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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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bnt

MJohnston wrote: »

That's what the references to "uppers" are about in people's posts

I know, and you know, but I'm thinking of casual visitors who might not be familiar with such specific jargon.

typhoony

doubt there will be a battleground, more like a dying front with snizzle. at least the easterly is there on most of the models but it looks a weak affair maybe the east seeing some light snow at times, it will depend on uppers and dew points

Kermit.de.frog

To back up what Blizzard is saying (assuming we don't get the full brunt of an easterly incursion) - we need to watch the front attempt to make inroads from the Atlantic at the start of next week - coming up against very cold eastern airmass and followed by a very cold north Atlantic airmass some time on Monday.

The two could meet over Ireland. This will weaken and stall the front but not before a potential dumping of snow.

Still that's 120+ hrs out yet. If it gets within 96 potentially exciting for those who have not seen an actual frontal snow event in many years. Quite a bit of cross model support has to be said.

MJohnston

bnt wrote: »

It might be worth reminding ourselves that the temperatures shown on these charts are not ground level temperatures, but temperatures at certain pressure heights. 850 HPa corresponds to ≈ 5,000 ft (1500m) ASL, 500 HPa to ≈ 18,000 ft (5000m), and 250 HPa to ≈ 34,000 ft (11000m). The last-mentioned is doubly interesting because that's where airliners fly and the jet streams roam. (Apologies to the folks who know all this already.)

That's what the references to "uppers" are about in people's posts

bnt

It might be worth reminding ourselves that the temperatures shown on these charts are not ground level temperatures, but temperatures at certain pressure heights. 850 HPa corresponds to ≈ 5,000 ft (1500m) ASL, 500 HPa to ≈ 18,000 ft (5000m), and 250 HPa to ≈ 34,000 ft (11000m). The last-mentioned is doubly interesting because that's where airliners fly and the jet streams roam. (Apologies to the folks who know all this already.)

Oneiric 3

nacho libre wrote: »

Impressive cold air well into the Atlantic from a northwesterly!
It would be quite something if that -12 air made it all the way here from a north westerly. Has it ever happened before?

As Syran mentions, Jan 1984 seems to have set a precedent:

BLIZZARD7

Kermit.de.frog wrote: »

A little more amplification of the jet stream and there could be a surprise from the east in the next day or two showing up on the models heading in to the second week of February...?

Absolutely, and with that this mornings runs trending colder again in the mid-term, the ECM has cold uppers over Ireland or very close to over us for most of the run. An easterly may be on the cards sooner than looked possible just a day or two ago.

Il he watching the 120-168hr timeframe closely for improvements on the next few runs, UKMO the best performer at +120/+144 for the past few runs.

+144hrs ECM- Given movements so far the -8c or lower uppers over the UK may just make it to us by the time this is at +96 to +120hrs-

ECM0-144.GIF?31-12

+168hrs - Cold air entrenched, this is very close to a snowy picture given a touch more amplification.

ECM0-168.GIF?31-12

Ninja snow events in this timeframe may just appear for us.

Gefs also showing growing interest in the outer reaches as the big strat warming moves closer in time.

Kermit.de.frog

A little more amplification of the jet stream and there could be a surprise from the east in the next day or two showing up on the models heading in to the second week of February...?

gfsnh-5-120.png?18

George Sunsnow

That pretend feed in the gfs is actually contending with a lot more modification than the northerly in 2010 as it’s crossing a lot closer to more NAD exposed Ocean
It certainly has made land fall in Ireland before
Don’t ask me when ,( I remember things but not specifics,it’s age :O )but it has made it
-10 or -11 850’s from that direction if the pretend feed ever became a reality would really plaster Ulster,Connaught and north Leinster with snow showers and thunder!

gabeeg

The 18z is looking very interesting. East and West colliding in a new Cold War.

Anyone remember similar happening before?

nacho libre

IMG_20180130_183655.png.b94d733c84cd6c846aa316e1f9c2390b.png

Impressive cold air well into the Atlantic from a northwesterly!
It would be quite something if that -12 air made it all the way here from a north westerly. Has it ever happened before? I know in 2010 we had but that was from a proper northerly feed with less modification en route to contend with.

Oneiric 3

nacho libre wrote: »

An unusual enough chart that, squeezed from both directions! You know the north westerly airflow will win out, at least over Ireland.

We really are the piglet in the middle, aren't we?

-8 to the left of me, -10 to the right,

Here we are stuck in the middle of you.

BLIZZARD7

nacho libre wrote: »

Yeah i think this attempt will fail because of the cold Canadian air( if it were to plunge down into the sea off Portugal, we would be laughing), but a bit later on in February things will hopefully fall into place with the effects of the mjo starting to show on the models. Another good indicator is if Kermit the frog and Gaoth Laidir agree that the parameters are perfect for snow! Then we will really be in business.

Aha one can dream

Later into Feb we have potential strat effects coming into play too, Mean zonal winds expected to see a big drop/potential reversal-

nacho libre

[QUOTE=BLIZZARD7;106000413

MJO now almost certain to move into high amplitude phase 7, we could see some very nice charts soon if the models see a continuing progression into phase 8.[/QUOTE]

Yeah i think this attempt will fail because of the cold Canadian air( if it were to plunge down into the sea off Portugal, we would be laughing), but a bit later on in February things will hopefully fall into place with the effects of the mjo starting to show on the models. Another good indicator is if Kermit the frog and Gaoth Laidir agree that the parameters are perfect for snow! Then we will really be in business.

BLIZZARD7

nacho libre wrote: »

An unusual enough chart that, squeezed from both directions! You know the north westerly airflow will win out, at least over Ireland.

Indeed the outlook on all the main models is a bit unusual looking, not sure it will translate into unusual weather for us but we definitely aren't looking at the usual stuck in a rut atlantic charts (albeit the bitter Canadian air flowing into the atlantic may have something to say about that). Given the depth of cold to our northwest and building cold to our east/North east, it wouldn't take a huge amount of luck to see a colder version of the early December snowfall in the coming weeks.

MJO now almost certain to move into high amplitude phase 7, we could see some very nice charts soon if the models see a continuing progression into phase 8.

nacho libre

gabeeg wrote: »

UKMO has the beginnings of an easterly at 120

GFS disagrees, but is moving towards it

UW144-7.gif.835d761406dccfe25c610d9a1583dc04.gif

An unusual enough chart that, squeezed from both directions! You know the north westerly airflow will win out, at least over Ireland.

nacho libre

George Sunsnow wrote: »

I’m siding again with Joanna Donnelly who tweeted recently that 240 charts are about as useful as kindergarten crayon classes

They are useful if they are showing our default pattern. In other words if a 240 hour chart from the ECM is showing mild southwesterlies it is more than likely correct. What she should have said is a 240 hour charts depicting easterlies for Ireland, or anything against the climactic norm, is about as useful as kindergarden crayon classes.
Anyway, I think we may well have a cold start to March based on what is happening in the stratosphere.

gabeeg

UKMO has the beginnings of an easterly at 120

GFS disagrees, but is moving towards it

Donegal Storm

There's been little to get excited about even if you were looking to the far reaches, the past few weeks runs have been about as bland and uninspiring as you could ever hope for at this time of year. The lack of posts recently speak volumes and it doesn't look like changing any time soon

pad199207

I’ve only stayed in the +96hrs club since middle of December and believe me it is a much happier life. I wouldn’t look back to those days of getting excited beyond that.

George Sunsnow

I wouldn’t rule anything out but still side with our climactic norm
Before modeling or in the era of basic modeling forecasters didn’t have the ‘luxury’ of computers going off on one to this extreme or that
Outcomes were simply unknown 8 days ahead and to be honest we’re seeing evidence on this thread time and time again that we’re no better off today
I’m siding again with Joanna Donnelly who tweeted recently that 240 charts are about as useful as kindergarten crayon classes

sryanbruen

Every op run on every model today has handled the low in question this weekend differently by quite a substantial margin. The changes between each GFS run today have been evident; but the difference between the UKMO and the GFS 12z runs at +144 is stark. Therefore, to rule anything in or out at this stage is still a pretty risky move in all honesty and I wouldn’t personally be ruling out another significant change between now and next week. The JMA is still going for a bit of an easterly early next week for what it's worth - the UKMO is in agreement.

It's all a very messy picture! Ah god, the headaches from this.

Meteorite58

The models , for the moment anyway, trending towards Hp the week after next. The Jet forecast to take a Northerly route.

sryanbruen

Ireland is just abouts on the knife edge of a beasterly on the ECM 12z:

However, then cold air starts to try and flood in from the west:

The GFS OP has backtracked today with milder solutions for early February but there is a lot of scatter in its ensembles and I mean A LOT of scatter, take Dublin's GEFS 12z for example:

There are some quite cold ensembles mixed in there!

I'd like to post this brilliant comment regarding model runs by my friend James over at GWV:

I seem to think the only certainty we have at present is that the models, have really been struggling since the start of winter, possibly before, with Fantasy Island being closer than you think normally. Just because a model or models show a solution in one run or multiple runs doesn't necessarily ,"Make it so," to quote Captain Picard unfortunately. Hence what the models giveth the models can take away, given that the further predicted events are from the initial conditions the greater the error will possibly be. Try not to get too excited or upset about what you see.

esposito

Looks interesting with the cross model agreement. Let’s hope the ECM and UKMO come on board for a more sustained cold outbreak. Getting tired of these 1 to 2 day a cold weather “events”.

sryanbruen

Plenty of cold model runs to look at for early February, see the latest ones below for example.

Even the GEM (which was in its own world yesterday with what it was showing) is showing the prospects of cold tonight.

sryanbruen

I'll just leave this here from the GFS 12z for early February

typhoony

GFS certainly keen on the idea of the Atlantic train slowing down, charts at +180 show a high sending a tongue out to Scandinavia, ripe for an early Feb easterly,very likely scenario with low developing over southern Europe

Captain Snow

Very Nice . Cold into Europe.

esposito

Ecmwf 12z looks interesting for coldies from 192 onwards. Pattern change? Far out in FI I know but encouraging anyway.