Models, teleconnections and nowcasting

[knocker]

The ecm inevitably has a different take on next week establishing a new high cell over the UK. Quite obviously the detail next awaits sorting

[knocker]

Major differences between the GEFS and EPS mean anomalies this morning with the latter tending to lose amplification over Europe, albeit retaining a rather benign outlook

 

[knocker]

The difference between this morning's ext anomalies was noted above.But in this context it is aso worth noting the the midnight also stands out within the last three GEFS runs

[knocker]

Like being an elongated warm sector with the wave on the front just discernible

[knocker]

According to the ecm the second bout of amplification of the mid Atlantic subtropical high gets underway at t96

By t144 the ridge is under pressure from a front associated with the deep trough over Greenland The front actually stretches all the back south of Newfoundland

And from there

 

Edited March 17, 2020 by knocker

[knocker]

Still no agreement between the ext anomalies this evening but are we looking at more favorable possibilities with the tpv better aligned allowing some amplification of the Atlantic subtropical high in conjunction with the low pressure to the south? Given the swings and roundabouts of late bo further comment for now

[knocker]

The North Atlantic 500mb and surface analysis for midnight

The belt of rain associated with the trailing front will move slowly south during the day. Showery rain over Scotland as the surface low tricks north of there. Remaining very mild in the far south

The front continues it's very slow progress overnight with pulses of heavy rain running along it. clearer and colder further north with showers still over western Scotland

Not a lot of change tomorrow with the front still lingering in the south

On  Friday the ridge moves east over the UK so a dry day with sunny intervals. And away to the west the next anticyclonic wave is starting

The amplification continues with a strong subtropical ridge across the UK, but is under some pressure from another intense trough that has tracked into the NW Atlantic. Generally a dry weekend with sunny intervals after frosry mornings with perhaps some cloud and light patchy rain in the south west

 

Edited March 18, 2020 by knocker

[knocker]

According to the gfs the next three days are essentially about the very strong ridge battling against incursions from the tpv to the north west

[knocker]

The ecm for the first half of next week

Edited March 18, 2020 by knocker

[knocker]

This morning's ext mean anomalies

The alignment of the tpv; amplification of the mid Atlantic subtropical high; and the trough to the south of the UK would appear to be the key players at the moment. The latter facilitates divergence of the upper flow in mid/easernt Atlantic resulting in a slack gradient over the UK. Obviously the detail of this yet to be nailed down but certainly not looking too bad as an overview

[knocker]

The second subtropical amplification is well underway by t96 with a lobe of tpv near the tip of Greenland

And the upper trough associated with the latter moves east across the Atlantic over the next 48 hours and the surface front could well bring some strong winds ans rain to N/ Ireland and Scotland with some very respectable temps over England and Wales on Tuesday

 

 

Edited March 18, 2020 by knocker

[knocker]

The ecm has a similar general evolution with detail differences

[knocker]

Some similarities between the strat and trop profiles this evening with the ecm

[knocker]

The ext anomalies are all more or less on the same playing field this evening

Main lobe of the tpv northern Canada; some amplification of the subtropical zones mid Atlantic and eastern Europe; and a trough Iberia. All of this results in a split Atlantic upper flow which becomes quite weak over the UK The surface anysis will obviously depend on how precisely this pans out temps likely to be a tad below average

[knocker]

By the weekend the ridge is well established aligned NE across the UK whilst to the NW another deep low has tracked a tad south of the Denmark Straits. But a deconstructing  upper trough to the west of Ireland has 'split' the ridge and an associated cold front is creeping east So generally sunny but rather chilly but still some cloud and patchy rain from the finally dissipating front

Over Monday the front, followed by another system continues slowly east bringing rain and strengthening winds to the NW later

The fronts bring further rain to the north on Tuesday but weakening by Weds but it is noticeable warm over England and Wales

By Thursday the ridge has reasserted itself as another trough swings into action in the NW

 

 

Edited March 19, 2020 by knocker

[knocker]

The complication next week is that the ecm has a wave forming on the front which is much more active giving a period of unsettled weather midweek. Little confidence in the detail until this is sorted

[knocker]

The front and band of rain continues to linger over southern regions today Dry with sunny intervals elsewhere but the shallow low and associated fronts will bring showers to Scotland and N Ireland

[rowan fawdon]

Really appreciate your descriptions of what's happening Knocker. I am scraping bits of understanding together gradually, and as a beekeeper the state of the weather can be quite critical, quite apart from the general day to day -can I cut the grass type of thing. Regards, Rowan, from the other end of the county.

[knocker]

1 hour ago, rowan fawdon said:

Really appreciate your descriptions of what's happening Knocker. I am scraping bits of understanding together gradually, and as a beekeeper the state of the weather can be quite critical, quite apart from the general day to day -can I cut the grass type of thing. Regards, Rowan, from the other end of the county.

Thanks rowan, appreciated

[knocker]

The weekend looking mostly dry and sunny, maybe some cloud and the odd spot of rain in the south at first and the odd shower in the NW

Things get a tad more complicated into next week as the previously mentioned front tracks east but the wave developing on it is thwarted somewhat by further amplification of the ridge Another reasonable day but becoming quite windy in the south

Things go into the melting pot after that as events upstream have knock on effects down and it's all a bit of a mess so best left there

Edited March 19, 2020 by knocker

[knocker]

The gfs det fits loosely within the GEFS 6-10 mean anomaly. The key here appears to be the quite intense core of the tpv over northern Canada with associated trough to the NW of the UK whilst boosting the east European ridge

But the tpv and trough retreat rapidly in the ext period, but leaving a trough over the UK whilst  the subtropical high amplifies in mid atlantic Await the EPS

Edited March 19, 2020 by knocker

[knocker]

The EPS follows a similar evolution as above  So at the end of the day the ext anomalies indicate the re-orientation of the tpv with the subtropical highs in the Atlantic/eastern Europe amplifying to various degrees with a trough established UK >south  All resulting in a very slack gradient over the UK which makes the surface analysis difficult to pin down, and depending on precisely how it all actually pans out

[knocker]

The North Atlantic  500mb and surface analysis for midnight

A cold start to many areas this morning but less so in the south where the front is still bringing some cloud and the odd spot of rain/drizzle.Also some rain in East Anglia courtesy of a wee trough running down the east coast. The cloud in the south may well break somewhat during the afternoon whilst elsewhere will generally be sunny with some showers creeping in off the North sea which will also depress the temps a shade

A clear night for most areas with a widespread frost

Sunday a day of sunny intervals with variable cloud, particularly in the south west where the front is still lingering, and feeling a tad chilly in the very brisk south east wind

By Sunday another trough has tracked into the NW Atlantic and a deep surface low is just south east of the tip of Greenland Further east a front (previously mentioned) is 'splitting' the ridge but as yet with no impact on the UK where it will be dry but a bit chilly in the south in the still brisk south easterly wind

Monday a dry and warmer day but the aforementioned front(s) may bring rain to the far NW late on

A wave develops on the front over Monday night which brings some wet and windy weather to the NW on Tuesday whilst other areas remain dry

[knocker]

I'll just stick to the next three days with the gfs as the detail is tricky and a long way from being nailed down. The bare bones are:

A lobe of the tpv breaks ranks and tracks east; the trough(s) to the south and SW of the UK become more prominent; and the ridge migrates east

Edited March 20, 2020 by knocker

[knocker]

For the latter part of next week the ecm indicates a lobe of the ipv tracking east to the north of the UK; the abdication of the intial ridge east; and then some quite intense renewed amplification of the Atlantic subtropical high