Model Output Discussions 18z 31/01/2016

[nick sussex]

You can see the difference here between the NAM 12hrs run at T60hrs and the ECM 00hrs to T72hrs:

 

The NAM has phased the low leaving Newfoundland with the shortwave and further on it absorbs this, the ECM has the shortwave further se and hasn't absorbed this.

Only 30 minutes to wait now before the key timeframe on the GFS 12hrs run. I almost can't watch!

 

 

Edited February 8, 2016 by nick sussex

[karlos1983]

7 minutes ago, wishingforsnow said:

The main issue of confusion is the shortwave, I think ECM is just throwing around a different scenario which at the moment remains an outlier across the model output, and I hope it stays that way. 

I would urge on the side of caution all the time the ECM is not on board with its operational. Hopefully the 12z will clear this up. crazy really that we are talking about within +72 hours. nervey 12z  output coming up 

[weirpig]

11 minutes ago, karlos1983 said:

I would urge on the side of caution all the time the ECM is not on board with its operational. Hopefully the 12z will clear this up. crazy really that we are talking about within +72 hours. nervey 12z  output coming up 

I agree Karlos  however one good thing is that the early 12z models that have come out seem to absorb the shortwave.  positive trends

[nick sussex]

In terms of non-related shortwave drama news the GEFS/GFS continue to increase the amplitude of the MJO signal into phase 7.

Bear in mind the UKMO view of February prospects didn't think this would be a factor as they expected a low amplitude signal.

The GEFS originally was the least interested in moving the MJO through the phases. Still waiting for the other models to update. Normally the ECM has the best MJO verification so that's really the key one.

The ECM has updated and that's less interested in terms of MJO amplitude. A big divergence between that and the GEFS.

Edited February 8, 2016 by nick sussex

[winterof79]

More adjustments to the fax charts like this one overnight are very welcome

 00z

12z yesterday

528 dam well established through the UK on the latest update.

Edited February 8, 2016 by winterof79

[winterof79]

Do we have phasure

Affirmative Houston

Edited February 8, 2016 by winterof79

[IDO]

4 minutes ago, nick sussex said:

In terms of non-related shortwave drama news the GEFS/GFS continues to increase the amplitude of the MJO signal into phase 7.

Bear in mind the UKMO view of February prospects didn't think this would be a factor as they expected a low amplitude signal.

The GEFS originally was the least interested in moving the MJO through the phases. Still waiting for the other models to update. Normally the ECM has the best MJO verification so that's really the key one.

I would not rely on any MJO indices verifying at the moment as the current MJO composites have the US heading into a warm phase, yet a PV lobe is set to put them in the freezer:

  

Other background signals are more likely to control the upcoming pattern, more over the Minor SSW? All in all not great for the UK for any cold blocking before March at least. Instead we are hunting for the scraps that the US don't want. A far greater chance of the Euro high edging north from later in the month than any cold block. Week 3 and 4 CFS still keen on that scenario:

CFS w3 and w4:   London T850s: 

Hard to see where any prolonged cold will come from though not discounting transient cooler spells. Though looking at the 30 year average and the next 16 day forecast for uppers from the GEFS mean, just seasonal temps rather than any cold period^^^ Hopefully GFS are correct for the end of the week, to make something out of the jet sinking. Will see soon. 

 

[nick sussex]

The GFS 12hrs run does make a little more drama with another weak shortwave to the nw but thankfully doesn't fall at the first hurdle and phases the main one.

Still its rather nerve shredding and it seems quite complex with the models struggling with this shortwave energy near the UK.

[weirpig]

1 minute ago, nick sussex said:

The GFS 12hrs run does make a little more drama with another weak shortwave to the nw but thankfully doesn't fall at the first hurdle and phases the main one.

Still its rather nerve shredding and it seems quite complex with the models struggling with this shortwave energy near the UK.

Isnt it always  compex  with this troublesome little isle

[wishingforsnow]

So there is a good trend going for the phasing of the shortwaves at the moment, which is positive 

[Methuselah]

Set phasers on stun. 

[Harsh Climate]

Fridays possible snow event in the south on friday falling as mainly rain according to the 12z. Uppers just too mild.

[Harsh Climate]

Does increase the risk for north midlands/south yorkshire though

[nick sussex]

The track of any shortwave low running into the UK is likely to change between outputs. So as for any snow on the northern flank its unlikely the detail will be sorted out for a few days.

At least the GFS so far hasn't backed the ECM which is a relief.

[weirpig]

Midlands  wales north  snow on friday

[seabreeze86]

GFS sticks with its earlier runs just slight variations with the shortwaves.

But looks more promising in the medium term

Could pull down a decent northerly from there i would think

[phil nw.]

As Nick S said we wont know for certain on when,where Friday's snow risk will be for some days yet but currently GFS continues to slide that first low along the south coast/channel area so areas with 0C dewpoints and near freezing surface temperatures will be somewhere north of the track.

Cold air coming south behind the low after it crosses so maybe some back edge snow further south before it clears.

 

[phil nw.]

UKMO at T96

also continues to slide the low towards the channel/s.coast similar to GFS with the cold air to it's north .We will soon see if the ECM will go the same route this evening.

[Bristawl Si]

That damned Azores High!

If Corbyn will never push the button then i will.

[snowray]

5 minutes ago, phil nw. said:

UKMO at T96

also continues to slide the low towards the channel/s.coast similar to GFS with the cold air to it's north .We will soon see if the ECM will go the same route this evening.

The great thing about this is that its now only 4 days out, surely ECM will come on board later on.

 

[Ali1977]

UKMO looks better than the GFS with the orientation of the slider/s...If the ECM follows then the coldest 4/5 day period of winter could be coming, especially with regards snow opportunities for the south.

[Snowy L]

ECM on its own now. GFS has ruined the fun being annoyingly too accurate this winter and the last 2 winters actually, hopefully it's accurate again.

[wishingforsnow]

15 minutes ago, Snowy L said:

ECM on its own now. GFS has ruined the fun being annoyingly too accurate this winter and the last 2 winters actually, hopefully it's accurate again.

Funny how GFS has gone from being the villain to hero

[TSNWK]

9 minutes ago, wishingforsnow said:

Funny how GFS has gone from being the villain to hero

Obs. it is showing the better outlook

[johnholmes]

1 hour ago, IDO said:

I would not rely on any MJO indices verifying at the moment as the current MJO composites have the US heading into a warm phase, yet a PV lobe is set to put them in the freezer:

  

Other background signals are more likely to control the upcoming pattern, more over the Minor SSW? All in all not great for the UK for any cold blocking before March at least. Instead we are hunting for the scraps that the US don't want. A far greater chance of the Euro high edging north from later in the month than any cold block. Week 3 and 4 CFS still keen on that scenario:

CFS w3 and 4:   London T850s: 

Hard to see where any prolonged cold will come from though not discounting transient cooler spells. Though looking at the 30 year average and the next 16 day forecast for uppers from the GEFS mean, just seasonal temps rather than any cold period^^^ Hopefully GFS are correct for the end of the week, to make something out of the jet sinking. Will see soon.