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

Meteorite58

Mod Note
This thread is for posting/discussing/analysing FI CHARTS ONLY i.e. Charts in the unreliable time frame, generally +T120 onwards

If your post does not specifically relate to an FI chart then it doesn't belong here - Off topic posts will be moved

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Captain Snow

With high pressure holding back the Dormant Atlantic. Can see a constant flow of Polar Low pressure systems heading down over western Europe. Maybe a Omega block forming later on in winter.....:D

pad199207

Until UKMO is onboard I am NOT being led down the garden path again!

If I remember correctly in 2012 the GFS and ECM were screaming promise as close as +96 until a huge backtrack to the UKMO .

icesnowfrost

It's great seeing so many models backing each other up. -8 uppers right into December. Don't want to see the work downgrade plz

Captain Snow

Like OMG

There is something big going to happen in wintery terms in the next 2 to 3 weeks. Unbelievable Runs.

LOL looks like everyone is the same page...

BLIZZARD7

snowstorm445 wrote: »

:eek::eek::eek:

18z GFS is stunning -

snowstorm445

:eek::eek::eek:

BLIZZARD7

AO forecast to fall through the floor- sustained below -3, the control run is extreme, someone find me an example of a -5/-6 AO that has not resulted in a severe cold spell for these shores. @sryanbruen that might be one for you.

IMG_0656.PNG.4b6781d1173c54d8e4a834334485ee07.PNG

IMG_0656.PNG.4b6781d1173c54d8e4a834334485ee07.PNG

Have to say, unless the UKMO is right and almost all other models are wrong - we are heading towards a really interesting spell of weather. Big similarities now with where we were in 1962, 1981, 2009, 2010. That of course doesn't mean we are in for a repeat by any means, things are looking very good though. Another winter to remember I hope...

Meteorite58

ECM showing a vigorous area of LP pop up North of us out in FI ( Polar low ? ) It did very well recently predicting the Genoa Low about 10 days out , will pick this to see how well it fares

GFS

BLIZZARD7

kod87 wrote: »

Brings in a reload of very cold weather but overall would be very dry as the high pressure is always very close to us

It's academic at this stage but yeah away from the North it looks dry. In reality though it's usually a case of get the cold in first and the snow will follow. So far we are doing very well on getting the cold in part. With some slightly different angles to that high on the ECM and a better angle of the low on Eastern seaboard of the US at +192 hrs we would have been looking at -10 to -12c 850 temps on a roaring North easterly rather than the -7/-8c and dry +216 chart. Not much point in trusting the models on such details til we get down to the +96 - +120hrs timeframe.

Encouraging signs all in all, UKMO only concern at the moment. UK met office outlook is staying cold out til mid December though - I think the ECM is leading the way here at the moment.

A rare situation to have reloading Northerlys, The Northern hemisphere looks primed to bring us an easterly later on too with the Siberian high growing in presence.

ECM Day 10 is heading towards yet another northerly eventually with a low dropping South and devoloping GH -

kod87

BLIZZARD7 wrote: »

Indeed, it seems that every time a northerly collapses we have another shot of WAA into Greenland and the subsequent northerly is that bit colder each time, long May it continue!

Brings in a reload of very cold weather but overall would be very dry as the high pressure is always very close to us

BLIZZARD7

Indeed, it seems that every time a northerly collapses we have another shot of WAA into Greenland and the subsequent northerly is that bit colder each time, long May it continue!

sryanbruen

The ECM 12z is pretty much a carbon copy of what the GFS 12z has on offer. High pressure retrogressing on 3 December before a northerly takes place on 4 December.

sryanbruen

The GFS 12z is showing signs of retrogression on 3 December before another northerly yet again takes place. Now that's what I call a Greenland block!

BLIZZARD7

AO forecast to go quite deeply negative, the NAO a little bit negative.

ao.sprd2.gif

Looking like a complete collapse and possible reversal of zonal winds, the Polar vortex is going to stay in tatters for the foreseeable if this happens. We are quite well setup for a prolonged cold spell to kick in, the question is will the blocking continue to be in favorable places...
I expect some serious charts to start appearing on the models over the next few days.

Meteorite58

Looks even nicer on the next run with a very cold air mass heading our way perhaps. Long way off but certainly trending cold.

The GFS has HP build to our W next week and nudges closer and over us as the week goes on. Presently showing a slow moving area of LP move down through Europe which would bring cold N and NE winds down over Ireland from about Tues, we being sandwiched between Hp and LP .

ATM nothing stormy showing up on the charts for the next week or so.

Tropical Tidbits

YLg7v5s.gif?1

nacho libre

Good grief the latest GFS is very good. It has a stellar Greenland high in place by the 11th of December. If we could only bank this chart:

gfsnh-0-384.png&key=31abeb3b83555847e6af478d14f3af9cefd5bd52bf24e8fa7df0839dbf7925e4

gfsnh-0-384.png&key=31abeb3b83555847e6af478d14f3af9cefd5bd52bf24e8fa7df0839dbf7925e4

sryanbruen

GFS 18z tries to bring in an easterly but fails. But at day 10, it isn’t important anyway. The fact that the model wants to continue cold and blocked conditions is good enough at this stage. Plus it’s still very uncertain when the first ridge next week bringing us the northerly will collapse.

George Sunsnow

-7c 850 air is fringing Antrim on the ECMWF on Wenesday
By Thursday it’s widespread into Leinster and the Irish Sea
That would put the white lad into most showers should they develop in areas like Rathdrum in Co. Wicklow and higher parts of South Dublin

And using my adjacency rule of thumb possibly into Docarchs back garden if he’s not too far from lamb Doyle’s

But anyhow,more changes will happen

If the pattern persists,our forum’s very own air pilot Gaoth Láidir usually has access to paid for aviation weather charts that he will drill into the yea or nae in your back yard specifics with ,as will no doubt MT

icesnowfrost

That blocking was kinda showing up a few days ago but run to run between th ECMWF and the Gfs where not in agreement, however it's great to see the GFS come into agreement.
Lots if dry weather though if we could get a few low pressure systems come up against that cold we could get decent snow ❄️

sryanbruen

Stetsonfrank wrote: »

What time is this issued sryanbruen?

Now, 9:30.

Stetsonfrank

sryanbruen wrote:

Just awaiting on seeing what the GFS 18z will show.

What time is this issued sryanbruen?

sryanbruen

The argument is over and done with. We've discussed it and it was more of a misunderstanding than anything. Leave it behind. As it's sorted now, time to get back to the point of this thread.

Just awaiting on seeing what the GFS 18z will show.

Gaoth Laidir

Highdef is right, the ECMWF shows the -8 isotherm nowhere near Ireland next Wednesday. Here's a zoomed in version of the actual numbers.

Here's the snowline, between 200-400 metres.

Floki

George Sunsnow has posted about the Irish Sea temperatures and advection.

So just to remind everyone that the irish sea is currently 13c (warmer than the sea in the west of Ireland) atm.
So if you wanted a perfect scenario for snow, you kind of have it maybe from Tuesday night onwards (for the east coast) with these cold upper air temperatures and warm sea could see a lot of precipitation (looks like snow) coming off the irish sea.
All depends if we get a north easterly and where this HP will be (and obviously cold air and dam line).

Also it would help if there was frost before any snow for snow to stick.
The west and north are getting it atm. Maybe the east will get some next week?

George Sunsnow

highdef wrote: »

I disagree. Firstly, I know that they are isotherms, in a similar vein to isobars.....lines that show equal units of something. I was just trying to keep it simple for everyone by keeping the language simple.

Secondly, the area you highlight is -6 to -8, not -8. This means >6 but <8 so therefore nowhere in Ireland can be at -8. In fact, as it's only the north and parts of the midlands within that particular shade of blue (which then stretches all the way to the very north of Scotland), I would hazard a guess and say that it's unlikely that any part of the island of Ireland is even at -7. As stated, it's only when you get to the very north of Scotland that you hit -8.

If you look off the coast of the northwest coast of Norway in your chart, you can see an area that is a lighter shade of blue to surrounding areas. Within this the 850 hPa temp is greater than -6 but less than -8. This is the same shading that you are referring to over the north of Ireland.

Just to be 100%, I did some colour sampling. The area you refer to over the north of Ireland has a colour of #0036FF. The area beyond the isotherm at the very north of Scotland has a colour of 0000FF - a different shade of blue, looks very similar on either side of that isotherm however it means that north of it, the temp is lower than -8 (between -8 and -10, when using the colour scheme as a reference). South of it is GREATER than -8 (between -6 and -8, when using the colour scheme as a reference). Therefore nowhere in Ireland is under -8 uppers in that chart and most likely are not under -7 either....probably nearer -6.

TWO’s chart viewer has the detail at some -7 in NI wenesday but widespread -7 air over the Republic and the Irish Sea thursday
The important thing to note it’s advecting in and not much yet to stop it
No point in arguing over a single degree as ideally we’d like -9 or lower for a while and Spidey senses are telling me that’s entirely plausible eventually ,all good anyway if you get me ?

sryanbruen

highdef wrote: »

I disagree. Firstly, I know that they are isotherms, in a similar vein to isobars.....lines that show equal units of something. I was just trying to keep it simple for everyone by keeping the language simple.

Secondly, the area you highlight is -6 to -8, not -8. This means >6 but <8 so therefore nowhere in Ireland can be at -8. In fact, as it's only the north and parts of the midlands within that particular shade of blue (which then stretches all the way to the very north of Scotland), I would hazard a guess and say that it's unlikely that any part of the island of Ireland is even at -7. As stated, it's only when you get to the very north of Scotland that you hit -8.

If you look off the coast of the northwest coast of Norway in your chart, you can see an area that is a lighter shade of blue to surrounding areas. Within this the 850 hPa temp is greater than -6 but less than -8. This is the same shading that you are referring to over the north of Ireland.

Just to be 100%, I did some colour sampling. The area you refer to over the north of Ireland has a colour of #0036FF. The area beyond the isotherm at the very north of Scotland has a colour of 0000FF - a different shade of blue, looks very similar on either side of that isotherm however it means that north of it, the temp is lower than -8 (between -8 and -10, when using the colour scheme as a reference). South of it is GREATER than -8 (between -6 and -8, when using the colour scheme as a reference). Therefore nowhere in Ireland is under -8 uppers in that chart and most likely are not under -7 either....probably nearer -6.

Sent you a PM to discuss this rather than upsetting others and flooding this thread with irrelevant posts.

highdef

sryanbruen wrote: »

You are reading it incorrectly. Firstly, those "black lines" are called isotherms. Isotherms are lines of equal temperature. Look at the key where -8c is on the key below the map (start at 0 and go down the scale to see what I mean if the blues are too similar to your eye sight). The area I have marked here is -8c, which is mostly northeastern Ireland.

I disagree. Firstly, I know that they are isotherms, in a similar vein to isobars.....lines that show equal units of something. I was just trying to keep it simple for everyone by keeping the language simple.

Secondly, the area you highlight is -6 to -8, not -8. This means >6 but <8 so therefore nowhere in Ireland can be at -8. In fact, as it's only the north and parts of the midlands within that particular shade of blue (which then stretches all the way to the very north of Scotland), I would hazard a guess and say that it's unlikely that any part of the island of Ireland is even at -7. As stated, it's only when you get to the very north of Scotland that you hit -8.

If you look off the coast of the northwest coast of Norway in your chart, you can see an area that is a lighter shade of blue to surrounding areas. Within this the 850 hPa temp is greater than -6 but less than -8. This is the same shading that you are referring to over the north of Ireland.

Just to be 100%, I did some colour sampling. The area you refer to over the north of Ireland has a colour of #0036FF. The area beyond the isotherm at the very north of Scotland has a colour of 0000FF - a different shade of blue, looks very similar on either side of that isotherm however it means that north of it, the temp is lower than -8 (between -8 and -10, when using the colour scheme as a reference). South of it is GREATER than -8 (between -6 and -8, when using the colour scheme as a reference). Therefore nowhere in Ireland is under -8 uppers in that chart and most likely are not under -7 either....probably nearer -6.

kod87

The ecm does what the gfs does and leaves the high basically sitting on top of us. Nothing particularly exciting about those charts atm, it will be cold next week for sure but nothing prolonged and should be relatively dry everywhere. temps slowly rise as the high pressure settles over us.

highdef

sryanbruen wrote: »

Ireland having upper air temperatures between -4 to -8c on Wednesday on the ECM 12z :eek:, only +120hrs away.

Did I mention, this is an upgrade from the very cold ECM 00z!

Unless I'm reading that chart incorrectly, it looks like -4 to -6 uppers over Ireland with the -8 uppers barely touching the north of Scotland. There are black lines separating temperatures every 4c and no black lines between colours for half way in between the 4 degrees. So 0c would have a black line between colours (0c actually has a thick black line, the rest a thin black line) as would 4c but 2c would have no black line separating the colours. Not sure if I have explained this very well!

Easterly Beasterly

George Sunsnow wrote: »

Yup
I mentioned it in the general winter thread

Looks like we are entering a pattern if that high does stay that far west

-8 850 air would be enough with current Irish Sea SST’s to pummel the east coast with showers and they would be wintry with quite a lot of settling snow on higher ground and perhaps lower ,isn’t it getting interesting

Ah GS.. You know how much I love snow but I'm heading to New York on Wednesday for 5 days and it's mild over there, can we not delay it for a few days??

The ECM certainly looks interesting and I think something might be brewing!