Scottish weather discussion - Spring 2023/24

[Snowandrocks]

As above - an absolutely beautiful display that a phone camera doesn't even come close to capturing. 

We sat for a good half an hour just watching with a cup of tea, tucked in out of the roaring wind. 

Edited December 24, 2023 by Snowandrocks

[Gogoslo]

The skies above Aberdeen city centre this afternoon was stunning.  

[lorenzo]

Not one of my own images but just got sent this from Aberdeenshire.. 

 

[Sprites]

55 minutes ago, Bats32 said:

What a beaut!

The biggest Kestrel I've ever seen 

[Ravelin]

Just now, lorenzo said:

Not one of my own images but just got sent this from Aberdeenshire.. 

 

So impressive even aliens in flying saucers came to see it. 

[101_North]

I wouldn't fancy cutting about in a sleigh in that wind

[Kirkcaldy Weather]

On 12/12/2023 at 18:24, Kirkcaldy Weather said:

It's all connecting really neatly from my POV which aligns to the current MJO cycling particularly phases 3 through 5/6

I mentioned the phase 3 setup would come into reality from mid December 

This coinciding with feedback of a positive North Atlantic Oscillation which I mentioned here  

Into December week 4 it's clear to see the feedback of phases 3 and 4 which drive surface temperature patterns across most of the Northern Hemisphere into above average scenario though most significant will be where the main blocks reside particularly Canada and the Maritimes then adjacent with a secondary high toward Russia. The below average surface temperature areas will be California and Mexico, Greenland, parts of Asia and across Alaska, maybe Florida 

As the phase 5 feedback comes through by Dec week 4 paired with the positive NAO and energies from the tropospheric vortex we'll need to be VERY mindful of storm developments / deep cyclones  

Use these as a general idea

Not surprising too watching as some strat warming is appearing also into Dec week 4 which was a timeframe ive had in my mind since Nov week 4

On 20/12/2023 at 18:39, Kirkcaldy Weather said:

Very detailed post incoming

My thinking holds steady with the pattern evolutions over the Christmas and heading toward the New year period, the broadscale setup is that of a developing Scandinavian - Baltic trough, this setup was always probable into week 4 of December 

 

perfect timing with your post @Jo Farrow thanks  

Looking solely into the dynamical situations for Christmas itself as mentioned in my posts above / recently the highest probalistic outcomes of below average surface temps were always best for northern UK 

With a prominent section of the Jet crossing the UK its easy to understand the milder trends particularly on the southern flank 

Also easy seeing why the flow will change orientation from a Northwest flow to that of more Westerly influence which again you'd not typically connect with prolonged below avg weather.

850hpa anoms

Surface temperatures anomalies 

Looks like a legit chance of a snow event particularly for the northern,northwestern and Northeastern sections of Scotland through Friday and Sat with precip forming along the frontal boundary between the cold and warm air

 

 

For Christmas itself current trends show a feature starting across Northern Scotland which moves south sometime on Christmas Day, this might bring an opportunity for a classic white Christmas dependant on 528 dam position and Dewpoints feeding into said feature.

Looking further into what's unfolding further afield, as the MJO is progressing through the Western Hemisphere and Africa I'd be expectant for some cyclonic developments within these regions and lo and behold we see a double rossby wave break over Africa with the 1st giving snowfall in Algeria and the 2nd bringing a persisting low over Morocco which might also see some snowfall there.

 

This should help to develop further lows toward the UK in the run up to New Year

In my post from 7th December I spoke of the re emerging trend of a classic El Ninò Style Jet, this paired with the PNA being positive .. more on that in a min. Has already given a record breaking storm on that route via the Gulf into the Northeast 

 

 

Looking back at what I discussed from December 5th 

Excellent representation with the ongoing and in parts record strength block particularly through the UK, North Atlantic and Maritimes--> Canada

 

 

also we now have our cut off low development through California into Mexico 

 

 

 

 

The PNA has strengthed within the + phase and this brings a new storm threat in about a weeks time 

I'm expectant of a shift from the deep cold which has and is currently residing across Asia, East Asia particularly as high pressure moves across Korea and Japan through Christmas this switches towards above average temperature scenarios 

"As the phase 5 feedback comes through by Dec week 4 paired with the positive NAO and energies from the tropospheric vortex we'll need to be VERY mindful of storm developments / deep cyclones "

'Looks like a legit chance of a snow event particularly for the northern,northwestern and Northeastern sections of Scotland through Friday and Sat with precip forming along the frontal boundary between the cold and warm air"

Pleasing seeing all the snow reports from our residential correspondence members in said areas @Scottish-Irish Skier I was like how's he posting snowy snaps having forgot you've snuck off into Aberdeenshire

'For Christmas itself current trends show a feature starting across Northern Scotland which moves south sometime on Christmas Day, this might bring an opportunity for a classic white Christmas dependant on 528 dam position and Dewpoints feeding into said feature." 

Main story into Christmas is all dependant on a development of a frontal wave, currently this looks like developments begin to our west by early Christmas morning as the big fella brings our

As discussed above we still see the prominence of a section of the Jet across the UK which looks to position favourably as this frontal wave forms combining with another boundary setup which @Hawesy has described as was present with the Fri-Sat snow. 

 

Looks to see this wave developing increasing precipitation rates and with increasingly chillier 850s beginning to undercut, where the dewpoints start to become increasingly supportive this sees the change over into snow with current signs from Perth, maybe Cairngorm and over near Dundee possible extention outwith. 

I'll be mega surprised if we aren't sitting with at least yellow snow warning covering this waving activity. Once the pivot and movement further south southeastwards begins this coinciding as the -4/-5 850hpa really undercuts which really increases the opportunity for a quite significant snow event into parts of central Scotland and into Stirling, Fife and eventual progression towards Edinburgh etc etc

 

Fronts

WWW.AVIATIONWEATHER.WS

---

Fronts - full text of the classic FAA guide

'If this tendency persists and the wave increases in size, a cyclonic (counterclockwise) circulation develops. One section of the front begins to move as a warm front, while the section next to it begins to move as a cold front (C). This deformation is a frontal wave.

The pressure at the peak of the frontal wave falls, and a low-pressure center forms. The cyclonic circulation becomes stronger, and the surface winds are now strong enough to move the fronts; the cold front moves faster than the warm front (D). When the cold front catches up with the warm front, the two of them occlude (close together). The result is an occluded front or, for brevity, an occlusion (E). This is the time of maximum intensity for the wave cyclone. Note that the symbol depicting the occlusion is a combination of the symbols for the warm and cold fronts.

As the occlusion continues to grow in length, the cyclonic circulation diminishes in intensity and the frontal movement slows down (F). Sometimes a new frontal wave begins to form on the long westward-trailing portion of the cold front (F,G), or a secondary low pressure system forms at the apex where the cold front and warm front come together to form the occlusion. In the final stage, the two fronts may have become a single stationary front again.'

  

 

Well this is a brilliant example of the complexities involved with newest data suggesting the boundary remains North of the central zones with biggest impact over Cairngorms etc 

Quite incredible and shows that even within 24hr range these multi million pound / dollar supercomputers still struggle in setups such as these.

12z 

 

 

 

"Looking further into what's unfolding further afield, as the MJO is progressing through the Western Hemisphere and Africa I'd be expectant for some cyclonic developments within these regions and lo and behold we see a double rossby wave break over Africa with the 1st giving snowfall in Algeria and the 2nd bringing a persisting low over Morocco which might also see some snowfall there. This should help to develop further lows toward the UK in the run up to New Year'

Yep, we've got an initial cyclone coming in by the 27th with a number of impactful conditions. 

High Ground Snowfall on the leading edge 

 

Jet increasing in strength 

Looks like we'll need to be very alert for impacts from Gales from a Southeast direction initially on the 27th

Getting some Arwen esque vibes into the 28th once this cyclone transfers over into the North Sea, might be some impactful wraparound gales from similar directions as Arwen

I think the meteorological agencies over in the Netherlands, North Germany,Poland and perhaps Denmark will be concerned with this system.

 

[Klippie]

Isn't the weather amazing...firstly lashed with rain...now blown to bits by the wind...late December clear skies but the temp is 8deg/C...its all wrong..!!!

[tiff]

Sitting in the van at Cairngorm ski centre, wind has died down a lot and getting colder, snow forecast for tomorrow. Hopefully the reindeer will show up. Merry Christmas folks!

Edited December 24, 2023 by tiff

[Sprites]

This evening 24th December just before 4pm 

 

[Sceptical]

Grabbed this photo just before sunset. 

 

[lorenzo]

Okay this is mind boggling ! PSC in the moonlight.

Link to original post https://x.com/sjb_astro/status/1739014965514649779?s=20

[Halfamilefromnowhere]

Merry Christmas everyone, 3C here and sleety showers with severe gales easing slightly. Wandered over to Cassley Falls near Rosehall about 8 miles now of Lairg today. Huge amount of water rushing down with the valley below flooded right across

[Hairy Celt]

Just started to look at the forecast for the 27th, Wednesday, as we're due to drive down to Edinburgh. Hmm. 4x4 with new winter tyres I think. Certainly a possibility of some snow for a fair stretch I'd say...

[Hairy Celt]

I see my jaffa cakesy bit about weather warnings has vanished. Some thing never change on NW lol. If you tell me which bits offended you I can post the bowdlerised version. Cheers!

Also: if Catchmydrift is out there anywhere anonymously, I hope all's well with you. We all miss you.

Edited December 24, 2023 by Hairy Celt

[Quinach]

Last few shots of the stunning nacreous display today as the sun set (shown chronologically).

Very kind of Castle Fraser to have an ideally situated picnic bench to sit and relax and watch it all for an hour, the changes in colour over time was stunning, though not shown to its best with the camera phone.

[tiff]

5 degrees at the Cairgorm ski centre, 1 degrees in Aviemore. Flat calm, not a ripple on Loch Morlich, still forecast snow.

[Ravelin]

Well that makes it an official white Xmas here, it's snowing lightly. 

[mountain shadow]

3 minutes ago, Ravelin said:

Well that makes it an official white Xmas here, it's snowing lightly. 

Pictures please!

[lorenzo]

Merrx Xmas All - have a magic day - especially you lucky buggers with SNAW !

[Ravelin]

3 minutes ago, mountain shadow said:

Pictures please!

It was very light and brief, wouldn't have shown on a picture. Maybe later when it's supposed to be heavier, if it's snow, and if it isn't too dark. 

[lorenzo]

 

[Northern Strath]

Merry Christmas folks! After a frosty start and some sleety mince it’s just started snowing and this is the snowiest Christmas Day outlook we’ve had for absolute years. Slàinte!!

[Kayemill]

Merry Christmas everyone!

[howham]

Merry Christmas!  Not sure if we'll get some snow later or not.  Currently slate grey skies but feeling cold enough.