Model Output Discussion - cold spell to end Autumn

[Methuselah]

5 minutes ago, memories of 63 said:

 

Whisper it, theOp is a cold outlier 

What does that make the purb that had London's 850Hpa at -13 then!

[karlos1983]

2 minutes ago, Ed Stone said:

What does that make the purb that had London's 850Hpa at -13 then!

the trend setter 

Edited November 28, 2017 by karlos1983

[Seasonality]

1 minute ago, Ed Stone said:

What does that make the purb that had London's 850Hpa at -13 then!

It was the 2m temp, not the 850s. And that one was a true outlier. I always thought an outlier was well away from the rest of the spread, but I could be wrong on this. I thought in terms of the op run itself it was more bottom of spread but not wild outlier. Regardless, we'd all be very silly to take such output at that range as anything other than amusement.

[Gavin Hannah]

Going to pose a theory here. Looking at the ens,  the greatest cluster of runs between the 3rd and 5th are roughly following the op.  Going with flow I would suggest therefore that the really mild runs (yellow, purple etc) and anything that has deviated well away from this cluster can be binned.

Edited November 28, 2017 by Gavin Hannah

[chrisbell-nottheweatherman]

10 minutes ago, Gavin Hannah said:

Going to pose a theory here. Looking at the ens,  the greatest cluster of runs between the 3rd and 5th are roughly following the op.  Going with flow I would suggest therefore that the really mild runs (yellow, purple etc) and anything that has deviated well away from this cluster can be binned.

I see your argument; perhaps we can say that anything showing 850s of more than 5C is likely to be in a smaller cluster?

[Chesil View]

Just now, feb1991blizzard said:

Yes, its an absolute right old dumping.

Well i'm working on a roof in deepest Dorset with flocks of Fieldfares flying above me which according to country lore are a precursor to cold and snowy weather. So I can confirm that GFS 06 will verify exactly as shown. ?

[Weather-history]

Comparisons with today's chart with GFS 06z 240 hrs ago

ECM 0z from 240 hrs ago compared to todays

This is the ECM mean for today from 240hrs ago

Edited November 28, 2017 by Weather-history

[geordiekev]

1 hour ago, Frosty. said:

Definitely the best run of the winter..errr..I mean autumn so far!!

Here is Frosty's highlights of the Gfs 6z..there's plenty of them but a snow shovel isn't included!!..BOOM

Looks like you've spilt a bottle of Tipex on some of those, at least I'm hoping the above pic isn't literal 

[Frosty.]

Confidence becomes low from next midweek but I can't really detect any downgrade to the further outlook, cold is more likely with high pressure to the north / west..or northwest of the UK with lower heights to the east / northeast with the UK in a cold northerly type arctic flow with sunny / clear spells and wintry showers with snow to all levels and plenty of frosts and ice..sounds very encouraging, especially considering the mostly poor 00z runs!

Edited November 28, 2017 by Frosty.

[nick sussex]

All is well the NAVGEM 06hrs run keeps the corridor of hope open!

Clean flow and no shortwave spoiler at the crucial timeframe.

This has been an emergency Code Red desperation use of an output that we normally ignore!

[northwestsnow]

1 minute ago, nick sussex said:

All is well the NAVGEM 06hrs run keeps the corridor of hope open!

Clean flow and no shortwave spoiler at the crucial timeframe.

This has been an emergency Code Red desperation use of an output that we normally ignore!

Another piece  of positive news- yes its only NAVGEM but again it will be using new data- as Karl says METO still just about keeping the faith- hopefully a swing back on the 12zs...:)

[markw2680]

I don’t no if I’m coming or going lol, couple of nights ago it was cold cold and more cold, looked this morning and it had all gone and mild, look again now and it’s well all over the place is probably the best way to describe things. Who knows I’m sure it will be different again this evening and then the complete opposite again by morning. We do love a rollercoaster don’t we. Including myself even though it’s very frustrating 

[knocker]

7 minutes ago, northwestsnow said:

Another piece  of positive news- yes its only NAVGEM but again it will be using new data- as Karl says METO still just about keeping the faith- hopefully a swing back on the 12zs...:)

The METO further outlook doesn't get updated for a couple of hours.

[Frosty.]

3 minutes ago, knocker said:

The METO further outlook doesn't get updated for a couple of hours.

It's been updated, it's different to yesterday but still sounds good..for coldies!

Edited November 28, 2017 by Frosty.

[bluearmy]

1 minute ago, Frosty. said:

It's been updated, it's different to yesterday but still sounds good..for coldies!

its now updated overnight and early/mid afternoon

thats the overnight.

[Frosty.]

2 minutes ago, bluearmy said:

its now updated overnight and early/mid afternoon

thats the overnight.

That's a shame, my hopes were raised for a minute there!!

Still, the Gfs 6z was a cracker..

[Ali1977]

2 minutes ago, Frosty. said:

That's a shame, my hopes were raised for a minute there!!

Still, the Gfs 6z was a cracker..

The update may be better for coldies yet - their models may not have wavered like the GFS/ECM did overnight 

[nick sussex]

The newly named corridor of hope is shown here!

You must maintain a clean flow not interrupted by shortwave energy. I've circled the key features, black shortwaves, the purple is the Pacific troughing moving east.

As you can see from the differences between the GFS 00hrs run to T138 hrs and the new GFS 06hrs run to T132hrs, the latter has the clean flow and also a bit more amplitude to the Pacific troughing.

Events over ne Canada are crucial because as the upstream flow amplifies it phases the low in the west Atlantic with that shortwave over sw Greenland both then head east and you're caught on the wrong side of that amplified wave.

Just having the clean flow won't by itself deliver the northerly within a reasonable timeframe, you'll still need a little bit of luck but theres zero hope if the shortwave shows up to the sw of Greenland.

 

 

 

[Frosty.]

15 minutes ago, Ali1977 said:

The update may be better for coldies yet - their models may not have wavered like the GFS/ECM did overnight 

Fingers crossed, after all the excitement it would be very disappointing if it comes to nothing, the Gfs 6z brought back a welcome spark of hope from some of yesterday's stellar output...Hoping for a much improved 12z set of op's to erase most of the 00z output  from my memory!☺??

[gottolovethisweather]

48 minutes ago, Frosty. said:

Confidence becomes low from next midweek but I can't really detect any downgrade to the further outlook, cold is more likely with high pressure to the north / west..or northwest of the UK with lower heights to the east / northeast with the UK in a cold northerly type arctic flow with sunny / clear spells and wintry showers with snow to all levels and plenty of frosts and ice..sounds very encouraging, especially considering the mostly poor 00z runs!

Indeed to my mind, one word sums up the outlook as far the forecastable outlooks can go within the realms of all our model's expertise and forecasting abilities. In general, it's a cold BLOCKED or BLOCKY type pattern, with wintry potential, be it icy mornings or wintry spells, there ain't much mild mush around. BLOCKED I say, not BOLOCKED. 

[bluearmy]

Given the multitude of eps clusters from the 00z suite, I doubt the next runs are going to resolve anything 

[minus86BriJ]

Just to boost the spirits even if only a tiny bit, I stumbled on this quote from an American met site this morning.  Zero in the way of specifics but nice to see this mentioned in context with the US further outlook.

"There is the potential for such a pattern to begin to take shape during the first week in December with a block [an atmospheric traffic jam] anticipated to develop near Greenland," according to AccuWeather Senior Meteorologist Brett Anderson.

https://www.accuweather.com/en/weather-news/stormy-pattern-may-return-to-us-by-second-week-of-december/70003378

 

Edited November 28, 2017 by minus86BriJ

[Gavin Hannah]

26 minutes ago, nick sussex said:

The newly named corridor of hope is shown here!

You must maintain a clean flow not interrupted by shortwave energy. I've circled the key features, black shortwaves, the purple is the Pacific troughing moving east.

As you can see from the differences between the GFS 00hrs run to T138 hrs and the new GFS 06hrs run to T132hrs, the latter has the clean flow and also a bit more amplitude to the Pacific troughing.

Events over ne Canada are crucial because as the upstream flow amplifies it phases the low in the west Atlantic with that shortwave over sw Greenland both then head east and you're caught on the wrong side of that amplified wave.

Just having the clean flow won't by itself deliver the northerly within a reasonable timeframe, you'll still need a little bit of luck but theres zero hope if the shortwave shows up to the sw of Greenland.

 

 

 

 

My money is on greater amplification and a cleaner flow as you have highlighted. Time and again, the models are being stymied in the attempt to return to mild / zonal. December is going to be a blocked month. (Wouldn't bet the house just yet). With the output we are getting run to run, I think we can simply ignore anything beyond day 5.

 

[frosty ground]

10 minutes ago, bluearmy said:

Given the multitude of eps clusters from the 00z suite, I doubt the next runs are going to resolve anything 

So more runs needed 

[comet]

4 hours ago, Seasonality said:

Well said Karlos. The thing about this forum is that there are plenty of enthusiasts, perhaps even a few dramatists if I'm being cheeky , but only a few experts. Tamara is very much one of the few and her posts are always worth paying attention to.

Her latest update will not be very accurate if the 06z gfs run verifies. Remember we are all amateurs on here there are no experts with a crystal ball. the UK model was the first to delay ridging in the Atlantic because of trough disruption while the other big two went ahead guns blazing now they are playing catch up. We could be on the cusp of something special and while I have lost all faith in Mr Cohen it would fantastic if he was right for once.

looking forward to the afternoon and evenings runs with great expectations.