Model Output Discussion - 15th March onwards

[minus10]

Well approx 108mm of rain received for March here in my wgc garden, following on from just a dry 4mm for February . 

Had 80 mm in January.

Looking at the period September 2022 to March 2023 we have had approx 546 mm of rain, over 1/2 metre so pretty wet period overall...good for soil moisture recovery.

Also since start of December 2022 have had 37 nights where frost has occurred. The 10 day severe cold spell in December with snow lying for seven of those days, followed by coldish frosty second half of January 2023 and then two further coldish frosty spells in February although not as severe.

An interesting winter here.... .....now lets hope for some drier and warmer weather...high pressure looks likely to be a player for at least the next couple of weeks although not overly warm if the means are anything to go by..gefs and eps 0z

...dry and average temps although scope within those means for a south easterly to develop as referred to by @mushymanrob above..

this also more pronounced on the geps..0z

...in the meantime some good drying weather out there for all those gardeners doing the spring tidies..with some sun thrown in and the chance of warming up a bit too later in the period..

..enjoy the spring displays..

 

 

 

Edited April 1, 2023 by minus10

[johnholmes]

wgc please?, good to read your winter update, certainly a lot of rain

[minus10]

Welwyn Garden City John...in hertfordshire...thanks

[Summer tyre]

6 hours ago, IDO said:

^^^ Accumulated precip IMBY (London) looks great after today until around D9 based on GFS op:

 

This interesting dog leg structure (the green 'river') running through Wales and dropping across Hampshire looks almost exactly like this morning's rain radar. Is there a reason this is persisting?

[summer blizzard]

If we put aside the GEM which never properly builds the high, GFS and Euro basically try to push the Atlantic around day 9.

[virtualsphere]

6 hours ago, Snow tyre said:

This interesting dog leg structure (the green 'river') running through Wales and dropping across Hampshire looks almost exactly like this morning's rain radar. Is there a reason this is persisting?

The animation looks like it's taken from the GFS 0Z run so will show all accumulated rainfall after midnight & so include this morning.

[minus10]

Whats clear from the models for next 10 days+ is the formation of the scandi high....0z eps/gfes anoms , means..

...this clear from the ens for Oslo for next 10 days or so..gfes/eps 0z

...this should ensure it staying mainly dry over most of the country with maybe exception of far north west..also winds from between a south and east quarter should allow for reasonable temps although maybe bit chilly on the east coast..nice spring weather to get out and about....

...further on in the extended mixed signals although probably a fall in pressure owing to troughs from the north west or the south but really too far away to worry about...

..for me just now waiting for this cloud to clear and the sun to make an appearance from the north east...

..come on! ...you can do it..

 

 

 

Edited April 2, 2023 by minus10

[thestixx]

 The very end of the run showing a potential link up of the Azores and Scandi highs... Now that would feel lovely after such a wet March!

 

[Summer8906]

4 minutes ago, thestixx said:

 The very end of the run showing a potential link up of the Azores and Scandi highs... Now that would feel lovely after such a wet March!

 

Indeed, maybe that 20C in April could come off after all! (with a big caveat of course that this is just one run).

[Rain All Night]

Just catching up, and there don't seem to have been any unexpected developments since Friday...

The blip day for most of us looks like Thursday now, although many areas seem like they might only see a small amount of rain with any luck, and it looks like the first two days of the long weekend may be dry...

Some chilly nights at first, but also the chance of feeling a little warmth in the daytime later on (into the bank holiday weekend) if the cloud and wind in any given location would permit it...

It looks like the Atlantic trough may pose a threat again towards the end of the bank holiday weekend, with some suggestion that it may try to hook up with a cousin somewhere over southern Europe later on...

Edited April 2, 2023 by RainAllNight

[Don]

4 hours ago, Summer8906 said:

Indeed, maybe that 20C in April could come off after all! (with a big caveat of course that this is just one run).

I would be surprised if we don't hit 20C at some point this month.

[Kirkcaldy Weather]

Time to do a recap of my previous outlook and looking to where we are likely headed now & upcoming weeks

"First we are at the beginning of a super high amplitude MJO progression in phases 7 + 8 "

This was one of the highest amplitude phases 7 & 8 ever seen 

Also the effects I mentioned for the accompanying WWB (westerly wind burst) bringing the historical triple did La Ninà to its end materialised "This MJO progression at high amplitude in phases 7 + 8 will be producing a substantial WWB which will bring the rare triple dip La Ninà to an end"

"Certainly opportunities over the next 7-10 days roughly, for snow events in various areas of the UK and frequent frosts some of which becoming increasingly severe particularly with any laying snow." 

We did see many regions of the UK and Ireland have brilliant snow events (yes my jealousy and amazement remains for you Sheffield members ) and low temperatures which you'd probably class as at the severe end for March. I know there were many comparisons on twitter to the snowfalls in 2010, overall March was a quite remarkable month of weather actually I was probably one of the most Unlucky in terms of snow as I didn't see any laying and only 1 brief bit mixing in a shower BUT my highlight of March no question is the STUNNING CB and Anvil from a meaty snow shower which was approaching Edinburgh   

Also have to mention the pressure reading I got of 967.08 hpa on the 13th .. impressively low.

I also discussed there were likely to be further conditions which were conducive for Atmospheric river events once again drenching California, its been mindblowing just how many have occurred throughout winter  

End result the biggest accumulative snowpack in history (also plenty of rain records in the lower elevations) 

'For Mid > latter stages of March we will see a fresh development of blocking ..be watching for high pressure setting up to the east and/or near to the UK with repeat retrogression into Greenland'

We've had another pretty fast progression through phases 1-5 and are verging on the arrival into phase 6

We see the current setup resembles March phase 1 quite closely 

 

 

The signs for continuing high pressure sitting to the east ties to phase 2 in March 

 

Phase 3 composites are similar but I just wonder if we might at least for a bit of time have the high centred to draw in the flow from the East 

 

CFS Certainly giving signs 

Though brief the travel through phase 4 should eventually have low pressure around the UK 

Arriving at the current stage of phase 5 which will see high pressure develop to the south of the UK, possibly extending towards us at times 

 

 

 

[ANYWEATHER]

Looks more than likely that the Atlantic will be making appearance around about mid weekish then this time next week. At least a few good days of dry weather to look forward too

[Rain All Night]

Atlantic trough says "I will let you have your dry Easter Sunday, but make the most of it, for in time I will seek reimbursement..."

 

[Don]

1 minute ago, RainAllNight said:

Atlantic trough says "I will let you have your dry Easter Sunday, but make the most of it, for in time I will seek reimbursement..."

 

Will the high tell the Atlantic to do one though?! 

[minus10]

35 minutes ago, RainAllNight said:

Atlantic trough says "I will let you have your dry Easter Sunday, but make the most of it, for in time I will seek reimbursement..."

 

Looks like Ecm and Icon the most bullish with trough activity next weekend from the charts you have posted...then there is the 'blip' this Thursday...looks like it might not be as dry as i thought although still remain fairly confident that we will get at least some decent weather..

...problem will be if the higher pressure ends up too far north east and our good ole friend the Azores high doesnt ridge in..... allowing the trough space...

Edited April 2, 2023 by minus10

[Eagle Eye]

On 20/03/2023 at 15:13, Eagle Eye said:

 

The destructive influence of the WWB can be seen at just day 3 really well now and it'd setting up a more semi-zonal kind of setup with a jet retraction rather than an equstorward jet as the AAM falls from the recent -VE EANY though the retraction is unlikely yo be large. The SE US ridge isn't entirely stable in terms of advection given that it's the start of US storm season it can easily be pulled up via WAA from troughs and that may favour a weak RWT like pattern especially as momentum rises rather than falls over the North Atlantic and so I could see the rising of the UK-Scandi high possibly sometime around April. AAM is unlikely to rise enough for it now and the North Pacific Jet stays slightly retracted buy I think eventually we'll see a poleward shift/extension and as we go into Spring that may favour AWB that leads to a UK-Scandi type high. Given the nuetral/Nino ENSO state expected and how the AAM has been acting over Winter, there may be a slight favour towards a warmer summer however thers only if the high is forced correctly. As it could quite easily be forced into the mid-Atlantic if the SE US ridge remains in place as that's the typical response given that setup as a Rossby packet 'pushes through'. Alternatively, if the forcing from the background signal is for AWB similar to early March then unlikely early March; the high might be pushed more towards a UK-Scandi high and that's typically a warm summer flow as far as I know. It's what some of the seasonal models are showing with an Ekman pumping esque WAA scenario which is really not good for the heat haters.

I miscounted for surface slack flow with destructive divergence at the mid-troposphere level accounting for slack line cold development in opposition to the pivot of the high. The extreme low-levels (e.g surface skin layer or the area roughly up to the 925 hpa area) will lose a lot of heat by radiation and at this time of year this hangs about just about. Given a few months and that quickly changes with very warm 850's and warm air artificially trapped near the surface so this same setup would be a lot more potent in Summer.

The thing is that the constructive wave influence of the AAM and destructive local influences (e.g. zonal wavebreaking supporters such as destructive WWB's of which one is expected relatively soon over the more influential than it's given credit for area, the north Pacific) given the transitioning of the ENSO and the near neutral AAM are likely to mean that forcing will remain generally pattern like and I think the UK-Scandi high could set the tone for the Summer and that's a hot summer setup. Alternatively, the fall of the east US ridge might allow it to be a bit wetter and maybe less hot but I still think it could be quite a warm summer given the strength plumes now hold (also appear to be getting drier so harder for the classic thunderstorms unless a subtle trough or something similar advects moisture but I think that's just me) and also the east US ridge has been setup there for a while now.  

The NPJ Phase Diagram appears to be going back to where it was about a month ago, hence my thoughts behind a repeating pattern appear to be backed up.

Edited April 3, 2023 by Eagle Eye

[Paul]

Steven Keates on LinkedIn: Debut Met Office analysis chart… Life milestone ticked

WWW.LINKEDIN.COM

---

Debut Met Office analysis chart… Life milestone ticked

Nice human story to go with the models!

[minus10]

Well the ecm 0z going for a bit more rain now for Thursday/ Friday..

...not really what was wanted although i suppose still good for soil moisture in some areas...

...after that it returns to the theme of hp to the north east and an easterly of sorts...none too warm but still pleasant in the sun..

...before teasing a better warm up in 10 days...

Gfs 0z not on this page presently for 10 days..

..still a pleasant se flow i should imagine...

ahh well...must admit more cloud about this morning than i thought would be the case...come on sun...i know your there !!

 

 

[damianslaw]

No post in 9 hours, firmly into the quiet season in this thread it seems, generally April and May seems to bring a lull in here.

What are the models showing, all very average typical April weather - not the April showers mind (never quite know where that phrase comes from, perhaps used to denote that April seldom brings deluge and sustained periods of rain, but more fits and bursts, and certainly polar airstreams are often common and produce homegrown convection by now..). Anyhow any rain forecast for the forseeable will come from frontal activity, with the atlantic doing battle somewhat with continental heights, the latter does appear to have the slightly upper hand right now, but won't be strong enough to prevent fronts from invading by Wednesday through until Friday - could be quite wet for many. Thankfully just in time for the long weekend things look set to calm down, with high pressure back on the scene from the NE. Into next week perhaps a repeat performance, but with heights lurking to the SW ridging in we may pull in a feed of mild tropical air for a short while boosting temps - further into the middle of the month signs the atlantic could easily return. 

[Rain All Night]

Good Friday through to Easter Sunday look dry for most of us on all the 12z runs, though a few are cutting it a bit fine on the latter:

They all agree that the trough breaks through on Easter Monday:

The GFS ensemble prefers us to remain within the influence of the trough thereafter (from what I can see of it so far, the ECM ensemble agrees on this), and it makes us wait until deepest FI for an intervention from the Azores; the precip anomalies for week 2 aren't horrible though.

For the south coast at least, the ECM ensemble meteograms are nothing to complain about, looking particularly at the precipitation and geopotential heights, and also noting the often above-average 2m temps:

Edited April 3, 2023 by RainAllNight

[Rain All Night]

FWIW, week 3 looked decent on the ECM extended ensemble this morning:

This afternoon's ensemble shows ridging appearing at the end of week 2, as the GEFS did.

Edited April 3, 2023 by RainAllNight

[Metwatch]

Nice ending on the ECM operational this evening, with an almost brief plume set up and probably locally the first 20°C. Other than that not seeing much signs for anything overly warm in the next 10-14 days. 

Perhaps the second half of the month we'll see something warmer. 

Edited April 3, 2023 by Metwatch

[mushymanrob]

Well this chart is a very welcome one! high pressure domination, Southwesterly sourced upper flow, 564DAM height nudging the Southwest, that suggests to me a lot of warm, mainly dry, very pleasant, fine Spring weather!

[*Stormforce~beka*]

34 minutes ago, mushymanrob said:

Well this chart is a very welcome one! high pressure domination, Southwesterly sourced upper flow, 564DAM height nudging the Southwest, that suggests to me a lot of warm, mainly dry, very pleasant, fine Spring weather!

About ruddy time too! How long does it last?