Models, teleconnections and nowcasting

[knocker]

The massive amplification of the ecm over Greenland occurs over the last two frames. Is it supported by the clusters? I think not

Out of interest the lower strat

 

 

Edited May 1, 2020 by knocker

[knocker]

Midday sat image

[knocker]

Low over northern UK and associated cloud

Edited May 1, 2020 by knocker

[knocker]

Presumably everyone is au fait with the NH evolution in the medium term so a quick glance at the specific with this evening's gfs. Looking not too bad but the regional detail will depend on the position and orientation of the surface high

 

[knocker]

The ecm illustrates that a slight adjustment of the energy distribution and thus the pattern leads to a markedly different surface analysis

And

Edited May 1, 2020 by knocker

[knocker]

No big surprise that there are major differences between the medium term mean anomalies this evening but perhaps the fact that the GEFS is the odd one is

worth noting the difference between the det run and the EPS

Edited May 1, 2020 by knocker

[knocker]

The North Atlantic 500mb and surface analysis for midnight and current sat image

The country is in a very slack gradient today between troughs as the subtropical zones begin to amplify strongly. After a chilly start in places it will generally be a day of sunny intervals and showers which will be more concentrated and perhaps heavy  in the north and east. By late afternoon cloud and some patchy rain will encroach the south west courtesy of the frontal system associated with the trough

The showers will fizzle out overnight leaving a clear night for most but still patchy rain in the south west and also some over northern Scotland courtesy of the wee trough

A similar story on Sunday as the high pressure starts gaining more traction but showers will pop up again, mainly in the north and central areas

By Monday the high pressure is aligned across the UK so generally a dry and sunny day but a front will bring showers to the east and the cloud will persist in the south west. The usual caveats re. eastern regions are beginning to apply

By Tuesday the low and fronts to the south west are taking closer order and a band of rain will track into southern regions

The rain will die out through Tuesday evening resulting in a dry and sunny day on Wednesday but....well you know the rest

Edited May 2, 2020 by knocker

[knocker]

To continue with the gfs. The tpv lobe/trough in the NE develops as another trough tracks east across the Atlantic which develops into yet another cut off low to the south west of the country whilst in between these actions the European subtropical high ridges strongly north west eventually forming a high cell

The UK is more or less in no-man's-land as all of this is going on so generally remaining dry but with showers around and more unsettled weather creeping up from the south west by the weekend. And by then some marked variation of regional temps as cooler air arrives from the north east

Edited May 2, 2020 by knocker

[knocker]

As far as I can see the main difference between the ecm and the gfs later next week, and it's a big one, is that the former does not have the energy flow across the Atlantic interrupted, at least not until later, resulting in the formation of a cut off low. Thus a low tracks across the Atlantic by the weekend. A different ball game

 

Edited May 2, 2020 by knocker

[knocker]

Pleasant morning down here but almost total Ci cover

[knocker]

The key to the latter half of the ecm det run was the free movement of a trough across the Atlantic to become and intense low over southern Scandinavia as it merges with the tpv in the NE. The mean ens is not so keen on this

So we end up here with the Atlantic ridge Euro trough combination still to be sorted

Edited May 2, 2020 by knocker

[knocker]

The crucial time frame on the ecm det run is between t156 and 168 where it slips the trough east toward the UK. Not strongly supported by the clusters

Edited May 2, 2020 by knocker

[knocker]

Midday sat image

[knocker]

The 06 ecm concentrates the rain on Tuesday in the far south west

 

[knocker]

Today convection developing over the UK with low to east

 

Edited May 2, 2020 by knocker

[knocker]

This evening's gfs has a trough breaking east but tracks it south west of the UK

[knocker]

The difference Sat. 00 from the 12 and 00 ecm det runs

[knocker]

The ext anomalies continue to be of little use trying to pin down the evolution. The overall NH pattern is okay with ridging NW north America into the western Arctic adjacent to the tpv with troughs into Europe and north east North America/Atlantic. Whilst downstream the subtropical high amplifies in mid Atlantic with the added complication of low pressure in the region of Iberia. The alignment and intensity of these features in the Atlantic/European arena are critical to the upcoming detail for the UK so a watching vrief still the percentage play

[knocker]

The North atlantic 500mb and surface analysis for midnight and the sat image

The frontal system in the south west has brought a lot of upper cloud to much of western regions of the country including a band of rain  which will track east across southern regions this morning whilst showers, some heavy, will develop in the  N/NE. The temps reflect the cloud cover

Remaining cloudy in the south tonight and intermittent rain in eastern regions courtesy of the stray front

The aforementioned front will bring some rain to eastern England on Monday but the front in the Channel is weakening so where the sun breaks through it will be quite warm. Further north plenty of sunshine and showers but the onshore wind is picking up

By Tuesday the high pressure is being 'squeezed' by the energy flows and some thundery rain may ingress the SW/S

The 'squeeze' continues over Wednesday/Thursday as the trough to the south west edges north and a front associated with this will bring some showers to western regions over these days. Apart from that generally sunny and quite warm

 

Edited May 3, 2020 by knocker

[knocker]

To continue with the gfs over the weekend, The energy exiting the eastern seaboard south of the tpv lobe continues to make inroads and a trough tracks east across the Atlantic and absorbs our old trough. Thus more unsettled weather is introduced for this period, likely sunshine and showers. Still generally warm on Friday but more of a spread over the weekend

Edited May 3, 2020 by knocker

[knocker]

Predictable the ecm disagrees with this as the trough is diverted south east by further amplification of the subtropical high to phase with the tpv lobe over northern Scandinavia which introduces much colder air on Sunday. To be continued

Edited May 3, 2020 by knocker

[knocker]

Regarding the ext anomalies this morning, the comments from last evening still very much pertain

[knocker]

The ecm sets up it's cold plunge between t156 > 192 with the alignment of the ridge and the Scandinavian trough as it phases with the breakaway trough to the south being critical

Not too bad at 156

Some cracks starting to appear by 168

And it's definitely not the percentage play by 192

And just to note the actual 850mb temps at t192 and the max surface. Albeit it is not likely to verify

 

Edited May 3, 2020 by knocker

[knocker]

Frontal surface from that wee occlusion at 650mb at Albermarle?

[knocker]

Next weekend the gfs has further amplification of the subtropical high blocking trough movement in the west and north resulting in some unsettled weather pushing north on saturday and an easterly component with the surface wind

Edited May 3, 2020 by knocker