FI Charts ( T120+ onwards) Winter 2018 / 2019 READ MOD NOTE IN FIRST POST

Silent Running · 25-01-2019 6:14pm

Marengo wrote: »

Yikes:eek:

Oh please, no. I'm on a ferry and driving across to London on the 5th.

sryanbruen · 25-01-2019 6:33pm

UKMO 12z is pretty comical at 144 hrs, blocking getting going over the Arctic with wedges of high pressure all around the circle. The UK and Ireland are under a relatively mild and unsettled southwesterly.

Marengo · 25-01-2019 10:36pm

Silent Running wrote: »

Oh please, no. I'm on a ferry and driving across to London on the 5th.

Don't worry.. 12 days out and i'm sure it'll be gone on the run coming out in an hour

Monkeynut · 25-01-2019 10:49pm

Marengo wrote: »

Don't worry.. 12 days out and i'm sure it'll be gone on the run coming out in an hour

i was thinking the same thing, by the 5th, the model will be outputting the same situation for the 15th.

NMB · 25-01-2019 11:27pm

GFS looking good UKMO i’m Pretty sure will add to the cold solutions coming through over the next 24 hours and locking in next week - dusting and extra dusting it’ll all work out .(dusting is not drifts or inches but lovely)

Meteorite58 · 26-01-2019 12:27am

Looking forward to seeing how this weather evolves around next Thurs . Deepening areas of LP moving in over Ireland and seem to merge. Very complex systems with numerous fronts and troughs and possible waves forming , cold air probably giving a wintry mix, could have windy conditions but not necessarily so .

hatrickpatrick · 28-01-2019 1:20am

Deep FI once again, but a full-on polar vortex split at 500hpa has appeared, beginning around 168h:

The 12z run didn't show anything like this, but it did show some "wedges" of blocking trying to edge their way northward from various angles, so let's see if anything resembling this run remains on the 0z or 6z.

One can hope, anyway

nacho libre · 28-01-2019 2:16am

One could also hope that high that sinks back over us is eventually sucked back northwards by the arctic high, opening the door to frigid north easterly- i doubt it will happen, but who knows.

nacho libre · 29-01-2019 4:54pm

One of the models lifts the pv from Canada in fi, if that were to happen it could get interesting, others continue the theme of heights trying to rise to the north east but fail- that's more believable considering the story so far this winter.
UKMO seems to be on its own now in still predicting blocking by mid February.
I would love to know what glosea 5 is seeing. It won't be a huge surprise if they backtrack in a couple of days given the latest ec46.

Gonzo · 30-01-2019 1:19pm

I have a sneaky feeling we could potentially have another cold spell from about the 12th or 13th of February.

Several GFS members are trending colder again from that date. Nothing out of the ordinary right now, but something worth maybe keeping an eye on. I feel like I'm clutching every last straw I own for something to happen this winter.

There are signals showing the High possibly positioning itself over Scandinavia from the 11th of February, an easterly could develop from that point.

This is well out in FI but hopefully a sign towards potentially a colder and more easterly second half of February.

GFS positioning of high, with easterly winds progressing through the continent.

Control run also shows High over Scandinavia and some easterlies close to us

This run has the high over Greenland with north-east winds over Ireland by the 14th of February.

I realize this is extreme straw clutching, but I remain in hope for winter to give it one last shot before March. In these runs i'm more looking at signs of blocking, rather than the wind direction or depth of cold over Ireland.

nacho libre · 30-01-2019 2:32pm

Well the GFS can be good at sniffing out new trends, but i'll only believe it if all three major models are in sync and it gets down to t-48, we've been led up the garden path too many times this winter.

sryanbruen · 30-01-2019 2:40pm

nacho libre wrote: »

Well the GFS can be good at sniffing out new trends, but i'll only believe it if all three major models are in sync and it gets down to t-48, we've been led up the garden path too many times this winter.

Focus on the trend of that Siberian or Scandi High as that has been a feature across multiple models (not just the GFS) for runs and days now. Speculation say this Siberian High is the response of the SSW finally showing itself as the downwelling successfully occurs on February 1st and the latest GFS shows impacts from the downwelling likely to continue for the foreseeable future when just a few days ago, it was looking like a short impact as the westerlies propagate back down. This is not what it's showing today.

NAO sticking positive and the AO signalled to go back to neutral by the second week of February on the GEFS today.

ECM 0z showed the high pressure in the places mentioned but not good for long-term potential if it's cold you're after.

All just for fun. This has been an infamous Winter of model volatility of course after all.

snowstreams · 30-01-2019 3:17pm

I often look at the scottish ski resorts to get an idea of how cold our winter has been.
And this year its not looking good for them.

Cairngorm still only has 0.5 of 32 km open and its nearly february.

So most precipitation this year must have been from mild wind directions in scotland too.

nacho libre · 30-01-2019 3:43pm

sryanbruen wrote: »

All just for fun. This has been an infamous Winter of model volatility of course after all.

Yes, i saw that, but what i meant is the three major models backing a rather cold outlook. I m getting the impression you don't see that happening, because any scandi high won't likely last long enough to advect cold our way. You can already see the UKMO has downgraded their outlook based on the recent EC46 update.
I think what we've all learned this winter is that background signals mean diddly squat, if you don't get potent wave breaking activity in the straosphere to increase the odds of a favourable troposheric response, that is essentially why we've been stuck in this half- way house solution of cold, due to the vortex splitting less favourably and leaving lobes of vortex in a less than ideal location, but not quite cold enough to ensure we get snow all the way in this setup. So it has been a timely reminder that not all SSW events work in our favour.

pistolpetes11 · 30-01-2019 3:49pm

For me all the Teleconnections , MJO , EC Monthly Anomaly charts etc etc are a busted flush , all winter long things have been pointing towards a blocked pattern and thus far nothing .

What has become apparent is what an effect an SSW event can have on our winter , this time around the chips didn't fall into place for us , the lobe sitting up about Canada has energised the Jet stream sending system after system across the Atlantic which has pretty much dominated our winter .

nacho libre · 30-01-2019 4:00pm

pistolpetes11 wrote: »

What has become apparent is what an effect an SSW event can have on our winter , this time around the chips didn't fall into place for us , the lobe sitting up about Canada has energised the Jet stream sending system after system across the Atlantic which has pretty much dominated our winter .

Yes that's essentially it, i just wonder why the Wave 2 activity was so weak, and the downwelling was so slow after the SSW, compared to last years SSW. Had it anything to do with the QBO going from an easterly phase to a westerly phase?

Maybe this post should be moved to the Stratosphere Thread.

PukkaStukka · 30-01-2019 5:38pm

snowstreams wrote: »

I often look at the scottish ski resorts to get an idea of how cold our winter has been.
And this year its not looking good for them.

Cairngorm still only has 0.5 of 32 km open and its nearly february.

So most precipitation this year must have been from mild wind directions in scotland too.

I was over there at the start of January. It was mild and no significant snow was observed, even on the peaks

pistolpetes11 · 30-01-2019 6:54pm

Nabber · 31-01-2019 10:09am

ECMWF trending in the right direction at +200
ECM1-240.GIF?31-12

sryanbruen · 31-01-2019 11:33am

The Scandinavian High certainly continues to be a trend across the model output this morning again.

nacho libre · 31-01-2019 11:37am

sryanbruen wrote: »

The Scandinavian High certainly continues to be a trend across the model output this morning again.

Yes an interesting Icon and ECM run.

gerrybhoy · 31-01-2019 11:46am

sryanbruen wrote: »

The Scandinavian High certainly continues to be a trend across the model output this morning again.

That good for snow/cold weather?

sryanbruen · 31-01-2019 12:35pm

gerrybhoy wrote: »

That good for snow/cold weather?

Depends.

A Scandinavian High is frequently associated with cold easterly winds in Winter but there are different factors we need to consider.

First factor I like to consider is the fetch. This factor is more important at the start of an easterly spell (if it's cold you're after) as the cold air mass is not established at this stage. Is the easterly wind sourced from southeastern Europe originally? Is it sourced from Siberia originally?

Another factor I like to consider is the exact positioning of the high pressure. Is it sending a ridge down to us? Is it too far south to pull in the easterly and as a result the easterly wind is going into central or southern Europe? Etc.

An infamous example from February 2012 showing the high too far south to bring in an easterly wind to Ireland and the Atlantic is attempting to veer the winds westerly. Ireland was one of the mildest countries during the February 2012 cold wave for Europe with temperatures struggling or failing to go below freezing after February 2nd.

archives-2012-2-3-12-0.png?

This is a pretty obvious one but another factor is the state of the air mass that is pushing in from the east. Usually by February, the majority of air masses from the east tend to be very cold and snow conducive with 850hPa temperatures below -10c as the continent has cooled down dramatically from the Summer season at this stage, compared to say November or December when the continent is only cooling down gradually from a long Summer season. Even easterly winds in March tend to be colder than in November or December. This doesn't happen all the time.

Scandinavian Highs in January to March are usually good for getting short but severe cold spells like January 1987, February 1991, February/March 2018 etc whilst Greenland Highs are best most of the time for prolonged cold spells like 2010. Sometimes on occasion, you can even get both like 1895 and 1947 which produce exceptionally severe weather.

Classic example from February 1895:

archives-1895-2-6-12-0.png?

gerrybhoy · 31-01-2019 12:54pm

Top man

Neddyusa · 31-01-2019 1:11pm

Nabber wrote: »

ECMWF trending in the right direction at +200

That High Pressure is not likely to be any sort of a match for the 950mb low SW of Greenland though...

Calibos · 31-01-2019 1:18pm

I knew that Feb 2012 stuck in my head for some reason sryanbruen. I was pretty sure I used it as an prime example of Ireland being the most northerly place on the planet snow free most Winters. Just checked the Snow Cover charts for around that date sryanbruen and sure enough Feb 5th 2012 was the snow cover chart date I always used! I also used to use it to shut up the UK Snow lover moaners to show them that we have it even worse than them. IIRC, the furthest Westerly extent of the Snow that year was the Welsh Coast. GRRRGGHHHH!!

sryanbruen · 01-02-2019 8:14pm

sryanbruen wrote: »

The Scandinavian High certainly continues to be a trend across the model output this morning again.

Quick look at the latest output show the Scandinavian High signal has been weakened and depending on the model you look at is in various places including eastern Europe, northeastern Europe or Siberia.

GFS 12z shows relatively high pressure over northern Greenland, northeastern Europe as well as Canada. It later turns into a very mild setup in FI as winds veer southerly of something akin to that of the exceptionally mild spell of February 1998. Problem here is the lack of a Euro trough. Pressure is too high over Spain to allow the low pressure to dive south and force the blocking over Canada to link with the high to northeastern Europe.

ECM 12z just shows Atlantic depression after depression barrelling throughout its run and very unsettled.

derekon · 01-02-2019 8:19pm

Yes, the latest ECM does not inspire confidence for the coming week to ten days. Atlantic firmly in control. The wait goes on............

D

Gonzo · 01-02-2019 8:30pm

This afternoons models are probably the worst I've seen since late November/early December from a cold perspective, that GFS loaded with muck and temps close to the teens. A very big shift from yesterday. Tomorrow will probably be something different again.

sryanbruen · 02-02-2019 9:24am

sryanbruen wrote: »

Quick look at the latest output show the Scandinavian High signal has been weakened and depending on the model you look at is in various places including eastern Europe, northeastern Europe or Siberia.

GFS 12z shows relatively high pressure over northern Greenland, northeastern Europe as well as Canada. It later turns into a very mild setup in FI as winds veer southerly of something akin to that of the exceptionally mild spell of February 1998. Problem here is the lack of a Euro trough. Pressure is too high over Spain to allow the low pressure to dive south and force the blocking over Canada to link with the high to northeastern Europe.

ECM 12z just shows Atlantic depression after depression barrelling throughout its run and very unsettled.

The same theme continues but ECM showed a blowtorch run this morning with Spring definitely arriving early in the second week of February. Low pressure systems getting pushed to the north by high pressure to the south drawing in long fetched southerly to southwesterly winds. Again very akin of February 1998.

FI Charts ( T120+ onwards) Winter 2018 / 2019 **READ MOD NOTE IN FIRST POST**

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FI Charts ( T120+ onwards) Winter 2018 / 2019 READ MOD NOTE IN FIRST POST