Model Output Discussion - 18z 31/10/15 onwards

[stodge]

Evening all

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015111412/ECH1-72.GIF

 

Whether (so to speak) we get a notable cold spell or not, it's still an extraordinary chart in contrast to last year. 

[Summer Sun]

A cold north to north easterly flow next Saturday

 

[Mucka]

Main model comparison charts 144h (NH worse to first?)

 

[radiohead]

Ecm168 much better GH amplification

 

Though it looks like it will go the way of a toppler there. In contrast to yesterdays ECM :

 

Edited November 14, 2015 by radiohead

[Mucka]

JMA going with the toppler solution this evening

 

[TSNWK]

Topple or no topple.. What is striking to me is the complete absence of vortex to our north west.. If it does topple then plenty of scope for reload all the time the polar vortex is way to east and north..

[Daniel*]

A cold north to north easterly flow next Saturday

Cracker of a chart! Also note the kink in the flow a disturbance a general spell of sleet/snow on that would affect coastal parts of SE England. I'm not sure whether this assessment is correct? It will change but it is nice to see. NE'ly is what we want I gather for us southern/eastern folk there'd be some instability and to a certain extent no horrid wishbone as a direct northerly brings.

Edited November 14, 2015 by Daniel*

[Summer Sun]

The north easterly continues at t192 before the high moves in though remaining chilly

 

[Methuselah]

A cold north to north easterly flow next Saturday

 

Not a bad chart for the time of year; I expect to see an unpleasant mix of rain, sleet, wind and a miserable 4/5C, should it happen. At least down here with the SSTs still rather high...For localities further inland and on high ground...BINGO!

[Captain Shortwave]

The ECM would bring scope for some pretty heavy showers moving off the north sea given low heights and the SSTs still being on the mild side as its November. We would need to see the 850s improve by a degree or two to guarantee widespread snow showers though.

Probably the chart for Sunday would be a better fit (850s between -5 and -7C), probably snow for Scotland with a wintry mix further south going by these charts.

A north easterly would be pretty decent for central/eastern England and the usual parts of northern and eastern Scotland. Not a bad result for a toppler scenario with the risk of heavy snow in places before conditions settled down with sharp overnight frosts.

 

Still it is the ECM and one of the more positive solutions, so be wary especially with the UKMO being pretty poor tonight.

Edited November 14, 2015 by Captain shortwave

[fergieweather]

Still it is the ECM and one of the more positive solutions, so be wary especially with the UKMO being pretty poor tonight.

? UKMO-GM goes cold into Scotland by Fri (eg see T+132 below) before even colder air spreads south into weekend. Timing differences between models, but same hymn sheet ultimately: a cold/colder snap for anywhere from 2 to a few days.

Edited November 14, 2015 by fergieweather

[shaky]

? UKMO-GM goes cold into Scotland by Fri (eg see T+132 below) before even colder air spreads south into weekend. Timing differences between models, but same hymn sheet ultimately: a cold/colder snap for anywhere from 2 to a few days.

hi fergie!!!is there still a chance of a more prolonged cold spell from the models you look at behind closed doors!!!i remember you mentioning a chance of a channel low!!!

[Summer Sun]

Good ens support from ECM for a colder snap later next week

 

[knocker]

The GEFS T240 anomaly has the ridging slightly east over Greenland, cut off low western Atlantic, ridging to the SW of the UK and trough Scandinavia. This indicates to movement of the cold snap east post T192 and the commencement of a warmer NW flow, The ecm is not in complete agreement with this although both have lost the HP NE Canada, It has no cut off low and it has the ridging to the west of the UK but the net result is the same. The transition from a cold northerly plunge post T192 to a warmer (relatively speaking) NW flow. This is not completely dissimilar to what is suggested on the det. models.

 

The GEFS 11-15 continues with this theme with ridging to the SW of the UK. The ext ecm doesn't go along with this completley but does suggest a westerly flow and just to confuse things drops a trough over us at T360 so make that an unsettled westerly flow.

 

[bluearmy]

My observation on the extended eps knocks, is the Atlantic anomoly pushing back north days 11/12 before it falls away and a lowish anomoly drops into nw Europe for the end of the run, (all the time post day 10, a euro low anomoly persists, though not too low). Will be interesting to see how much the clustering is on the cold side for London re that low euro anomoly.

[MPG]

The GEFS T240 anomaly has the ridging slightly east over Greenland, cut off low western Atlantic, ridging to the SW of the UK and trough Scandinavia. This indicates to movement of the cold snap east post T192 and the commencement of a warmer NW flow, The ecm is not in complete agreement with this although both have lost the HP NE Canada, It has no cut off low and it has the ridging to the west of the UK but the net result is the same. The transition from a cold northerly plunge post T192 to a warmer (relatively speaking) NW flow. This is not completely dissimilar to what is suggested on the det. models.

 

The GEFS 11-15 continues with this theme with ridging to the SW of the UK. The ext ecm doesn't go along with this completley but does suggest a westerly flow and just to confuse things drops a trough over us at T360 so make that an unsettled westerly flow.

Funny how things change. You post chart after chart showing low heights over Greenland. Then when pressure does rise over greenland you forget to dicuss what that actually could mean for the UK and talk about westerlys at T360!!

[phil nw.]

A glance at the latest fax's show,in the short term,the troublesome wavering frontal systems bringing the pulses of heavy  rain to some areas over the next few days.

 

just some snapshots of what is looking quite a wet few days for many of us.

All coming courtesy of the jet straddling the country with wave depressions running north east.

 

Then we look to the north west as we see the upstream Atlantic ridge forcing the polar front back south over the UK bringing much colder air with it.

 

Slight differences in timing and ridging but essentially the 3 main models all go with the Northerly at T144hrs.

There could be some snow interest with a wave development as the coldest air arrives,with -6 or -7C uppers,as it comes down against warmer air.

This is a week away yet of course but some added interest to monitor as this colder spell get's closer.

 

Compare the current surface temperature anomalies over the next 3 days with what's modeled for next weekend and we see the stark downward change to come.

 

 

The Warks temp graph looks very cold with possible freezing temps for a short while over next weekend before easing up somewhat later.

 

these have been quite consistent for several days in  heralding this change around the 20th as have the Euro suite.

 

A noticeable widespread cool down is on the way then which looks like extending into week 2 of the model runs this evening.

 

[jethro]

Genuine question.......

 

If all the prayers are answered and everything comes together for it to snow next weekend, would it even settle? It's been incredibly mild, not a glimmer of a frost to date, so surely the ground would be far too warm for settling snow?

[Liam J]

Funny how things change. You post chart after chart showing low heights over Greenland. Then when pressure does rise over greenland you forget to dicuss what that actually could mean for the UK and talk about westerlys at T360!!

I'm sure I've seen people posting T384 GFS charts over the last few days? So what's the difference? Not everybody likes cold & snowy weather and members don't have to like cold & snowy weather to be able to post in this discussion....So they may want to discuss other possible solutions based on the current output, some people hunt for cold while others may not. 

Edited November 14, 2015 by *Sub*Zero*

[phil nw.]

Genuine question.......

 

If all the prayers are answered and everything comes together for it to snow next weekend, would it even settle? It's been incredibly mild, not a glimmer of a frost to date, so surely the ground would be far too warm for settling snow?

HI Jethro,

Not wanting to take things off topic but In my experience wet can become white if the surface air drops below 0C-whatever went before.

[jethro]

HI Jethro,

Not wanting to take things off topic but In my experience wet can become white if the surface air drops below 0C-whatever went before.

 

Thank you.

[PolarWarsaw]

Funny how things change. You post chart after chart showing low heights over Greenland. Then when pressure does rise over greenland you forget to dicuss what that actually could mean for the UK and talk about westerlys at T360!!

 

Well, according to some posters - there was no site of a day that was below +2 above the normal average from now until March, with a constant zonal, W/NW pattern and constant/persistent zonality. As far as I'm concerned the best posters on the site are the ones who are the most informative, most laid back and look at the entire general picture regardless of the type of pattern...that way selective weather periods don't get ramped up.. and changes to alternative weather that isn't perhaps a posters favourite doesn't get over-looked. 

 

It's very off-putting to enter this thread to see poster(s) spouting about a specific weather pattern in a manner that's basically so over the top that it can only be attempting to bait people...let alone the need to boost the post count and nudge the reputation bar up slowly! But that's another story. 

 

So then, after a fluid last couple of days where we have waxed and waned between differing solutions at both the opposite ends of the scale, it appears that we are slowly bringing together the foundations for the next 7 or so days;

 

- A very wet and windy week ahead, especially in the North of England, Scotland and Northern Ireland where flooding could become a huge issue. 

- Cooling off towards the weekend with a colder spell (degree of cold yet to be decided - although a couple of days of colder weather look more accurate at this stage than a 'period' as such).

 

- 3 options on the table thereafter;

*A return to Atlantic conditions

*A period of chilly High pressure dominated quiet weather

*The chance of a reload. 

 

Currently - I'd go with a period of high pressure looking most likely, with it being a coin toss between Atlantic returning/A reload.

 

 

Enjoy your evening folks!

[fergieweather]

Thank you.

No, you rightly point out the distinction between snow *falling* versus *accumulating*. And yes, ongoing depth temperatures at many lowland sites are likely to mitigate against anything other than temporary settling. However, this depends on PPN rates too. Either way, it's too early to even discuss snow in any semblance of reality. The actual pattern is yet to be resolved... it's still effectively a whole week away. For what it's worth, last two EC runs accumulate truly measurable snow only over northern uplands (Snowdonia/Pennines northwards). But it's only November, so it'll take a proper run of ongoing cold conditions to drop depth temps down into a reliable window for prolonged settling, irrespective of diurnal cycle.

[MPG]

Well, according to some posters - there was no site of a day that was below +2 above the normal average from now until March, with a constant zonal, W/NW pattern and constant/persistent zonality. As far as I'm concerned the best posters on the site are the ones who are the most informative, most laid back and look at the entire general picture regardless of the type of pattern...that way selective weather periods don't get ramped up.. and changes to alternative weather that isn't perhaps a posters favourite doesn't get over-looked. 

 

It's very off-putting to enter this thread to see poster(s) spouting about a specific weather pattern in a manner that's basically so over the top that it can only be attempting to bait people...let alone the need to boost the post count and nudge the reputation bar up slowly! But that's another story. 

 

So then, after a fluid last couple of days where we have waxed and waned between differing solutions at both the opposite ends of the scale, it appears that we are slowly bringing together the foundations for the next 7 or so days;

 

- A very wet and windy week ahead, especially in the North of England, Scotland and Northern Ireland where flooding could become a huge issue. 

- Cooling off towards the weekend with a colder spell (degree of cold yet to be decided - although a couple of days of colder weather look more accurate at this stage than a 'period' as such).

 

- 3 options on the table thereafter;

*A return to Atlantic conditions

*A period of chilly High pressure dominated quiet weather

*The chance of a reload. 

 

Currently - I'd go with a period of high pressure looking most likely, with it being a coin toss between Atlantic returning/A reload.

 

 

Enjoy your evening folks!

Waxing and waning!! Ha, you have been reading too much of Fergie's weather language book! Only today it looks like a toppler could be a good bet, this still has time to change. I think the met and even John Holmes have been caught out by the change in pattern especially with regards to the 500mb charts.

[suxer]

I'm sure I've seen people posting T384 GFS charts over the last few days? So what's the difference? Not everybody likes cold & snowy weather and members don't have to like cold & snowy weather to be able to post in this discussion....So they may want to discuss other possible solutions based on the current output, some people hunt for cold while others may not.