The hunt for cold - Model discussion (late November)

[northwestsnow]

1 minute ago, SLEETY said:

hmm thought the high was going to retrogress towards greenland,then when low res kicks in,gfs decides to display utter junk.Might as well end the run at 240 or whenever low res kick in.

Yes i agree..

Low res is generally not worth paying attention to whether cold or mild..

GFS brings a colder flow for Christmas, and as i said earlier, i think ukmo is a bit,but perhaps crucially better at 144.

Only my two penneth but imo the chances of a mainly dry and cold christmas have increased this evening.

[Methuselah]

My hunch was that the tail-end of the 12Z operational would be noticeably dissimilar to that of the 06Z...so that's 365 successive days, on which my hunch has paid-off. We don't call it 'Fantasy Island' for nothing!

[fromey]

Something a little positive as we go forward.

fromey

[Mike Poole]

Evening all, considerably fewer posts than the last couple of days, and I think that's because we're now in a betwixt and between period.  Actually the potential for a northerly wind at Christmas has actually increased compared to yesterday, but the potential won't go anywhere in my opinion, FV3 at T204:

Amplification there, but the high heights in Spain the spoiler.

Still 9 days away so time to change. 

Longer term, the strat developments continue unabated, with FV3 showing indications of a split being the eventual result of the SSW consistently (noting we can only see the temperature plots at 10mb - if anyone knows a site we can see more info on the strat for the FV3, please give details!).  Nothing at all today to indicate the massive January potential has reduced.  As we were...

Edited December 16, 2018 by Mike Poole

[Kirkcaldy Weather]

if we enter the new year with the stratosphere in this state surely it would only be a matter of time before the PV is destroyed and the possibility of colder weather coming our way would be on the rise. @Mike Poole

 

looking for any signs of possible immediate responses to the strat warmings, only found 1 from that run but hopefully more develop in future runs

think we could be singing this soon to the PV 

 

Edited December 16, 2018 by Kirkcaldy Weather

[feb1991blizzard]

Just wished you could see all levels of the GFS parallel.

[Kirkcaldy Weather]

GFS P also goes into the new year looking for the split warming event 

[tight isobar]

Some rapid responces flagging up..indicated via- the 'wafz'..

The trop-having a rapid heat notion..

And downwelling looking very quick!!

A second minor warming in the strat also looking fairly reasonable of decipher!!and 

Displacement immenent...and a probable split later dec-..looking the main man...

Some staggering height annoms on the operationals..in coming days look nailed.

Some real and decent..and very rapid responces...are looking increadible!!..

And some very note-worthy winter weather in the mid-upper latts could be making the headlines late dec...early jan..

And the probable placements have us..well in the firing line...

The gain going into overide !!!°

Edited December 16, 2018 by tight isobar

[Mike Poole]

OK, so this is now the 7th consecutive FV3 run that has shown to a greater or lesser extent this evolution with regards to the SSW, here T360:

The angle is consistent with the tweeted GloSea5 image as far as I can see.  The op GFS has been less consistent but I am inclined to go with the FV3 on the grounds of the higher resolution in the timescale, that is the timescale after the technical SSW but running up to the consequences.

Edited December 16, 2018 by Mike Poole

[Badgers01]

38 minutes ago, Mike Poole said:

Evening all, considerably fewer posts than the last couple of days, and I think that's because we're now in a betwixt .....

Props a bit of early model fatigue too - maybe realism as well Singularity, reminds us that it might not be till the middle of next month that we see the impacts of a SSW that has not yet begun - this is more of a marathon than a sprint !

[northwestsnow]

EC looks an improvement this evening too..16-192 shows the Atlantic ridge gaining a bit more ground than the morning run.

Edited December 16, 2018 by northwestsnow

[Johnp]

6 minutes ago, northwestsnow said:

EC looks an improvement this evening too..16-192 shows the Atlantic ridge gaining a bit more ground than the morning run.

I don't recall synoptics like that ever actually verifying, so I'm expecting big changes in the next few days.

Edited December 16, 2018 by Johnp

[northwestsnow]

EC is indeed an improvement.. Christmas day looks cold..:-)

[nick sussex]

Keep the faith folks ! 

The zonal winds are decreasing , the models can often play catch up in these situations .

Still a messy picture but if we can get some luck with the toppling ridge as in a bit more amplitude . That would be a bonus .

[I remember Atlantic 252]

240 on EC but boxing day few flurries possible, SE especially, 850's just about okay, all change on next run though as it's deep FI

[northwestsnow]

Nice little trough trapped over France at day 10.. likely becoming very cold by night on Boxing day..

Helen Willetts might have been onto something..

[SLEETY]

11 minutes ago, Johnp said:

 

I don't recall synoptics like that ever actually verifying, so I'm expecting big changes in the next few days.

That Arctic high might become a bigger player than is currently being shown on the models I think.Certainly bitterly cold air becoming established over Eastern Europe,-24 hpa showing up! which is what you want to see ,just need it to back west,eventually!

Edited December 16, 2018 by SLEETY

[tight isobar]

7 minutes ago, nick sussex said:

Keep the faith folks ! 

The zonal winds are decreasing , the models can often play catch up in these situations .

Still a messy picture but if we can get some luck with the toppling ridge as in a bit more amplitude . That would be a bonus .

Yeah..certainly..the raws..seem to be miss firing-on the upper layers...and spike responces at hand.

Even this 1 snap ecm 12z op..

Has to my eye underestimate..on the flow...and maybe moreso that tap in -injection of cold out east/north east..

Again im sticking....xmas the doors open...the party starts...

Confidence growing 4 me..

And the raw-datas..should begin 2 pull a line on the above mentioned!....

Within coming days.

 

Edited December 16, 2018 by tight isobar

[BLAST FROM THE PAST]

3 hours ago, Tim Bland said:

That sounds like a bit of a backtrack from what you what you were saying a week ago “don’t make any travel plans around Xmas” we were all going to be snowed in where we not?

That stands, be where you want to be over the Xmas hols is what I said Not your quote Tim...get it right pal....now where is your LRF?

 

BFTP

Edited December 16, 2018 by BLAST FROM THE PAST

[ITSY]

Both GEM and ECM showing abundance of potential, esp the former. 

The SLP graph for N England also shows high pressure on the upward turn towards the end period. All, for me, initial signs that post Xmas/NY we are heading into a period of enormous possibility post SSW....

 

Edited December 16, 2018 by ITSY

[Cheshire Freeze]

Oh I do love it when the vortex (temporarily) fires up just before a SSW. Usually leads to fireworks when it goes 'pop' 

[Methuselah]

The GEFS ensemble, for 850mb temperature Aberdeen) shows remarkable inter-member agreement until after Xmas dinner, and then realises there's rather too much cognac in its pudding:

 

The corresponding runs for Northampton get pi55ed a little sooner:

 

The SLP ensemble suggests that the signal for a general rise in pressure is still gaining momentum:

 

[nick sussex]

1 minute ago, northwestsnow said:

Nice little trough trapped over France at day 10.. likely becoming very cold by night on Boxing day..

Helen Willetts might have been onto something..

She’s always been a fave of mine . She does like the  cold and snow and hasn’t become one of the mild ramping brigade at the BBC!

The thing at the moment is we have the decrease in zonal winds and then the displacement of the PV which makes the models more unreliable than normal .

The first hurdle is to overcome the shallow low over the UK. , it hangs around .

We want that clearing away and allowing a clean pattern upstream to help push the ridge east/ne.

After a few underwhelming days I’m a bit more interested now !

[BLAST FROM THE PAST]

3 hours ago, johnholmes said:

So what is it in your water that suggests that please?

No model of any duration, no other lrf makes that much of the probable cold spell in January.

Have a read JH....I did it in October

 

BFTP

Edited December 16, 2018 by BLAST FROM THE PAST

[bluearmy]

Just now, CreweCold said:

Oh I do love it when the vortex (temporarily) fires up just before a SSW. Usually leads to fireworks when it goes 'pop' 

That you said it twice!

it would be interesting if it did show a strong uptick as that would presumably show that any reversal will also downwell quickly ... (assuming the uptick was strat led and not the result of trop influences - the Berlin data is useful for that but only available to day 10)