Model Output Discussions 06z 04/11/16

[Grimers]

12 minutes ago, Grimers said:

The ECMWF model shows a very deep low to the SW of Wales bringing gale force SW winds to SW parts of the UK on Sunday, this is something we haven't seen since 2014!

 For some reason, I can't edit the above post, but this is what it should say...

[Summer Sun]

ECM

14th to 20th

Temperatures close to average for most slightly above average in parts of the south - mixed signals for precipitation

21st to 27th

Temperatures slightly below average in the far west and slightly above average in the SE elsewhere no strong signal - precipitation slightly below average in the far west no strong signal elsewhere

28th to 4th

No strong signal for temperatures - precipitation slightly below average in parts of the north and west no strong signal elsewhere

[Frosty.]

Today is the last proper mild day for a little while according to the Ecm 00z op and midweek is the transition period from mild to progressively cooler / colder weather from the NW with showers becoming more frequent, heavier with hail and thunder and as the colder air digs in, the showers becoming increasingly wintry with snow on hills, especially central / northern uk and night frosts becoming widespread for a time. The weekend starts cold and showery but then a deepening complex depression swings in from the SW bringing wet and windy weather NE across the uk and on the leading edge, a short spell of wet snow for the hills of northern england and scotland before slightly milder air follows. Into next week it stays unsettled but after a generally chilly start, gradually becomes milder.

Edited November 15, 2016 by Frosty.

[Iceaxecrampon]

Well certainly an interesting weekend on the cards *if* all goes to plan.

17th snow risk marginal at present but as ever elevation is the key.

T+120 classic channel low bringing about cold v mild battle to the midlands one to watch.

Further LP for the midlands giving the Jocks a reload  seem to be under siege from all sides.....

 

Edited November 15, 2016 by Iceaxecrampon

[Summer Sun]

GEM is certainly consistent with milder air for next week 4 runs in a row now

[I remember Atlantic 252]

2 minutes ago, Summer Sun said:

GEM is certainly consistent with milder air for next week 4 runs in a row now

Not bad SS, only thing is here I doubt it'll be dry! but much prefer this to channel low, rain and 4°

[Frosty.]

The GEFS 00z mean also indicates slightly milder air encroaching from the south next week but in fact, not as bullish as yesterday and actually staying on the chilly side further north.

Edited November 15, 2016 by Frosty.

[fergieweather]

30 minutes ago, Summer Sun said:

GEM is certainly consistent with milder air for next week 4 runs in a row now

 

Yes, and it can't be dismissed given ongoing ENS spread in EC right through rest of the month. If there is to be a swing towards more markedly cold conditions rest of Nov and early Dec, we're yet to see that evidence emerge decisively and unambiguously. It's unsurprising given huge uncertainty even by Sunday (some threatening looking output, yes, but could all prove a total non-event) and gulf in direction in 850hPa temps thereafter. Whilst extended range output into 1st half Dec is very interesting, we shouldn't automatically equate those signals with profound cold a la 2010, or blizzards, or any other unsupported extrapolations I've seen appearing on twitter. Given nearer-term huge uncertainty, the prospects further into the 10-30d period are really no clearer... at present.

[Ravelin]

GFS 6Z strengthens the channel low early hours Sunday...

Edited November 15, 2016 by Ravelin

[Ali1977]

I can't post pictures but the GFS looks stormy on Sunday, and as the cold air tucks in behind it it could become Wintry on high ground in the Midlands and Wales - not sure the South will see anything though, uppers look too warm although heavy precip may make a difference.  WAA into Greenland looks stronger too, not sure on the effect down the line.

[jvenge]

2 minutes ago, Ravelin said:

GFS 6Z strengthens the channel low early hours Sunday...

It's quite interesting to see the ensembles head in all kinds of different directions in a relatively short period (less than 24 hours). They don't even agree at T96, but after that they start comings up with all kinds of options.

[feb1991blizzard]

Blizzards on the Northern flank

.

[andymusic]

Wales could get it's first major dumping of snow this saturday night  if that low swings in in the right way

 

[I remember Atlantic 252]

only high ground I feel though 20 years on, the 20th Anniversary of my snowfest!

[feb1991blizzard]

8 minutes ago, fergieweather said:

Yes, and it can't be dismissed given ongoing ENS spread in EC right through rest of the month. If there is to be a swing towards more markedly cold conditions rest of Nov and early Dec, we're yet to see that evidence emerge decisively and unambiguously. It's unsurprising given huge uncertainty even by Sunday (some threatening looking output, yes, but could all prove a total non-event) and gulf in direction in 850hPa temps thereafter. Whilst extended range output into 1st half Dec is very interesting, we shouldn't automatically equate those signals with profound cold a la 2010, or blizzards, or any other unsupported extrapolations I've seen appearing on twitter. Given nearer-term huge uncertainty, the prospects further into the 10-30d period are really no clearer... at present.

True Ian but even that last chart posted by Gavin from the GEM still looks primed for something down the line, timeframe very uncertain but I don't see many charts pointing to mild (barring a w - based -NAO), but see loads pointing to long term cold.

[bradymk]

Second LP crossing southern U.K. on Monday on this run is much further south. More heavy rain, and potentially snow for some from this.

Saturday night/Sunday starting to look quite stormy now too.

[Ravelin]

Second low on Monday coming in way further SE on the 6Z than the 0Z, better heights around Greenland too...

6Z   0Z

[fergieweather]

1 minute ago, feb1991blizzard said:

True Ian but even that last chart posted by Gavin from the GEM still looks primed for something down the line, timeframe very uncertain but I don't see many charts pointing to mild (barring a w - based -NAO), but see loads pointing to long term cold.

Yes, I'm not suggesting 'mild' given numerous pointers in the other direction. What I'm stressing here is some people misrepresenting current signals as automatically equating to *profound* cold and suggesting via twitter that it's the outcome we are seeing. 

[Eskimo]

The lows are certainly tracking more and more southerly after each run on the GFS.

[feb1991blizzard]

2 minutes ago, fergieweather said:

Yes, I'm not suggesting 'mild' given numerous pointers in the other direction. What I'm stressing here is some people misrepresenting current signals as automatically equating to *profound* cold and suggesting via twitter that it's the outcome we are seeing. 

Oh yes agreed, the fact that I'm yet to see 1 Ensemble member levelling out below -10 850hpa temps for any length of time  (that's the one thing concerning me), never mind seeing the majority do just that, which is what I need to see before I think its a done deal. I just think though that we will get a few bites at the cherry here even if the first few are a fail.

Edited November 15, 2016 by feb1991blizzard

[Grimers]

I sense a lot of snow lovers in here are getting hooked on the GFS model, we should remember that the ECMWF model is better at predicting low positions at this time scale. However, the GFS model could be correct and snow instead of rain could be more of an issue.

[Ravelin]

Easterly incoming at t240!!!

Oh, wait, what's that you say, the uppers are warmer to our East?

[A.J]

22 minutes ago, fergieweather said:

Yes, I'm not suggesting 'mild' given numerous pointers in the other direction. What I'm stressing here is some people misrepresenting current signals as automatically equating to *profound* cold and suggesting via twitter that it's the outcome we are seeing. 

^^^ The voice of reason!....Always best to keep our feet firmly planted on the ground against some of the hyperbole we see on social media...Promising movements on the outputs this morning, but it's small steps at a time, what will be, will be.............on a side note the latest output seems to be strengthening its signal for a very wet and windy end/start of the week courtesy of 2 southerly tracking lows, and as mentioned yesterday, if atmospheric parameters fall into place, rain might not be the only ppn falling out of the sky for some 

[knocker]

15 minutes ago, ajpoolshark said:

^^^ The voice of reason!....Always best to keep our feet firmly planted on the ground against some of the hyperbole we see on social media...Promising movements on the outputs this morning, but it's small steps at a time, what will be, will be.............on a side note the latest output seems to be strengthening its signal for a very wet and windy end/start of the week courtesy of 2 southerly tracking lows, and as mentioned yesterday, if atmospheric parameters fall into place, rain might not be the only ppn falling out of the sky for some 

Oh yes indeed. And the ext EPS this morning has the Azores nudging north in the vicinity of the UK giving some gentle zephyrs from a westerly quadrant and temps a little above average.

[bluearmy]

24 minutes ago, Ravelin said:

Easterly incoming at t240!!!

Oh, wait, what's that you say, the uppers are warmer to our East?

As has been stated day after day on here - the 'mild' GEM output is just a variation on a theme. However, any continental feed at this time of year will feel cold and if it's slack enough could be very chilly!

noted Ian's comments re the rest of November - never has been any convincing evidence that deep cold will arrive before the final few days and that remains under review re the hang back of Euro heights to our se. 

The eps do remove that hang back by day 15 which is in line with the para ec 46.

it may well be that the week 2 pattern is less clear than those that follow re the broad evolution.