Models, teleconnections and nowcasting

[knocker]

As mentioned in a previous post the main feature today is the low and associated fronts tracking E/SE across the country bringing further outbreaks of rain/snow in the north and very windy for a time across central Scotland, Fairly frequent showers in Wales and western regions of England with more persistent rain associated with the last occlusion noving SE down the spine of the country in the afternoon. A cold day, particularly late on as the wind veers northerly

At the moment there is still a lot of wintry weather over western Scotland

which will not move very far before the next batch arrives, not clearing to wintry showers until the occlusion has passed through

[knocker]

Having been through this previously, suffice it to say the next low arrives on the scene over the weekend and exits to the NE arriving at this position by midday Sunday

Twenty four hours later the ridge is battling to stay in touch

It is only partially successful but help is at hand in the form of further amplification of the subtropical high to the west so, despite some spoiling tactics from a trailing front and the cut off low to the south,high pressure is reestablished

And to continue this with the medium term GEFS mean anomalies.

 

Edited March 12, 2020 by knocker

[knocker]

This waiving and trailing front

is a bit of an irritant next week according to the ecm

[knocker]

No significant changes with the EPS ext mean anomaly this morning with the ridge edging a tad east. So hopefully a drier period (The Atlantic does retain some influence to the NW) with light winds in the relatively warm airmas, The surface temps subject to the usual diurnal spread in these situations

[knocker]

Frontal surface on the Camborne Midday sounding?

[knocker]

The long trailing front has been mentioned previously and this evening the gfs really develops the wave.It awaits to be seen whether the ecm is interested in this scenario

Edited March 12, 2020 by knocker

[knocker]

Predictable the ecm differs

And prior to the passage of the front

Edited March 12, 2020 by knocker

[knocker]

The ext anomalies are flip flopping about which does not fill one with any confidence in the detail of the likely pattern change

This evening the EPS is the more amplified with the Trough/ridge with the former further east in the Atlantic.As we know the precise configuration is important regarding the position and strength of the high cell and the EPS version would likely have it to the north east of the UK

[knocker]

Tonight's NOAA nearer the GEFS which really merely confirms this awaits more agreement apart from the fact it should be dry

Edited March 12, 2020 by knocker

[knocker]

The North Atlantic 300mb wind and surface analysis for midnight

A few showers around this morning but apart from maybe some NE coastal regions these should clear leaving a not bad day for most with the wind also abating. But cloud from the frontal system tracking up from the south west will arrive through the morning followed by rain in the early afternoon reaching SW Wales by 1800

The rain will spread east through this evening and overnight but tending to fragment as the front weakens with the heaviest pulses in the SW and south. The wind picking up again in the north.

The patchy rain will clear eastern regions through Saturday morning leaving England and Wales with a dry and relatively sunny day but cloud and heavy rain from the next system will encroach N. Ireland by 1400 and spread quickly east

Amplification previously described now occurs ceasing any eastward movement of the trough resulting in a showery day on Sunday with sunny intervals once the band of rain associated with the cold front clears slowly to the south east

By Monday the ridge has moved east to be over the UK but it's under pressure from the trough in the Atlantic which has deepened and tracked NNE to the Denmark Straits. So although it will be a dry day with light winds rain will effect the far NW courtesy of the frontal system associated with the said trough

overnight and through Tuesday patchy rain will move slowly south east with the front but south of this it is very mild courtesy of the long fetch from the south west

Edited March 13, 2020 by knocker

[knocker]

According to the gfs over the next five days high pressure in charge with just the odd regional blip. So dry with light winds with temps a tad below average but a fair diurnal range

 

[knocker]

And the ecm for the same period and the general comments also apply

[knocker]

The GEFS and EPS ext anomalies this morning are looking to extend the ridge north east and the indications, at thus stage, of the surface high cell being to the NE/E of the UK If this is the case the outlook would be dry with temps generally a tad below average but perhaps with a fair diurnal range. But there could well be a lot of regional variations with this, and cloud amounts, depending on the precise surface analysis

 

Edited March 13, 2020 by knocker

[knocker]

Not too much point in this but does illustrate the possibilities with the high cell. With sunshine and light winds a great improvement on many weekends of recent vintage

[knocker]

Interesting energy flows. Will be interesting how the ext anomalies compare later

 

 

Edited March 13, 2020 by knocker

[knocker]

This evening's ecm has the second wave of amplification beginning at t120

 

[knocker]

Not bad agreement between the ext anomalies this evening. Main lobe of the tpv over the  central Arctic with the subtropical ridging NE over the UK and low pressure in the Mediterranean area. This indicates a dry period with light winds with temps a tad below average.This covers a fair diurnal variation with morning frosts but hopefully plenty of sunshine so mot unpleasant

 

[knocker]

According to this morning's ecm the changing point is after the movement of this front over Tuesday and Wednesday as the subtropical high amplifies in mid Atlantic

So by Friday we are here

Which leads to the weekend

 

[lottiekent]

I always enjoy reading your posts Knocker. Thanks, Charlotte

[knocker]

Thanks Charlotte

Although there are some differences the ext mean anomalies this morning they are very much on the same page.The tpv has re-aligned but with the help of the Aleutian ridge there is still a lot of energy exiting the eastern seaboard.  The importance of this is probably better understood in the context of the alignment of the ridge over the UK onto Europe, which will play a key role in the day to day assessment of the UK weather. The north east bound energy across the Atlantic, aided and abetted by the trough to the south, appear to play a key role in this

In a nutshell we are looking at a more settled and dry period with temps a tad below average but the regional variations of this and cloud amounts will need to await the precise position of the ridge

[knocker]

Rain will clear most areas this morning but not Scotland, NW England and Kent

But the next system is tracking north east and heavy rain from this will effect N. Ireland by mid afternoon and sweep across Scotland and northern England in the next six hours, followed by heavy showers

But from midnight through to 0700 some heavy pulses of rain along the trailing cold front will effect Wales and the north midlands

The front will continue to track south east through tomorrow by which time wintry showers and much colder air has been introduced to Scotland

 

 

Edited March 14, 2020 by knocker

[knocker]

Next weekend with the 0600 gfs

[knocker]

The recent outputs from the EC weeklies are not coming to fruition so a quick look at the revised punt for the end of March/beginning of April

28-04

Still the tpv aligned Arctic/N. Canada with low pressure over the Mediterranean with substantial influence from the subtropical high in the eastern Atlantic Thus temps around average and dry

04-11

No significant changes/ Perhaps a tad less influence from the high

[knocker]

Subsequent to the amplification of the mid Atlantic subtropical high at t120 this evening's gfs has an upper trough disrupting west of Ireland and then some interplay with cut off upper low to the south which makes for an interesting surface analysis

And some interesting max temps in France on Thursday

Edited March 14, 2020 by knocker

[knocker]

Similar comments as above but the ecm take for same times