Model output discussion - mid January

[Banbury]

10 minutes ago, Tim Bland said:

A chance of snow in the south tomorrow morning ..

My App is also showing that

[nick sussex]

Just been looking at the NCEP monthly forecast for the USA.

High uncertainty for February because of the MJO.

I know the MJO has come in for derision but to be honest at this point that seems the only trigger that might deliver more sustainable cold.

We really need it to scoot through as quickly as possible to phase 6 then phase 7.

The high pressure located over or to the south of the UK is a likely outcome. Where that goes afterwards will dictate the early February weather .

So more amplitude upstream will pull that north or ne and that’s what we need to see!

[beng]

20 minutes ago, nick sussex said:

Just been looking at the NCEP monthly forecast for the USA.

High uncertainty for February because of the MJO.

I know the MJO has come in for derision but to be honest at this point that seems the only trigger that might deliver more sustainable cold.

We really need it to scoot through as quickly as possible to phase 6 then phase 7.

The high pressure located over or to the south of the UK is a likely outcome. Where that goes afterwards will dictate the early February weather .

So more amplitude upstream will pull that north or ne and that’s what we need to see!

Looks like a few ensemble member from this morning GFS get into Phase 7 - judging by a few developing a block of sorts to the East towards early Feb. By no means big agreement on that from the GEFS though yet.

It won't guarantee a Feb 91 repeat obviously - but probably the last chance for most of us in the far south (sorry my back yard!) before the spring (March snows don't deliver in Surrey).  If we do get a phase 7->8 transition in early to mid Feb, it might deliver a  decent surface pattern though.

 

Edited January 19, 2018 by beng

[beng]

1 hour ago, Weather toad said:

Nice little trend setting up with a strong MLB southern Britain. It will be interesting to see where the extended EPS takes this in the next few days. Cold already Building to the East unlike those phantom easterlies. 

This would be consistent with MJO Phase 6 - can we get it beyond that though?

[Scandinavian High.]

Long way out but  continue to see higher pressure to east/north east colder weather for south of Britain maybe  weather will  balance it self out give us in the south east some colder weather and with it coming from easterly  Direction with proper cold to east maybe we can hit the jackpot we'll see.

[Devonshire]

1 hour ago, Banbury said:

1 hour ago, Tim Bland said:

A chance of snow in the south tomorrow morning ..

My App is also showing that

Although since neither South-West nor South-East see snow on that - and barely anything South of the M4 - then I'm not sure there is any chance of snow in the South on that chart!

[Banbury]

11 minutes ago, Devonshire said:

Although since neither South-West nor South-East see snow on that - and barely anything South of the M4 - then I'm not sure there is any chance of snow in the South on that chart!

Luckily I am North of the M4 lol

[stodge]

Morning all

A chance for me to take a medium term look at where the models are showing.

Starting with ECM 00Z at T+240 (January 29th):

The Azores HP (or a version of it) has finally got as far NE as NW France but the orientation brings mild or very mild TM air over us. Hard to think there wouldn't be a lot of cloud in that airflow but at 1040MB there's a possibility we might see some breaks to the lee of high ground so sunny and very mild days and foggy nights for a few but otherwise benign and largely settled. Worth noting the Atlantic seems pretty quiet at this time.

GEM 00Z OP at T+240:

A lot of similarities with ECM - the Atlantic a little stronger and the HP a little weaker and a little further south but for the British Isles the mild or very mild SW'ly airstream continues.

GFS 00Z OP at T+240:

Slightly different. The Atlantic is, as is often the case with GFS, much stronger with a very deep and vigorous LP to the east of the Faeroes. Further into FI, the European HP tries to build NE into Scandinavia but it's a struggle against the northern arm of the jet and at T+384 is centred over Poland and the Baltics and, as we all too often see, the very cold air is heading into the Balkans (-12 and -16 850s) while for the British Isles it would became colder especially over the SE under light winds with fog and frost possibly becoming more prevalent.

GFS 00Z Control at T+240:

Not too far removed from the OP in all honesty. The HP is centred over eastern Europe and not oriented well but there's the faintest hint of a continental drift for SE parts. Into further FI and the Control sets up a new HP over the British Isles before it declines SE into Europe.

So to the GEFS Ensemble panel at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

There's a strong anticyclonic theme in the GEFS not I think reflected in the OP. I'd say a majority have HP in control and a significant minority have that HP to the north, north east or east of the British Isles with one or two having the MLB centred over the British Isles. I'd say those showing outright Atlantic dominance are in the minority this morning.

To summarise, the transition to a much milder pattern is set but any spell of unsettled conditions is looking of short duration with strong signals for a pressure rise from the SW through the end of next week. January looks to end and February to start on an anticyclonic note but where the HP will end up is wide open at this time. It's also worth noting the changes in the Polar profile.

[Man With Beard]

I think the EC clusters are pretty much on the same page as Stodge's comments above. It looks like we will see a surge from the Azores High towards Europe in the D8-D12 period, but where it will go is hard to place yet. UK high or Central Europe High are strong possibilities. A raise of heights into Scandi is still there but the ECM has trended away from this option slightly in the past 36 hours. Here's D11:

[beng]

11 minutes ago, Man With Beard said:

I think the EC clusters are pretty much on the same page as Stodge's comments above. It looks like we will see a surge from the Azores High towards Europe in the D8-D12 period, but where it will go is hard to place yet. UK high or Central Europe High are strong possibilities. A raise of heights into Scandi is still there but the ECM has trended away from this option slightly in the past 36 hours. Here's D11:

Should go through the UK initially and then build to the East or NE (early Feb - hopefully) - if the MJO move goes for us.

Edited January 19, 2018 by beng

[That ECM]

This was my post from Tuesday.

 

As much as I took the Micky this morning with regards to the ecm, the far reaches of the gfs have shown heights in our area for the last couple of days. I have noticed before that if the output keeps churning out models with strong heights in "good/bad" areas in fi they may just be picking up a signal that the detail has yet to be agreed on. This has caught my eye over the last couple of days. The chart shown is the latest but if you look through the previous runs, gfs, recently you will see this on numerous occasions. 

Ecm may well have been on its own but is it playing with a signal for heights to build on around our part of the world? 

 

 

 

Today's commentary would be similar.

 

There is a strong signal for heights in out part of the world. It's the detail of where it resides that will be important. 

Edited January 19, 2018 by That ECM

[FetchCB]

Near Record breaking High pressure over UK to start Feb if GFS is to be believed

 

 

 

http://onlinelibrary.wiley.com/doi/10.1002/wea.35/epdf

[ArHu3]

19 minutes ago, That ECM said:

This was my post from Tuesday.

 

As much as I took the Micky this morning with regards to the ecm, the far reaches of the gfs have shown heights in our area for the last couple of days. I have noticed before that if the output keeps churning out models with strong heights in "good/bad" areas in fi they may just be picking up a signal that the detail has yet to be agreed on. This has caught my eye over the last couple of days. The chart shown is the latest but if you look through the previous runs, gfs, recently you will see this on numerous occasions. 

Ecm may well have been on its own but is it playing with a signal for heights to build on around our part of the world? 

 

 

 

Today's commentary would be similar.

 

There is a strong signal for heights in out part of the world. It's the detail of where it resides that will be important. 

Very reminiscent of late January 2012, with a bit of luck we could end up in a similar scenario like February 2012 

 

http://www.meteociel.fr/modeles/archives/archives.php?day=22&month=1&year=2012&hour=12&type=ncep&map=0&type=ncep&region=&mode=0

[mulzy]

From the GEFS 6z set for the period Feb 1 to Feb 4, there are 5 decent members (P1, P2, P8, P9 and P19) and 4 reasonable members (P7, P13, P14 and P18).

This shows there is hope for early February folks.

 

[mountain shadow]

1 hour ago, beng said:

Should go through the UK initially and then build to the East or NE (early Feb - hopefully) - if the MJO move goes for us.

Isn't that the problem though, it's nigh on impossible to get a decent amplitude MJO wave into 7 and 8 during La Nina

[frosty ground]

On 18/01/2018 at 11:56, frosty ground said:

A distinct split in the Ensembles around the 28th 

These look like sets of ensembles from December and earlier this month, a 5 day mild spell and then a dip to below average. If the pattern repeats we should start to see the jet take more of a NW/SE trajectory allowing more PM air over the UK. 

So the split on the 28th has gone leaving the milder output

But the 25th has now firmed up on a 2 day cool down, it's almost like history is repeating itself.

[North-Easterly Blast]

2 hours ago, stodge said:

This year's La Nina is only a weak to moderate event - history shows us that weak to moderate La Nina events have coincided with decent winter cold, it is strong La Nina events that almost guarantee a milder than average winter.  Winter 1995-96 had a La Nina of -0.9, but still managed to be a cold winter overall - with cold periods in Dec and from late Jan through Feb.  Winter 1984-85 also saw a La Nina of -1.0, but was still cold overall, especially January.  Winter 1955-56 saw a La Nina of -1.1, but still saw a very cold Feb.  Winter 1954-55 saw a La Nina of -0.7, but was cold from January to March.  

My conclusion is that many weak to moderate La Nina winters have been decent for cold, or at least seen a decent cold spell - but of all the nine strong events since 1950 (anomaly much below -1*C), not one has coincided with a cold winter, though one did coincide with a very cold start to winter (Dec 2010), but all the rest were average to mild all the way through - and on occasion even exceptionally mild (1988-89).

 

 

[Summer Sun]

Mild UKMO extended temps into the teens for some I would imagine

[booferking]

CFS goes for HLB early Feb we can only dream.

[Fozfoster]

18 minutes ago, booferking said:

CFS goes for HLB early Feb we can only dream.

Looking good but CFS !!!! stands for Couldnt Forecast Sh*t ......................or  it seams for most of this winter lol.

[Bradowl]

7 hours ago, Tim Bland said:

A chance of snow in the south tomorrow morning ..

Showing good deal further north east now on this.

 

[N/A]

18 hours ago, Daniel* said:

An unwelcome slap in the face for coldies. Has it really been cold? Not really been cold in London while you do need some layers well it is winter! Some parts of Siberia, Yakutia region got down to -62C few nights ago. In fact official thermometer broke it was that cold some unofffical readings of -67C been reported now that is cold. This winter has been fairly benign in all areas so talking about a break? The recent gales was a long time coming. I find gales more interesting weather than standard fare, rather have that to mix up the tedium of searching for proper cold and snow. 

 

Well this week has certainly has been a kick in teeth for all us coldies in the S&SW UK  to say the very least but I can assure you Daniel it's been colder in London than here in Tenby. I said as soon as they mentioned it,that this heavily modified polar maritime airmass is rubbish for us and were therefore very unlikely to see any snow away from high ground and unfortunately that was the case. Since 1st January we've had 4 rounds of severe gales damaging buildings including mine, cars, trees as well as bad coastal flooding in places. The wind obviously not so strong in London being inland, even yesterday mornings storm wasn't as strong as it was here despite it still deepening. So IMO it is a very welcome relief to see the lows tracking north to allow a decent break from the gales even its set to turn unseasonably mild. 

Edited January 19, 2018 by Dafydd Tomos

[mb018538]

Anyone willing to bet the high pressure build that the models keep showing doesn’t come off? Nearer the time it will have underplayed the Atlantic influence, and a low will plough through and keep it flat and unsettled. Seen it all winter, so I’m going to go for it again!

[mulzy]

2 minutes ago, mb018538 said:

Anyone willing to bet the high pressure build that the models keep showing doesn’t come off? Nearer the time it will have underplayed the Atlantic influence, and a low will plough through and keep it flat and unsettled. Seen it all winter, so I’m going to go for it again!

UKMO and GEM are following your script for starters!  Pretty flat...

[Tim Bland]

??