Model Output Discussion - Spring Has Sprung

[Mike Poole]

No sign of the clusters this evening.  ECM 46 has a few points of interest, here’s sea-level pressure anomaly:

Signal remains for high pressure to the NW until mid March.  But where does it get the Greenland high for w/b 5th Feb from?

Zonal winds:

Again an increase in the cluster going for an SSW around 16th Feb.  

MJO:

This is a slight concern - for days the actual MJO has verified more amplified than the model predictions consistently.  But there is little signal in the model to now move it into phase 8 with any amplitude, do we keep the faith or will it fall at the final fence? (It has form for this!)

Edited February 2 by Mike Poole

[Lukesluckybunch]

13 minutes ago, LRD said:

EC46 still shows high pressure anomalies around to our north and NW but it now appears to be much closer to us. It's a subtle shift but it's there

The cold temp anomalies are still there for week of 12th but have been watered down that week and following weeks

Week of 12 Feb

19th Feb

Sorry, I know it's not what most of us on here want to see

You can clearly see where the bulk of the cold is..eastern Europe as always!I think we are leaning more towards something dry and chilly if I had to guess now.

Edited February 2 by Lukesluckybunch
Adding

[sebastiaan1973]

3 minutes ago, Lukesluckybunch said:

You can clearly see where the bulk of the cold is..eastern Europe as always!I think we are leaning more towards something dry and chilly if I had to guess now.

That is the air pressure anomaly

[LRD]

4 minutes ago, Lukesluckybunch said:

You can clearly see where the bulk of the cold is..eastern Europe as always!I think we are leaning more towards something dry and chilly if I had to guess now.

Apologies Luke - I didn't make it clear that they are weeks 2 and 3 pressure anomalies. Not temps (although I did mention temps so the misunderstanding is my fault)

[suxer]

17 minutes ago, LRD said:

EC46 still shows high pressure anomalies around to our north and NW but it now appears to be much closer to us. It's a subtle shift but it's there

The cold temp anomalies are still there for week of 12th but have been watered down that week and following weeks

Week of 12 Feb

19th Feb

Sorry, I know it's not what most of us on here want to see. It's still not bad but it's just not as good

But it was always going to happen ,but don't like this model anyway 

[damianslaw]

I highly doubt any model at this range will have the track and depth of the low pressure being forecasted to move in from the SW on the 8th, pinpointedly correct, its six days away. Expect lots more variability from the models in the days ahead on how they forecast this feature. Consequently reliable timeframe is short, 4-5 days tops, the outlook day 6 on all determinant of the behaviour of said feature.

Worth a comment on ECM as it shows a possible plausible evolution, heights building over the UK as the trough pulls east, every chance they then build quickly north in a cold surface pool. 

Edited February 2 by damianslaw

[bluearmy]

2 hours ago, feb1991blizzard said:

@bluearmy

what stock do you place in the GEM ens? ( i know going back a good few years you used to post the NAEFS), I've never really used them until recently, I suspect you know why i'm asking but for those that don't -

 

Good question 

with only 20 members, the mean tends to be more definitive. But if it has the correct solution this means thee are likely less incorrect members to dilute the mean as often happens with the eps.   In general, if the geps mean isn’t interested in a solution then I tend to wait for it to catch up before having any confidence. 

[Lukesluckybunch]

1 minute ago, LRD said:

Apologies Luke - I didn't make it clear that they are weeks 2 and 3 pressure anomalies. Not temps (although I did mention temps so the misunderstanding is my fault)

It's ok mate..looking at the first one the centre of the high looks to be over iceland..but with it extending southward into the uk..which could be indicating a mainly dry and cold scenario.without any real source of cold

[LRD]

Better news on the ECM 850 ensembles. Not the full set...

[AO-]

43 minutes ago, Mike Poole said:

No sign of the clusters this evening.  ECM 46 has a few points of interest, here’s sea-level pressure anomaly:

Signal remains for high pressure to the NW until mid March.  But where does it get the Greenland high for w/b 5th Feb from?

I have seen worse for February. Great anomaly chart with a high probability of Northeasterlies. I still prefer the Scandies over Greenies as they haven't delivered so far. In case they did deliver it was a cold snap rather than a spell. 

[johncam]

The ECM is what we are looking for , high migrates to the NW 

[WYorksWeather]

ECM seems to want to blow up more of a mild sector on the mean further north between 8th and 10th, whereas GFS didn't really show this. Ridiculous variation in the extended as well.

The meteogram for Reading is also showing only a modest drop below average in terms of temperature.

As others have said, no signal for prolonged or deep cold. Details of next week's chances are still to be ironed out I think.

Looking at the mean chart to try to get a sense of the synoptics.

At day 5, we see the Iberian high start to retreat, and colder air is coming in behind it. 850s don't map on exactly to snow chances, but you would say that anywhere above the -4C line has a chance through northern England.

 

at day 7 the Iberian high has retreated away, but mild air is still hanging on in the south. Near average across England, and a little colder in Scotland. Shows how the subtle differences in the ECM compared to the GFS affect our chances - a couple of degrees higher with the 850s may well render any snow a very marginal event. Details matter.

 

At day 9, the high clears away to our east. We have quite an odd situation, with no real blocking, but the cold air solidifies. With most of the UK under -4C at 850hPa there's a chance that any lying snow at this point could hang around through this period.

 

By day 11 though, all change. Our old friend, the Iberian high, starts to make a comeback. Not mild, but less cold air begins to move in from the west.

 

At day 13 though, it's still not quite as annoyingly positioned. An Iberian high centred over the Mediterranean keeps the very mild air further away. However, we're back to standard winter fare - a bit of brightness maybe under a UK high?

 

And the day 15 chart is much the same.

 

In summary, the ECM is going for the best of any cold and snow chances to be next week, and after the low clears, possibly a cooler zonal flow, but not overly cold for the time of year.

Hard to know exactly what to make of this, as there is a lot of averaging going on of course in the mean charts, but it strikes me as reasonably plausible. It would also fit with the fact that EC46 has tonight erased the cold signal over the UK after week 2. Of course, EC46 is not the only game in town, and for a bit of optimism, the CFSv2 actually maintains the cold signal through late February (admittedly, it's not a very strong signal, only up to 1C below average, but it is still there).

Lots more still to figure out over the coming days. Things I'll be following over the next few days:

• Whether any date records will go over the next three or four days of exceptionally mild conditions
• Snow chances for the middle of next week
• Whether the cold will continue beyond mid-month

I probably have about another two weeks of cold chasing in me (with a short extension for a week or two in the unlikely event that we have a BFTE incoming).

At that point, I'll switch to hunting for the first widespread 20C of the year, and possibly the first 15C 850hPa isotherm.

[Rain All Night]

10 hours ago, RainAllNight said:

0z/6z deterministic runs, Fri 2nd to Fri 9th (day 7)

GEM is what we'd wish for, ECM/UKMO are what I suspect we will get. But you never know...

0z ensemble means, Fri 2nd to Sat 17th (day 15)

We have slightly more agreement now on a (brief) mean northerly on 10th/11th Feb. Again the passage of the low through us is looking a little faster, it looks to be over with by the start of Monday 12th Feb. The later height rise has slipped east a bit on the ECM ensemble, making it less appealing, though it is still leaning against a trough downstream over Scandinavia and eastern Europe. GEM's version, while still further west, doesn't look quite as striking as in previous runs. Nonetheless, it's still a strong signal for high pressure to take back control in some form.

12z ensemble means, Sat 3rd to Sat 17th (day 15)

Still a strong signal for high pressure to be taking back control after the big low passes through us - high pressure centred slightly to our west, and a trough over eastern Europe. A spell of dry and perhaps fresh-feeling weather to come for mid-February.

12z deterministic runs, Fri 9th (day 7)

A snow event for most of us not looking too likely now. GEM

Edited February 2 by RainAllNight

[northwestsnow]

18z looking good at 102

[Tim Bland]

Sofa so good

Edited February 2 by Tim Bland

[Harsh Climate]

 northwestsnow

I think we are going to see a dumping for Northern England Thursday on GFS 18z.

System looks good 100 miles further south atleast.

[seabreeze86]

Big snow event on the 18z and not a million miles away 

[northwestsnow]

18Z BANKKKKKKKKKKKK IMBY

[Harsh Climate]

 northwestsnow

You watch by this time tomorrow it Will be southern England getting the heavy snow, those southward corrections!

[Tim Bland]

12z Vs 18z …is it shifting south ?

[Ali1977]

 northwestsnow not talking deep FI here neither, if this falls right it could just keep snowing for days for some , cold air digging in as it goes on! 

[northwestsnow]

Surely GFS can't be wrong at 96-102..!!

Just for once GFS just for once be right ...

 

[Harsh Climate]

 Ali1977

Someone's going to hit jackpot here, can't see it heading as far south as France or as far north as Shetland.

If this run verified I wouldn't even be bothered what comes after Thursday.

[Ali1977]

Some Amber warnings possible if (still a big if) this was true - I’m quietly confident for some snow IMBY to be fair 

SE in the mix too, huge amount of snow opportunities on this run 

[feb1991blizzard]

 northwestsnow

It's a snorter but i've news for you - oh yes it can with snow charts, it can be wrong with snow charts on the analysis chart.