Models, teleconnections and nowcasting

[knocker]

Still no agreement between the ext anomalies this morning regarding the alignment of the tpv and amplification, if any, of the subtropical high over the UK and Europe. But forebye this, with positive anomalies in this area the outlook still portends a quieter spell of not unpleasant weather with the detail to be sorted by the det runs

[Zak M]

A dry and warm day to come on Tuesday, with the only exception being the far north where a few spots of cloud and rain is possible.

   

Overnight on Tuesday and into Wednesday the band of rain will start crawling to parts of Scotland and N. Ireland in the night. The south should see mild temperatures overnight.

   

Wednesday will also be a fine day, with loads of sunshine on offer and temperatures surpassing 20c in the south. In the south however, a few showers could develop. The band of rain that was once over Scotland and N. Ireland will start to crawl into parts of N England

   

[knocker]

Looking at the clusters you could perhaps take a punt that the det run is over developing the weekend low but I wouldn't bet the woodshed on it

[knocker]

Nice depiction of the cold front and clear skies over Europe

[knocker]

The gfs continues to take the weekend low north of the UK thus little impact on the latter

[knocker]

The ecm has a shallow trough moving east Frid/Sat bringing showery conditions and at times persistent rain to the country

And over Saturday night another trough arrives from the west and starts to phase with it but  is forced south east by the resurgent subtropical high to the west with the weather staying changeable

 

Edited April 6, 2020 by knocker

[knocker]

The North Atlantic 500mb and surface analysis for midnight

Once  the odd spot of frost/mist has cleared a dry and sunny day for most. But increasingly cloudy in the north west with the wind picking and also more cloud creeping into the far south, courtesy of the weakening warm front

Overnight the cloud and patchy rain in the NW will track very slowly south east to reach N. Ireland whilst there is also some intermittent rain/drizzle on the warm front as it nudges north

Still cloudy with patchy rain over N. Ireland and western Scotland on Wednesday but generally dry and sunny elsewhere

Little change on Thursday with cloud still in the vicinity of the front in the north. But a low and associated fronts has tracked north west of Ireland

The aforementioned fronts cross the country on Friday resulting in showery outbreaks and some longer periods of rain.

On Saturday another frontal system has arrived from the west so another day of sunshine and showers with some longer periods of rain

The gfs surface analysis is so much at variance with fax by Saturday that I'm inclined to await for the ecm before musing further on the weekend. And there is a problem with WB in any case this morning

Edited April 7, 2020 by knocker

[knocker]

In the meantime a quick glance at the EC weeklies update for the last week of April and first of May

23 > 30

The tpv in a familiar position with the main lobe/trough northern Canada/NW Atlantic with the westerly upper flow abating considerable in the eastern Atlantic courtesy of some positive anomalies over western Europe. Indications of a quiet spell with temps a tad above average

01 > 08

Nothing drastically different but perhaps a tad more changeable with temps nearer average

 

 

[knocker]

The ecm is much closer to the fax and goes on to indicate a changeable, showery weekend, as the North Atlantic subtropical high amplifies  again

[knocker]

The 06 ecm take on the temps for the rest of the week and quite wet in the north as fronts track NE

And currently cloud creeping in here courtesy of the weak warm front

[knocker]

The cloud layers as alluded too above

[knocker]

By way of variation this evening's gfs does drop the trough over the UK on Sunday as it phases with the tpv lobe but quickly snuffs out that little arrangement by amplifying the subtropical high north east which sets up a chilly north easterly over the UK

[knocker]

The progression of the ecm is along the same lines but quite a big difference in detail by t144 which is no great surprise

Edited April 7, 2020 by knocker

[knocker]

The North Atlantic 500mb and surface analysis for midnight

Some rain persisting today in the vicinity of the weakening front in the north but generally a dry and sunny day and perhaps warm enough in the south east to trigger the odd shower (as always the model max temps are not definitive)

The patchy rain over N, Ireland, some areas of Scotland and northern England continuing to tonight, otherwise dry and clear

Still some patchy rain in the north as the front re-orientates,courtesy of the movement of the low west of Ireland, but sunny and warm elsewhere with possibility again of the odd shower being triggered

By Friday the aforementioned shallow low is near Iceland and, although the old front has now dissipated, further fronts are approaching from the west bringing rain to western parts later in the day. Further east and to the south remaining warm and sunny

A not dissimilar day on Saturday

But note the new low south west of Iceland which tracks south east as the subtropical high amplifies, and phases with the trough to the NE in the proximity of the UK on Sunday. Ergo a day of sunshine and showers

 

 

[knocker]

According to the gfs the ridge quickly becomes more influential over Monday/Tuesday but there is still a lot of energy in the system

And by Wednesday the results of the interaction of this energy and the amplification of the subtropical zones is continuing to evolve as the ridge comes under pressure. Best left here

Edited April 8, 2020 by knocker

[knocker]

The ecm has the ridge/high cell showing a tad more resilience next week

[knocker]

The alignment of the tpv/troughs, along with the interaction between the subtropical high and low pressure west of Iberia, is continuing to cause problems in the ext period. And until that is resolved the detail will continue to remain elusive

Edited April 8, 2020 by knocker

[knocker]

Some max temps Thurs > Sat from the 06 ecm

[emmett garland]

A breath of fresh air Knocker but looks like my highest temp of the week comp will be beaten today as tomorrow looks cooler..  I think I have 23.6 for Northolt tomorrow but nevertheless a stunning forecast so early in April 

[Zak M]

Saturday looking to be the warmest day of the year so far, with 23c+ temps possible in the SE

[knocker]

The front across northern Scotland and some cloud bubbling up ib the south

[johnholmes]

They do well illustrate how the Asxx Fax and visual are so alike, at least today!

[johnholmes]

5 hours ago, knocker said:

The alignment of the tpv/troughs, along with the interaction between the subtropical high and low pressure west of Iberia, is continuing to cause problems in the ext period. And until that is resolved the detail will continue to remain elusive

As you say k the detail remains elusive but then 500 mb contour charts never do give such detail. As,I think, mushy commented a few days ago, use the 500 mb anomaly charts IF they are consistent over several days and with one another and match the nearest synoptic chart to them and it will give a pretty good surface picture.

At least that is what I have found over the years I have used both.

[knocker]

15 minutes ago, johnholmes said:

As you say k the detail remains elusive but then 500 mb contour charts never do give such detail. As,I think, mushy commented a few days ago, use the 500 mb anomaly charts IF they are consistent over several days and with one another and match the nearest synoptic chart to them and it will give a pretty good surface picture.

At least that is what I have found over the years I have used both.

Quite agree John and consistent is the key word of late in the ext period

[knocker]

The ecm this evening has the trough tracking south east west of Ireland on Sunday so unsettled but becoming less so on Monday as the high ridges north east but a fair bit cooler

Ans the high pressure remains in charge Tues/Weds