Model Output Discussions 12z 01/09/2016

[Mucka]

30 minutes ago, karlos1983 said:

This is not a great run out to 144 on GFS or UKMO on the face of it. That said, mild South Westerlies look unlikely for any great length of time.

 

I actually think there are some encouraging signs on that UKMO 144 chart Karlos and there is a slight move toward increasing heights over Scandi in the mid term.

If that proves correct and strengthens then it will increase the chances of backing the pattern west and increasing amplification in the Atlantic if the next low slides.

If this happens current GFS output will look to have been extremely over progressive - though at this point it may still be proved correct.

Lot's of "ifs" in this post.

 

Edited November 1, 2016 by Mucka

[Ravelin]

8 minutes ago, The PIT said:

Well

 

 

A quick Google for London and...

The weather continues to get colder in November in London, UK, when autumn is blending into winter. This month is characterised by falling temperatures, with daily highs decreasing from 13°C on November 1st down to 10°C by November 30th, only exceeding 16°C or falling under 5°C one day out of every ten.

http://www.holiday-weather.com/london/averages/november/

So 13C in London on the 14th looks fairly average to me. OK, maybe a degree above, but that then harks back to the old chestnut of how exactly "mild" is defined.

Edit: Average for Inverness is 8c, so that's bang on.

Edited November 1, 2016 by Ravelin

[Geordiesnow]

Much prefer the UKMO as it shows a slightly stronger shot of cold because of no pesky shortwaves just to the south of Norway so instead of a Northerly, we maintain the NE'ly flow and with a slacker flow, frosts would be more harsher and widespread than the GFS would be and any showers over the NE could well be wintry. 

I think the medium range is looking more and more likely that the PV will start to develop over Greenland but it may not fully mean a return to Atlantic conditions as if we get a scandi high forming, then that would most certainly complaicate matters. The GFS has any attempts of a scandi high all in the wrong place and angle therefore the Atlantic does battle through quite easily, I won't mind either way, would not mind some wet and windy weather as it should be in Autumn.

[The PIT]

1 minute ago, Ravelin said:

A quick Google for London and...

The weather continues to get colder in November in London, UK, when autumn is blending into winter. This month is characterised by falling temperatures, with daily highs decreasing from 13°C on November 1st down to 10°C by November 30th, only exceeding 16°C or falling under 5°C one day out of every ten.

http://www.holiday-weather.com/london/averages/november/

So 13C in London on the 14th looks fairly average to me. OK, maybe a degree above, but that then harks back to the old chestnut of how exactly "mild" is defined.

A bit high that figure. For here it's 8.5C the number shown there is 12C so definitely mild. It's all mute as it's deep FI and as T144 shows from earlier today a lot will change.

[northwestsnow]

Im suprised there hasn't been more said about the ukmo 120-144 as it shows the scandy high putting up a block and potentially helping in angling the jet more favourably than the GFS.

[pdiddy]

39 minutes ago, knocker said:

 

Re the MetO probabilities, If one assigns the xs where they fall in the scale, you get:

"Very Warm" 8% chance

Warm 17%

average 14%

cold 31%

very cold 29%

I'm sure the weighted average of those would also point to a much colder outcome than is being suggested

 

Edited November 1, 2016 by pdiddy

[Paul]

Can we keep it to the models in here please, plenty of places to discuss meto forecasts and the upcoming winter elsewhere on the forums. 

[knocker]

Welcome to the Canadian - Scandinavian express

Edited November 1, 2016 by knocker

[fergieweather]

41 minutes ago, Tamara said:

La Nina often features amplified Atlantic patterns in late autumn and early winter, but the tendency is for the upstream Pacific pattern to take control if this ENSO regime establishes into and through the winter - with anticyclones spun up over the Central Pacific which serve to push the jet northwards and create temperature gradients across Canada and the US which fuel the Jetstream downstream - especially if upper cooling down-wells from the higher layers of the stratosphere.

Yup. Abnormally weakened stratospheric PV 1st half winter, says GloSea, before flipping other way to much stronger into Feb. But there's much water (or zonal winds) to pass under the bridge before we get too clever into that period.

[northwestsnow]

4 minutes ago, knocker said:

Welcome to the Canadian - Scandinavian express

Yes, GFS really cranking up tp the jet this evening, quite a big difference at 144 to ukmo though so still lots of uncertainty moving forward.

[northwestsnow]

2 minutes ago, fergieweather said:

Yup. Abnormally weakened stratospheric PV 1st half winter, says GloSea, before flipping other way to much stronger into Feb. But there's much water (or zonal winds) to pass under the bridge before we get too clever into that period.

Suits me Ian

I much prefer the colder stuff to come in Dec and Jan with the shorter days/weaker sun etc . As you say, time will tell..

[knocker]

4 minutes ago, northwestsnow said:

Yes, GFS really cranking up tp the jet this evening, quite a big difference at 144 to ukmo though so still lots of uncertainty moving forward.

Really just emphasizes.IMO of course, the battle going on between the Atlantic high pressure and the energy zooming out of Canada and the cold air in these troughs which has ratcheted up the thermal gradients and causing much of the volatility in successive runs down the line.

Edited November 1, 2016 by knocker

[Day 10]

19 minutes ago, northwestsnow said:

Fascinating ukmo this evening

http://old.wetterzentrale.de/pics/Rukm1201.htm

http://old.wetterzentrale.de/pics/Rukm1441.html

Scandy high anyone

Yes, quite like the UKMO 144, following on from lastnights ECM. 24hours on, interesting ECM coming up as the models are starting to diverge.

GFS UKMO ECM???

[bluearmy]

28 minutes ago, fergieweather said:

Yup. Abnormally weakened stratospheric PV 1st half winter, says GloSea, before flipping other way to much stronger into Feb. But there's much water (or zonal winds) to pass under the bridge before we get too clever into that period.

Once we have the pfj suppressed way south a ramping up of the strat vortex for the second half of winter could mean plenty of sustained interest for this thread !!

 

[Abyss]

1 hour ago, knocker said:

It's the just published winter forecast. I assumed that's what you were talking about but I admit I didn't check.

Do you have a link to that FC? Thanks

[knocker]

3 minutes ago, Abyss said:

Do you have a link to that FC? Thanks

http://www.metoffice.gov.uk/services/public-sector/contingency-planners

[Summer Sun]

Next Sunday and into Monday looks to be the point where the colder air will reach it's peak beyond this it's open to doubt with plenty of  scatter among the ensembles though a slight recovery in the 850's does appear to be a good bet at this stage from the 9th

[Ali1977]

The ECM was actually pretty good this morning, the Atlantic didn't make any in-roads at all throughout the run. If it's the same again this evening I'm going to say the GFS isn't correct, 'not saying the ECM will be but the UKMO looks more like this mornings ECM than the GFS. The GEM however is more like the GFS!! 

Anyway, over to you ECM!! 

 

[Ali1977]

So which one is correct, ECM better with regards cold and it's longevity 

Edited November 1, 2016 by Ali1977

[Geordiesnow]

6 minutes ago, Ali1977 said:

So which one is correct, ECM better with regards cold.

Both look similar to me in fairness, the PV is going to ramp up over Greenland which will collapse the Atlantic ridge but what is uncertain is if any developments over Scandinavia will play out regarding our weather.

Regarding the weekend's cold, just like the UKMO, its a cleaner NE'ly flow therefore its a colder flow than the GFS, really hope the GFS backs down regarding its shortwave development just to the south of Norway but whichever way you look at it, a 2-3 day cold blast looks likely.

Edited November 1, 2016 by Geordiesnow

[Frosty.]

Thank you Ecm, the 12z shows an increasingly cold weekend and staying cold early next week..very nice

[karlos1983]

Scandi heights showing up on the ECM.

by the way @Mucka that video, I've only just picked myself up off the floor. 

 

[Daniel*]

toppled ridge elongating much more to Scandinavia evident this is significant! +ve heights perhaps establishing over Scandinavia (nope they sink away to the SE +192 more runs needed, who knows the cold could be extended). Feeling rather cold for the S/E with a long drawn north/easterly.

Edited November 1, 2016 by Changing Skies.

[Frosty.]

Some low thicknesses too, good job Ecm!

[Frosty.]

Surface conditions would stay cold into midweek across England and Wales with widespread frosts where skies clear, proper November weather showing on the Ecm 12z. A 5 day cold spell..not bad huh

Edited November 1, 2016 by Frosty.