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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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gabeeg

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

Anyone remember similar happening before?

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!

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

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.

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:

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.)

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

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.

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

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.

MJohnston

bnt wrote: »

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

Well this is the Technical Discussion thread, so there's going to be lots of terminology they aren't familiar with.

nacho libre

With an easterly, given the continent is in the freezer, we don't need upper air to be as cold as say from a north westerly for snow to fall, also dew points from an easterly should be lower due to dryer air. As well as that snow can fall with -2 uppers from a frontal event, if the wet bulb temperature is low enough(0.6)
Although, as you say, what will likely happen is the front decays over Ireland. I just hope you are wrong and this is one of these rare occurrences where everything goes right and we see Met Eireann talking about significant accumulations even to lower levels.

George Sunsnow

Aye snow just needs the air below freezing and not above 1c or so at the surface from cloud base to ground

So if fast moving air at 5000 ft is -2c and advected surface air from sea level to 1000ft from a freezing UK is around 0c or 1c, your precip will probably be snow
It happened in 2010
It often happened in the 80’s

Kermit.de.frog

George Sunsnow wrote: »

Aye snow just needs the air below freezing and not above 1c or so at the surface from cloud base to ground

So if fast moving air at 5000 ft is -2c and advected surface air from sea level to 1000ft from a freezing UK is around 0c or 1c, your precip will probably be snow
It happened in 2010
It often happened in the 80’s

Solid ECM. The "beast from the east" vs the, eh, "beast from the west":pac: You'll be able to see the beast from your house;)

Progress is progress.

ninebeanrows

Yea - they aren't your picture postcard Synoptics but they are cold and very interesting with numerous sliding snow events possible. An interesting 10 days aheadðŸ‘

JCX BXC

Went from nothing to this, quite interesting.

Extremely skeptical for my location as always, what's frontal snow 10km inland could be rain here.

George Sunsnow

Kermit.de.frog wrote: »

You'll be able to see the beast from your house;)

Progress is progress.

Hopefully I won’t need a really powerful telescope!

kod87

Kermit.de.frog wrote: »

Solid ECM. The "beast from the east" vs the, eh, "beast from the west":pac: You'll be able to see the beast from your house;)

Progress is progress.

Yes, and we would be stuck in the sleety ****e in the middle, typical

squarecircles

Ahhhh The auwl elongated triangular finger of green slime.

There it is,stretching from deep in the Azores,curving and arching beautifully with precision,so as to envelope Ireland and only Ireland in its moist intimate Bossom.Its a deep,deep love affair,oh saucy! ...

...Deep cold to our north east,and unusual cold splurging southwards in the north Atlantic,but there it is,the ever present elongated triangular finger of green slime that somehow manages to position itself perfectly to prevent the cold reaching ireland,the same finger of slime that prevents hot Spanish plumes encroaching over Ireland in summer.

It prevents and shunts the deep cold pool away to the east before it strides slowly eastwards, then as the deep cold from the north Atlantic staggers foward,it falls apart moments before reaching our shores,by about 50 miles,modifies and dilutes into watery mi-wadi,like an unfit athlete that's run out of breath.Its hilarious,if you ever watch the -10 hpa isotherm approach Ireland it just dies a death as it approaches,no matter which angle it's coming from,it will side step us and hop up to Scotland,it's will dance around us and easily pour itself over southern england,
Before the final kick in the teeth - watching it ouzze down towards Spain and the med with such grace and ease and swagger.

Rinse & Repeat.

gabeeg

Are the islands themselves responsible for the high?

Like, should I hate them and their peoples?

MidMan25

gabeeg wrote: »

Are the islands themselves responsible for the high?

Like, should I hate them and their peoples?

Yes a few tiny dots in the middle of the Atlantic responsible for a huge high pressure :pac:

Meteorite58

Been following the ECM on next Mondays potential and certainly a great study perhaps ( for me anyway :pac: ) for a front running into cold air and producing snow. The ECM can be shy enough at predicting snow but promising at this early stage, but still 5 days away. Looks like the Eastern side of the country with the most chance but if this comes off it will probably have a rain/ sleet start and maybe a sleet / rain ending?.

Tues looks very cold also but at that stage looking like a NW'ly feed of wintry precipitation. In general looking quite cold. Four days ago it was looking like HP's and a big change since so anything can happen .

gabeeg

Bit more bite in the Easterly on the pub run

It's an amazing run. Not so far into FI at all.

Oh god, please happen

typhoony

bit of an upgrade on this run and something for everyone. the jet is in an unusual position and with a quiet Atlantic we also get an unusually cold source from the north west as well being on the edge of an easterly. interesting times ahead

BLIZZARD7

The 18z GFS sends Ireland and the UK into the freezer, -10c 850hpa temps pouring in from BOTH the East and North West, a snowy Nirvana if this were to come to pass.

Now let's get this inside +96hrs...

Snowbiee21

I’ll leave this one here❄️

gabeeg

It's getting well into the unreliable timeframe now, but it's impossible to stop watching.

Nearing five days of freezing temps and snow possibilities from pretty much every direction.

pad199207

That 18z is NOT without interest

George Sunsnow

pad199207 wrote: »

That 18z is NOT without interest

Now there’s an under statement...

pad199207

George Sunsnow wrote: »

Now there’s an under statement...

I know wouldn’t be like me