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Cold hunt - models and chat


Paul
Message added by Paul

Please ensure that the majority of your posts in this thread are model related - a theme of model discussion needs to run throughout.
Some off topic chat and reactions are ok, but please use other, more relevant threads for entirely off-topic chat (such as snow reports, met office forecasts and general chat/moans about the weather or this winter).

For more no banter and just model discussion please head to the new focused model thread - this is also a great place to post (or cross post) your longer model summaries or thoughts around the models.

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Posted
  • Location: Coniston, Cumbria 90m ASL
  • Weather Preferences: wintry
  • Location: Coniston, Cumbria 90m ASL
3 hours ago, CreweCold said:

March 2006 polar NWly delivered even at this altitude. 

March 2013 was epic!;

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Posted
  • Location: Tyrone
  • Location: Tyrone
2 minutes ago, bluearmy said:

The nwp ops are headed to a possible NH split around day 10/12. If this begins to gain traction, then all bets are off as the month turns ........

I take it 1yr beast from East anniversary is off for Feb then.

ECM1-96.gif

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Posted
  • Location: STEVENAGE, HERTS (100M ASL)
  • Location: STEVENAGE, HERTS (100M ASL)
25 minutes ago, bluearmy said:

The nwp ops are headed to a possible NH split around day 10/12. If this begins to gain traction, then all bets are off as the month turns ........

18z GFS not far off a split 

 

032E590D-E8FC-4375-9227-15DED31A0FCF.png

D2593F8C-4275-4C16-83C5-A402340B07E9.png

Edited by Tim Bland
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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
11 minutes ago, bluearmy said:

A bfte isn’t going to strike in feb ...........

We aren't actually that far off the same type of synoptics we had at the end of Feb last year, WAA through mid atlantic, deep long wave trough out west, and an initial surge of mild southerlies..

Alas - we seem destined not to see a pronounced easterly, not enough cold pooling to the NE putting a force on the ridge, with more energy in the northern arm of the jet..Looking at the synoptics shown end of Feb on paper we should be under a cold continental airmass - alas, the origins of the ridge are from med.. there is no cold feed from anywhere.

Would be good to have some experienced voices speculating over longer-term drivers as we move into March, any signals to shift us out of a protracted spell of weather that has seen the ridge dominate - unusually so. Indeed we had a 3 week omega block end Dec into Jan, and we have another one now, almost in the same place- highly unusual during the winter - can't help but think the way the SSW impacted on the northern hemisphere was in the end the death knell for any sustained cold weather this winter - its all set up wrong - the weak atlantic hitting  brick wall over and over again.

I'm just taking cursory glance at the models at the moment - awaiting more concerted signals to shake us out of a very stubborn pattern - something will come along eventually... when is the question?.. - most probably the natural weakening of the PV as we move through early Spring. Just hope come summer we are not longing for the synoptics of winter 18/19! 

Edited by damianslaw
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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level
43 minutes ago, Kentspur said:

How's the EC46 tonight any more Greenland height teases

Its about time the EC46 received its p45 and did one 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

npsh500.png npsh500.png

Yeah okay - a very delayed March 2013-style tropospheric vortex split event it appears, but given the vertical mean zonal wind profiles of late it's more likely to be tropically-driven (MJO into P1) with some help from the lower stratospheric vortex not being in a rampant state (just near-average which is pretty tame in early March).


Even with the Nina-like interference ongoing, EPS look a bit too happy to propagate the MJO merrily on through P2-P3 at a fairly quick pace (nearly all members are doing this; it's quite odd actually!) so if a major HLB episode is to appear in early March, I don't expect them to pick up on it until if and when they change their MJO projection.

I've had this nasty feeling that March would yet again prove to be a winter hangover rather than a launchpad into spring, but at this stage place it at 1/4 odds given the tendencies of recent months.

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Posted
  • Location: st albans
  • Location: st albans
8 minutes ago, Singularity said:

npsh500.png npsh500.png

Yeah okay - a very delayed March 2013-style tropospheric vortex split event it appears, but given the vertical mean zonal wind profiles of late it's more likely to be tropically-driven (MJO into P1) with some help from the lower stratospheric vortex not being in a rampant state (just near-average which is pretty tame in early March).


Even with the Nina-like interference ongoing, EPS look a bit too happy to propagate the MJO merrily on through P2-P3 at a fairly quick pace (nearly all members are doing this; it's quite odd actually!) so if a major HLB episode is to appear in early March, I don't expect them to pick up on it until if and when they change their MJO projection.

I've had this nasty feeling that March would yet again prove to be a winter hangover rather than a launchpad into spring, but at this stage place it at 1/4 odds given the tendencies of recent months.

Given that the MJO analogues aren’t  reflected in the output trop pattern through phases 7/8/1, why do you think the MJO being in non HLB phases will preclude them actually verifying??  The MJO has been a poor forecasting tool thus far this winter .....especially so since the SSW - I don’t see why things should change now ........

Edited by bluearmy
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
4 minutes ago, bluearmy said:

Given that the MJO analogues aren’t  reflected in the output trop pattern through phases 7/8/1, why do you think the MJO being in non HLB phases will preclude them actually verifying??  The MJO has been a poor forecasting tool thus far this winter .....especially so since the SSW - I don’t see why things should change now ........

Sods law!!

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

Even better split on the 18z GEFS than the 12z.

There is likely to be some crazy stonking NH profiles by 384.

Edited by feb1991blizzard
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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
1 hour ago, bluearmy said:

Given that the MJO analogues aren’t  reflected in the output trop pattern through phases 7/8/1, why do you think the MJO being in non HLB phases will preclude them actually verifying??  The MJO has been a poor forecasting tool thus far this winter .....especially so since the SSW - I don’t see why things should change now ........

Phase 1 is what I’m looking at a possible lagged response to, which doesn’t need as much Nino cooperation to force some HLB, usually aligned through Greenland-Iceland vicinity.

Phases 2-3 are indeed different, supporting blocking near-east of the UK more at mid-late like we have now, but as I said, I’m a bit sceptical of EPS’ fast propagation on through these. 

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Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast

Looks like tight isobar maybe correct, could be a huge downturn in temps as we head in to March, AGAIN. 

I think it's happening AGAIN we have had two wintry Marches in 5 years and maybe AGAIN, incredibly fascinating that March is the new winter month❄️

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.

Interestingly ECM , GFS and GEM ops all retrogress the euro high to Greenland around the same timeframe on this mornings runs. One to watch as we head into early March. 

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Rapid changes overnight on the ECM. This looks very like the models responding to the movement of the MJO .

Phase 7 takes high pressure further north , phase 8 should see heights dropping to the south . 

All the more remarkable because last nights ECM ensembles showed nothing in the way of cold for the next ten days .

The MJO was really the only thing keeping us interested to see if that could change the pattern. 

We need a few more runs to see if this response is too quick or whether we have a chance of something wintry early March .

 

 

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

UKMO extended remaining dry and settled as high pressure continues to dominate

ukm2.2019022600_168_lant.troplant_prp_fcst.gentracker.thumb.png.feebf4ba8b96d9341bd60da0ab068367.png

Some rain around today and tomorrow but it looks like it'll be increasingly patchy the further east it moves

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Posted
  • Location: North east Hampshire
  • Location: North east Hampshire
29 minutes ago, prolongedSnowLover said:

See what the Ecm mean looks like later. But it looks promising on the op this morning

3D4409A4-F2ED-444C-B15F-9C9497008085.png

Outlier I'm afraid, Gavin has already brought the breaking, bad news.

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Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast

Doesn't mean it's wrong though  even if the op is an outlier  do you really think this exceptionally mild weather is going to last until summer , think a big shock to all the mild rampers in here sooner then they would hope for

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill
7 hours ago, Singularity said:

Phase 1 is what I’m looking at a possible lagged response to, which doesn’t need as much Nino cooperation to force some HLB, usually aligned through Greenland-Iceland vicinity.

Phases 2-3 are indeed different, supporting blocking near-east of the UK more at mid-late like we have now, but as I said, I’m a bit sceptical of EPS’ fast propagation on through these. 

Just my thoughts; I am not seeing any MJO forcing at the moment. What I see is a trop response to the current pattern. The wave train has ground to a temporary halt, due to extensive troughing to the east, and the UK arena is at the end of the line. Some energy from those HP cells is building north, to release that pressure, whilst the main thrust works a route to the south. That is why we are only seeing wedges into HL. They are not sustainable if the forcing is not from the MJO.

Looking at the 500hPa temps I am not seeing wave propagation into higher latitudes:

anim_asb7.gif

With wedges they will move within the flow so any cold steered to the UK will be temporary.

Although there are some models suggesting the current active Rossy Wave interference may be subdued, we still have the downwelling Kelvin Wave mixing out the MJO signal (composite). Maybe the MJO lagged feedback will come later, but I am unsure why with the constructive interference so far this winter we can suddenly expect the MJO to override the base trop pattern?

As for the models, this is 10 days away and we know they tend to overhype any pattern change and downgrade as we move to T0, so if it is indeed another false dawn we shall see that in the next day or so as newer data conflicts with climate composites.

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
22 minutes ago, Summer Sun said:

ECM is a cold outlier unsurprisingly

London

graphe_ens3_php.thumb.png.0e1702faf062cdd7dfccfb4d823bc69a.png

Southern Scotland it goes both warmer and colder than the mean 24th onwards

sco.thumb.png.0caaf5337e8979575116a795d9aa8e8a.png

Bearing in mind cross model op agreement on that outcome ECM ens could just be lagging behind the curve somewhat and even they are still trending downwards. Could be a false dawn like so many this winter. Like I said earlier not getting excited at all but a trend to watch as we enter March.

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