Focussed Model Discussion

[knocker]

This morning's fax charts. Oh what a complex web we weave

 

Edited January 31, 2019 by knocker

[snefnug]

Who is planning to deceive?

[knocker]

The upper occlusion I believe!

[bluearmy]

4 minutes ago, knocker said:

The upper occlusion I believe!

Usually the death knell for an ‘event’ ........ most were relying on that first occlusion ..........

[jethro]

1 hour ago, knocker said:

This morning's fax charts. Oh what a complex web we weave

 

But what does it mean for weather on the ground? I haven't a clue what all those squiggles mean, please can you translate the charts into a weather forecast?

[knocker]

9 minutes ago, jethro said:

But what does it mean for weather on the ground? I haven't a clue what all those squiggles mean, please can you translate the charts into a weather forecast?

Pretty much what I've written previously for the south west I think the uncertainty arises more later in the south east and east when the front  becomes stationary and starts to fizzle out

Edited January 31, 2019 by knocker

[jethro]

6 minutes ago, knocker said:

Pretty much what I've written previously for the south west I think the uncertainty arises more later in the south east and east when the front  becomes stationary and starts to fizzle out

Thanks Knocker.

[knocker]

The rising sun highlighting the front

[knocker]

Brilliant high res sat image at 1100 ( courtesy Dundee Satellite Receiving Station). Still some neg temps and fog around

[chrisbell-nottheweatherman]

3 hours ago, jethro said:

But what does it mean for weather on the ground? I haven't a clue what all those squiggles mean, please can you translate the charts into a weather forecast?

See p.53 of the following PDF - it's what i use to remind myself of the difference between how frontolysis and frontogenesis are shown on a FAX chart:

https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/library/factsheets/factsheet_11_weather_charts.compressed.pdf

[chrisbell-nottheweatherman]

5 hours ago, knocker said:

This morning's fax charts. Oh what a complex web we weave

 

I sometimes wonder whether thev forecaster that compiles these is having a laugh.  It seems as though they think "small gap there - I know, stick another trough/upper front in".

[Jo Farrow]

4 hours ago, jethro said:

But what does it mean for weather on the ground? I haven't a clue what all those squiggles mean, please can you translate the charts into a weather forecast?

Most of those drawn around UK are surface occluded fronts (filled in black semi circles and triangles), but across Wales/ Midlands is one with open /white semi circle and triangles that's an upper front. Usually just a band of cloud, medium level but could still give patchy precipitation, so noted on the chart.

Near Newfoundland there is a Frontolysing cold front which is weakening, 

[knocker]

The front is just west of Cornwall at midday (moderate rain here)

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-6.67,51.56,2223

[knocker]

The latest wrf hot off the press and the midday analysis

 

 

[knocker]

Interesting we have gone from moderate rain wind gusting 45mph and a temp of 5C to no wind, and moderate snow as the front arrives

[jay1lk]

3 hours ago, knocker said:

Interesting we have gone from moderate rain wind gusting 45mph and a temp of 5C to no wind, and moderate snow as the front arrives

The Kernow snow shield has been penetrated

[knocker]

34 minutes ago, jay1lk said:

The Kernow snow shield has been penetrated

Yes indeed. Sidney disappeared clutching his nuts tout de suite. It was actually a very interesting couple of hours

[knocker]

The ecm has a cheeky little low break away from the main trough Monday 00 and it develops quite quickly to bring some wet and windy weatherduring the dayy. It moves into the North Sea and loses it's identity fairly rapidly but equally rapidly the nest frontal system arrives midnight Wednesday with more wet and windy weather. This again is a precursor to another system in a fairly mobile atlantic

[knocker]

This evening's output from the wrf

[damianslaw]

On 29/01/2019 at 20:12, knocker said:

 

 

No surprise to see the atlantic revving into gear next week with a more normal westerly mobile flow, thanks to all that cold air spilling out from NE USA/NE Canada. Frontal systems zipping through bringing wintry precipitation in the north -places with height, but becoming milder mid week, so snow reserved for northern hills by then only. 

I doubt this is the start of a full on atlantic zonal onslaught, more just a reaction to the displaced PV over NE Canada/NE USA, which looks to be imploding on itself over the coming days.

Longer term - an undulating jetstream most likely, and every chance of significant height rises building over the UK in time, will they go NW or NE?

[knocker]

The 500mb and surface analysis for midnight and the 0300 UK surface chart

As can be seen on the latter still a band of snow, rain and sleet across central southern England. This will slide south east during the day and fragment whilst elsewhere wintry showers but mainly in Scotland and down the east coast. A cold day not helped by a stiff breeze.

Another cold night, particularly in Scotland, with a continuation of wintry showers, still concentrated in the north and coastal areas but some of snow will drift inland.

Pretty much the same mix on Saturday with wintry showers, tending to be of snow inland, but becoming less frequent. And another cold day after an icy start, albeit quite a bit of sunshine in most areas.

After some brief ridging a complex trough will traverse the country through Sunday and Monday thus there will be periods of rain, sleet and snow and it will be quite breezy. Still cold on Sunday but temps on the rise by Monday.

By Tuesday the aforementioned trough has mover east to be replaced by a transient ridge but there is still much going on out west in the Atlantic. A deep low has tracked north to be east of the tip of Greenland and it's associated front, aided by another frontal system trailing way back to the south west, will bring cloud and rain to western regions during the day. Temps now above average.

[knocker]

According to the gfs the rest of the week continues changeable, courtesy the phasing of the warm/cold air in a fairly fluid Atlantic, But by the weekend the subtropical high has temporarily gained some traction as it ridges north east and that puts a break on the eastward momentum. Temps varying around the average.

[knocker]

At Wednesday midnight the ecm has a deep low south east of Greenland with the associated front bringing wind and rain to the northern half of the UK/ Once this has passed through generally unsettled with an upper trough dominating the eastern Atlantic and by Friday another low has tracked north east , on a frontal system that trails way back to south east of Newfoundland, which swings along the Channel and brings more persistent rain the south of the country. The upper trough then slides east until the end of the run by which tine the subtropical high to the west is ridging strongly into Iceland. Temps around average but a tad colder at the end

[knocker]

Still the snow/rain mix around southern central regions and even south Wales , Very cold in the north of Scotland

Edited February 1, 2019 by knocker

[knocker]

Looking at the ext EPS this morning I feel like breaking into song with Ella

"That ol PV has me in its spell"

Any way enough of this frivolity I'm off see Sidney after yesterdays flurry

 

Edited February 1, 2019 by knocker