Model Output Discussion - A cold start to Spring?

[MJB]

Tuesday morning a band of snow moves South

Tuesday lunchtime the band becomes slow moving

Tuesday Evening widespread could be more showery in nature but wintry scene for the UK

Wednesday morning snow into the SW 

Wednesday lunchtime snow moving slowly North .......very slowly.

Wednesday evening snow across a large part of England and Wales 

Early hours of Thursday snow M4 Northwards snow struggling to move up the country 

Snow Thursday morning still going - probably Oxford northwards

Thursday lunchtime the same areas are still seeing snow falling 

Thursday evening the snow retreats South 

Some areas could see snow falling for 24 hours 

Please don't take these charts seriously JFF 

 

Edited March 4, 2023 by MJB

[Ali1977]

2 minutes ago, MJB said:

Tuesday morning a band of snow moves South

Tuesday lunchtime the band becomes slow moving

Tuesday Evening widespread could more showery in nature but wintry scene for the UK

Wednesday morning snow into the SW 

Wednesday lunchtime snow moving slowly North .......very slowly.

Wednesday evening snow across a large part of England and Wales 

Early hours of Thursday snow M4 Northwards snow struggling to move up the country 

Snow Thursday morning still going - probably Oxford northwards

Thursday lunchtime the same areas are still seeing snow falling 

Thursday evening the snow retreats South 

Some areas could see snow falling for 24 hours 

Please don't take these charts seriously JFF 

 

The way these systems are heading in some places could have some serious snow, for areas around the M4 some show none stop snow for 48 hours - other runs have none of course!! 
 

What is also noticeable is Ice days mid week and severe frosts - ignore these 4/5c max on the apps, if theses snow it’ll be much much colder 

[Captain Shortwave]

Yep quite a few models bring a band of rain/sleet/snow southwards Monday night into Tuesday that fully introduces the Arctic airmass.

Tuesday looks cold everywhere (generally 2-4c at best)

Tuesday night looks very cold with just a light northerly wind, -10c looks quite widespread across Scotland and -5c across a good part of England and Wales.

It does look like for the moment that the biggest threat of snow looks to be from fronts rather than showers (Monday night and then the risk in the south on Wednesday). For the time being there doesn’t seem to be much enthusiasm for a strong we northerly that could drag in heavy showers off the North/Irish sea.

[MJB]

11 minutes ago, Ali1977 said:

The way these systems are heading in some places could have some serious snow, for areas around the M4 some show none stop snow for 48 hours - other runs have none of course!! 
 

What is also noticeable is Ice days mid week and severe frosts - ignore these 4/5c max on the apps, if theses snow it’ll be much much colder 

I agree , if this falls right some lucky people will  see some good falls of snow 

Edited March 4, 2023 by MJB

[mulzy]

ECM Plume for Reading suggests the cold air will be in place till Friday and then a significant warm-up (at least in the south).  Friday is FI and there are chances that this warm-up will be pushed back.

[DAVE_ALLEN]

9 minutes ago, mulzy said:

ECM Plume for Reading suggests the cold air will be in place till Friday and then a significant warm-up (at least in the south).  Friday is FI and there are chances that this warm-up will be pushed back.

Agreed any sign of mild, it’s FI. Positive thinking. It’s been working a treat this week as re intro mild on weds has been pushed back at least a couple of days.  Deep snow over southern snow fields will help to enhance the block with the surface air remaining frigid

[PiscesStar]

5 minutes ago, DAVE_ALLEN said:

Agreed any sign of mild, it’s FI. Positive thinking. It’s been working a treat this week as re intro mild on weds has been pushed back at least a couple of days.  Deep snow over southern snow fields will help to enhance the block with the surface air remaining frigid

I suspect the mild showing will get mixed out even for us southerners.. The lows will trsject further south on subsequent runs the closer we get to target.  Also, I see signs of further retorgreddion northwestward of the high which will reinvigorate a northerly outbreak.... 

[geordiekev]

JFF but this looks spellbound. Not bad for March & breadth of countrywide chances

[nick sussex]

You can clearly see the 850 ensemble spread here in relation to the track of low pressure day 5 into 6 .

Somewhere will get lucky where they get possibly two all  snow events just don’t ask me where exactly !

 

Edited March 4, 2023 by nick sussex

[geordiekev]

4 minutes ago, PiscesStar said:

I suspect the mild showing will get mixed out even for us southerners.. The lows will trsject further south on subsequent runs the closer we get to target.  Also, I see signs of further retorgreddion northwestward of the high which will reinvigorate a northerly outbreak.... 

The interesting thing about the set up is the lows as they get squashed, instead of normally warming as they cross Atlantic are actually drawing more cold as they traverse towards us

[Man With Beard]

28 minutes ago, mulzy said:

ECM Plume for Reading suggests the cold air will be in place till Friday and then a significant warm-up (at least in the south).  Friday is FI and there are chances that this warm-up will be pushed back.

It was a bit of an outlier, but I noted another snow event on the south coast on the ECM op next Saturday - just to demonstrate how the supposed milder weather may not take hold anywhere in the UK, possibly. But the ensemble guidance remains a lifting of the snow line to the midlands or northern England by next weekend. For now!

[Wingman Blue]

1 hour ago, Mike Poole said:

Good run from the GFS this morning.  A good example of how the incoming Atlantic lows react to the block, which on this run is strong enough to make them disrupt, elongate, break up and slide on approach:

If we believe the block is continuing to exert pressure, then you would expect to see this rather than the dartboard low of the 18z.  Track of these lows, even the first one is massively uncertain still.  But given the runs coming out it is possible to envisage the train of lows running more south as we approach T0 if some of the models are underplaying the blocking and therefore keeping the cold in place over more of the UK - obviously, snow chances for different regions conflate what is the ‘best’ track, but we just have to wait and see really.

The most believable model since the last pulse of the SSW. 

[Chrisover93]

Thoughts?

[TEITS]

A clearer pattern emerging in the model output but subject to change.

Snowfall event on Wed looks to affect the S especially anywhere S of the infamous M4. The following day the risk extends further N with locations such as Midlands/Wales/E Anglia most at risk. At the same time those in the far S could see temps briefly warm up. Into the weekend the risk of snow moves even further N affecting N England/Scotland and at the same time locations such as Midlands etc will also see the brief increase in temps. As the low across the N tracks E then colder N,lys returning for everyone. At this stage the forcing from the blocking over Greenland suggests the cold spell continuing.

However what could happen is the snow event on Wednesday tracks even further S missing everyone. The following event also tracks further S and doesn't reach the Midlands and affects those further S.

[Liam Burge]

9 minutes ago, Chrisover93 said:

Thoughts?

Follows in line with what the MetO said in their outlook on Youtube. A 60% chance of a channel-low type scenario happening which would favour South West England + South Wales.

It does seem that the GFS is following that scenario again, and in my mind is probably the most likely scenario to happen based on past events.

[Purga]

Glory Alleluliah midweek for the South from UKM - fingers crossed.

[MJB]

3 minutes ago, Purga said:

Glory Alleluliah midweek for the South from UKM - fingers crossed.

I'd like that to be about 50 miles further North 

[MattStoke]

9 minutes ago, Purga said:

Glory Alleluliah midweek for the South from UKM - fingers crossed.

Hence the UKV, which uses UKMO data, shows this.

An interesting watch, for sure. It’ll be a few days until there’s sufficient confidence regarding the track of these lows and fronts.

[Polaris]

If I were living South of m4 I would be very interested in a possible snow event early next week. 
As 90% of the time, ppn always corrects South until +06hrs so even here it’s not guaranteed. 

[Tim Bland]

ECM and GFs both have the sweet spot as central areas & wales later in the week. All still to play for with lots of changes to come I  think ..

[Scandinavian High.]

I wouldn’t be surprised south of m4 sees two big snow events coming week the possibility is there.

[bluearmy]

1 hour ago, iceman1991 said:

Might be wrong but how many times this happend  on models and the low pressure system corrects more and more south when gets closer to the time and normally ends up in france or channel underestimate the blocking 

That’s what usually happens 

the ‘that’s just our luck’ scenario this week would be the initial low being v shallow and passing through N France and the second one to be a little deeper and head through the channel but still to far south to bring precip away from the coast where it would be rain (only the moors of s Devon and Cornwall would see any snowfall that sticks). The passage of the second system removes the colder uppers from s england and the next system is deeper and heads into the country through n wales - the snowfall is restricted to high elevation n england and n wales and that’s temporary as milder air comes through. Colder air digs in behind once the system has passed through but not cold enough to deliver anything but chilly rain thereafter as we find ourselves under the jet.  The Scottish ski industry has a brilliant few weeks though! 

that’s the glass almost completely empty version ! 

I think @IDO’s post above will be closer 

[Guest]

The GEFS ensembles have become really messy on the overnight run:

The mean is pretty pointless given the spread but compared to yesterday many more milder and wetter solutions. A change is on the way for sure.

[mbrothers]

2 minutes ago, Tidal Wave said:

The GEFS ensembles have become really messy on the overnight run:

The mean is pretty pointless given the spread but compared to yesterday many more milder and wetter solutions. A change is on the way for sure.

I guess you could call it a change after the change

[Guest]

ICON 06z trends a little north for the Wednesday feature:

 vs 

Edited March 4, 2023 by Guest
Correct chart