Model output discussion 10/02/21

[Mike Poole]

Well the plot thickens as the ECM clusters show an unanimous atlantic ridge T192-T240 (purple border), confused now re earlier output:

Still think it is time for some virus busting WARMTH though!

Edited February 27, 2021 by Mike Poole

[Griff]

5 minutes ago, Mike Poole said:

Well the plot thickens as the ECM clusters show an unanimous atlantic ridge T192-T240 (purple border), confused now re earlier output:

Still think it is time for some virus busting WARMTH though!

Cold is favoured when a veteran member decides winter is over... We need you Mike, take one for the team  

[stodge]

Evening all

It looks like another quiet evening on the Model Output Discussion thread but there were clear signs of a brief colder interlude next weekend as a lobe of HP broke off from Greenland and headed south across the British Isles before declining and allowing milder air back in.

As always, we'll start with the medium range charts from GEM, ECM, GFS OP and GFS Parallel.

T+144 (March 5th):

T+240 (March 9th):

At T+144, the models all look on the same page. The HP is moving quickly down over the British Isles with an accompanying push of much colder air as the NE'ly air flow moves down in front of the HP cell (-8 850s widely across the British Isles by T+144). From there, we have two scenarios - GEM, GFS OP and Parallel all have the HP declining quickly south west and opening the door to the Atlantic trough to move in from the north west. GFS OP and GEM have a notable negative alignment on the trough - Parallel is less certain. On its own tonight is ECM with a more complex evolution keeping the HP cell just to the north west of the British isles a little longer. As it declines south west, the Atlantic doesn't fill the gap and a new ridge moves up from the south west but the cold air persists.

Moving on and the longer range T+312 and T+384 charts from GFS OP, Parallel and Control as well as CFS:

T+312 (March 12th):

T+384 (March 15th):

As you might expect, no strong signal as we move toward mid month. The models suggest a longer or shorter period of Atlantic dominance with some cold and stormy conditions possible - Parallel looks particularly chill approaching mid month.  It's hard to see a clear trend.

It certainly looks as though we will see something much colder later this week and over the weekend as the sinking HP from Greenland pushes a NE'ly air flow in front of it down across the British Isles. From there, a period of Atlantic dominance which itself looks quite cold and stormy is the favoured outcome before perhaps a more settled trend mid month. Those who thought we had seen the last of winter a fortnight ago might be in for a surprise as the week develops.

Edited February 27, 2021 by stodge

[Mike Poole]

7 minutes ago, Griff said:

Cold is favoured when a veteran member decides winter is over... We need you Mike, take one for the team  

Veteran? I’ve only been posting regularly in here since the BFTE 2018 (joined 2013).  Most of the true veterans have stopped posting about this winter anyway.  I am switching to summer mode now, and hope that will either a) help trigger a winter resurgence as you suggest, or b) allow us to talk about weather that might realistically do some damage to this horrid virus and hopefully some sunny warmth along with that.

[MATTWOLVES 3]

Perfect illustration from Nick F as to why you don't rule out Winter just because its about to become March! Welcome aboard my cold chasing posse Nick...free membership for you

Seriously folks the extended ECM mean is pretty eye catching for this time of the year..out towards the 9th of March and we have a cluster of runs going below-10 850s.. Thats pretty impressive in its own right! The chase commences....we need to keep as many of you coldies onboard....because the chaser is a mean mean hater of cold  

 

[Don]

2 hours ago, Mike Poole said:

Yes but it is a transient ridge, on all models, and what follows is not wintry, but then, by that time it is spring and with the virus and everything I want a warm up now.  It was interesting yesterday to flirt with some cold options but they’ve gone now, apart from a sharp frost next Thursday, so roll on summer...

Those thoughts about re-joining the March cold spell club didn't last long, did they?! 

Edited February 27, 2021 by Don

[Battleground Snow]

Hmmm 18z icon with a step back to the ECM solution, maybe it is on the money after all, 

ECM mean is colder than the 00z run, with some -11s in there now.

[Mike Poole]

9 minutes ago, Don said:

Those thoughts about re-joining the March cold spell club didn't last long, did they?! 

No.

[Gowon]

 

49 minutes ago, MATTWOLVES said:

Perfect illustration from Nick F as to why you don't rule out Winter just because its about to become March! Welcome aboard my cold chasing posse Nick...free membership for you

Seriously folks the extended ECM mean is pretty eye catching for this time of the year..out towards the 9th of March and we have a cluster of runs going below-10 850s.. Thats pretty impressive in its own right! The chase commences....we need to keep as many of you coldies onboard....because the chaser is a mean mean hater of cold  

 

I'll always be on a lookout for snowy weather right up to the point where it's physically impossible.  

Edited February 27, 2021 by D.V.R
deleted extra words

[Don]

8 minutes ago, Mike Poole said:

No.

Well, all I can say is I hope you re-consider during the next few days  The last few days have been very spring like and I went for a 12 mile walk today in a t-shirt and wish I'd worn shorts, it was that warm in the sun!  I want a final winter blast before spring proper!

Edited February 27, 2021 by Don

[damianslaw]

Short term, all models in agreement of a quiet spell with high pressure ruling the roost. Pleasant days with mix of sun or bright conditions, some patchy cloud in places, early morning frost and possible mist or fog.

By Thursday, models all show high pressure breaking off from Greenland and moving down through the UK next weekend, bringing colder NE feed. Feeling raw in the east possible wintry showers and generally cold for all with temps below average.

Divergence thereafter, two scenarios likely:

High pressure sinks south allowing Atlantic in, but not atypical zonal, given heights likely to sit to the far SW  a cold longwave rough settling over UK, heights forced far to the west in and behind.

High pressure tilts more to the east and south east, staying settled and relatively chilly, with heights trudging back west.

Both scenarios suggest mid Atlantic heights by mid month and a possible northerly or north easterly or north westerly airstream.

I don't foresee a very mild picture at all. Odds of colder better than milder. Could all change tomorrow..

[Nick F]

52 minutes ago, MATTWOLVES said:

Perfect illustration from Nick F as to why you don't rule out Winter just because its about to become March! Welcome aboard my cold chasing posse Nick...free membership for you

 

Thanks for the invite Matt, accepted. I enjoyed the early February cold spell, it brought sub zero days and just enough snow to take the kids sledging, so was a shame to see it go and get replaced so quickly by spring warmth. I know it's a lot harder to create such cold 3 weeks later in early March, but not unheard of. Doesn't bother me seeing winter return, it's more interesting than warmth in March, lets face it, it's mild or warm most of the year, so gets a bit boring. EC certainly not painting a returm to mild like we saw last week, it's looking decidedly chilly from later in the week, perhaps turning cold.

Edited February 27, 2021 by Nick F

[Don]

19 minutes ago, Nick F said:

Doesn't bother me seeing winter return, it's more interesting than warmth in March, lets face it, it's mild or warm most of the year, so gets a bit boring. 

Too bloomin right I say!  Lets hope we get a March cold spell, even if it is fairly short lived.  Lets face it, at the end of August people often hope for more warm/hot weather in September, so why can't coldies want cold in March?!

Edited February 27, 2021 by Don

[Frosty.]

For sure tonight’s ECM 12z ensemble mean becomes colder than last night’s 12z mean..baby steps!!!....  

Edited February 27, 2021 by Jon Snow

[MildCarlilse]

[phil nw.]

I expected a a 2 or 3 day cold snap based on previous ens guidance. That ecm mean output though has raised an eyebrow suggesting something more prolonged. 

[Mike Poole]

Just now, lassie23 said:

I throw in the towel in June usually.

Very sensible!  Snow happened in June 1975:

One of the most remarkable weather events of my lifetime actually, even though I was 4 at the time! Marginal, I hear you cry?  But it happened.  

[Battleground Snow]

Azores high further west like the ECM this run, but still quite a big difference between the 2 models.

[Blessed Weather]

Some overnight posts discussing past late snowfall experiences and preferences, etc., have been moved over to the Winter Chat thread.
Thanks.

[johnholmes]

In the near term, this week, I do not like what I see. A moist slack flow off the N Sea=yuk, low ST and mist each day long!

[IDO]

Not that we need proof that ecm just cannot do heights well post d8 compared to other models, it has, as expected flipped in line with other models now showing an Atlantic flow. Compare this morning and yesterdays 0z at d9 today:

IMBY looking at the gefs:

Dry for the next 8-days apart from the cold front Wed-Thur, temps dropping from mild mid-week to slightly below average for a few days before recovering. Unsettled post-d8. Run of the mill stuff really although the jet looks to be tracking to our southern regions so on the cooler side of the upper flow. Based on the cyclic nature of the NH profile I would expect further heights to build in the Atlantic post d13?

[damianslaw]

1 hour ago, IDO said:

Not that we need proof that ecm just cannot do heights well post d8 compared to other models, it has, as expected flipped in line with other models now showing an Atlantic flow. Compare this morning and yesterdays 0z at d9 today:

IMBY looking at the gefs:

Dry for the next 8-days apart from the cold front Wed-Thur, temps dropping from mild mid-week to slightly below average for a few days before recovering. Unsettled post-d8. Run of the mill stuff really although the jet looks to be tracking to our southern regions so on the cooler side of the upper flow. Based on the cyclic nature of the NH profile I would expect further heights to build in the Atlantic post d13?

Trend week 2 March, unsettled and cool, a more southerly positioned jet with trough aligned NW-SE, possibly cyclonic, mid Atlantic heights as azores high retracts to the west, may be an evolution to a northerly. GFS has run with this trend for a bit and now ECM.

[bluearmy]

2 hours ago, IDO said:

Not that we need proof that ecm just cannot do heights well post d8 compared to other models, it has, as expected flipped in line with other models now showing an Atlantic flow. Compare this morning and yesterdays 0z at d9 today:

IMBY looking at the gefs:

Dry for the next 8-days apart from the cold front Wed-Thur, temps dropping from mild mid-week to slightly below average for a few days before recovering. Unsettled post-d8. Run of the mill stuff really although the jet looks to be tracking to our southern regions so on the cooler side of the upper flow. Based on the cyclic nature of the NH profile I would expect further heights to build in the Atlantic post d13?

Not sure we know where this is going for the period days 6 to 10. Yesterday was high height anoms and by this morning we are looking at sliders and wedges. However wedges tend not to make sledges in March.

[IDO]

31 minutes ago, bluearmy said:

Not sure we know where this is going for the period days 6 to 10. Yesterday was high height anoms and by this morning we are looking at sliders and wedges. However wedges tend not to make sledges in March.

That is the case for the ecm op (wedges) but the gfs less keen on that and I wonder if the ecm op is till over-playing heights? Looking at its mean, the wedge-like d8-10 is not distinct.

gfs d9 mean -v- ecm:

I would say models are converging from a "mean" perspective after a few days of entropy?

[mushymanrob]

4 hours ago, johnholmes said:

In the near term, this week, I do not like what I see. A moist slack flow off the N Sea=yuk, low ST and mist each day long!

"dead skies"...... dreadful weather conditions...

Also, some are saying they dont want mild now because its mild most of the year..... but its not the same! these early warmer days in the sun are so refreshing and dont compare to warmth at other times of the year.

Edited February 28, 2021 by mushymanrob