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Posted
  • Location: Lancing
  • Weather Preferences: Sun, Snow and Storms
  • Location: Lancing
Posted

1732879156151867403049239372381.thumb.png.08d025fc6315976478a9b6736947564b.png17328792266498796147543278881992.thumb.png.46b9a5b96454d9cf5410637a66b5d68a.png

Control has a ridge building and colder air arriving by next Saturday.

  • Like 3
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  • Insightful 1
Posted
  • Location: East Surrey
  • Weather Preferences: snow or warm&dry
  • Location: East Surrey
Posted

GEFS 6z mean at 240himage.thumb.png.143ee2339445463e494d87e9846835b9.png

Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
Posted

Still don't see anything more than transient cold shots during the first half of the moment.

 

chrome_screenshot_Nov 29, 2024 11_55_42 AM GMT.png

  • Like 1
Posted
  • Location: Solihull, West Midlands. - 131 m asl
  • Weather Preferences: Sun, Snow and Storms
  • Location: Solihull, West Midlands. - 131 m asl
Posted
1 hour ago, That ECM said:

FI illustration by gfs in back to back runs.😩

IMG_1765.png

IMG_1766.png

These 2 charts illustrate that the arctic weather as regards the PV have not been resolved.

In fact they haven't a scooby at the moment.

Until the programs (all the varieties ) can get a grip of this we will see major flipflops from run to run....

It is a symptom of the uncertainty. Sure is entertaining though!!

MIA

  • Like 6
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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
Posted (edited)

 Midlands Ice Age  Midlands Ice Age MJO forecasts are a concern now..certainly EC is progging COD no sign of even low amplitude Phase 6..

I'm hoping after seeing the 00z clusters but no confidence, fingers crossed ..

Seen this many times where we've waited for some Atlantic ridging day 8 onwards and the models always seem to find shortwave energy usually from horrible vortex lobes  as we tick down...

 

Edited by northwestsnow
Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth
Posted

 bapper great to see you back.👍 Stella’s all round would have been a better name imo.😄

  • Like 5
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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
Posted

 Met4Cast the latest MJO forecast not looking great though?  Obviously not to say it’s correct though.

  • Like 2
Posted
  • Location: Solihull, West Midlands. - 131 m asl
  • Weather Preferences: Sun, Snow and Storms
  • Location: Solihull, West Midlands. - 131 m asl
Posted (edited)

 Blessed Weather

The really interesting question is 'is the barrier a physical barrier or is it model made'?. 

I have always believed that the MJO chart that we see,  is produced as a result of the model output and not used as an input.

All that the models see is the normal physical conditions (temp, pressure, humidity, wind etc)  and hence any 'barrier' either must be picked up either as a physical height anomaly or through the blocking in terms of temp, pressure , wind , etc.

The accuracy of which will be clearly determined by the number of weather stations in the area.

Any thoughts?

MIA

Edited by Midlands Ice Age
  • Like 4
Posted
  • Location: Islington, C. London.
  • Location: Islington, C. London.
Posted
3 hours ago, StretfordEnd1996 said:

Oh hello there GFS, those uppers really start to bite in this run!

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Now that's a proper old fashioned northerly blast.😃

Posted
  • Location: Saddleworth, historically West Yorks, 225m asl
  • Weather Preferences: All 4 seasons and a good mixture of everything and anything!
  • Location: Saddleworth, historically West Yorks, 225m asl
Posted

 LetItSnow Yes doesn't look to bad does it.

My expectations are that we will get some sort of N'ly influence around D9-12 give or take - but I can't see it being a classic nor can I see heights setting up and staying North for a considerable period. Hopefully something better than a toppler though. 

Just a nice middle-of-the-road mid spec typical 3-5 day N'ly blast akin to maybe last week would be good. I've learned over the years it's not always about chasing that record breaking NE/E'ly. Especially pre-Xmas.

  • Like 2
Posted
  • Location: Hadleigh, Suffolk
  • Weather Preferences: An Alpine climate - snowy winters and sunny summers
  • Location: Hadleigh, Suffolk
Posted

 Midlands Ice Age Hi MIA. It's a physical barrier and the paper I mentioned describes the physical processes that likely impact the MJO progress. The issue is that the processes are poorly simulated by the models. The relevant sentence in my post is "Observations show that the MJO tends to be significantly weakened when propagating eastward into the MC region...." (my italics). The bit I didn't include from the paper goes on to describe the issues models have and (hopefully) answers your query:

"The MC barrier effect, however, is poorly simulated in current GCMs [models] and most forecast systems exhibit large deficiencies in predicting the MJO propagation through the MC (see section 3.4). These model shortcomings in simulating and predicting the MJO propagation through the MC are partially due to our poor understanding of the underlying physics responsible for the MC barrier effect."

Just a quick mention - the research paper is around 3 years old and some improvements have no doubt been made to how models handle the problem. But imho it is highly unlikely that the models have fully cracked it and the fact there are two distinct camps about will/won't the MJO progress past the MC later this December rather suggests modelling problems are still very much in existence.

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Posted
  • Location: Hadleigh, Suffolk
  • Weather Preferences: An Alpine climate - snowy winters and sunny summers
  • Location: Hadleigh, Suffolk
Posted

 northwestsnow Thanks for showing that later RMM chart. I had used the latest EMOM ensemble forecasts as they are also bias corrected and go right out to 29th Dec. But interesting that the later run you show, whilst only going out to 13th Dec, gives a hint that just maybe the ECM signal will emerge past the MC. Fingers crossed for those of us of a cold persuasion.

  • Like 4
Posted
  • Location: Hadleigh, Suffolk
  • Weather Preferences: An Alpine climate - snowy winters and sunny summers
  • Location: Hadleigh, Suffolk
Posted

 Don Keep the faith Don. The MJO is notoriously difficult to forecast past a couple of weeks. Much water to go under the bridge yet.

  • Like 2
Posted
  • Location: Steyning, West Sussex
  • Location: Steyning, West Sussex
Posted

If only we could bank this FI run. About as likely as snow in the underworld, and so transient, it will unlikely survive a few more runs. The high to our South West is not going anywhere far enough to allow true cold to penetrate.

IMG_2430.jpeg

  • Like 1
Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
Posted (edited)

 northwestsnow Correct if wrong but haven't recent cycles of the MJO been highly amplified and played a large part I think in the colder episodes we've had since June. Last week's cold spell I think was attributed to the MJO 7-8-1 lag affect combined with AAM, albeit short in duration.

I don't claim to understand how it behaves, and even when in favourable cold phases it can be overriden by other factors notably the power of zonal winds when there is a strat-trop connect and ENSO. Conversely cold spells can occur when MJO is in less favourable state depending on PV behaviour - strat warming etc. 

Its a complex situation. Will be interesting to view upcoming MJO forecasts.

 

 

 

Edited by damianslaw
  • Like 4
Posted
  • Location: Buckinghamshire
  • Location: Buckinghamshire
Posted
On 22/11/2024 at 16:26, Jordan S said:

into the first week of December and I can see the potential for lows to take occasional more southerly tracks, occasional north/northeast airflows to develop, from the presence of higher pressure building over or near to Greenland, bringing the possibility of snow on northern edge of precipitation over the UK as lows move east/southeast, particularly for northwestern parts but then possibly southern parts of the UK, before we go back to something milder more widely possibly.

Alternating patterns really as we go through the first week of December, unlikely to be lengthy freezing cold and widespread snowy conditions but also quite unlikely to be persistently very wet and very mild, something more so in-between largely dominating, which could mean rather average conditions for the time of year overall which of course is snow at times in some northern areas especially on high ground particularly from overall northwest winds during these, *largely rain in the south and milder at times with west/southwest winds, but the chance of some brief snow.

Breaking it down into probabilistic chances now..

First week of December..

Most likely.. 60% currently..👇

Rather average overall alternating colder and milder interludes everywhere, higher pressure at times to our west/northwest, snow risks at times in the north, snow risk occasionally over more southern areas.

 

Less likely.. 25-30% currently 👇

We see very mild, wet and windy pattern take hold with potential storm systems over or nearby the UK.

 

Least likely.. 10-15% currently👇

A lengthy cold spell with widespread snow risks, higher pressure firmly over Greenland and west, allowing a more sustained north/northeast flow, southerly lows threaten the south..

How's this week shaping up compared to what I was saying was likely/possible last week?

Well the risk of snow does increase for northern areas from a southeast moving band of rain on Tuesday, more-so over high ground, north/northeast winds do occur albeit extremely brief visitor at the beginning of the week just beforehand with it's influence more over the north, particularly Scotland with snow showers for a short time in some places here ✅

Snow risk is indeed low in the south, though in actual fact its very low to be honest, the general pattern is rather close to giving temporary sleet/wet snow further south had the front moved southeast just that little bit earlier which was possible but very unlikely now, a small chance the precipitation stagnates almost becoming cut off temporarily from the dominant flow in the south with a wintry mix falling on high ground here, though unlikely. ✔️

It is likely to turn milder again more widely for a short time mid week (Wednesday-Thursday) especially with west/southwest winds further south. ✅

 

Adding to this but with subtle changes, what looks to be the most likely scenario/case is a sort of blent of outcomes from the most likely one I mentioned previously and the less likely (25-35%) outcome that I said which mentioned particularly mild and stormy.

So neither of these scenarios perhaps being totally in force but a blend of what you can describe as most probable, so repeating myself a bit here now but with snow risk in the north albeit brief at the beginning of next week, with a northerly component to the wind beforehand before northwest then west/southwest winds moves in bringing milder air, though not particularly mild and especially for central and southern parts of the UK, along with very windy and wet weather at times.

EUROPE_TMP850_78_MOB.thumb.jpg.c8bc3bab75a76758734164122200ed1e.jpg

EUROPE_TMP850_102_MOB.thumb.jpg.0ea6357472447ebf1c09b0ac0d63be68.jpg

 

The snow risk does look to increase for many northern areas once again latter part of next week, that doesn't mean it's likely to snow for many necessarily but the likelihood is relatively high at times that precipitation will be of a wintry nature at least on high ground in some areas, especially Scotland, but not exclusively on high ground I wouldn't of thought with winds from the north/northwest possible at times mostly here late next week, the risk is highest between weather systems so amounts of any snow may be generally small if they do occur.

A particularly windy spell increasing at some point between 5-7th so Thursday-Saturday time next week bringing perhaps the strongest winds across northern Ireland, England and Wales, gusts may reach upto 50-60mph in some inland areas, with few coastal areas possibly upto 70-75mph, heavy rain moving across the country, some sleet/snow on high ground in the north possible.

EUROPE_OVERVIEW_174_MOB.thumb.jpg.5aa0acc057817d80e43a23397d21b60c.jpg

Will update details as we get closer.

Second week of December summary.. 👇

Going into the second week of December the general pattern looks to continue though there's the possibility of a brief settled spell at the beginning of the second week (8-9th) especially in the south, but it doesn't look like lasting with strengthening winds and more low pressure systems moving through, perhaps further north this time with higher pressure closer to the south in general, bringing the strongest winds over northern UK with gales possible from the west/northwest.

Snow risk would be up and down in the north throughout, wintry showers a possibility in some other parts further south behind any southeast moving lows, rather wet overall in the north, less so in the south possibly though still rain at times of course with this pattern, temperatures average to perhaps a little above average, though potentially trending colder more widely late on..

  • Thanks 1
Posted
  • Location: Solihull, West Midlands. - 131 m asl
  • Weather Preferences: Sun, Snow and Storms
  • Location: Solihull, West Midlands. - 131 m asl
Posted

 Blessed Weather

Thanks BW ...

 

It  seems very similar to what we see off the point of Greenland where 50 miles also seem to make the models go wobbly at the knees...🤪

I wonder if there are any other of these spots?  

  • Like 1
Posted
  • Location: East Surrey
  • Weather Preferences: snow or warm&dry
  • Location: East Surrey
Posted

Everything seems more west at 138h at the gfs 12z

Posted
  • Location: Lancing
  • Weather Preferences: Sun, Snow and Storms
  • Location: Lancing
Posted (edited)

 Jacob Upstream it looks worse than the 6z unfortunately, let's see if we can get the heights to build into Greenland though 

Edited by Mcconnor8
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