Greenland High.[All Seasons] Stats, Developments plus linking of downstream effects

[Kirkcaldy Weather]

This will be a very useful thread particularly given the dominant GH presence for a large chunk of this year

On 21/06/2023 at 17:53, Kirkcaldy Weather said:

I've been doing a bit more studying around the Greenland High and found a couple of great papers sometimes they don't link correctly but the first if you type Extreme Greenland blocking and high-latitude moisture transport

 

Just a moment...

RMETS.ONLINELIBRARY.WILEY.COM

 

Blocking the way | NCAR & UCAR News

NEWS.UCAR.EDU

 

This super pic showing the temperatures associated with the extreme 2010 Greenland High 

Arctic Oscillation Chills US and Europe

EARTHOBSERVATORY.NASA.GOV

---

This map of the land surface temperature shows that the first week of December was exceptionally cold in northern Europe and the eastern United States.

I done a bit of work and created the pressure and temperatures from the most recent Greenland Block of December 2022 these from weeks 1 and 2 of December 

Clear similarities with 2010 which fits as the UK recorded temperatures that were closest to the 2010 setup 

https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/interesting/2022/2022_04_december_low_temperatures_v1.pdf

"Prolonged spell of low temperatures, December 2022
The UK experienced a prolonged spell of low temperatures accompanied by snowfalls from
8 to 18 December 2022 as an Arctic Maritime airmass brought hard frosts, with daytime
temperatures struggling to rise above freezing and accompanied by widespread lying snow
(although generally not deep). Daily minimum temperatures fell widely to between -5°C and
-10°C across the UK on several nights – with hard frosts even in cities and coastal areas,
and some locations below -10°C. On 12 December Braemar recorded a daily maximum
temperature of -9.3°C, the UK’s lowest maximum (excluding mountain stations) since
December 2010. This was one of the most significant spells of low winter temperatures to
affect the UK since the exceptional December of 2010."

 

 

[Kirkcaldy Weather]

Lovely seeing such a rare setup play out 

On 26/10/2023 at 21:18, Kirkcaldy Weather said:

 

A rare pattern by the very beginning of November in regards to a legit cut off Greenland High, a VERY rare beast bringing back the 09/10 vibes. Note the separation of energy has occurred as our block from Scandi has split with the formation further east connecting through Alaska and the Pacific Northwest with the rest over Greenland as discussed and something I mentioned on October 8th

'I'm eagerly awaiting the approach into Halloween  be looking particularly toward the patterns getting retrogressive in nature with scope for further blocking which looks to have the opportunities of origin towards Scandinavia'

Nice viewing as the composites are starting to show in alignment to the continuing phase 8-1 snailpace MJO movement 

 

 

July 

 

[matty40s]

On 08/09/2023 at 17:05, Kirkcaldy Weather said:

This will be a very useful thread particularly given the dominant GH presence for a large chunk of this year

 

I have seen quite an ominous model for around the 25th November, will try to find it.

[Kirkcaldy Weather]

Mid January 2024

This period of weather has developed as a result of the suite of teleconnective feedback working in tandem as discussed in depth across many of my posts since latter December and within my winter outlook. 

On 11/01/2024 at 14:31, Kirkcaldy Weather said:

 

 

 

Super happy with the evolution since Late December now its becoming clearer in some finer detailing of this upcoming significant cold episode.

• Significant cold front moving south bringing significant below avg surface and 850hpa temperature anomalies by Sunday January 14th
• Surface temperatures point to a severe winter weather event.

"Through Jan week 2 toward the aforementioned middle month period we'll have the -NAO,-AO,PNA,El Ninò,MJO and Easterly QBO feeding towards the setup going retrogressive this will have a couple of significant changes with a westwards moving trough which links with expectations into elongation with the centre over the Baltics, Scandinavia as this is occuring the high pressure and block will shift northwestward to reside across Greenland this is more supporting of colder 850hpa temps likely from the Northeast, we maintain below average surface temps during this with possible scope for these to get colder"

'Seeing the heart of these colder temperatures at surface and upper level becoming centred through Europe with just the far south of the UK clinging to is perfectly anticipated thanks to the phase 7 feedback'

Note the movement northwards of this cold anomaly from phases 7 into 8

From the above we can Note the significance of both 850hpa temps and in particular surface temperatures as both will contain anomalies roughly 15 > 20 Degrees BELOW AVERAGE, this will give multiple ice days in succession with liklihood of significant ice days over Scotland and Northern regions of England though there will be ice days for Ireland  

A timeframe with a focal point towards wintry precip event(s) will be from January 16th through 18th with the cyclone in the Atlantic starting the merging process to the Scandinavian Baltic Trough

7 day precip anomaly. I'm expectant of significant flash flood event[s] for Portugal and its border into Northwest Spain

Such an excellent showcase of all the teleconnective feedback coming into one stunning meteorological display

"My thinking holds steady with the MJO working into the Maritimes generally Mid Jan maybe into January week 3 as this increases cyclonic developments seeing these sorts of 500hpa setups during that period is very plausible.''

 

Following the MJO passing across the Maritimes we begin seeing feedback of phases 1 and into 2 as January week 4 gets started a high forms toward the Maritimes which might extend through Canada, also I'm starting to notice the trend toward cut off low development toward Mexico, far Southwest US  

 

The peak strength to this Greenland High is occuring between now [January 15th] and lasting for roughly the next 5>6 days, some parts of Greenland will likely be seeing record hpa values for this timeframe which are often depicted by the Black and purple anomalies over various model suites. Also some noteable High temperature anomalies in parts of Greenland.

As covered in various posts this event is bringing significant & severe winter weather including the UK and Ireland with multiple Ice days, snow events of varying varieties and intensity > snow streamers over North Northeast and Northwestern Scotland, also a small feature on a Northwest >> Southeast orientation which is set to bring further snowfall to the above areas whilst extending to include a large majority of Scotland including Central, some getting further East in Scotland and latest data is suggestive of a possible significant snow event particularly toward Northwestern England, potentially extending into the pennines, Northern Ireland may also receive snowfall.

Whilst a lower likliehood scenario there remains a chance of precipitation running across the far Southern > Southeastern Coast of England, this could fall as a wintry mix including snow.

As mentioned in my quoted post as an Atlantic cyclone begins the merging process linking to the Scandinavian Baltic Trough which is also an elongating sector of the Tropospheric Vortex this will see the beginning of the expected significant/ severe flash flooding event(s) particularly focusing over Portugal and into Northwest Spain. Ahead of this also within the same connecting troughing we'll see a transitioning rain event which will develop into a significant snowfall through France into the Netherlands and other low countries such as Belgium this event will gradually shift its focus and impacts further South and Southeast through parts of Germany and once more a significant event into the Alps. Eventually this wintry weather moves eastward into other areas of Europe.

As the Greenland High begins intensification the EXTREME and historical level cold [see my posts in the Global model thread and the record threads] which had began development from Western Canada / Northwest America begins transitioning / expansion gradually Southeast & Eastward

850hpa temperature anomalies

Surface Temperature anomalies

Actual surface temperature 

This is depicted excellently if we look at the Arctic and North Atlantic Oscillation values. 

[Kirkcaldy Weather]

 

[Kirkcaldy Weather]

Stunning

Looking like the pressure will be at -> near record strength into the first days of April across Greenland an absolute beauty of a negative NAO overall and values now look to exceed those of January.

[Kirkcaldy Weather]

As the Greenland High builds this will interact with an elongating Tropospheric Vortex from Alaska across a large part of the Arctic resulting in a significantly cold setup with 850hpa temperatures of at least -16 with indication of -18s too across Iceland with significantly below average temperatures at Surface and upper levels.

[Kirkcaldy Weather]