Model output discussion - heading into 2018

[feb1991blizzard]

EPS an improvement - more defined Atlantic ridging and the Troughing becoming scandi then sceuro  dropping right the way into central and Southern Europe, would rather it a bit further West and that's probably why MET OFFICE are calling drier spell, perhaps they see us more being affected by the Atlantic ridge than the trough.

[stodge]

8 hours ago, feb1991blizzard said:

EPS an improvement - more defined Atlantic ridging and the Troughing becoming scandi then sceuro  dropping right the way into central and Southern Europe, would rather it a bit further West and that's probably why MET OFFICE are calling drier spell, perhaps they see us more being affected by the Atlantic ridge than the trough.

Yes that's the message from the 12Z output as I see it. Short milder spells alternating with longer spells of PM influence.

Plenty of support at the very end of 12Z GEFS for a return of blocking to the north and east but we'll see.

[mb018538]

https://twitter.com/MJVentrice/status/945646450016444416?s=17

looks to me that we are in for an extended period of lockdown as the strat cools - ties in with the model output showing what we all dread...the purples and blacks over the pole, with strong winds and rain for the UK. I wouldn’t expect any breakout until the middle of January at the earliest now.

[Ross Andrew Hemphill]

GFS 12z giving Scotland and Northern England a potentially significant snow event on Friday morning, a marked upgrade on 850s giving rise to this. One to watch... 

[snowbunting]

The PV looks like it will finally leave the eastern seaboard of the USA if the ECM is to be believed from about day 7 to 10.   Big change in the synoptics on the way.  

[knocker]

Although generally speaking the anomalies this evening are in the same ball park there are differences that do impact downstream albeit still leaving an unsettled picture

Upstream all agree on a fairly diffuse vortex with a centre near northern Canada but the EPS disagrees on the orientation of this, and thus the trough over eastern North America, mainly because it's less amplified over the latter and makes much less of the ridge into Alaska. This also reflects on the orientation of the trough running south east from Greenland where, for example, the GEFS has it more aligned towards the UK whereas the EPS pushes it further east. This perhaps allows the Azores HP to push a little further north and become a little more influential although at the end of the day we are still looking at a strong westerly upper flow perhaps becoming more inclined to a N/S split? So as mentioned still unsettled with some wet and windy episodes not ruling somwe wintry stuff as systems nip through. The temps varying around the average, perhaps a little below.

The disagreement upstream continues into the ext period as also does the orientation of the UK trough and thus the east European ridge albeit we still have a strong westerly upper flow. Just some doubt about the direction of travel of the Atlantic systems as they approach the UK which of course will be sorted by the det, runs as we proceed.

Edited December 26, 2017 by knocker

[bluearmy]

51 minutes ago, Singularity said:

Curiously, while GFS has the 10 hPa level becoming pretty strong for a time and then weakening a bit, the 1 hPa is shown to weaken slowly but surely throughout the 16 day period. 

The result is, if nothing else, an interesting shape to the temperatures .

 

Wave 1 at the top of the strat is predicted to go off the scale by gfs as we head through towards the end of week 2. The displacement shown is obviously a response to that. Whether that forecast makes it down to day 10 remains unclear.

[northwestsnow]

14 minutes ago, bluearmy said:

 

Wave 1 at the top of the strat is predicted to go off the scale by gfs as we head through towards the end of week 2. The displacement shown is obviously a response to that. Whether that forecast makes it down to day 10 remains unclear.

Theres a warming ongoing over NW Russia, it was picked up by GFS a good while ago- the current low level warming is forecast to tail off in a few days before another warming takes place, this time making inroads to the north of greenland..

[damianslaw]

Sometimes it does well to look at general trends, and short -term developments, in the short-term range we are seeing a more robust colder pattern than first expected a few days again, yes the atlantic is set to pounce later in the week, but not before allowing quite cold conditions to develop over the next 48 hours, and will struggle to make inroads over the north until Saturday. Also the models are backing away from a southwwesterly long drawn fest, and there are hints the azores high won't ridge into Europe and instead will position itself in a location allowing a predominantly westerly flow, more northwesterly for the north, so yes perhaps a mild blip to end the week in the south at least, but I wouldn't be surprised to see secondary low/trough features pop up next week, just like this evenings, forcing the azores high back west , and allowing a more pronounced polar maritime airflow at times to start to Jan, more so in the north. So yes whilst it looks unsettled and atlantic driven, I'm seeing suggestions of cold zonality at times at least for the north, which will be different to many recent January's and I'm only talking first half, second half of winter is an unknown.

[bluearmy]

1 minute ago, northwestsnow said:

Theres a warming ongoing over NW Russia, it was picked up by GFS a good while ago- the current low level warming is forecast to tail off in a few days before another warming takes place, this time making inroads to the north of greenland..

These warnings at 10hpa are generally just surfing around the edge of the vortex. I don't see them achieving much. A huge wave 1 at the top of the strat would be far more interesting but I fear time is slowly ticking away now and a strengthening vortex early Jan isn't desirable unless its clearly just temporary (which isn't currently obvious)

[feb1991blizzard]

8 minutes ago, bluearmy said:

These warnings at 10hpa are generally just surfing around the edge of the vortex. I don't see them achieving much. A huge wave 1 at the top of the strat would be far more interesting but I fear time is slowly ticking away now and a strengthening vortex early Jan isn't desirable unless its clearly just temporary (which isn't currently obvious)

I always find with those though that they don't sustain or propagate well or do much damage damage unless they come with a + temperature profile - indicated by those pale purple colours on the Instant weather maps, even if its the red colours (around freezing), the just tend to fizzle out on future runs.

[feb1991blizzard]

Ha Ha - GFS finally corrects itself wrt track of the low at T6, it had the heavy snow over me on every run for the last week!!!, now its got a few fluffy flakes just clipping me, which is what will happen.

EDIT : in fact strictly speaking the event was already underway by 1800 hours so you could even be cruel and say its the analysis chart.

Edited December 26, 2017 by feb1991blizzard

[bluearmy]

12 minutes ago, feb1991blizzard said:

Ha Ha - GFS finally corrects itself wrt track of the low at T6, it had the heavy snow over me on every run for the last week!!!, now its got a few fluffy flakes just clipping me, which is what will happen.

EDIT : in fact strictly speaking the event was already underway by 1800 hours so you could even be cruel and say its the analysis chart.

We don't usually pay much attention to the exact track of systems. Clearly this one and two week ago we have and both times gfs has corrected itself pretty much  after the event! Ecm has been spot on with the point of entry from around T84 on both occasions. 

[feb1991blizzard]

DELETED.

Edited December 26, 2017 by feb1991blizzard

[feb1991blizzard]

Some of these GFS runs today have had a touch of the Second week of Feb 2009 (10th ish??) about them - a true blizzard for the south.

[ukpaul]

GFS has not changed track of the system and associated snow chances over the Pennines for around 72 hours.

[Tim Bland]

4 minutes ago, feb1991blizzard said:

Some of these GFS runs today have had a touch of the Second week of Feb 2009 (10th ish??) about them - a true blizzard for the south.

Quite similar to the earlier run so a good possibility. Shame the uppers are not lower but pleanty of time for upgrades 

 

[ukpaul]

4 minutes ago, feb1991blizzard said:

Some of these GFS runs today have had a touch of the Second week of Feb 2009 (10th ish??) about them - a true blizzard for the south.

No, but the sort of thing that would be interesting for our area. 

[Tim Bland]

GFS 18z Delivers for most a few days later! As I said a week ago about this week - we don’t need eye candy Synoptics to deliver the goods at this time of year! 

 

 

[January Snowstorm]

Hard to find any crumbs tonight...

Not very mild just a continuation of cold rain really. This particular spell was well flagged by GP & Co 

 

[ACCOUNT DELETED]

Will it won't it????

GFS 18z (last run before the expected snow) continues to show widespread snow across much of Wales and S&C England (including the coasts this time) might set my alarm for 4am and hopefully watch the snow falling in Porthcawl, either that or it'll be a big let down again like 10th Dec! 

[Martz]

I’ve been following this forum as a lurker for about 9 years and I am feeling compelled to post for the first time ever. Looking at the models, and following many of the very informed contributors on here in the last week or so I made a huge call. My friends 6 year old daughter’s father died a couple of months back, and she asked me if it snow over the Xmas period for her dad. Thanks to you guys and your very informative posts on the models, in conjunction with those who specialise in the longer range teleconnections, on Saturday when she made her wish, I was able to make a prediction for snow tonight or tomorrow. It delivered tonight. I woke her up and took her into the garden to see it. Needless to say it was a very special moment for her, her mother, and me as well and I want you to share that with me. This moment was a direct result of the effort you guys put into educating us mere mortals on the subject of meteorology. When I feel my knowledge is at an appropriate level I look forward to contributing further.....

Apologies to the mods if you feel this is off topic but I thought it would be something worth sharing.......

[knocker]

Today any rain sleet and snow still around wil clear the south east leaving the whole country in a colder N/NW airstrean with wintry showers in the north and west with strong winds along the coast, possible gale force. Overnight the winds will slacken a tad but still fresh around the coast with showers but elsewhere clear and thus quite a severe frost. Tomorrow a cold day with still the odd shower but a front will approach the south west later bringing patchy rain with perhaps snow on the high ground.

Friday sees the aforementioned front tracking slowly north east whilst a wave that has formed on it slips across the Midlands 981mb at 1200. the combination of this could produce snow on the leading edge of the front particularly on the higher ground in the north and in Scotland. Meanwhile a low has formed off the south east coast of the US on the southern edge of the upper trough which is tracking quickly north east and 'bombing' as it goes and is in mid Atlantic 971mb at same time. It continues to move quickly north east and deepen and by 12 on Saturday is 948mb west of the Hebrides and it's associated front is clearing the UK having brought patchy rain and snow over the high ground in the north. But more importantly accompanied by strong winds with gales in the west, severe over Scotland.

Apart from some strong winds the low has dragged some warmer air in and by 12 Sunday the low is over southern Norway with the UK in a strong westerly flow with temps around average and showers along western coasts. But more disturbances are en route from the eastern seaboard and one such tracks across southern England Sunday.night/Monday morning bringing rain to the south

The low quickly clears and the Azores tries to ridge north east but now there is a major upper trough area to the west and north west with a sharp delineation between the cold and warm air noted by a 160 kt jet running SW-NE and by 12 Tuesday this is quite marked as weak fronts and strong winds suppress any attempts of the Azores to ridge.

So 30 hours later after the passage of another low across the south with more rain the surface wind veers WNW and the colder air makes some headway with gales along western coasts and wintry showers. Best left here but just to note this looks like being a windy period with the possibility of severe gales in some places.

Edited December 27, 2017 by knocker

[knocker]

The models are certainly struggling with this mobile and complex patter albeit they agree on unsettled and windy. For example at T84 the ecm has a low forming in the southern quadrant of the Atlantic trough in mid Atlantic and has it bombing north east to be a little intense feature 970mb over south west Scotland 24 hours later (Sunday 00)

[bluearmy]

1 hour ago, knocker said:

The models are certainly struggling with this mobile and complex patter albeit they agree on unsettled and windy. For example at T84 the ecm has a low forming in the southern quadrant of the Atlantic trough in mid Atlantic and has it bombing north east to be a little intense feature 970mb over south west Scotland 24 hours later (Sunday 00)

the 00z ecm run hasnt got past day one yet knocks?