RAMP!

Lol.

Sounds to me as though it could be in the same or similar category of strength to the SSW that took place in Feburary 2018. From what I recall reading here at the time, it was one of the strongest SSW events ever recorded.

BBC monthly outlook

Summary

Cold start to January, less cold and wetter later.

_________________________________

Wednesday 6 January – Sunday 10 January

Staying cold but dry and calm for most.

For the rest of this first full week of 2021, the UK is expected to be sat between a weakening low pressure system in central Europe and a strengthening high pressure system west of Ireland. This will keep things feeling a bit colder than normal with a northerly wind bringing in plenty of bands of cloud and occasional precipitation. The air is still going to be cold enough that showers expected in eastern areas Wednesday and Thursday will likely be wintry even to low levels, bringing a risk of icy patches. On Thursday and Friday some bands of rain will spread southwards over the UK, although for much of Scotland this will fall as sleet or snow.

This weekend the weather is likely to take a turn towards something drier and sunnier, especially in southern areas, as high pressure develops to the west of Ireland and pushes cloud away. There is a bit of uncertainty on the temperatures at the moment, with some milder air toppling over the top of the ridge of high pressure into Scotland and eventually spreading into southern areas. This will mean by Sunday temperatures will have widely moderated to nearer normal, perhaps even a bit above normal in some spots. A weak front will be draped across northern coasts of Scotland Saturday and Sunday, keeping it damp and grey there, but some good sunshine is likely further south, making a change from the rather grey and cold first half of the week.

Monday 11 January – Sunday 17 January

Turning wetter and not as cold.

For the second full week of 2021 we expect a gradual shift in the weather pattern as we head through mid-January. This will see the high pressure off to the west of Ireland begin to diminish and retreat southwards into the Mediterranean. At the same time, the jet stream (a band of fast moving air in the upper atmosphere that drives weather systems) will strengthen over the North Atlantic, bringing a return of Atlantic weather systems and a more unsettled pattern (although likely not until the weekend).

For much of the working week it will likely continue to be cold and mostly dry. Rain will be most frequent in northern areas from weak fronts drifting along the top of the high. These will bring some milder air as well, and this may occasionally reach down into southern areas. However, this will only be 1-2 days of temperatures nearer to normal for mid-January before colder air returns. Snow showers will ease for the east as the winds become more north-westerly.
As fronts begin to move in from the west later in the week, they will bring some more widespread rain as well as milder air from the sub-tropical Atlantic. There is a chance that the high may retreat a bit quicker which will allow the Atlantic weather systems to push in earlier in the working week. This would lead to a milder and wetter pattern throughout the country.

Monday 18 January – Sunday 31 January

Staying unsettled with a risk of cold spells.

For the end of January, the more progressive pattern with frequent Atlantic weather fronts is expected to continue. The jet stream will often be overhead, leading to temperatures being near or a bit above average, especially in the south. The fronts and nearby jet stream will make for a rather changeable weather pattern as lows move through quickly and brief ridges of high pressure drift in between them. These highs will bring some colder air and make for frosty nights at times.

Heading later into January there is a growing risk of some of these cold snaps become more widespread and longed-lived. They are still expected to be the exception rather than the norm like we saw over the holiday break, but by late-January there is potential for some sharp cold snaps between fronts.

The main alternative scenario is high pressure in the Mediterranean building further north into central Europe, resulting in the colder polar airmass sticking around for longer. This would lead to calmer, drier, and colder weather, mainly for the southern half of the country. Scotland would still expect wet and windy conditions even in this scenario, so confidence in the forecast is a bit higher for them.

Further ahead

We will have a closer look at the second half of the month along with the threat of any late January cold snaps

https://www.bbc.co.uk/weather/outlook

Weather warnings issued for most of western and central UK for ice and some snow especially for the hills. 1-3cm 

Monday 11 Jan - Wednesday 20 Jan

Sunday begins with a band of cloud and patchy rain pushing in southeast across Scotland. Brighter and colder conditions follow to the far northeast of Scotland and Northern Isles, though further wet weather is likely later. Into Monday, high pressure to the west will decline allowing Atlantic frontal systems to bring in milder conditions, with temperatures closer to the average for this time of year, though further wintry hazards across the far north. Then past Wednesday, as this high pressure develops to the southwest of the UK, mobile and cyclonic northwesterly flows bring unsettled conditions with outbreaks of rain and, at times, strong winds as well as occasional colder temperatures. Drier, more settled conditions are then probable across the south of the UK, with frost and fog fairly prevalent.

Wednesday 20 Jan - Wednesday 3 Feb

Confidence for this period is low, though there is a signal for Atlantic mobility to weaken which perhaps allows conditions, at least in the north, to become drier and for temperatures to be closer to average. However, there is still a chance of cold air outbreaks in the north as flow across Scandinavia pushes across the North Sea. This would confine more unsettled conditions to the south, with the potential for milder than average temperatures. Further, this boundary between the cold and milder conditions could also allow for some significant snowfall where the two air masses meet.

https://www.metoffice.gov.uk/

https://www.facebook.com/287501884208/posts/10158268406074209/

Take a look at the 10 day trend. Stay behind after class for a look at the possible impacts from the SSW. Also the fact that there are different types of SSW apparently, with this one more common in promoting SWlys🤔

Great summary there from the met office on ‘competing influences’ beyond 10 days.

What I take issue with at the moment is part of their long term written outlook:
“ Further, this boundary between the cold and milder conditions could also allow for some significant snowfall where the two air masses meet.”

Further what? Further north? Further into the forecast?

I think it should read "Furthermore" or "In addition".

Thanks for Sharing this - but it's confusing - I mean why is it that this particular SSW is more associated with milder south westerly's in what way? or was he referring to the La Nina? Also if this is the case why is eastern Europe and NE states sill able to get cold weather? Another thing - he said La Nina usually favours milder second half to winter - well winter 2017/18 was a la Nina winter and we had a cold 2nd half thanks to a SSW. So it's not a guarantee. 

https://www.eveningexpress.co.uk/fp/news/local/overnight-temperatures-to-hit-6c-in-aberdeen-as-gritters-set-out-early-to-combat-frozen-roads/ 

Where do they get this nonsense from? Like hell it will be getting to -6C here tonight.

We no longer get any weather that is newsworthy so they literally have to make it up

Yet again it's another evening of mind-numbing static temperatures that refuse to drop. For once it actually is below freezing, but only here in the outskirts. It's a whopping -0.8C which is actually warmer than it was three hours ago 

We'll be lucky to see -2C tonight at this rate and, needless to say, more coastal parts of the city i.e. the majority of the city will be milder.

After watching the Met O 10 day trend forecast , I think we are going to very lucky if we get v cold weather over the UK 

It's be interesting to have a basic explanation of what type of SSWs promote south westerlies and why, along with a comparison with the current warming.

A lot of the papers on SSWs go over my head but I think it's accepted SSWs that result in a split PV have a fairly strong correlation with bringing colder weather to NW Europe.

Displacement warmings don't have a strong correlation and quite often bring unsettled (and milder) weather to the UK, presumably because the PV is displaced to somewhere like N.America and that just serves to super charge the jet. 

So is the current event now thought to be a displacement rather than a split (I thought it was expected to split the PV?) and if not why is this particular split vortex event believed to be one in which we're more likely to go mild than cold? Has this been determined by other warmings in the same areas? Computer modelling? Previous warmings in a La Nina state? Lots of questions!

I kind of got the feeling the MetO want to put something out rowing back on the medias SSW = cold and snow headlines as that was referencing the Met Office and they presumably don't want people to think they're forecasting cold and snow when at this stage the effects are very much uncertain and mild remains a plausible outcome.

At least Aberdeen has seen snow in this easterly?

We - here in Devon have failed at not only getting any snow but not frost or temperatures reaching 0c. in fact past 3 nights it hasn't fallen below 2c. Just pathetic. We are stuck at +3.5c. 

Tuesday 12 Jan - Thursday 21 Jan

Sunday begins with a band of cloud and patchy rain pushing in southeast across Scotland. Brighter and colder conditions follow to the far northeast of Scotland and Northern Isles, though further wet weather is likely later. Into Monday, high pressure to the west will decline allowing Atlantic frontal systems to bring in milder conditions, with temperatures closer to the average for this time of year, though further wintry hazards across the far north. Then past Wednesday, as this high pressure develops to the southwest of the UK, mobile and cyclonic northwesterly flows bring unsettled conditions with outbreaks of rain and, at times, strong winds as well as occasional colder temperatures. Drier, more settled conditions are then probable across the south of the UK, with frost and fog fairly prevalent.

Wednesday 20 Jan - Wednesday 3 Feb

Confidence for this period is low, though there is a signal for Atlantic mobility to weaken which perhaps allows conditions, at least in the north, to become drier and for temperatures to be closer to average. However, there is still a chance of cold air outbreaks in the north as flow across Scandinavia pushes across the North Sea. This would confine more unsettled conditions to the south, with the potential for milder than average temperatures. Further, this boundary between the cold and milder conditions could also allow for some significant snowfall where the two air masses meet.

https://www.metoffice.gov.uk/

This has nor even been updated, another METO mess. It is for Tuesday onwards and starts with Sunday! Changed the dates and not the forecast.

Martin

I posted an interesting paper about SSWs the other day, but to keep things VERY simple consider this. There are about 6 SSWs per decade on average. That suggests about 15 to 20 since 1990. Now consider how many really "good" cold spells there have been in that period. Also consider that some of them probably occurred when there wasn't an SSW.

Take 2 with the text updated this time

Tuesday 12 Jan - Thursday 21 Jan

Confidence is particularly low at the start of this period. Cloud, rain and stronger winds, heaviest in the north and west, sinking south later. Drier conditions in sheltered east and southeast areas, with colder, brighter, and more settled conditions to the north of these regions. Temperatures rather mild in the south, to cold in the north. It is expected that high pressure will then develop to the southwest of the UK, generating a changeable north-westerly wind with outbreaks of rain and, at times, strong winds as well as occasional colder temperatures. Drier, more settled conditions are then probable across the south of the UK, with frost and fog fairly prevalent. Temperatures closer to average, but large day to night temperature contrasts under clear skies.

Thursday 21 Jan - Thursday 4 Feb

Confidence for this period is low, though there is a signal for winds from the west to weaken which perhaps allows conditions, at least in the north, to become drier and for temperatures to be around average to a little below. The south is more likely to see unsettled conditions with the potential for milder than average temperatures here, but this will also bring a risk of further snow where this meets the colder conditions to the north.

https://www.metoffice.gov.uk/

Looks like Spain is the place to be for snow over the next few days. Google translated quote from the Spanish AEMET website ....

In the interior of the peninsula, the most relevant will be the heavy snowfalls in large areas. They are already
producing in the southeastern quadrant of the Peninsula and some areas of the center. After a slight
decrease in rainfall during the next night, will intensify on Friday and Saturday
extending from south to north to a good part of the Peninsula and the Balearic Islands, Galicia being the
probably less affected. The snow level will vary significantly from north to south, ranging between 800-1200 m in Andalusia, 
500-1000 m in the rest of the southern half, 400-700 m in the central zone and 200-400 m in the northern half.
Throughout these days it is very likely that the most important snow accumulations will be
produced in Castilla-La Mancha, Community of Madrid, interior of the Valencian Community, south of
Aragon and mountains of eastern Andalusia, with thicknesses that will probably reach 20
centimeters in a fairly generalized way and even locally, especially in the environment of the
Iberian System and mountainous areas of the southeast, 30-50 centimeters.
It is likely that on Sunday 10, with the retreat of the storm to the northeast, they will improve
the weather conditions that have given rise to this special advisory. However, on Sunday and
on Monday heavy rains are still likely in southern Andalusia and Ceuta due to the
approaching a new storm. As of next Monday it is also probable that there will be
a general stabilization of the atmosphere being significant the following days frosts
intense nights

Fair point, Brian.

As an example of what you say at the end, as far as recall, neither the December 2010 freeze nor the month-long one we had during the preceding winter came about as a result of a SSW. I stand corrected if I am wrong about that though.

Can't remember whether it was 2009 or 2010, but one of them was signposted consistently by the MetO as soon as it came into the 30-day range - they were spot on, too. That was Glosea 4 being used at the time and it was the first time that model came into widespread mention - must have been picking up on something in the stratosphere, but I can't remember what.