Model Output Discussions 12z 01/09/2016

[Daniel*]

Give this a watch very impressive - nothing is set in stone with unusualness like this WAA is ongoing, such warmth getting to the pole. Sowing the seeds for proper winter weather in mid latitudes, one hopes the UK is in amongst it. 

[feb1991blizzard]

3 minutes ago, knocker said:

No indication tonight from the anomalies that anything sinister is lurking in the woodshed. They are all in the same ball park regarding the general upper pattern and just some minor differences vie the precise orientation of the trough to the east and the Atlantic HP. Ergo the upper flow will be in a westerly/north westerly quadrant with temps perhaps a little above average.

Do the NOAA CPC 6-10 and 8-14 day charts not show a mean North Easterly flow with blocking in the Atlantic ridging right up into Greenland and the pole?

[blizzard81]

9 minutes ago, knocker said:

No indication tonight from the anomalies that anything sinister is lurking in the woodshed. They are all in the same ball park regarding the general upper pattern and just some minor differences vie the precise orientation of the trough to the east and the Atlantic HP. Ergo the upper flow will be in a westerly/north westerly quadrant with temps perhaps a little above average. The WAA into the Arctic continues.

There would appear to be no significant change to this scenario in the 10-15 period.

You should be concentrating on the forecast for the UK, not western Canada

[Allseasons-Si]

5 minutes ago, knocker said:

No indication tonight from the anomalies that anything sinister is lurking in the woodshed. They are all in the same ball park regarding the general upper pattern and just some minor differences vie the precise orientation of the trough to the east and the Atlantic HP. Ergo the upper flow will be in a westerly/north westerly quadrant with temps perhaps a little above average. The WAA into the Arctic continues.

There would appear to be no significant change to this scenario in the 10-15 period.

Sorry for knocking on your woodshed door (pun intended) knocks

but wouldn't the temps for a W/NW be cooler

also to add,re;- the noaa charts that you have posted show a NE wind with a trough over scandy and a hp cell stretched from mid atlantic through the pole,just looking at those red lines but what does the green lines mean,still getting my head around these charts.

[knocker]

10 minutes ago, feb1991blizzard said:

Do the NOAA CPC 6-10 and 8-14 day charts not show a mean North Easterly flow with blocking in the Atlantic ridging right up into Greenland and the pole?

Not according to how I read them.The 6-10 has ridging mid Atlantic with positive anomalies but if you look at isohypse there is a fairly slack flow from the north west. There is also the slack area of low pressure to the south west. The 8-14 is not hugely different.

 

Edited October 24, 2016 by knocker

[feb1991blizzard]

1 minute ago, knocker said:

Not according to how I read them.The 6-10 has ridging mid Atlantic with positive anomalies but if you look at isohypse there is a fairly slack flow from the north west. There is also the slack area of low pressure to the south west. The 8-14 is not hugely different.

 

Ok, sorry, I bow to your knowledge then, you being a pro or ex pro.

[knocker]

3 minutes ago, Allseasons-si said:

Sorry for knocking on your woodshed door (pun intended) knocks

but wouldn't the temps for a W/NW be cooler

also to add,re;- the noaa charts that you have posted show a NE wind with a trough over scandy and a hp cell stretched from mid Atlantic through the pole,just looking at those red lines but what does the green lines mean,still getting my head around these charts.

I don't know where you both getting this NE Upper flow from. The green lines are the isohypse or the contour lines which indicate the direction of flow. You have to take care not to translate the anomalies into the surface features, Unless of course I am reading this incorrectly.

[Nouska]

14 minutes ago, feb1991blizzard said:

Do the NOAA CPC 6-10 and 8-14 day charts not show a mean North Easterly flow with blocking in the Atlantic ridging right up into Greenland and the pole?

Positive anomalies indicated by red hatched lines - not necessarily indicative of flow pattern.

[knocker]

5 minutes ago, feb1991blizzard said:

Ok, sorry, I bow to your knowledge then, you being a pro or ex pro.

I don't have a huge previous knowledge of previously reading NOAA charts this is just my understanding of them, As I mentioned just now think roughly where the surface features will go. You perhaps get a better idea on this by comparing to the GEFS and ecm as they are actually in pretty reasonable agreement.

Edited October 24, 2016 by knocker

[feb1991blizzard]

Just now, Nouska said:

Positive anomalies indicated by red hatched lines - not necessarily indicative of flow pattern.

See what you mean now, but surely those are huge positive anomalies though?

[knocker]

1 minute ago, feb1991blizzard said:

See what you mean now, but surely those are huge positive anomalies though?

Fair to middling.

[feb1991blizzard]

Just now, knocker said:

I don't have a huge previous knowledge of previously reading NOAA charts this is just my understanding of them, As I mentioned just now think roughly where the surface features will go. You perhaps het a better idea on this by comparing to the GEFS and ecm as they are actually in pretty reasonable agreement.

Yes I see now, you are right. Still better though (for future prospect of HLB) to have the +ve anomalies over Greenland than -ve.

[Allseasons-Si]

4 minutes ago, Nouska said:

Positive anomalies indicated by red hatched lines - not necessarily indicative of flow pattern.

Thanks,but if you have a positive anomaly to the NW you have a NE wind,not?

2 minutes ago, feb1991blizzard said:

See what you mean now, but surely those are huge positive anomalies though?

 

[knocker]

15 minutes ago, Allseasons-si said:

Sorry for knocking on your woodshed door (pun intended) knocks

but wouldn't the temps for a W/NW be cooler

also to add,re;- the noaa charts that you have posted show a NE wind with a trough over scandy and a hp cell stretched from mid atlantic through the pole,just looking at those red lines but what does the green lines mean,still getting my head around these charts.

I was just using the ecm 6-10. You actually get an idea of the flow from it as well as it happens. That little upper trough to the south west does back the flow in the south. It's known locally as the Sidney effect.

 

Edited October 24, 2016 by knocker

[knocker]

9 minutes ago, feb1991blizzard said:

Yes I see now, you are right. Still better though (for future prospect of HLB) to have the +ve anomalies over Greenland than -ve.

That is indeed true.

[feb1991blizzard]

5 minutes ago, Allseasons-si said:

Thanks,but if you have a positive anomaly to the NW you have a NE wind,not?

 

Because heights are usually so low over Greenland,  even a +ve anomaly doesn't always mean that heights are higher relative to surrounding area.

[Nouska]

55 minutes ago, feb1991blizzard said:

See what you mean now, but surely those are huge positive anomalies though?

They are not as big as they might appear - at this time of year it is normally a big mass of very low heights over the polar regions.

The NOAA anomalies there are also double blends ie. blending five day period and also mix of models. There could well be individual days with more northerly or north easterly influence but it will be mixed out on those charts.

Flow might be easier seen on the contour map for day 11 without the anomalies shown.

Edited October 24, 2016 by Nouska
Edit to add climatology on which anomalies are calculated.

[bluearmy]

Can't say I agree with some of the last hours posts on here. 

Going to bed now so I can't post but mean 6 or 8 day charts showing the average upper flow are not likely to indicate what we would see day to day. 

[Ravelin]

Thing still rather uncertain for this time next week. We've gone from this on the GFS 12z...

To this on the 18z....

Broadly the same in most of the Northern Hemisphere but quite a difference in our neck of the woods. No doubt each run is going to fluctuate for a few days yet before things become clearer. 

[swfc]

oz just seems to blow up and loses most heights towards the nw and greenland be it in fi.not a great thing to see but who knows?????

Edited October 25, 2016 by swfc

[Polar Maritime]

The GFS this morning certainly shows the Atlantic pushing through into the run..

[northwestsnow]

GFS is a bit of a dogs dinner, GEM shows the way forward -

http://old.wetterzentrale.de/pics/Rgem1681.html

http://old.wetterzentrale.de/pics/Rgem1921.html

http://old.wetterzentrale.de/pics/Rgem2401.html

Strong heights to the north and cold air building across Western Russia , scandy and the Baltic countries ..

http://old.wetterzentrale.de/pics/Rgem2402.html

[Ali1977]

Has anyone seen the GFS ENS, the GFS Op run is only supported slightly at day 10 and beyond by 1. Again, the ENS look great for coldies. I know the Op is a more powerful computer but I've never seen it on its own at day 10.

hard to see in this picture , Op is the one in the bottom right.

Edited October 25, 2016 by Ali1977

[knocker]

Today

Basically a N/S split. South of a line mid Wales east mainly cloudy with perhaps some light rain in places. North of this dry with more sunshine. Feeling quite mild in the south but not quite so in the north where some places start the day with quite a heft frost.

So to the delights of the GFS

HP ridges in from the south west, initially resulting in a N/S split with the upper trough to the north bring a strong westerly flow to Scotland resulting in some wet and windy weather on Thursday. Thereafter a high cell influences all of the UK until slipping away SE and by midnight Monday when frontal systems are nudging in from the west initially affecting NW Scotland.

The fronts track south east into the North See where the upper low intensifies creating an upper trough to the east which becomes an integral part of the conduit, starting with the Canadian vortex,  transmitting energy east then south east

On the surface the HP hangs on for a while as the systems run around it to the north but eventually it is relegated south west and a fresh NW flow ensues.

 

 

 

Edited October 25, 2016 by knocker

[doctor32]

At just 6 days out we have a difference between ukmet and gfs @ 144hrs:

ukmet showing a low pressure to the sw of uk affecting the high in antlantic, compared to...

gfs which has no low in same area what so ever.

 

ukmet would look very different from then on compared to gfs.