ground.

"netweather imbyism is perhaps creeping into some posts because the models are not showing a convective shower train for the east"

Yes Nacho, and ironically some of that imbyism coming from posters prone to regularly ridiculing the imbyism and "toys-out-of-the-pram" posts of Netweather

What Rebel browser posted above is no less valid in this thread than the potential cold easterly talk of last week, so no need to poo-poo it.
The thread title is FI afterall

Meteorite58

Yes a wintry outlook from around Sun/ Mon with a cold airmass coming out of Greenland which looks to be around much of the week. 850hPa temps dont look tremendously cold at this stage but cold enough for wintry precipitation I think with the greatest chance of snow especially from next midweek perhaps unless this goes belly up.Would imagine plenty of showers of hail and possible thunder around the coasts too at times. Winds look fresh through the week especially on coasts only leading to a windchill factor I would presume making it feel very cold. Will be interesting watching this unfold and become clearer nearer the time.

Looking windy Sunday before winds change to a W / NW direction sourced from Canada/ Greenland.














Strong jet next week which seems to be keeping to the S of Ireland keeping High pressure to the S and letting the colder airmass N of it develop.

Gaoth Laidir

At just 1800 km, Belmullet is closer to Greenland than it is to Vienna, but that's still a lot of track across an ocean that's still up to 11 °C between here and there.

nacho libre

One crucial difference this time is we have an usually cold westerly airflow source, and the more unstable it is the less time for modification. Bear in mind we also have got heavy snow from the west in recent years from a less cold airflow. Provided the models don't back track, i think in the early days of next week we have a good chance of seeing some snow.

Rebelbrowser

nacho libre wrote: »

One crucial difference this time is we have an usually cold westerly airflow source, and the more unstable it is the less time for modification. Bear in mind we also have got heavy snow from the west in recent years from a less cold airflow. Provided the models don't back track, i think in the early days of next week we have a good chance of seeing some snow.

Dumb question but I always keep meaning to ask - what does "unstable" mean in that context and what is the significance of instability? thanks in advance anyone......

DOCARCH

Rebelbrowser wrote: »

Dumb question but I always keep meaning to ask - what does "unstable" mean in that context and what is the significance of instability? thanks in advance anyone......

Showers....basically. The more unstable, the bigger/heftier the showers.

Rebelbrowser

Lots of pink for next week still on the GFS but these GFS precipitation charts verify for accumulating snow in Ireland about 5% of the time I'd say. Pick of the bunch below.



Meanwhile there is good model correlation n the actual set up next week. ECM and GFS for next Wednesday below...



and

typhoony

I remember back in the 80's we used to regularily get cold NWesterlies, next week looks like a throw back to one of those setups, Showers driving into the west and NW with hail sleet snow even thunder in an unstable airflow. anywhere from north galway should get some heavy prolonged snow showers, usually the showers don't push any further west than the north midlands.

beefburrito

typhoony wrote: »

I remember back in the 80's we used to regularily get cold NWesterlies, next week looks like a throw back to one of those setups, Showers driving into the west and NW with hail sleet snow even thunder in an unstable airflow. anywhere from north galway should get some heavy prolonged snow showers, usually the showers don't push any further west than the north midlands.

You're on the ball there.
I remember frequent weather like this until around 1997 ish.
Winter's were always a mixed bag,but from St Stephens day until around March frost,flat calm and offshore winds and glassy ocean conditions were more common than the dirty mild muck we're used to now.

This winter aint too bád,I remember endless calm frosty weather.

Great conditions for Fishing for flounder's in the estuaries, they loved the cold calm weather.

Whiting,coalies and Cod loved those times too.

I wonder do fish migrate according to the weather conditions.

BLIZZARD7

GFS and ECM differ quite a bit when you look at the ensembles though, Gefs offering far more potential for sliding lows/snow events with the Jet digging deep south east into Europe.

GEFS 06z, Quite amplified- Intermittent snow possible.




ECM 00z Ensemble mean, less amplified, flatter pattern.



The Ski resorts in the Alps will continue to get dumped on if the GEFS is closer to reality.

BLIZZARD7

Strat warming now starting to appear consistently on the GFS also -