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FI Charts (T120+ onwards) Summer/ Autumn 2018 READ MOD NOTE IN FIRST POST

Lumi

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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Meteorite58

Thanks MidMan25.

Opened a new Winter FI Thread and moved the posts from the 1st of Dec. in there.

Will close this one so as not to cause confusion.

MidMan25

Should this thread now be closed?

Meteorite58

Lp's never far away out to +240 with inevitable winds and rain. Fluctuating temps with cold uppers traversing the country at times. Temp changes as the frontal air masses go through. Towards the end of next week looks quite windy .

Scandi Block on the GFS wayyyyyyy out in FI

sdanseo

A wet auld week to come. Nearly a month's worth of rain for many places over the next 10 days if ECM is to be believed.

Reckless Abandonment

Vortex falling apart. this could be fun down the road

hatrickpatrick

12z GFS shows heights trying to build towards Iceland again at 240h. Waiting for the 12z ECM to roll out and see if it follows...

sdanseo

GFS, ECM, GEM, UKMO, NAVGEM all progging that nasty looking low for next week in one form or another.

GFS showing it sub-955mb around 25W, ECM showing it almost as deep just north of us. UKMO, we need another 24hrs visibility, it's mid Atlantic on Tuesday at the end of the run.

Meteorite58

ECM and GFS over the last couple of runs starting to look very unsettled next week with the Atlantic becoming mobile again from around next Tues . The models are beginning to tease out the look of the week and looks like there could be numerous lows and their associated fronts moving close to or over us and current charts showing potential for strong winds and heavy rain at times. This is evolving and will take a different shape over the next few days until the models nail them down.

The Jet seems to be awakening again. Looks to pick up next week , just staying S of us and steering the Lows towards us .The GFS showing it really firing up way out in FI.

Darwin

Always worth reading the long range forecast from the UK met office. Latest thoughts are they are suggesting any Atlantic interlude in early December may be short lived and we return to a blocked settled position for mid-December (which I'm hoping applies to Ireland as well!)
The 6z GFS @ 192 hours shows temporary snow in the making for Northern counties.

hatrickpatrick

Snowbiee21 wrote: »

Can we get updates as 18z rolls out , please

Trust me, you don't want to know. 🙈

The consensus right now is that the models are only useful out to a few days, because the situation in the Atlantic is very unusual, and thus they're all going a bit haywire trying to resolve it. That big, more or less stationary low anchored to our West is responsible for a lot of the havoc.

A few of the regulars on Netweather have gone so far as to suggest everyone takes a few days off from model watching, since it's so frustrating right now and whatever long term solutions they throw up are genuine all-out FI, with massive flip flops going on all over the place. It's a fascinating battleground scenario if you're just interested in how the models work and how they're going to handle this, but if you're actually hoping for a particular solution and the process of getting to it is less interesting, you don't have much to gain by watching this except causing yourself an unnecessary emotional rollercoaster

Snowbiee21

Can we get updates as 18z rolls out , please

Meteorite58

ECMWF , UKMO and GFS pushing the cold out pass next weekend for a couple of days on latest runs. GEM wants to bring in milder air Tues, the ECM and GFS after around Weds .

Kermit.de.frog

We could be maintaining this cold easterly regime for quite a few days yet.

gfseu-0-162.png?12

Be interesting to see how this evolves over the next few days but some low hanging fruit to be had for winter fans.

sryanbruen

Chris_5339762 wrote: »

In my (very limited) experience I've found that when the New York area floods with snow (as has happened) it tends to enhance the jet and we end up with storms and bad weather. Wonder if this will happen now and push this cold area back?

That's what *usually* happens when there is a northwest to southeast trajectory of the jet stream across North America. High pressure builds to the west of the US but on the other side low pressure digs down from Canada into the northeast with cold air plunging down from Canada at the same time. This cold air pushes down towards the jet stream and hits the relatively warm waters of the Atlantic Ocean. The contrast in temperature leads to an intensification in the jet stream. This is what happened in Winter 2013-14, the atrociously wet and windy Winter and the wettest ever recorded before 2015-16 came along.

Something like this is usually as a result of the path of the jet stream which I mentioned but also can be as a result of the positioning of the blocking. Around this point in time, it's more the path of the jet rather than the blocking as the blocking has yet to retrogress to Greenland.

Some years the blocking can be very powerful and extensive to the point where it can be cold (even bitterly so) on both sides of the Atlantic. This was the case in 2009-10, 1995-96 and 1962-63. 1977-78 was another Winter that had several instances of such though it was more temporary than prolonged.

A weakening in zonal winds in the stratosphere as predicted by the GFS and CFS ensembles (if they verify obviously) during latter part of November and for some December should result in more extensive blocking over the Arctic but as ever with the weather, it's no guarantee. If more extensive blocking doesn't appear during the said periods and the zonal winds weaken to very slow speeds then I think it should appear around or just after Christmas.

The models are still trying to get a grip on where this blocking to the north will exactly sit as well as where the trough to our southwest will anchor. If I was to make my own educated guess, I'd lean more towards an Atlantic onslaught as I've previously stated, I expect nothing special this side of the Winter. However, I think "very mild" conditions like we have seen for a good part of November are unlikely with this Atlantic onslaught as the jet stream will be more meriodional (due to various factors including the approaching solar minimum) and or on a southerly track.

The pattern is one where slight adjustments can make huge differences. High pressure is trying to get into southern Europe but there is also blocking over Greenland (apart from some GFS runs during the first few days of December which show a strengthening of the Polar Vortex).

Let's wait and see, shall we?

Meteorite58

Yea the ECM out at + 240 hinting at a strong Jet coming out of the US , the GFS also far out in F1 shows a stronger Jet we will see.

Gonzo

we could have a fairly active Atlantic dominated theme leading up to Christmas. Charts have changed alot from the increasingly wintry theme that was showing up to last Thursday.

Chris_5339762

In my (very limited) experience I've found that when the New York area floods with snow (as has happened) it tends to enhance the jet and we end up with storms and bad weather. Wonder if this will happen now and push this cold area back?

Meteorite58

The main models atm showing LP's and their associated fronts having more of an influence on our weather next week. ECM shows us on the milder side of the boundary between milder Atlantic weather and cooler airmas over Europe with blocking having an effect deflecting or slowing the LP's even though it looks wet and windy at times on this run . GFS shows LPs more progressive passing close to the S or over us it towards Europe. GEM shows the Scandi high having less of an effect blocking out the Lows. Looks to be not as cool as earlier charts were showing.

The days runs trending more Atlantic I think for now.

Meteorite58

Artane was right in that the Low never deepened as earlier runs were suggesting for around next Sun. Disturbances are showing up around next weekend possibly leading to some wet showery weather, how they develop will need to see, probably a bit less cold next weekend but looks to turn cold again the following week .ECM keeping the colder more seasonal theme going out to +240. The present run showing colder air sinking down from Scandinavia towards the end of the run meeting moist air and currently showing that it could create snow in Scotland ( now if that cold air advects further S and gets a bit colder.....) Weather nudging in from the Atlantic quieter than of late and being mostly held back and some LP's keeping S of us . Darwin said it in the Winter thread a lot depends in what way that Low off Ireland at the end of the run develops . The Jet for the most part keeps to our S, keeping the colder air boundary up over us.

GFS after +240 not as cold and showing Lows coming in off the Atlantic.

Kermit.de.frog

Just use image tags...

UW144-21.GIF?18-17

Snowbiee21

Snowbiee21 wrote: »

Ukmo as off 144 hours

Won’t let me post , file too but surely someone can add

Snowbiee21

Ukmo as off 144 hours

Kermit.de.frog

Ireland on the cold side of the polar front throughout tonights ECM run which ultimately brings the cold air to the north closer as we go forward.

And it's situations like this that can turn in to potential frontal snow events...

But i'm just highlighting the trend. UKMO/GEM/NAVGEM/ICON are all taking a similar angle post 144. Ignore the actual charts at that range though.

As long as Ireland remains cold side of the polar front it's game on.

Artane2002

I'm still sticking to what I said earlier for the moment. I don't think the low will be quite as deep as what is being shown (maybe closer to 990 or 995 hPa?), we still are pretty far out for now. Also wrt the possible cold spell, I think the ECM should improve but the GFSP should back down a little giving us something close to a halfway house solution. I'm no expert though... my reasoning is because I feel like the factors are too favourable for an ECM solution but the GFSP is too extreme and we rarely get something to that extreme. We shall see.

Meteorite58

Artane2002 wrote: »

I think the ECM is probably over-deepening the low to the south on the 25th but we'll see

There again this morning Artane2002 and deepens it and brings it up over Ireland by Sunday.

Just going by today's run looks Wet and windy next weekend on this one anyway. Another low out to the SW making it's way towards us early the following week, getting blocked in perhaps on this run leading to wet weather. GFS very different , GEM has a look like the ECM but with colder airmass .We will see. Could easily change .

hatrickpatrick

ECM 0z is...... Interesting O_o

Not really sure what to make of this. Very peculiar setup.

ECM1-192.GIF?17-12

BLIZZARD7

Models are a mess this morning, around +120hrs seems to be a defining timeframe in terms of where we are going and currently all of the models are in disagreement at this point.

UKMO at +120hrs is a pretty decent chart all things considered. Lots of chopping and changing to come I feel, no sign of a roaring Atlantic and the PV is staying well away from Greenland.

hatrickpatrick

I'd call the 18Z GFS an upgrade on what we've been seeing today. Still not as epic as what we saw earlier this week in FI, but very much all to play for it would seem.

Artane2002

I think the ECM is probably over-deepening the low to the south on the 25th but we'll see

Meteorite58

ECM 12Z showing LP off the S next Thurs feeding in windy wet weather to the SE, S on a SE'ly wind. And thereafter shows LP off the S /SW having an influence on our weather out to the end of the run, which will modify the cold airmass reaching us and perhaps not letting it cool down too much . Will be interesting if it keeps up this trend.

What I am seeing in the ECM 12Z :From Thurs out to the end of the run ( Mon 26th ) showing LP off the S /SW with rain bands at times moving in mainly to the S of the country and more so on Southern coastal counties. Possibly quite breezy on Southern coasts at the end of next week at times. ECM showing cool but not extreme cold out to +240 hrs. If it keeps the present setup then looks mildest in the S of the country, coolest in the N .

ATM showing the coldest days Tues and Weds, not as cold after out to Monday ( highs of 8 to 10 in southern counties from Thurs perhaps , cooler the further North ) but the wind will give a cooler feel.