FI Charts ( T120+ onwards) Winter 2020 **READ MOD NOTE IN FIRST POST**

Gonzo

probably a very good time to give the model watching a break for a few days and concentrate on other things. One thing is certain, we won't have a cold spell within the next week. A few days it looked like we might be able to have a decent alignment within the models but we now seem more uncertain than we were a week ago.

nacho libre

sryanbruen wrote: »

2010 didn't have a SSW though so that comparison is already out the window, there were other things at the time that would have led to unusual certainty such as a favourable North Atlantic SST profile or tropical forcing. 2018 had 3 spikes of uncertainty associated with 3 up spikes in warming. We're going to have another minor warming during the weekend into early next week.

The problem with today's runs are everything has trended west from the Greenland ridge to the west Europe low so that the cold air is displaced into the north Atlantic/Iceland, even from ensemble members. The fact this has occurred leaves much confidence to be desired.

Tropical forcing remains weak and this is likely another reason as well as the unusual SSW evolution, that the models have been finding it difficult on how to get a hand in the blocking. I gave my thoughts that I don't expect a significant cold spell because of a vortex lobe over North America with the Eurasian vortex lobe also being somewhat on the large side for comfort, intertwined by an Atlantic or Greenland ridge.

Just more noise to those who have been saying this is "nailed on" is absolute nonsense. Fantasy Island couldn't reign more true than it does now.

I was wrong about 2010, but i think the the overall point is still valid, the models were much more certain of a colder outbreak at those times. Perhaps the uncertainity is down to the mjo phase not being favourable to enhance a hlb, but i think the main issue is that we ended up with a displaced vortex that left a section of vortex over NA. It's always a bad sign for us to get a robust high latitude block when a section of the vortex travels over to North America.

There is a way this still go right for us eventually if the pacific ridge were to extend further eastwards it could link up with other highs and force the cold over Finland and Russia our way.

nacho libre

Gonzo wrote: »

probably a very good time to give the model watching a break for a few days and concentrate on other things. One thing is certain, we won't have a cold spell within the next week. A few days it looked like we might be able to have a decent alignment within the models but we now seem more uncertain than we were a week ago.

The area of interest was always after the 20th, but it does look like if it is going to happen it will be delayed further now. Giving the models a break for a while sounds like a good idea, but we all know the temptation to look is too great.

nacho libre

AuntySnow wrote: »

I'll just leave this here

https://twitter.com/Arklowweather/status/1349317019133472770?s=19

I see what you are saying, but the trend has been for everything to shift too far west. You could be right about small adjustments making a big difference but i'm not confident it will happen for us in a favourable way. The change in the ensembles suggest this. It is also backed up by the tweet from Ventrice about the GFS forecast, which you posted about yesterday.

Billcarson

When the models dont properly firm up on a potential cold spell, then the spell rarely happens. Even though there can be wobbles of course but if they are flipping and flopping about as they are now then the chance of a cold spell over the next while is surely unlikely

Of course I talking about a cold spell of note,not some half arsed rubbish.
Onwards to feb we look imo.................

BLIZZARD7

I'm not convinced either way yet, yes the trend overnight was in the wrong direction but equally it had swung quite a bit Colder in the previous day or two...

With the SSW still unresolved and warnings still ongoing, all to play for still in my opinion. FI is 96hrs right now.

Villain

The Met Eireann monthly forecast has gone from:

Week 1 (Friday 08 January to Thursday 14 January)

High pressure is expected to influence Ireland’s weather during this week. A north or northeast air-flow looks set to dominate early in the period before the air-flow becomes variable as high pressure builds in over the country. Mean air temperatures are expected to be below average with a risk of frost, ice and some wintry precipitation. However, it looks set to turn a little less cold later in the period. Soil temperatures are expected to run below the seasonal-norm. As high pressure will be the dominant feature of the weather, is expected to be drier than normal for early to mid-January with only small amounts of rainfall forecast.

Week 2 (Friday 15 January to Thursday 21 January)

Forecast confidence declines in week 2 but there is an indication that weather conditions will turn more unsettled. High pressure is forecast to decline with some frontal systems moving through. Mean air temperatures are expected to be near-average for January with a reduced risk of frost and ice as compared to previous weeks. Rainfall totals are expected to be higher than in previous weeks with rainfall amounts forecast to be around average for mid-Winter, possibly higher than average in parts of the south.

Week 3 (Friday 22 January to Thursday 28 January)

By late January, there is lower confidence in the forecast but there is a signal for weather conditions to remain fairly unsettled with low pressure situated close to Ireland. Mean air temperatures are expected to be above average with a reduced risk of frost and ice as compared to the climatological average. As low pressure will quite dominant with frontal troughs nearby, it looks set to be wetter than average across most of the country. Forecast confidence falls lower by the end of the period but it looks set to stay rather unsettled.

Week 4 (Friday 29 January to Thursday 04 February)

By forecast week 4 confidence is much lower. However, there is a trend towards unsettled weather with low pressure expected to be positioned nearby Ireland. Mean air temperatures are forecast to be slightly above average for the time of year across much of the country whilst rainfall totals are projected to be above average.

to

Week 1 (Friday 15 January to Thursday 21 January)

With high pressure becoming dominant in the north Atlantic and low pressure over mainland Europe, Ireland will lie in a mainly northeasterly airflow. Temperatures for the period will be around normal to begin but as this northeasterly airflow becomes established it will feed in colder air towards the end of the week, bringing the risk of frost at night. However, this cooler northeasterly flow will bring drier conditions than normal over much of the country, though precipitation along the east coast will be closer to normal most likely due to showers feeding in off the Irish Sea, with the potential for wintry precipitation.

Week 2 (Friday 22 January to Thursday 28 January)

Low pressure will be the dominant feature for this period, largely centred over northern Europe and Scandinavia. The dominance of low pressure will bring generally unsettled weather to Ireland in this week. Precipitation amounts are indicated to be near normal or slightly above for the time of year, as showers or spells of rain are fed in over Ireland on a mainly northerly airflow. This will also keep temperatures quite cool with a continued risk of frost at night.

Week 3 (Friday 29 January to Thursday 04 February)

Low pressure is set to continue to dominate for this week, with conditions over Ireland remaining unsettled. Again, this will bring cold temperatures, with current indications suggesting that temperatures across Ireland will be slightly below normal for the time of year, with the risk of overnight frost. It will also maintain a northerly airflow over the country. This will feed in showers or spells of rain at times, though precipitation amounts across the country look likely to be near normal.

Week 4 (Friday 05 February to Thursday 11 February)

Confidence in this period is low at this stage. However, indications suggest that a broad area of low pressure will continue its dominance across northwestern Europe and Scandinavia. This will maintain cold temperatures and the risk of overnight frost. A more easterly component to the airflow will bring slightly drier conditions to Ireland than previous periods.

Note the 22nd to 28th did have Mean air temperatures are expected to be above average to now say keep temperatures quite cool with a continued risk of frost at night

TheMilkyPirate

I'll take perturbation 11 from the GEFS please :pac:

nacho libre

I'd like that easterly Met Eireann mention to be brought forward to later this month, much better than the cold rain they suggest up to that point. It's an awful update really.

mickger844posts

Mod Note Thread has drifted back into posts that belong in the Winter Thread. Can we try to keep on topic which is Model/Technical Discussion Only. Thanks

Meteorite58

Unsettled look to the ECM 0Z next week, , LP dominant, possibly wintry at times, on the wet side. Does show some snow potential on higher ground but too early for any specifics just that it is modeling pockets of cold enough air at times to produce maybe wet snow but for now would think it is erring more towards sleet mix.

Weather coming from the W, NW and N for much of the week.

It has a January look to it for sure.

ninebeanrows

AuntySnow wrote: »

I'll just leave this here

https://twitter.com/Arklowweather/status/1349317019133472770?s=19

I am sorry but there is surely a better example to be shown of model uncertainty than that:D

The charts looks remarkably similar considering the time range!!

I do agree of course, that a lot can change in the next few days, particularly as the impact of the reversal of the stratospheric zonal winds burrows down.

If we can keep the jet as far south as possible there will be chances for snow-events even if we don't get the deep cold pool we desire.

Sleety_Rain

Sleety_Rain wrote: »

I am sorry but there is surely a better example to be shown of model uncertainty than that:D

The charts looks remarkably similar considering the time range!!

I do agree of course, that a lot can change in the next few days, particularly as the impact of the reversal of the stratospheric zonal winds burrows down.

If we can keep the jet as far south as possible there will be chances for snow-events even if we don't get the deep cold pool we desire.

In fairness now,those are 120's on Friday
Those more or less happened
Beyond 120 most certainly didn't which was my point

ninebeanrows

Big differences between the UKM and GFS this evening, GFS looking interesting but UKM very different.

ninebeanrows

UKM 120hrs


GFS 120hrs

sryanbruen

Euro heights, North Atlantic heights.

N Europe trough, Atlantic trough.

You can't make this stuff up. Any time there is Euro heights like that though, you can pretty much forget about a cold spell.

Rebelbrowser

Thus far the 12z GFS shows an absence of deep cold pooling anywhere in NW Europe.....

pauldry

Thats Monday later in the week there may be still some cold and snow. I know I know Im straw clutching but we need positivity these days (weatherwise anyways)

Kermit.de.frog

Will someone not think of my little heart!

icesnowfrost

Why as soon as the latest few runs (bar the 12z) don’t look as good that some people start with the “ well that’s it it’s all over “
The models have been really good overall this winter regardless of the outcome and one 24hr period of a downgrade and not even a full downgrade does not mean a proper cold spell is not coming end of next week. Already the 12z looks better than the last few runs.
Anyway for me nothing much has changed there’s still a decent chance of a cold snowy weather out of this.

Villain

The OP and Control are well above the mean on the early GEFS out to 192, in terms of 850 temps.

ZX7R

Might be worth bearing in mind the fi charts were only getting to terms with the last strat event another due to start in the next two to three days.
This will probably make them go crazy.

Nabber

Mixed bag on the Ensembles... some beauties tho!

nacho libre

This looks somewhat similar to a run a few days ago. I'd take this.

Dazler97

Kermit.de.frog wrote: »

Will someone not think of my little heart!

Wow kermit that's very similar to storm Emma etc, I hope models keep this up

Slashermcguirk

It’s always the way on here. Lots of great discussion most of the time but the moment less good charts appear it’s talk of game over etc.

We all know that these could change back to cold again at any point, I don’t know why people throw in the towel so quick. By tomorrow the charts could be different again for even early to middle of next week. The charts have been constantly up and down in recent weeks, I wouldn’t rule anything out

icesnowfrost wrote: »

Why as soon as the latest few runs (bar the 12z) don’t look as good that some people start with the “ well that’s it it’s all over “
The models have been really good overall this winter regardless of the outcome and one 24hr period of a downgrade and not even a full downgrade does not mean a proper cold spell is not coming end of next week. Already the 12z looks better than the last few runs.
Anyway for me nothing much has changed there’s still a decent chance of a cold snowy weather out of this.

Gonzo

I don't think anyone was throwing in the towel, more just total frustration at the models flipping from one thing to another with very little reliability beyond 72 to 96 hours. I was suggesting a break from the models for a few days hoping that the models themselves will begin to settle down regardless of what's it store, however in the middle of January it is not easy to try and avoid model watching for a few days.

bazlers

UKMO is good. GFS 12 z recovering ..
sun is blank, southerly tracking jetstream.
Rollercoaster on the incline once more.

Zogabomb

bazlers wrote: »

UKMO is good. GFS 12 z recovering ..
sun is blank, southerly tracking jetstream.
Rollercoaster on the incline once more.

I already puked a few times this morning, I'm considering getting off at this stop!

munsterlegend

bazlers wrote: »

UKMO is good. GFS 12 z recovering ..
sun is blank, southerly tracking jetstream.
Rollercoaster on the incline once more.

Met Office update today was encouraging but I don’t think anyone really knows what will happen beyond 120Hrs at this stage. Could be good for the U.K. but hope we’re not too far west to miss out.