Model Output Discussion - Spring Has Sprung

[Cambrian]

The afternoons and early evenings are giving better and better value as spring gets underway.

Temperatures very reasonable for central and southern England this afternoon in the southeasterly draw off the near continent, ahead of the approaching low, here on the 0z ECM op, better indeed than for most of France and Iberia, where temperatures are subdued to say the least…

 

…and getting pegged back generally for the UK and Ireland by tomorrow as the low pressure passing through to the south slowly fills over southern UK and Ireland but pulls us around into an easterly flow. 

 

A slow but steady improvement during the week, as wafts of heights from the south, combine with the longer days and a southerly flow to deliver the vast majority double figure afternoon temperatures by Thursday, as a more organised belt of showery rain approaches from the west. Southeast Spain up into the twenties. 

  

In keeping with what we often see early on in the season, the gradual upward trend in afternoon temperatures is not emulated by the early morning temperatures, with frosts likely for many midweek. 

 

The Friday feature looks potentially interesting. Good levels of precipitable water down the spine so with this marked diurnal heating, scope for some early spring convection to enhance the belt of showers as it passes through.

 

All very fitting for the second week of March, which will do nicely. Have a good one.

[damianslaw]

Not commented on the models for a number of days, namely because all they have been showing are very benign, quite non-descript synoptics.

We currently have a north-south split, its chilly in the north with a feed off a cold N Sea, pegging temps in the 6-7 degree range, whereas further south the feed is off a milder continental location meaning low double digit maxes. Tomorrow set to be poor for most, chilly, rain or just low cloud. 

As we enter next week a change to a milder slack South/ South west flow but also the return of the atlantic trough, rain will become an increasing feature as fronts move through, they may become stuck as heights attempt to build to the NE as suggested by the ECM, but these look a weak feature and I expect the foreseeable to be atlantic driven, rain, or lots of cloud, chilly at night in any clear spots, temps a little above average but no early appreciable warmth on the cards. Sunshine limited sadly.

Longer term - very uncertain, heights may build to the NW sending low pressure further south meaning lower temps again and possibly very wet.

Just a feeling things may become interesting from either a cold or warm perspective in time for easter. Late March often marks the period of year when we see our least common place synoptics, easterlies, northerlies and odd cyclonic pattern behaviour... 

Edited March 9 by damianslaw

[Mike Poole]

GFS 12z is interesting in the second half of the run, from T192:

First, a welcome period with high pressure in charge over the UK, which would be long overdue and pleasant.

Right at the end, the NH pattern looks very much as though the SSW is having an effect, and splits the vortex.  GFS has been playing around with stronger blocking scenarios towards the end of the month, so one to watch as we count down to Easter.

[Polar Maritime]

Some rather interesting charts will crop up now as above given the SSW that's been well advertised.. 

[Mike Poole]

ECM clusters not offering much insight out to day 10, just one cluster from T120-T240.  But in the extended we have this from the 12z:

Cluster 1 looks fairly standard +NAO, i.e. wet.  But the others look moe interesting, cluster 2 has a weak block just north of the UK.  Cluster 3 goes for the cross polar ridge, as per the GFS 12z.  Cluster 4 develops a strong block just south of Greenland.  

[stodge]

Evening all

A mild week once we get rid of the weekend's LP - a long trough aligned positively from mid Atlantic to Scandinavia feeds a flow of TM air from the south west so above average temperatures but rain for western and north western parts through the week.

Hints next weekend heights from the north will elongate the trough more to the east as the jet is pushed south so the unsettled conditions spread to eastern and southern areas but beyond that far from clear. Obviously, 12Z GFS OP has plenty of interest but Control is more mundane so we'll have to see if it is an outlier or the start of a new trend to a pattern change.

The ongoing SSW doesn't seem to have an immediate impact - my thought it might be a final warming not correct but the "recovery" in the jet from a reversal is nowhere that we saw in mid January - the zonal winds move back slightly westerly but it looks more like the proverbial dead cat bounce.

[Kentspur]

 Mike Poole  damianslaw EC46 showing Greenland and Iceland Blocking and introduces colder temps with a more North of East flow after this milder period by late March typically didn't 2008 do this also after the very mild February?

[Daniel*]

Using Birmingham clear signal for something milder next week then temps start falling below average into following week. The forecast in Arctic is very cold, so will be interesting to see what happens.

Edited March 9 by Daniel*

[feb1991blizzard]

 Polar Maritime

Yes, split vortex signature showing up nicely now, a few more runs before the nosediver flatliners show in quantity on the graph.

[ANYWEATHER]

2 hours ago, near northampton said:

Models are showing some colder solutions, but they have been showing these for months, NWp is  struggling with an acceleration in CC  IMHo, even in our small part of the world warmth records are falling at an ever faster rate 

Absolutely rubbish, models are hinting at colder ,warmer scenarios, given the time of year ,the Atlantic goes quieter, historically ,as the PV becomes  weaker between March and April and May. Not surprisingly we are seeing colder solutions on the table.  Anyway  , the Atlantic is cowarading down to the message from the East.....

Edited March 10 by Cambrian
Post edited to maintain focus on model output

[WYorksWeather]

GFS 18z

The GFS 18z shows a milder interlude from around day 3 to day 7, with a typical chart below from day 5 showing an unsettled but south-westerly flow.

Beyond day 7, the pattern first flattens out, and then we look to get a brief northerly toppler type setup, with some fairly cold air into the north, maybe enough for some snow, but probably restricted to higher ground as the airmass temperatures are not really that notable. This chart from day 11 shows the progression.

By day 13 we have the -8C line down across Scotland and parts of north and eastern England.

Shortly thereafter, we then look to have another mild sector making its way in. 

Might post again later on when the full model has run and we have the ensemble view to look at. I suspect this will wind up as a cold outlier.

 

 

Edited March 9 by Cambrian
Post edited to remain focused on model output

[Don]

2 hours ago, Kentspur said:

EC46 showing Greenland and Iceland Blocking and introduces colder temps with a more North of East flow after this milder period by late March typically didn't 2008 do this also after the very mild February?

Late March and early April 2008 were indeed cold and wintry with a white Easter for some.  Also, think early April 1989 which was also cold and wintry, following an exceptionally mild winter.  I'm not saying something similar is necessarily likely this year, but with the current SSW, it is definitely something to watch!

Edited March 9 by Don

[WYorksWeather]

As I expected, the depth of cold into northern England was towards the bottom of the 18z GFS ensemble. Not quite an outlier though I guess.

[Don]

 WYorksWeather definitely not an outlier, albeit at the colder end.  Needs watching is the only thing to be said really.

[RJBingham]

Not much of interest, either way

[TwisterGirl81]

Gfs 00z showing some warmth wafting up from Spain for the end of March, this would be more than welcome couldn’t see anything too cold either, it seems to be shifting to Eastern Europe so hopefully a good sign of the ssw not negatively impacting us by delaying spring   

Edited March 10 by TwisterGirl81

[Cloud 10]

Yesterday's ECM day 6 scandi high completely blown away.

 

Have to laugh really.

 

today.yesterday.

[northwestsnow]

 Cloud 10

Atlantic ssts are devastating the chances of high latitude blocking taking hold IMHO.

Welcome to the new UK  climate , I'd suggest the chances of cold winters are becoming more and more remote as the Atlantic warms...

Only my opinion of course...

 

[CoventryWeather]

 TwisterGirl81 I mentioned a risk of this happening a few days back - nice to see an op run showing the chance of it happening. 

The ECM ensembles less confident on a cold period and an increase in the warmer solutions - a trend is occurring now towards something warmer I think.

[LightningLover]

 TwisterGirl81  20-22nd March seems to be a semi-consistent time frame on the GFS for a very mild southerly- One to watch! I'm looking for warmth and thunderstorms now haha.

Edited March 10 by LightningLover

[Frigid]

The 00z was an extreme outlier, virtually no support from it's ensembles or other models at this point. 

[ANYWEATHER]

From  a purely selfish aspect ,this ten day chart from the ecm ,would be a good set up for convection.  Warm Spring sunshine, along with a cold ,unstable atmosphere, would give us some lively thunderstorms,  

[Met4Cast]

 Frigid

Unfortunate really because it’s the first good deterministic run for a while I said a week ago now that there’s no sign of anything notably cold or warm and that remains the case going forward through this month. 

Quite a bog standard affair, boring from a weather perspective but also from a wanting to get out and do things perspective. 

[Alderc 2.0]

 ANYWEATHER there is nothing remotely warm about that chart. Don’t really need the showers either. 

[CoventryWeather]

Also to point the GFS 06z towards day 10 is similar - Euro High, Atlantic trough and a warm southerly. Not as warm as the 00z but still warm. And dry. 

It's been the best model this winter for picking up trends in the midrange.