Model Output Discussion - Spring Has Sprung

[Chesil View]

  @Mike Poole

It was said  with tongue firmly in cheek Mike. Those who follow the strat and teleconnections were as you rightly say patiently waiting for things to unfold. 

However I do remember that the less patient among us weren't quite so sanguine about where developments eventually led. Namely the coldest end of Feb early/march spell since 1845!!

[Metwatch]

To me here it seems like there is a fight between tropospheric led drivers like the MJO, AAM following increased mountain torque etc, and the increasingly strong westerlies in the stratosphere later next week.

This sort of pattern you could see sliders across the channel pop up with a slight southward shift in the polar jetstream and the some of the PV move into Scandinavia. Some greenland / north Canada heights forming too, but the ESB would be seeing much colder air with that pattern. A large north Pacific ridge shown to form, which catches my eye but don't think that would do us any good. It would be a hard time to shake off those stronger westerlies in the strat I feel and heights to our south. All seems rather elusive to me.

 

 

Edited January 28 by Metwatch

[Kasim Awan]

  @Blessed Weather 

The risk of substantial cold is now very low. Looking at the models there is nothing to support substantial cold. 

[Dennis]

here the Jet EC12z ... check NE USA 

thats the breakpoint 

so wait on next runs and a MJO7 (event) is poss helping 

 

Edited January 28 by Dennis

[geordiekev]

34 minutes ago, Metwatch said:

A large north Pacific ridge shown to form, which catches my eye

Yeah GFS was toying with this extending to create an Arctic High, which did look interesting but dropped the idea but if Pacific High gets legs, who knows...

[bluearmy]

Come on @Mike Poole

let’s see those extended clusters …..

[Mike Poole]

ECM clusters T192-T240:

No surprise having watched the recent op runs, that there is only the hint of a change in the 10 day range, with cluster 1 trying to put an upstream ridge up.

T264+:

Much more promising than this morning’s effort in the extended.  Cluster 2 has a decent go at a Greenland high, actually ends up with the kind of height anomalies showing on the 46, with low heights to our south.  Cluster 3 might tend to develop northerly incursions with more modest wedges of high pressure.  Cluster 1 looks largely northwesterly flow.  

[geordiekev]

22 minutes ago, Dennis said:

here the Jet EC12z ... check NE USA 

thats the breakpoint 

so wait on next runs and a MJO7 (event) is poss helping 

 

Amazing how far South the disintegrated tPV is pushing the jet South, until you get to the Atlantic ofcourse then that Northern Arm just too strong to be of any use atm

[Frosty.]

I’m seeing some wintry potential from next weekend and at times thereafter, especially across the north but not exclusively!..the latest ECM highlights this, as does the latest update from Exeter, which wasn’t the case until today!..hopefully winter will be making a comeback during February.. fingers crossed etc!  

[WYorksWeather]

Worth flagging the potential for some more extreme Foehn effect temperatures at the start of February, after today's totally unexpected demolishing of the January record. UKV only has raw maxes of 12-13C, but after today, it could well be significantly higher.

Wind profiles look favourable as well, with brisk south-westerlies into Scotland and parts of Wales.

 

Looking further ahead, we don't have the ECM ensembles yet, but using GFS it's really very uninspiring.

All we have is temperatures nearer average by the end of the period. There's not a single run that gets temperatures in London below freezing at any point. 

If you look a bit further north, it looks like there's at least a bit of interest.

But again, look at that chart objectively. Somewhere like Newcastle, only a couple of runs getting below 0C at any point at the surface, mean not even touching -5C.

So, we're increasingly looking further ahead, trying to look for something into the second half of February. That is still very much possible, but we will begin to reach the point where we run out of time.

The current modelling is compatible, at best, with a few brief colder north-westerly or brief northerly toppler events which bring snow to the north. Quite possibly not even that.

And whenever the wind does turn south-westerly again, the spring-like February option will return. Those exceptional Azores SSTs are still there.

And at day 15, the anomaly actually increases.

Unless the synoptic setup is able to cut off those south-westerlies for a sustained period, as we saw in mid-January, we could see one of the mildest Februaries on record.

 

[Dennis]

  @geordiekev

if it verifies on this a whole complete other pattern is seen 

it knocked out the whole jet to west europe 

 

[sebastiaan1973]

MJO phase 8. For the first time. 

Edited January 28 by sebastiaan1973

[sebastiaan1973]

Zonal mean winds back to normal, a small part of the ENS shows a SSW

pdf2svg-worker-commands-788bdf985c-8zvvc-6fe5cac1a363ec1525f54343b6cc9fd8-G8j77e.svg

[AO-]

  @Mike Poole

To support it with the EPS for here. An improvement compared to this morning. Unfortunately I don't have the EPS (it wasn't interesting ) to show you.

[sebastiaan1973]

The chance for a positive NAO regime seems rather small. 

 

pdf2svg-worker-commands-788bdf985c-8zvvc-6fe5cac1a363ec1525f54343b6cc9fd8-G8j77e.svg

Edited January 28 by sebastiaan1973

[Mike Poole]

  @sebastiaan1973 Yes, good sign.  I wonder if actually that double back criss-cross that has been shown by the mean in phase 7 for days now is just an artefact of it being the mean of some runs that have the right signal and some that have it totally wrong.  I bet it won’t pan out like that, it’ll either dive into the COD, or maintain amplitude through 7 - and given the way it is trending, maintaining high amplitude looks much the more likely outcome (for once). 

Edited January 28 by Mike Poole

[bluearmy]

Steady as she goes towards a fairly wintry looking last two or three weeks of feb - week 2 probably limited to the northern half of the U.K. to begin with but beyond that could be the whole country 

[MJB]

  @Kasim Awan The risk of substantial cold is now very low. Looking at the models there is nothing to support substantial cold. 

Which period are you talking about Kasim?

[damianslaw]

GFS continues to throw up very varied fayre at the 6-10 day timeframe, often a sign a change is on the way, but until it closes in to the reliable timeframe less than 6 days hard to buy into any of the scenarios.

In these situations I do tend to believe ECM holds firmer on direction of travel 6-8 day timeframe. This evening's run is showing a northerly flow ready to dig south as the case by day 10, with north half of UK in proper cold air - sub 522 dam line.. this I do class as cold in early Feb.

UKMO showing a possible similiar scenario.

Polar maritime shots with the jet digging south could be the way we are heading early Feb with potential slider lows moving into increasingly colder air. 

In the meantime, more very mild weather on the way. 

[Cambrian]

Exceptionally good agreement between the 12z ECM op and ensemble mean at day 10, even better with the day 9 mean as it happens!

  

The heights anomaly chart for the day 10 op is interesting when put side by side with the T850s - due to the proximity of the low heights associated with the PV close to our northeast and generous pools of cold air to both our northwest and northeast, positive height anomalies even to the very north of Iberia do not prevent subzero T850s for all of the UK and Ireland and as cold as -4 to -8 away from the south. 

 

Even colder on the control, -4 to -8 for all of UK and Ireland off a similar heights profile…

 

There is no doubt that heights to the south do impede the southward progress of Arctic air, and albeit that in this case the modelled incursion is relatively short-lived, these models (at least) suggest that it evidently might be a bit more nuanced than assuming that positive heights anomalies over Iberia prevent potentially wintry weather for much of the UK and Ireland. 

[Rain All Night]

9 hours ago, RainAllNight said:

0z/6z deterministic runs, Sun 28th to Sun 4th

It looks as though the disturbance running to our north on Wednesday will not be noticed by the southern half of the country. Most of the T+168h frames see us poised to be denied much impact from the anticipated PV surge by the high pressure to our south, though note the more ambitious 6z GEFS ensemble mean below.

0z/6z ensemble means, Sun 28th to Sun 11th

The 6z GEFS is relatively generous with giving us a taste of the Scandi trough around the 5th of Feb. We then see suggestion of cooler mean surface winds from north of west into the second week of February, the influence of high pressure to our south seeming to have moved further west over the ocean rather than over the continent by this point.

12z deterministic runs, Mon 29th to Sun 4th

There is scarcely any difference between the models for the UK up to day 7 this afternoon.

12z ensemble means, Mon 29th to Sun 11th

It's now the ECM ensemble that is most willing to give us a shot of cold around 5th/6th Feb.

I note with disappointment that the strong signal for dry weather ends on the 5th Feb on the ECM ensemble.

Edited January 28 by RainAllNight

[Jordan S]

Certainly been a stormy weekend in the northern and western isles of Scotland, particularly today with higher gusts than anticipated from my previous post for today with gusts peaking up to a very strong and problematic 70-75mph, certainly very wild!

 

Looking at mid week once again and still looking like being very windy Wednesday for the same areas mentioned above but with the small potential for even stronger winds, severe gales with gusts most likely reaching a very strong and potentially disruptive 65-75mph once again but if the storm develops per some particularly nasty ensemble members, then from that one or two locations could record extremely strong and potentially damaging winds, (storm force winds) with gusts up to 85mph.. those highest gusts are more likely for the northern isles as this rapidly developing storm moves to our northeast accompanied by heavy and possibly squally rain which will work its way slowly southwards over parts of the UK before weakening further south with the higher pressure in place, certainly something to watch out for, for the few that live in these parts. 

Outlook beyond that largely unchanged to me since previous post on Thursday. Will update if anything changes to a larger than small degree in what I’ve covered for the outlook. 

[Catacol]

Well - here we go. ECM 192 shows the bulk of trough energy moving to the east, in line with strat forecasts, and ridging arriving out to our west. 

This fits with the drivers that have been described on multiple occasions, so I wont describe them again.

Won't be long before excitement builds in here once again.

[Mcconnor8]

Well the pub run looks improved on the 12z so far, not that it is much of an achievement.

[Daniel*]

Considerable pressure drop expected in Europe towards mid February if we can manage some high lat blocking courtesy of MJO, it’s looking more likely towards Greenland than Scandi the potential for wintry weather is there. The winter is not over with yet wouldn’t surprise me also if March is not without interest, but of course that’s not ideal for many.