Model Output Discussion - cold spell to end Autumn

[ScottishSnowStorm]

Can't understand why there is so little enthusiasm in here after the 0z runs?

[Dennis]

1 minute ago, ScottishSnowStorm said:

Can't understand why there is so little enthusiasm in here after the 0z runs?

me too tommorow we start winterseason 1dec 2017

[pdiddy]

1 minute ago, ScottishSnowStorm said:

Can't understand why there is so little enthusiasm in here after the 0z runs?

I think it's because the split on the 6th/7th has now favoured the milder solution having been firstly 85/15 in favour of colder, then 50/50... Still not certain in my view but more runs needed.

[mountain shadow]

2 minutes ago, ScottishSnowStorm said:

Can't understand why there is so little enthusiasm in here after the 0z runs?

Really?  Once we get model agreement inside 5 days for some good stuff then the excitement may build.

Any good charts are now back in FI. 

[knocker]

Broadly speaking the ecm is in the same ball park as the gfs up to around T144. At that time the high pressure is to the south of the UK with the latter in westerly zephyrs whilst the main trough is positively tilted in central Atlantic with associated fronts lying west-east north of Scotland and north-south west of Ireland.

A low breaks away from the main trough and tracks north east across Scotland Thursday morning, accompanied  by rain and gales, and phases with the colder air to the north as the front traverses the rest of the country.

The low continues east into southern Norway initiating a strong northerly flow over the UK with possible blizzards in the Scottish mountains as perturbations form in the flow.

The northerly more or less hangs around to near the end of the run but perhaps the most important feature here is the surging of the HP to the east of the N. American trough which combines with Euro high to form another high cell to the south west of the UK. whilst at the same time plunging the trough to the east, and the cold air, down to the western Mediterranean. Thus the UK is once again back in the eastern circulation of the high but what of the energy zooming around the top? Will it dives south east towards the low pressure to the south?

[ScottishSnowStorm]

Just now, pdiddy said:

I think it's because the split on the 6th/7th has now favoured the milder solution having been firstly 85/15 in favour of colder, then 50/50... Still not certain in my view but more runs needed.

go look at all models GFS, ECM, GEM, ICON all models seperate energy in the atlantic leaving low pressure around the azores all have better profile over canada all push hieghts into greenland on similar evolution and UKMO at 144hr looks similar to the rest so although no short term northerly really only GFS was holding onto we have cross model pattern emerging better than we had 

[cyclonic happiness]

Perhaps we've been too greedy expecting winter in autumn.

I'm sure we'll get something this winter, after all, four years with no lying snow has to be a record??

[pdiddy]

2 minutes ago, ScottishSnowStorm said:

go look at all models GFS, ECM, GEM, ICON all models seperate energy in the atlantic leaving low pressure around the azores all have better profile over canada all push hieghts into greenland on similar evolution and UKMO at 144hr looks similar to the rest so although no short term northerly really only GFS was holding onto we have cross model pattern emerging better than we had 

Hang on... you asked the question and I replied why there is, as far as you're concerned "so little enthusiasm".  I have looked at the models.  I'm not less enthusiastic.  That said, the Azores low you mentioned quickly fills and heights replace it, so back to +ve NAO.  That's what I see when I go look at the models.  Happy to hear your alternate reading of same?

[Kentish Snowman in Yorks]

3 minutes ago, ScottishSnowStorm said:

go look at all models GFS, ECM, GEM, ICON all models seperate energy in the atlantic leaving low pressure around the azores all have better profile over canada all push hieghts into greenland on similar evolution and UKMO at 144hr looks similar to the rest so although no short term northerly really only GFS was holding onto we have cross model pattern emerging better than we had 

Yes the heights around Greenland remain on the latest 0z runs so the Northerly although a little delayed still looks like a strong possibility in the 7-10 day time frame.

I am yet to see a model barrel the Atlantic through the UK on a flat jet and so until that is the prospect within a reasonable time frame I will be remaining optimistic.

Many areas will see some snow at least falling TODAY so that is not a bad position to be in heading into winter proper in my opinion!  

[Frosty.]

Big downgrades this morning, any cool / colder shots have been shunted back and reduced to brief topplers. This weekend and most of next week looks generally benign with higher pressure and gradually becoming milder from the west.

[Scandinavian High.]

Very interesting model watching over next few days I feel ecm saying yes colder later next week..

[ScottishSnowStorm]

4 minutes ago, pdiddy said:

Hang on... you asked the question and I replied why there is, as far as you're concerned "so little enthusiasm".  I have looked at the models.  I'm not less enthusiastic.  That said, the Azores low you mentioned quickly fills and heights replace it, so back to +ve NAO.  That's what I see when I go look at the models.  Happy to hear your alternate reading of same?

Wasn't meaning to come across like there was any kind of problem sorry if it seemed lile that. Was only saying all models are dealing with the atlantic better which is what was destroying the output because the lows didn't seperate and it all moved north so in the medium term along with eastern canada being better orientated then we have more hieghts pushed into greenland and less likelihood of the pattern flattening than we have seen and all models seem to agree on this so while no northely we aren't going zonal and anything aimed at greenland could develop as we go along 

[ScottishSnowStorm]

25 minutes ago, mountain shadow said:

Really?  Once we get model agreement inside 5 days for some good stuff then the excitement may build.

Any good charts are now back in FI. 

Can it be FI when 4 models in medium range are all showing similar evolution to the atlantic and canada?

[knocker]

The EPS 7-12 mean anomaly is not significantly different to last evening.The dominate features vis downstream are still the active Canadian vortex with the cold trough down the east of N. America and the channel to the trough to our east over N. Greenland There are very strong upper winds leaving the south of the eastern seaboard which swing around some mid Atlantic ridging south of Greenland to descend from the NW over the UK. This ties in with this morning's det. run which has 160kt jet south of Greenland towards the end of the run, It's difficult to see this period not being unsettled although there may well be a N/S split

[jvenge]

ECM Control showing a potent northerly from t192 to t240. Seems to want to reload it later in the run as well, although a mild interlude in-between.

ECM Mean is not an adament supporter of this, but one can see that there is likely a cluster of some sorts showing it. One imagines there is also one showing fairly toasty temperatures as well...

[snowking]

Something to be a little wary of out in the Pacific at the moment is this:

If this typhoon east of the Philippines does turn out to be a reality then the forecast recurvature will create all kinds of varying solutions hemispherically with consequences for the downstream longwave setup

This is not to say this changes our fortunes in any way, but just something to be wary of in day 7+ modelling at present 

[nick sussex]

All the outputs were wrong last night not just the ECM, all show a delay to the cold heading south which isn't great news.

Its now become even more complicated with more shortwave trauma than previously. Still a chance of a battle ground scenario and it still looks like positive PNA upstream so the PV shouldn't set up over Greenland.

At least the models are generally agreed that between T144 and T168hrs will be the make or break moment.

Shortwave energy to the sw splits in both the ECM and GFS, one shortwave low moves east.

That needs to happen.

 

 

 

[johnholmes]

Well this morning the anomaly charts show as below

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

On the face of it a 500 mb flow on all 3 from north of west. How cold? Looking at the contour heights predicted over southern UK then not that cold for early December. Also the charts have flicked about from a suggestion of a westerly to a more meridional flow so some uncertainty. My own feeling watchingthese every day for years now is that it will remain about average temperatures tending towards rather cold at times. The possibility of a deep cold outburst remains but there is little in these charts to suggest any prolonged cold outbreak.

[karyo]

21 minutes ago, snowking said:

Something to be a little wary of out in the Pacific at the moment is this:

If this typhoon east of the Philippines does turn out to be a reality then the forecast recurvature will create all kinds of varying solutions hemispherically with consequences for the downstream longwave setup

This is not to say this changes our fortunes in any way, but just something to be wary of in day 7+ modelling at present 

I think it also depends on which direction it is going. The further north it gets the more likely to disrupt the jet stream.

Which direction is this going?

[Summer Sun]

UKMO has moved away from the northerly now

t144

t168

[frosty ground]

3 minutes ago, Summer Sun said:

UKMO has moved away from the northerly now

t144

t168

Looks like Scotland will be under the Arctic air with the rest of the UK on the wrong side.

[karlos1983]

10 minutes ago, karyo said:

I think it also depends on which direction it is going. The further north it gets the more likely to disrupt the jet stream.

Which direction is this going?

Looking at GFS, this possible tropical cyclone looks to meander around just to the N east of the Philippines then generally head off in an East North East direction quickly becoming ex tropical and merging with storms in the east Pacific, before heading up towards the Aleutian Islands/Bearing Sea.

But the track will probably change quite a bit in future runs

Edited November 30, 2017 by karlos1983

[karyo]

2 minutes ago, karlos1983 said:

Looking at GFS, this possible tropical cyclone looks to meander around just to the N east of the Philippines then generally head off in an East North East direction quickly becoming ex tropical and merging with storms in the east Pacific before heading up towards the Aleutian Islands/Bearing Sea.

But the track will probably change quite a bit in future runs

Thanks Karlos. Worth watching I guess.

[ScottishSnowStorm]

8 minutes ago, Summer Sun said:

UKMO has moved away from the northerly now

t144

t168

Another model that splits the energy in the atlantic and also looks similar to the rest over eastern canada so pattern less likely to flatten out and still chances of a northerly 

[Daniel*]

7 minutes ago, frosty ground said:

Looks like Scotland will be under the Arctic air with the rest of the UK on the wrong side.

Most of the UK is cold S of London sees a south westerly flow. That shortwave again zipping eastwards odds of a snow event increasing mid next week however likely it won’t be white for all...