Winter 2017-18: Discussion

BLIZZARD7

I think this week's weather is just the appetizer for what's to come post SSW, of course a few things still need to go our way but I've rarely seen things line up this perfectly in the stratosphere. Things looking far far better than they were just a week ago (even then they were promising) The UK met office outlook strongly hinting at a cold East/North easterly dominated few weeks just shows the pros are very much on the same page. The only times I've seen them being this bullish about the cold prospects were March 2013 and November 2010. Quite possible we are heading towards a 1 in 20 year or better cold spell in the coming weeks IF these strat forecasts come to pass.

The last 3 GFS runs in the outer reaches of FI have started to show the type of tropospheric response one would expect given such a prominent SSW. Some bitter ensembles starting to appear.

We have been dealt a great hand of cards, the polar vortex has stood up and is about to leave the table. let's just hope that this is one of those special occasions where everything Falls into place.

nacho libre

Great forecast just there on the bbc - cold and more cold, with just the odd milder interlude for the next 10 days, and several chances of frontal snow in places. He also mentioned colder and more settled weather later on in February. That suggests a robust scandi high to me against a very weak Atlantic, likely more snow( of the dry variety) chances on offer. Exciting times indeed.

sryanbruen

Donegal Storm wrote: »

That might be a sticking point, I've read before that SSW's can take upwards of two weeks to propagate to the lower atmosphere so there's a good chance we'll be heading towards the end of Feb before anything interesting kicks off. At that stage I think most people are firmly looking forward to spring and warmth.

The GFS ensembles are pointing to prolonged below average temps though so hopefully we'll see some action sooner rather than later

As others have said, a PV split leads to a quick tropospheric response usually - such as in January 1985 where it brought the conditions I've shown which was about 2 weeks later after the initial warming at the very beginning of that year. I hope I can get the chance of seeing a snow event like 27 February 2001:

Can't find a video on it snowing in Dublin but that day brought with it more than 10cm of snow here. Here's a video of it in the UK:

JCX BXC

Nice bit of snow in Madrid this morning/afternoon.

sryanbruen

https://twitter.com/antmasiello/status/960548573623603200

Rock Lesnar

Very unusual here for me, as i look straight up, i have a clear sky to my left and cloud to my right, i seem to be right under the divide, looks like the cloud will slowly win out

sryanbruen

The BBC monthly outlook was quite interesting.

Monday 5 February Published at 10:00

Monthly Outlook

Summary

Longer days, but colder weather!?
Last week saw January 2018 draw to a close, and although many parts of the country ended the month on a particularly cold note, statistics for January show that, on the whole, the month was fairly unremarkable. Temperatures across many southern areas were slightly milder than average, as opposed to northern areas that were a touch colder than the norm. Some western areas were wetter than usual, but the far northeast of Scotland was distinctly drier. On the whole though, when averaged out across the UK the statistics paint a very average picture.

Looking ahead, it will doubtless be a relief to many that over the course of the next month, daylight hours increase by around 2 hours across the UK. Sadly for some though, as we make our way further into February and towards March, although the prospect of some drier and brighter weather might also be a welcome late winter boost, the air of optimism might be somewhat diminished by the likelihood that the UK will often be influenced by swathes of cold air invading from the east and north.

Read on to find out the details of the month ahead...

Monday 5 February—Sunday 11 February
Mainly cold, often dry, but with snow at times!
Monday will begin on a frosty note, but through daylight hours, most regions will enjoy plenty of dry weather, light winds and brighter spells. The exceptions will be southeast of England, where a raw northeasterly breeze will blow in wintry showers that will leave some accumulating snow on the hills of Kent, and a few light flurries of snow that may feed in from the east across central areas.

On Monday night, an Atlantic weather front will push into Northern Ireland and make progress southeastwards towards Scotland, northern England, Wales and the Midlands by Tuesday morning. The front will impinge on the cold air further east, meaning that many northern areas can expect snowfall. Further southeast on Tuesday, most parts will enjoy a fine, cold day, and only later will the weather front introduce the some patchy and mainly light evening snowfall.

Through the week, the Azores High (an anticyclone anchored over the Azores) is expected to extend towards the UK, influencing our weather, Indeed, on Wednesday pressure looks likely to build in again across most parts, resulting in another cold yet mainly dry day with just the odd flurry of sleet of snow for some coastal areas of eastern England and also around Irish Sea coasts.

Wednesday night into Thursday is expected to yield another Atlantic weather front that will round the top of the Azores high, bringing some snow to the northwest, but as the weather front sinks southwards towards the rest of the UK through Thursday, the influence of the high pressure will likely fragment any precipitation across southern areas. Later on Thursday, brighter, colder and showery weather is expected to once again feed in from the northwest.

Throughout the rest of the period, it looks likely that conditions will remain cold, with the influence of the Azores high continuing to be temporarily interrupted by incursions of weak Atlantic weather fronts moving across the UK from the northwest, bringing the risk of further wintry weather.

Monday 12 February—Sunday 18 February
If you love cold weather, happy days ahead!
Sometimes the middle of February can bring an unexpected theme of romance, and if you like your weather cold, you might fall in love with the forecast for this period!

The usual forecasting computer models are showing a reasonable levels of agreement that this period will begin on a similar theme to how the first half of February ended - namely that the Azores high will greatly influence the UK's weather. The position on the high pressure system will tend to mean that winds are initially dominant from the north or northwest much of the time. This will likely mean that weather conditions will often be cold, with a good deal of dry weather for most areas too, with a propensity for frosty nights. At times though, we are likely to see further Atlantic weather systems temporarily interrupt the influence of the Azores high, bringing briefly milder and wetter interludes. Such milder interludes will always bring the risk of snowfall as the milder air associated with fronts runs into the cold air that will so often be found over the UK.

Later in the period, models are also increasingly showing signs that the high pressure system centred over the Azores may interact with high pressure positioned over Scandinavia. Such an eventuality would result in further cold and often dry weather, with frosty nights. The intensity of the cold will likely become greater with time though as very cold, continental air filters in over the UK driven by biting easterly winds. Snow showers may also become prevalent across mainly eastern regions of the UK at times.

Monday 19 February—Sunday 4 March
Still cold, but possibly turning drier for all?
As we move through the last few days of winter and into early spring, weather forecasting models are indicating that pressure will likely remain high across the UK, and at this time of year, such a configuration will result in cold, predominantly dry days and frosty nights, with the risk of occasional sleet and snow showers near windward coasts. The exact position of the high will be crucial in determining the amount of cloud cover we can expect, and at this stage is rather uncertain.

The predictions offered by the standard weather forecasting models are also backed up by other specialised forecasting models, increasing confidence in the aforementioned outcome.

One such model is involved in predicting the behaviour of the stratosphere, the layer of the atmosphere directly above troposphere, the latter being where we live - at the surface of the Earth! On occasion, certain polar regions of the stratosphere can become anomalously warm.During such an occurrence, the jet stream in the troposphere that drives low pressure weather systems our way can be caused to slow and meander huge distances from the poles the the tropics and back. Such an eventuality can lead to what meteorologists sometimes refer to as a 'blocked pattern', in effect bringing slow moving areas of high pressure in the vicinity of the UK. At time of writing, the model in question was predicting a localised warming of the stratosphere which will likely result in high pressure dominating the UK weather in the closing weeks of winter.

All the evidence is pointing towards a cold end to February and start of March!

Next week
In next week's edition we will take a look further into March. We already suspect that March won't exactly roar 'in like a lion' - rather there'll most likely be a weak murmur of cold and icy weather. We might be closer to asking whether March will move out like a lamb though! Find out next week...

gabeeg

When are you hoping for the SSW to manifest itself in our weather, Syran?

sryanbruen

gabeeg wrote: »

When are you hoping for the SSW to manifest itself in our weather, Syran?

I am hoping to see charts like this around the last week of February, that seems to be the favourable time for it . If everything follows a similar suit as the January 1985 SSW, it's extremely good for cold lovers. Of course, March snowfalls will be less intense than any possibilities January would have though.

gabeeg

Cheers dude.

Hopefully we'll see the GFS throw a wobbly soon enough

sryanbruen

It seems the warming will propogate down to 30hPa very quick according to this chart, seems a bit skeptical to me. That's a bit too fast for it to go that extreme surely.

https://twitter.com/Forecas55175638/status/960630040974282752

sryanbruen

https://twitter.com/judah47/status/960652055479242754

sryanbruen

I usually don't give Netweather posts praise but man some posters on there have made brilliant posts recently, this one being an example regarding late February.

nacho libre

Ian Fergusson
✔
@fergieweather

Brrrr. An overall cold Feb unfolds according to latest ECMWF 30d modelling, with risk of E'ly flow developing further into the month. An interesting forecasting period ahead, on many levels...

This is encouraging to. I have to say i'm enjoying this cool continental air, if it can't snow this is the next best thing! Hopefully it does return by mid month with snow in the offing to!

Franz Von Peppercorn

The bbc report is so bullish on cold i’d take it as a ramp it if it were a poster here.

Pity this didn’t happen 2 months ago, but cold dry and bright is still better than murky Atlantic systems.

nacho libre

Franz Von Peppercorn wrote: »

The bbc report is so bullish on cold i’d take it as a ramp it if it were a poster here.

Pity this didn’t happen 2 months ago, but cold dry and bright is still better than murky Atlantic systems.

As blizzard7 mentioned earlier they have not been that bullish about a forecast since the cold out break in 2010. So it increases the confidence that something good is afoot if you like cold weather. We can get ice days after mid February, March 2013 being a prime example in the UK. The sun being slightly stronger can be conducive to hefty showers during the day too.

George Sunsnow

A word of caution here if you are a coldie
If this ends up in blocking,it could be blocking in the wrong place locally for cold
No one knows at this stage

ninebeanrows

EC monthly is going for very nice pattern by week 3

With large negative SLP anomaly over France/Spain/central Europe and positive SLP anomaly over Scandinavia northern latitudes.

pistolpetes11

Verification wise has it been on point this winter ?

Weathercheck wrote: »

EC monthly is going for very nice pattern by week 3

With large negative SLP anomaly over France/Spain/central Europe and positive SLP anomaly over Scandinavia northern latitudes.

Oneiric 3

Weathercheck wrote: »

EC monthly is going for very nice pattern by week 3

With large negative SLP anomaly over France/Spain/central Europe and positive SLP anomaly over Scandinavia northern latitudes.

The Atlantic surface pattern is still largely westerly though.

Oscar Bravo

Just watched the weather on BBC 1 there and they have fantastic new graphics, now in association the MeteoGroup.

Oscar Bravo

Gonzo

Oscar Bravo wrote: »

still not showing temps and symbols for Ireland unfortunately. It was great when they used to show information for Ireland back in the good old days back in the 90s and early 2000's. Their new forecast look great tho.

gabeeg

Gonzo wrote: »

still not showing temps and symbols for Ireland unfortunately. It was great when they used to show information for Ireland back in the good old days back in the 90s and early 2000's. Their new forecast look great tho.

I wouldn't exactly call the 90s and 2000s the good old days.

Also don't remember ever seeing them show temps for the republic

Gonzo

gabeeg wrote: »

I wouldn't exactly call the 90s and 2000s the good old days.

Also don't remember ever seeing them show temps for the republic

heres one example, they used to show all the information for Ireland until the new brown maps arrived.

https://www.youtube.com/watch?v=LjuwdWSoZR0

gabeeg

Gonzo wrote: »

heres one example, they used to show all the information for Ireland until the new brown maps arrived.

https://www.youtube.com/watch?v=LjuwdWSoZR0

That's mad. It used to drive me potty that they excluded us.

They certainly did back in the 80s, but then they had the excuse of a magnetic board and limited magnets

BLIZZARD7

Oh my... Something is brewing

Macy0161

Gonzo wrote: »

heres one example, they used to show all the information for Ireland until the new brown maps arrived.

https://www.youtube.com/watch?v=LjuwdWSoZR0

Can't see youtube at the moment, but growing up in England we used to get a nice buzz when BBC weather would have Longford on the map from time to time (and to a lesser degree Athlone :pac: )

sryanbruen

It does seem the GFS ensembles are certainly beginning to show signs of the effects from this incoming SSW for the AO:

George Sunsnow

https://www.facebook.com/askmen/videos/10155380193493723/