Model discussion - Warm spell ending as Spring begins

[MATTWOLVES 3]

11 minutes ago, Frosty. said:

Amazing 18z, now that's high pressure domination from next week, especially low res..great spring weather if that verifies!

Likewise from the para frosty, but this time the 18z playing down the cold! 

[MATTWOLVES 3]

A fair amount of scatter on the ensembles!! Tbh just about anything is possible, high pressure is looking a good call, not quite so confident in how temperatures will pan out longer term. 

[knocker]

Outlook - put simplistically upper troughs will move east over the weekend allowing the subtropical high to amplify in the eastern Atlantic. The configuration of the resulting surface high cell over the UK is rather dependent on the how the ensuing battle between this and the energy crossing the Atlantic pans out.

The Atlantic 500nb and surface analysis for midnight and the 0500 surface chart

The wave is currently over N. Ireland and deepening quite quickly as it tracks across the UK to be east of Aberdeen 975mb by 1800. The band of heavy rain, sleet and snow associated with the warm front is currently north of a line central Wales > Wash and this will continue to track north east through the day whilst at the same time the cold front  will move south east from Ireland to be over Wales and the far south west of England by 1800. Snow in Scotland could be quite significant down to low levels in the quite marked temp N/S contrast. Some quite strong gusty winds accompanying all of this, particularly over Wales and the SW/S regions of England

The rain belt associated with the cold front will continue south east during the evening clearing the Kent coast around 0300 leaving the country in a brisk, unstable north westerly with frequent wintry showers developing, particularly in western regions with Wales again in the firing line of the odd trough in the flow. Much colder generally with some frost around by Sunday morning.

By midday Sunday the low is 967mb over southern Sweden with the UK still in the quite strong north westerly airstream thus a much cooler day with temps a tad below average with frequent wintry showers in northern and western regions which could include hail, snow and even thunder in the mix.

Over Sunday night and through Monday the ridge does start to become established but there is a lot of energy exiting the eastern seaboard into the Atlantic and some frontal systems manage to ingress the north west bringing some cloud and patchy rain here with the rest of the country remaining dry.

Over Tuesday and Wednesday the high tends to be suppressed over the south of the country but less so on Wednesday, with any fronts either, dissipating as the manage to track south, or return north again. Thus cloud and some patchy rain in the North on Tuesday but confined to the far north on Wednesday which will be generally dry and quite sunny with temps on the rise over the two days and above average

[knocker]

Following on from this with the ecm. Pretty much in the same ball park as the gfs but varying a tad with the detail. Essentially through Thursday > Saturday the battle between the initial amplification of the subtropical high and the east bound energy is played out resulting in a temporary suppression of the ridge on Friday, But over the weekend a lobe of the vortex drops into the north west Atlantic promoting another surge of the high in mid Atlantic which eventually leads to a surface high cell over the UK by the end of the run. So generally dry with a fair amount of sunshine, with the exception being the north for a time, and temps a little above average.

Edited March 16, 2019 by knocker

[knocker]

The warm front across the north of England at the moment

[Summer Sun]

00z ECM shows high pressure starting to take over next week as we finally lose these deep lows and introduce some much calmer conditions

[MATTWOLVES 3]

Lots of high pressure on both the 6z runs beyond 7 days, even attempts to build them over scandy meaning temps suppressed! But obviously know wheir near as cold as it would have been a few weeks back! It's certainly looking like a more settled outlook though, and at times frost could be an issue, either way it's better than this blow you bald type weather we currently have. 

Edited March 16, 2019 by Mattwolves

[knocker]

The ext EPS this morning is not keen on sustaining the mid range amplification Await this evening

 

[Earthshine]

Excellent news that high pressure will begin to have a stronger influence on our weather next week.  I'm not even bothered about temperatures, just calm and potentially sunny weather will be very welcome following the wild weather we've had over the past week or so.

[Summer Sun]

The final 2 weeks of March are looking much more settled that obviously means a greater risk of frosts where skies clear overnight but by day it will be feeling more like spring once more

 

[Singularity]

24 minutes ago, knocker said:

The ext EPS this morning is not keen on sustaining the mid range amplification Await this evening

 

Thanks for your running commentary and analysis Knocker. Just a slight hitch here as technically it’s still amplification but of a mid-lat subtropical ridge extension rather than high lat extension or cut off high. I.e amplification of a less meridianal flow nature. Many on this forum use it solely to refer to the poleward ridging kind, so I can see where some confusion can arise. 

Promising signs if you enjoy fine spring weather late March. Interestingly, it doesn’t appear to be  driven by the MJO or similar this time around.

[knocker]

11 minutes ago, Singularity said:

Thanks for your running commentary and analysis Knocker. Just a slight hitch here as technically it’s still amplification but of a mid-lat subtropical ridge extension rather than high lat extension or cut off high. I.e amplification of a less meridianal flow nature. Many on this forum use it solely to refer to the poleward ridging kind, so I can see where some confusion can arise. 

Promising signs if you enjoy fine spring weather late March. Interestingly, it doesn’t appear to be  driven by the MJO or similar this time around.

Perhaps I didn't choose my words carefully enough  I was referring to the longitudinal position of the amplification. i.e, it;s moved east allowing the At;antic trough to become more influential again from this position.

Edited March 16, 2019 by knocker

[Frosty.]

My overview of the latest models is for a predominantly settled outlook the further south you are, more changeable the further north you are but with fine spells in the north too..much more pleasant than this week for sure!

[SLEETY]

Yes pleasant weather coming up and personally speaking looking forward to hitting the golf course again    but Still no sign of any Arctic Northerly or continental Arctic air Easterly, really dissapointing how it eludes us still. 

The high pressure belts to the South became the major player in the end during the winter season, and the very cold weather in USA didn't help either. 

The models picked up this return to a dryer and warmer spell a fair way out and its verified, if of course they had Been showing bitterly cold air at the same time we all know what would have happened..... 

 

[Singularity]

2 hours ago, knocker said:

Perhaps I didn't choose my words carefully enough  I was referring to the longitudinal position of the amplification. i.e, it;s moved east allowing the At;antic trough to become more influential again from this position.

Ah yes, I see what you mean there. Thanks for clarifying .

A fine balance between keeping the high building far north enough that conditions turn cooler with a risk of late frosts, and bringing too much of a maritime flow with disappointing amounts of cloud cover. 

Really interesting to have these signs of yet another prolonged period of very settled weather across the UK. For many months now we've been having settled runs of 2-3 weeks punctuated by changeable or unsettled runs of 1-2 weeks. It's like the rates of change have been slowed down - much as some have been anticipating as a consequence of Arctic amplification associated with climate change.

There's also an overall strengthening of the Hadley Cell theorised, which in could increase the persistence of the settled runs of weather even more should the sea ice continue to decline as most projections expect. This year the mean ice thickness away from the Canadian coasts is another metre or so down on last year's already record low amount, putting it mostly at 0.5 to 2.0 m, which is usually too thin to survive the melt season. So things might get a bit dramatic this summer... but nature has a habit of throwing surprises at us so I'm not going to presume too much at this stage.

Wandered a bit OT there, hope the mods don't mind at this quieter time? I can port it over to the climate forum otherwise.

[knocker]

The area of heavy rain, sleet and snow associated with the low as it tracks into the North Sea this afternoon will clear Scotland to be replaced by wintry showers which will tend to die out through the night until the early hours when the occlusion sinks south/

Elsewhere the belt of heavy rain associated with the cold front is currently over Wales and the south west as it tracks south east to clear the Kent coast by around 0100. This also will be followed by showers which may coalesce at times in the sundry troughs/convergence zones embedded in the north westerly flow.

The strong gusty winds in the south will more or less follow the path of the cold front. And by morning the whole country is in much colder air

[Frosty.]

A very decent spell on the way next week on the Gfs 12z operational with high pressure building in and then being reinforced by another high pressure cell from the west with all the weather action brushing around the top of the high and across the far north..so, it's looking good for most of us with plenty of dry, warm and sunny weather with temps into the mid teens celsius range and in favoured parts of the s / e more like upper teens c potential..a vast improvement on this week..looks even better following week with intensifying anticyclone over the uk!

Edited March 16, 2019 by Frosty.

[Mike Poole]

Good signs from the 12s of a settled spell developing towards next weekend.  It has been a while since we've had a prolonged windy spell of weather, and we've needed the rain, but it will be nice to see some settled weather if it verifies.  T180 on the ICON, GEM and GFS.

And the jetstream on GFS at same time.

Thinking longer term it will be interesting to see the extent, on average, that the jet pushes north.  

[knocker]

Clear spot in the 'eye' at 1500

[MATTWOLVES 3]

The para run bringing a lot of fine and settled Conditions, even beyond next week we have temps approaching high teens! It grieves me to keep bringing the same forecast with little chance of any significant cold, but if we can't achieve that, then high pressure in control bringing fine/warm conditions is the next best thing!! Bugger it.... Its only weather folks, their is always next winter to chase that elusive big freeze..... And I tell ya what when it comes off, we are gonna take the roof off this place! 

[Mike Poole]

Very strong signal for the high pressure to dominate for quite a while here on the GEFS 12z mean, T240 but still 1030 hPa over UK

[Frosty.]

10 minutes ago, Mike Poole said:

Very strong signal for the high pressure to dominate for quite a while here on the GEFS 12z mean, T240 but still 1030 hPa over UK

Wow that's EMPHATIC support..!!..it's disappointing that the winter total fail has spilled into spring but I guess it's par for the course where uk coldies are concerned, however, I don't think anyone would really be unhappy about warm anticyclonic weather..I hope this verifies!!

Edited March 16, 2019 by Frosty.

[Mike Poole]

ECM at T 240:

Its fascinating to me that this kind of settled scenario can be nailed by the models up to 10 days out, but that snow bringing scenarios in winter are always subject to uncertainty until 4 days out.   Obviously we will have to see how this evolution goes, but I have high confidence in the development of a settled spell, and longer implications for late spring and early summer to be a northerly flowing jet once again. 

[MATTWOLVES 3]

Ecm summing up the forecast over the next 10 day's, plenty of settled Conditions, a cooler blip next weekend, before pressure re builds the following week and temps warming up nicely.... 20c not out the question!! Wooooowwwwzer! 

[knocker]

After the first transition at the beginning of next week the second is next weekend when a lobe of the vortex drops into the north west Atlantic and promotes renewed amplification of the high in mid Atlantic.