Model output discussion - proper cold spell inbound?

[Always a red]

1 minute ago, Mucka said:

Oops, I meant further West, so a good thing. Can't edit now either. 

Cheers Mucka!

[Mucka]

GFS ensembles largely reflect the Op in that high pressure to the East is much more prominent and further West in FI

At 192 at time of posting so will be interesting to see how many bring in an Easterly by mid month.

EDIT

I forgot about GFS's inability to split energy in FI and send everything NE and not SE 

With that on board though a very good trend this morning (assuming it is a trend) to keep low pressure on NW/SE track and increase heights to the E/NE

Edited February 3, 2018 by Mucka

[SMU]

Just looking at the 00z UKMO & assuming today is day 1 then it’s a 6 day cold spell with plenty of opportunities for snow for many ( yes some more concentrated in SE ) but on this occasion that’s the luck of the draw -

upper temps between -8 & -10c for all 6 days barring a 6 hour window @ day 6 where it *MAY* turn to rain on Friday Before turning back to snow along the back edge - with still a chance of Friday upgrading to an all snow event depending on allignment etc-

Quite happy with that...

S

[Mucka]

GFS Op very much on the mild side  in FI

ICON has Tues snow band actually pep up across central regions

Edited February 3, 2018 by Mucka

[MattStoke]

Aperge now has Tuesday's front crossing England and Wales as all snow. It previously had the front dying out across the very far north and west.

ICON similar and has been all a long.

GFS is still the most progressive with it and the slowest to mix out the milder air, resulting in a wintry mix.

ECM is still the least progressive. It mixes out the milder air more quickly but the front doesn't get past West Wales or the far north of England. Model is yet to update this morning though, of course.

Still scope for a middle ground on that one, which could result in it being all snow quite widely but perhaps not reaching far eastern parts.

 

Edited February 3, 2018 by MattStoke

[Rayth]

Even at day 7 it’s far from the mean 

[KTtom]

6 hours ago, Nick F said:

Although the upper pattern looks disappointing later next week, not entirely convinced of the rounded vortex over Greenland and flattening out to zonal flow the GFS and EC seem keen on. A look at the EPS clusters suggest good support for trough disruption to continue in vicinity of the UK later in the week, with perhaps an underestimation from operational output of the positive height anomalies to our NE from WAA and surface cold block, thus overeagerness to push through Atlantic westerlies into NE Atlantic and NW Europe.

It has been noted elsewhere, namely from U.S. mets, that the model output today, particularly EC, seems to be contrary to what the analogs for the MJO phase response of the upper patterns should be. So we should perhaps be wary of looking past day 5/6 and as a result we may see some changes tomorrow to less zonal looking outlook beyond day 5.

But even if we do return to a more mobile and less cold pattern later next week, I feel fairly confident it will be short lived, as the upper pattern response to MJO through 7 to 8 and ensemble guidance points to blocking reasserting close to the NE from mid-month, which could be further bolstered by a SSW.

Just want to bump this excellent post forward for people to read this morning...such a shame it will get lost in pages of mainly drivel!

Edited February 3, 2018 by KTtom

[MattStoke]

ECM 00z rolling out. Tuesday's front a little more progressive than previous runs? Mild sector looks further east but is still quickly mixed out.

Models may be inching towards the middle ground, which would bring it as a band of snow to most parts.

Snow accumulation chart would suggest the front is a bit further east on this run but still struggles to get past Wales and the West Midlands. Shows some snow for far eastern parts too, but from North Sea snow showers rather than that front. Kent in particular looks well positioned for snow showers and maybe streamers, depending on exact wind direction.

Edited February 3, 2018 by MattStoke

[mulzy]

Oh dear!! ECM is very poor at day 5.  A significant mild sector encroaches the UK with heavy rain expected on Thursday.

It’s quite possible that the det is on the mild side of the envelope but the cold/cool snap will probably be over by Friday.  

On the face of it, snow chances look limited. Eastern coastal districts may do well as well as more western and central areas from that decaying front on Tuesday - but as ever surprise snowfalls are likely to happen.

To be honest, expecting little if any snow here in London.

Hey-ho, the search continues - interest now mid month for me - blocking could become prominent by then.

 

Edited February 3, 2018 by mulzy

[MR EXTREMES]

ECM dumps a euro slug and straight westerly.

All very messy although I'm extremely happy with next week's chances.

But models seem to revert back to what we recently been getting.

Hopefully we start seeing upgrades on the 12z but still happy with 6 day event.

[That ECM]

Watch the front  from t48 to t60 t 72 drift up from the se. Not something you see on a regular basis. Suggested 850's for the corresponding time. 

Edited February 3, 2018 by That ECM

[January Snowstorm]

The lack of comments says it all really.

Still a fun week ahead but the Atlantic looks like winning out end of week

[Rayth]

Is the progression of the ECM in the latter frames just going to be blamed on model climatology bias or is there something else the model is picking up on ... out my pay grade that one ! 

[Luke Best]

1 hour ago, KTtom said:

Just want to bump this excellent post forward for people to read this morning...such a shame it will get lost in pages of mainly drivel!

Also worth bumping is yesterday's excellent blog by Nick Finnis, which I found extremely informative and helped demystify the MJO.

https://www.netweather.tv/weather-forecasts/news/8716-analysis-of-whats-behind-the-pattern-change-bringing-deep-cold-to-uk-next-week

[snowice]

17 minutes ago, January Snowstorm said:

The lack of comments says it all really.

Still a fun week ahead but the Atlantic looks like winning out end of week

7am lack of comments 

[Frosty.]

The Gfs 00z saved the best chart until last..what a tease!!

[bluearmy]

9 hours ago, bluearmy said:

Following from Steve’s post, the eps clusters show 75/25 against the flatter op days 5/7. By day 8, it becomes 50/50 between the former nw/se flow into Europe and a flatter west/east flow. The extended looks fairly cold and tending back to  more blocked. tomorrow’s runs awaited! 

I meant to add a final sentence which was ‘ would you bet against the op with 25% support against the members with 75% ?

looks like you shouldn’t !!!!!!

[karlos1983]

2 hours ago, jvenge said:

GFS teases with height rises throughout the unreliable. With an amusing switch to the Iceland/Greenland route towards the end.

In the middle of the run, this air chart tells the story. It isn't mild in Europe, but also a lack of frigid air. Leading to conditions I will technically describe as "meh"

You say amusing, I would say perfectly feasible. We are still looking at a very toasty 10hpa, and now the start of that warming event we’ve been drooling at for days is inside 192hrs.

 

52 minutes ago, January Snowstorm said:

The lack of comments says it all really.

Still a fun week ahead but the Atlantic looks like winning out end of week

Actually it’s been a good set of 00z in my opinion, Azores high not so keen to push in this time, cold spell lasts longer and frontal snow more likely, should they make it in that is. Mon-Friday I would probably be commenting at 5:30-6:00am, but it’s Saturday morning, give us a break ?

Fridays 850’s look bettter on the UKMO, and there’s still plenty of wiggle room given the setup and the time frames involved for that mild sector to be eroded completely.

Claims of this being an ordinary February cold spell are imo wide of the mark. I would say -5 to -7 uppers for a couple of days is ordinary. We are going to experience -double figure values. It’s not ordinary. 

EDIT:

And Hot off the press, ECM a mild outlier compared to it’s members.

Edited February 3, 2018 by karlos1983

[nick sussex]

The ECM seems to be doing what it did the last time when it forecast the coldest solution and longest spell.

It dropped it then became the most progressive then after a few runs started backtracking .

Even with its latest change the models still show around a week of snow potential for the UK and the ECM op is one of the mildest solutions for the UK and a clear mild outlier at times.

 

[jvenge]

ECM has quite a range between minimum and maximum for Tuesday and Wednesday. Temperatures could still struggle to get above freezing in the south east. Most forecasts will generally choose the maximum temperature. Worth keeping in mind. 

 

[JBMWeatherForever]

The cold spell which is about to commence is unusual in how it has arrived and may well surprise some people with the amount of snow received during next week. I also am not convinced about the modellng of this complicated set up for later next week, the models bias looks to be coming into play by then. The end of the week could end up being very interesting.

Edited February 3, 2018 by JBMWeatherForever

[Chesil View]

I can understand the lack of posts looking at the operationals this morning however given the wider forcings that are coming into play I would expect the operational runs for week 2 to look very different come tuesday/weds.

My own interpretation of the situation is that we are at the beginning of a spell of cold phases through Feb with the coldest/snowiest spell likely later in the month.

[Polar Maritime]

Lots of overnight posts have had to go, On top of yesterday evenings today will follow suite... Please only constructive posts based on the 'Model Outputs' remembering there is a Model banter/moan thread for looser discusson or even BBC chatter. Hopefully this thread will run much cleaner and constructively today! ☺

Onwards and upwards.

Edited February 3, 2018 by Polar Maritime

[Frosty.]

17 minutes ago, karlos1983 said:

You say amusing, I would say perfectly feasible. We are still looking at a very toasty 10hpa, and now the start of that warming event we’ve been drooling at for days is inside 192hrs.

 

Actually it’s been a good set of 00z in my opinion, Azores high not so keen to push in this time, cold spell lasts longer and frontal snow more likely, should they make it in that is. Mon-Friday I would probably be commenting at 5:30-6:00am, but it’s Saturday morning, give us a break ?

Fridays 850’s look bettter on the UKMO, and there’s still plenty of wiggle room given the setup and the time frames involved for that mild sector to be eroded completely.

Claims of this being an ordinary February cold spell are imo wide of the mark. I would say -5 to -7 uppers for a couple of days is ordinary. We are going to experience -double figure values. It’s not ordinary. 

EDIT:

And Hot off the press, ECM a mild outlier compared to it’s members.

Yes karlos there is lots to look forward to in the week ahead, predominantly cold with widespread frosts and snow in places..very cold air moving in from the east early next week, that change will be felt tomorrow as a NEly flow increases and it will feel like freezing point despite the thermometer saying 4/6c around 41f.

[Nick F]

The trouble is in MOD many are always concentrating too hard on the demise of a cold spell. Doesn't look like milder air arrives across all areas until Sunday on current GFS and reliable timeframe for the models atm IMO is around t+144. Temperatures in low single digits at best for most this coming week, some spots, mostly with elevation or well inland, perhaps barely above freezing. Some snow potential, though nothing significant.