Model output discussion - The Hunt For Cold

[WalsallWeather123]

WOW. Sensational T168 aswell. Real classic coming up

[Jonathan Rhodri Roberts]

1 hour ago, JeffC said:

Aye but they'd tail off quite rapidly if the cold gets entrenched wouldn't it Moki? 

That's certainly possible as here on the coast in South Wales, the last week of October brought us 4 frosty mornings which is unusual as the sea temp in our part of the Bristol Channel was around 15C, just a week later it fell to 13C but after the mild, wet weather last week it remains at 13C 

[Mike Poole]

Extraordinary charts popping up left, right and centre, here are 3 I liked from the 12z GEM ensemble:

Proper frankfurter that one, then this:

[ICE COLD]

Day 10 ECM looks like the high it's starting to head towards Greenland ? 

[Mike Poole]

And the ECM leaves us on a bit of a cliffhanger at T240:

That low to the west, over or under? 

Under I think, but not sure!

[mulzy]

4 minutes ago, Mike Poole said:

And the ECM leaves us on a bit of a cliffhanger at T240:

That low to the west, over or under? 

Under I think, but not sure!

Almost certainly it will head north / north east - if it continues to deepen, could help pump the ridge northwards.  All rather pointless speculation at this range anyway.

[Mike Poole]

4 minutes ago, mulzy said:

Almost certainly it will head north / north east - if it continues to deepen, could help pump the ridge northwards.  All rather pointless speculation at this range anyway.

I'm not sure about that at all.  I really don't see how it could head north?  It's not like it's going to come racing through on the jet,I I think it's equally possible it will weaken more or less in situ and then prop up the block as a much weakened feature. We'll never know of course because the situation will never arise in the first place!

Edited November 11, 2018 by Mike Poole

[feb1991blizzard]

It will head North / North North East almost certainly, watch the evolution from 192-216.

Edited November 11, 2018 by feb1991blizzard

[blizzard81]

Great runs tonight for future cold potential. We really need to see the high pressure anomoly to our north west get stronger and stronger with every subsequent ensemble suite. This is what happened in the winters of 2009/2010. 

[Mike Poole]

10 minutes ago, feb1991blizzard said:

It will head North / North North East almost certainly, watch the evolution from 192-216.

Yes just watched the NH view and you are probably right, I watched the ECM on Euro view and it's not as obvious.  Sorry if my post was misleading.  But it's also a useful point, at this time of year need to look at the model output with a view of the whole N hemisphere to understand what's going on.

[ItNeverSnowsInWindsor]

A growing number of colder options on the gefs 12z ensembles towards the latter third of November. Let’s see if the pub run continues this trend

[bluearmy]

Eps headed in a similar direction to the gefs but a little slower with the retrogression - day 15 has the upper ridge broadly across the uk - the trend on the eps is slowly more retrogressive, run by run .... Russia going into the freezer and se Europe well below average for the time of year 

[damianslaw]

1 hour ago, Mike Poole said:

I hadn't, thanks.  Given what we've been talking about on here these last two weeks, I'm not very surprised at this update!  

Couple of things as we await the ECM, first from a flick through the ensembles, the Greenland high could arise from two quite different mechanisms, either the retrogression of the now nailed-on Scandi block, or that block drifts East and a ridge is pushed up behind from the Atlantic.  Or it could not happen at all - I'd give longish odds on that now though!

Second, all this discussion about getting the right synoptics  for cold later, it's ironic that the first two weeks of November look remarkably warm, GFS has 16C max on Friday:

The flip when it comes will be as sharp as the shift to warm in April!

PS, ECM T144!

Persistant (not short brief affairs) extremes of warmth and cold relative to the time of year - usually mean the atmosphere is in an abnormal state, and there is always then a greater chance of flipping from extreme to another, as the atmosphere seeks to balance itself out, whilst somewhere sees extreme warmth somewhere conversely sees extreme cold, usually a sign of a highly amplified pattern.

I read someones forecast for late autumn/early winter, can't remember who, but they predicted some major extremes of both warmth and cold, so perhaps not a surprise to see some of the forecasts being shown. Warm air advection into the Pole followed by cold air advection out of the Pole. 

This often happens in spring with the classic spring switcharounds when northerlies become southerlies and vice versa,with the atlantic blocked.

I know this isn't the place to discuss met office long range forecasts, but the GFS 12z developments of today would tie in with there expectations - northern blocking, jet going underneath, unsettled high risk of wintry precipitation.

[Mike Poole]

Just to wrap up the day when possibilities became probabilities, if not certainties, some further highlights from the 12s, first JMA T192:

Do I see a rabbit in the PV?  Bodes well.

Next the FV3 at T240, then T384 + strat:

Still a lot more yin than yang but early days.  

ECM mean at T240:

1035mb north of the UK on a mean chart in 10 days time, we're on to something! 

And finally the mostly forgotten FIM9 at T240:

Almost blowing kisses that one!

 

Edited November 11, 2018 by Mike Poole

[Methuselah]

This was the day I got my first pair of glasses; also, and more to the point, at around 4 p.m., a six-hour-long blizzard blew up, as the LP to the east slipped southwards...and (once again, memory permitting) temps fell from +2 to -5C in under an hour. I also think that day was a Friday! Could this winter be special too? 

[stodge]

Evening all

I don't normally think about winter until mid January but it's hard not to get wrapped up in what may be something we've not experienced for years - a decent spell of fog and frost and an inversion.

I've always gone with the adage "the road to extremely cold starts from extremely mild" - cold spells often materialise as the air flow flips suddenly from south or south west to east or north east. The classic is the Azores HP moving NE from the SW approaches to Scandinavia. 

I don't know if we will see anything remarkable from this at this stage but, as others have said, it makes a change from some late autumn/early winter charts when a 12-hour transient N'ly at T+360 is all we saw.

[Purga]

GLOSEA seasonal update now favouring a cold 850 anomaly (south) and N blocking.

[Newberryone]

Some unseasonable warmth being forecast from midweek with winds from a southerly quadrant. Just hoping future runs will continue the momentum with regards to the favourable orientation of this high and that it will soon be a case of short term pain for long term gain..

[ChezWeather]

Had a bit of a break from checking Netweather recently as we've had some pretty bog standard autumnal weather, nice to come back on and see some lovely cold charts! 

[Mike Poole]

The 18z ICON only runs to T120 so is not likely to resolve anything,but I was struck by this chart at T120, is this the  battle between east and west that could potentially define this entire winter?  Like a pair of boxing gloves:

 

 

Edited November 11, 2018 by Mike Poole

[Methuselah]

51 minutes ago, Newberryone said:

Some unseasonable warmth being forecast from midweek with winds from a southerly quadrant. Just hoping future runs will continue the momentum with regards to the favourable orientation of this high and that it will soon be a case of short term pain for long term gain..

Indeed. For the next two weeks, temps could be up-and-down like Jordan's knickers!

Edited November 11, 2018 by Ed Stone

[BLAST FROM THE PAST]

1 hour ago, Newberryone said:

Some unseasonable warmth being forecast from midweek with winds from a southerly quadrant. Just hoping future runs will continue the momentum with regards to the favourable orientation of this high and that it will soon be a case of short term pain for long term gain..

Unseasonable to the ‘average’ which I think is a good thing.  When the Jetstream becomes long term disrupted with huge meandering....expect this ‘unusual weather’.  And this is likely to bring a quick switch to another unseasonable set up

 

BFTP

Edited November 11, 2018 by BLAST FROM THE PAST

[Mike Poole]

Early doors on the pub run, but this looked to me to be of interest, higher heights into the Greenland area on this run T132, than the 12z.  Charts 18z first:

[ICE COLD]

Pub run looking very nice at T144 . 

[BLAST FROM THE PAST]

18z within reliable much better imo to 12z....wall of cold coming west with waa towards Pole more sharp.....the hints are that as per this summer, this winter will be similarly remarkable.....

 

BFTP

Edited November 11, 2018 by BLAST FROM THE PAST