Model output discussion - after the beast, what next?

[mb018538]

No comments on the 00z says it all really. Nothing much to discuss over the next week, low pressure in control, sunshine and showers with some longer spells of rain. Perhaps a window of opportunity as we head into April of a pattern change, but nothing definite as of yet.

[Summer Sun]

00z UKMO shows the coldest air never that far away from Scotland for the first 3 days of the Easter weekend the south would see the best of the temps with low double figures possible

GFS shows double figures more widely (always that bit lower in Scotland and at first Northern England) in fact by Easter Monday it shows temps getting towards the upper teens for some in the south

 

Edited March 26, 2018 by Summer Sun

[Frosty.]

Lovely warm and anticyclonic later in low res on the Gfs 00z with temps into the mid to upper teens celsius..i think even the most hard-core coldie wouldn't mind a spell of very pleasant spring weather towards mid april! ???????

Edited March 26, 2018 by Frosty.

[Summer Sun]

00z ICON shows milder air moving up from the south during Easter Sunday and Monday

Edited March 26, 2018 by Summer Sun

[winterof79]

12 minutes ago, Purga said:

All this talk of lovely mild weather - not according to UKMET thinking.

Or ECM op really

[Leon1]

18z Yesterday:                Looking at the differences it seems that we are more likely to have spring-like warmth and also more likely to have some cold weather. No certainty at all really.

 

00z This morn: 

[stodge]

Morning all

It's worth repeating (yet again because it's true) the transition from winter to spring is the conflict of contrasting air masses. The cold and often very cold air situated over Scandinavia and Greenland comes under assault from warmer Atlantic-sourced air. In a typical winter with a PV (albeit close to final warming) and Atlantic domination the battle can be brief and very one-sided as the jet comfortably pushes north and the cold air gets nowhere near the British Isles apart from a transient northerly.

In a post-SSW spring, however, with the PV shredded and the Atlantic moribund, it's a different story. With the jet held well to the south, the cold air over Scandinavia can be displaced south west across especially northern areas as LP systems slide ESE into Europe and create a trough which is counterbalanced by rising heights to the north and north west. The preponderance of Easterly winds in April is increased by a dormant Atlantic and it can be a slow journey into spring.

Let's see where we are this morning looking at the charts for Wednesday April 5th:

Starting with the ECM 00Z at T+240:

The morning ECM is dominated by the southerly displaced jet which maintains LP tracking west to east across southern Britain bringing spells of rain or showers. Colder air remains closer to the north with the risk of snow for higher ground. By T+240 the main LP is to the NE of Scotland but a secondary feature is developing to the SW and looks set to move NE toward southern England. Note the heights to the NW and signs of height rises over the Mediterranean so the evolution beyond here isn't obvious at all.

GEM 00Z at T+240:

A chilly and unsettled run from GEM with the Zero 850 line barely crossing the English Channel at any point in the next 10 days. That means cool if not cold weather accentuated by periods of brisk E'ly winds such as at T+240. LP over northern France with heights rising to the NW leave most of Britain in a brisk E'ly wind with plenty of rain or showers for southern areas and the risk of more wintry precipitation further north with uppers -4 or lower for many.

GFS 00Z OP at the same time:

Something very different with a pronounced build of heights from the Azores NE into France leaving the British Isles in a mild SW'ly air flow. Dry and possibly quite warm in the south but unsettled further north with rain or showers especially in the north west. The difference with other models begins after Easter when the LP stalls and digs the trough south to the west of the British Isles allowing pressure to rise across western Europe in response. Further into FI, the Atlantic quietens again and an HP builds over the British Isles settling the weather down.

GFS 00Z Control at T+240:

Slightly different from the OP in keeping the LP more in charge and less HP influence. The British Isles is in a chilly air flow as the trough extends NE from the east coast toward Scandinavia. The evolution further into FI is quite messy but a Scandinavian HP builds and then retreats and the Atlantic seems to be back in charge albeit on a slack jet.

The 00Z GEFS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

More spread than I have seen for several days. A number of members are keen to promote rising heights near the British Isles but most do so in a position and orientation likely to draw colder air across from the east or north. There is also the traditional GFS signal to "fire up the Atlantic" with a succession of very deep and vigorous LP systems but I'm to be convinced.

In conclusion, the next 7-10 days sees little respite from the cyclonic evolution that has been mapped for several days. LP remains over or close to southern Britain nd while that prevents the coldest air coming south, the north of Britain looks set to see disappointing temperatures and the continuing risk of snow. For southern areas, it just looks wet. GEM is again a cold evolution while ECM is only little better. GFS on the other hand continues the signal for raising heights after Easter and indeed the OP would see a swift transition to much drier and warmer conditions especially for the south.

To this observer, the OP is on its own at this stage and the continued cyclonic evolution of the Control doesn't convince either. It's one of those rarities where neither OP nor Control look realistic and while that might be symptomatic of the absence of any clear signal, the GEFS in mid-range are keen on raising heights close to the British Isles but to the north and west rather than to the south.

 

[Summer Sun]

06z GFS bringing the coldest air back further west

06z                                                                   00z

[bluearmy]

Later week 2 continues to see the chances of quieter more springlike conditions increasing 

no strong indicators on temps but from a suppressed starting point will take some time for things to warm up. I doubt the cold uppers will ever be too far away. 

I expect a different tone to tonight’s ec46 which has been steadfast on W Europe maintaining below av surface temps throughout April

we could see some Scandi heights establishing by mid April - not sure what that would bring if the southern arm stays strong 

Edited March 26, 2018 by bluearmy

[Summer Sun]

Some slight timing changes around Easter Sunday but overall the change to something milder continues to show nicely into early April

Could be quite wet at times but get in some drier spells with sunshine it would be feeling quite pleasant

Edited March 26, 2018 by Summer Sun

[Purga]

1 hour ago, Summer Sun said:

00z ICON shows milder air moving up from the south during Easter Sunday and Monday

Not to mention a widespread frost on Easter Sunday

Followed by soaring temperatures of up to 5-6 C

[Man With Beard]

EC clusters in the longer-term starting to turn from wintry options to more spring-like options over the past 36 hours:

    

What we're seeing is more and more clusters building better heights over Europe, and pulling the trough anomaly further west.

This may well lead to a SWly flow for the UK and, while this doesn't guarantee dry weather, this would at very least bring temperatures back to average, maybe even a bit above.

It's an emerging trend though - Stodge was quite right to be a little sceptical a few posts back - but a trend to watch, unless you wanted winter to carry on forever, of course

[stodge]

51 minutes ago, Man With Beard said:

EC clusters in the longer-term starting to turn from wintry options to more spring-like options over the past 36 hours:

    

What we're seeing is more and more clusters building better heights over Europe, and pulling the trough anomaly further west.

This may well lead to a SWly flow for the UK and, while this doesn't guarantee dry weather, this would at very least bring temperatures back to average, maybe even a bit above.

It's an emerging trend though - Stodge was quite right to be a little sceptical a few posts back - but a trend to watch, unless you wanted winter to carry on forever, of course

Thank you for the encouraging word. It's a trend GFS has been with for a while but still in low-res. The GEFS 00Z at T+240 didn't scream mild to me at all however - the pressure heights were to the north or west rather than the south. To be fair, the 06Z OP continues the trend of bringing back a zonal Atlantic with increasing height rises and both OP and Control end with anticyclonic dominance so it's definitely something but I'd rather give it a couple of days and see if the lifting of the jet achieves cross-model agreement and into hi-res before I'm convinced.

[frosty ground]

1 hour ago, Summer Sun said:

Some slight timing changes around Easter Sunday but overall the change to something milder continues to show nicely into early April

Could be quite wet at times but get in some drier spells with sunshine it would be feeling quite pleasant

Quite wet..... that's an understatement.....



The temps look bang average at best probably slightly below during the day above at night.

As for feeling pleasure in the sunshine..... well yeah its April!

Look how wet it's going to be......

Edited March 26, 2018 by frosty ground

[Summer Sun]

GFS ens is certainly picking up on a warming trend as we go into April 

06z ens today ?

2 days ago ?

With pressure not overly high we are likely to see a number of April showers or longer spells of rain especially at first maybe some higher pressure towards the 2nd weekend (circa 7th)

[SLEETY]

56 minutes ago, Summer Sun said:

GFS ens is certainly picking up on a warming trend as we go into April 

06z ens today ?

2 days ago ?

With pressure not overly high we are likely to see a number of April showers or longer spells of rain especially at first maybe some higher pressure towards the 2nd weekend (circa 7th)

Yes indeed some warmer weather soon maybe.But still some ensemble members touching the minus 10 line,which is incredible really for this time of year ,when some  recent winters  over the last 20 years we  have barely seen it touching the minus 10 line in mid winter!Hopefully this colder trend continues next winter

[Summer Sun]

Easter day could see the UK in between weather systems which would mean for many it would be mainly dry maybe some rain later in the afternoon towards Devon and Cornwall but it could be much worse that is for sure

 

[Summer Sun]

GFS and UKMO for Saturday afternoon

Scotland still well placed to see the coldest air how far south it may get into England still uncertain

Edited March 26, 2018 by Summer Sun

[Derecho]

Looks like a lobe of high pressure could fall over the Western Med. If it does then the low to the west could help pump up some milder air from the south.

The UKMO however doesn't develop this feature and has the low to our west disrupting as it heads our way at T144.

Colder easter weekend then recent runs but on the plus side its pretty dry too!

[Leon1]

GFS- The -5 pushes right across the country apart from cutting off bits of Devon, Dorset and Cornwall.

Nice widespread frost for Easter Sunday

Edited March 26, 2018 by Leon1

[bluearmy]

As has been said over the past few days, go back 6 weeks or more and plenty of the output over the next week is full of snowfall ........

hey ho ............

[Summer Sun]

Easter day and unsurprisingly we have 3 models showing differing 850's

GFS has cooler air going south

GEM has milder air pushing into the south

ICON is in the middle

[Leon1]

1 minute ago, Summer Sun said:

Easter day and unsurprisingly we have 3 models showing differing 850's

GFS has cooler air going south

GEM has milder air pushing into the south

ICON is in the middle

there has to be a conclusion to this madness sometime soon

[Summer Sun]

Just now, Leon1 said:

there has to be a conclusion to this madness sometime soon

Absolutely given that is a fairly good timeframe normally for more reliable output you would expect things to firm up very soon

[Derecho]

2 minutes ago, Summer Sun said:

Easter day and unsurprisingly we have 3 models showing differing 850's

GFS has cooler air going south

 

Yes lots of uncertainty but if its warmth you are after then the GFS is the best long term bet. High pressure sinks into the Med/ eastern Europe and the low stalls out west. Warmer uppers come up from the south and would probably stay for a fair while.



If you can't get a warm area of high pressure then this isn't a bad way to go for something that feels like Spring, though rain wouldn't be too far away.