Models, teleconnections and nowcasting

[knocker]

The important changes from the ecm over 48 hours

[knocker]

The boosting of the low pressure over southern Europe and splitting the energy routes quite early in the piece would appear to put a dent in recent prognostications, albeit not indicating anything drastic weather wise. Still the indications are it being pretty dry but best wait for things to settle down before attempting any detail

This evening's ext anomalies

 

Edited March 14, 2020 by knocker

[knocker]

Today and tomorrow is all about amplification of the subtropical high to the west and the dual movement and the low and associated waving front currently lying across England and Wales. The rain associated with the latter will gradually move south east through the day. It will be followed by showers in western areas whilst these will persist over Scotland, with some longer periods of rain, and it will be quite windy in the north.All of this should clear oversight resulting in a sunny day tomorrow after an early widespread frost.

Edited March 15, 2020 by knocker

[knocker]

Moving on from here. As can be seen another deep low has developed near the Denmark Straits and rain from the associated fronts will effect western Scotland and N. Ireland by 1600 on Monday and track across the north through the evening and overnight whilst the cold front starts to moves south east

The cold front more or less comes to a halt on Tuesday but a wave develops on it as further amplification starts to takes place and it begins to move north again for a time over Tuesday night and Wednesday

By Thursday we have reached the interesting stage of quite an intense high cell inmid Atlantic with the trough just west of Ireland starting to deconstruct

Edited March 15, 2020 by knocker

[knocker]

I'll continue over the weekend with the gfs as the developments are not without interest. Imo of course In a nutshell pressure is continually exerted on the ridge by developments in the west whilst the deconstructed trough engages with the cut off upper low to the south Easier to understand with the charts than me waffling as it's quite complex

[knocker]

The same general comments apply to the ecm but the subtle differences with the energy flows and alignment of the key players means that central Europe is about to go into the freezer

Edited March 15, 2020 by knocker

[knocker]

The front is through here but such is the nature of the beast still moderate rain to the NE

[knocker]

Apart from the usual problem of interpreting the clusters in a cohesive manner t144 today is an example where I personally find the map projection very restrictive

[knocker]

Any interaction between the troughs is a long way south on his evening's gfs

And the ridge developed by the new wave of amplification struggles against the energy from the west as it is forced east over the weekend veering the surface wind easterly. Becoming a bit chilly with morning frosts The ecm no doubt will have a different take on it

 

 

Edited March 15, 2020 by knocker

[knocker]

The ecm starts to differ from the gfs by t120 and is massively so by 144 maily because it is slow to deconstruct the trough which delays further amplification of the subtropical high

So no big surprise that the subsequent evolution is completely different

And a big factor in this

Edited March 15, 2020 by knocker

[knocker]

No help from the mean anomalies this evening. Running through the period the EPS has the tpv once more playing a very role active in the north west Atlantic which suppresses the renewed amplification of the subtropical high ridging north east to a great extent. Until this is sorted pointless in speculating further

Edited March 15, 2020 by knocker

[knocker]

Leaving aside the next two or three days at the moment and popping forward to around the time the ecm jumped ship yesterday. initially with EXter and the gfs and then just the latter

So by Friday we have the trough disrupting with the ridge edging east

The ridge continues to move east over the weekend resulting in quite a brisk easterly over the southern half of the UK but further support from the south west is a little curtailed by a lobe of the tpv dropping south over Greenland boosting the jet

I don't think it wise to venture much further ahead but for what it's worth the NH profile on Tuesday showing an invigorated TPV and much amplification in the Atlantic/Europe arena

[knocker]

And the strat

[knocker]

And the ecm take for the weekend

And by Tuesday

So not quite as straightforward as first seemed but still largely dry with perhaps some minor incursions, particularly in the NW

 

[knocker]

At the risk of stating the obvious the evolution at the moment is quite tricky

An overview of the ext anomalies which are not in agreement, would seem to indicate that the main players are the alignment of the tpv; the establishment of low pressure in the Mediterranean which facilitates diversification of the upper flow; and the amplification of the subtropical high north east How these three interact vis the energy flows will establish the surface pattern is key Suffice it to say at the moment the outlook is not bad, dry except perhaps for areas to the north and possible the south  Temps variable around the average with a fair diurnal range

Edited March 16, 2020 by knocker

[knocker]

Warm front approaching Lerwick with the cold front trailing back a very long way

[knocker]

The next bout of amplification gets underway on Thursday but the subsequent ridge/high cell has a struggle overthe weekend against the energy driving south of a new lobe of the tpv that  has developed in the NW Atlantic

So after a  day of sunny intervals and showers on Thursday becoming dry and quite sunny with the surface wind veering E/SE and becoming quite brisk in the south as the ridge is forced east

Temps on the whole a tad below average after some widespread morning frosts but quite pleasant in the sunshine

Edited March 16, 2020 by knocker

[knocker]

A glance at a couple of forecast soundings for Saturday illustrates how dry the air is as long as you avoid any clag under the inversion

[johnholmes]

41 minutes ago, knocker said:

A glance at a couple of forecast soundings for Saturday illustrates how dry the air is as long as you avoid any clag under the inversion

Yes, 'if' being the important word and probably not something that can be for this side of the Pennines

[knocker]

Everyone is aware of the general developments over the weekend so just a quick look at some detail from the ecm

[knocker]

The ext mean anomalies continue to be little help. The variation in the alignment of the tpv and downstream energy distribution means there is no consistency or agreement. So just a watching brief albeit nowt drastic lurking in the woodshed

[johnholmes]

1 hour ago, knocker said:

The ext mean anomalies continue to be little help. The variation in the alignment of the tpv and downstream energy distribution means there is no consistency or agreement. So just a watching brief albeit nowt drastic lurking in the woodshed

I have to disagree to some extent there k.

All 3 you show suggest +ve heights and -ve heights in roughly similar parts of the chart.Perhaps the main feature, best shown on the NOAA 8-14 chart, is the decrease in contour flow into the UK with the 6-10 fairly similar. My concern is for a surface high to set up to our east, fairly close to the UK with the dreaded flow off the cold N Sea. All who live east of the Pennines are well aware what that means in spring and early summer.

[knocker]

28 minutes ago, johnholmes said:

I have to disagree to some extent there k.

All 3 you show suggest +ve heights and -ve heights in roughly similar parts of the chart.Perhaps the main feature, best shown on the NOAA 8-14 chart, is the decrease in contour flow into the UK with the 6-10 fairly similar. My concern is for a surface high to set up to our east, fairly close to the UK with the dreaded flow off the cold N Sea. All who live east of the Pennines are well aware what that means in spring and early summer.

Yes I can see your point John but I was just wondering whether the energy from the tpv would push the ridge too far east and allow further amplification from the south west, The EPS doesn't appear very keen to build a high cell close to the UK in the east

Edited March 16, 2020 by knocker

[knocker]

The North Atlantic 850mb temp anomaly and surface analysis for midnight

The patchy rain from the warm front will soon peter out this morning leaving the southern half of the country fairly murky although the sun will breakthrough in some areas later and it is very mild, showers and windy conditions will continue over Scotland. But a wave deveops on the cold front and heavy rain will track east across northern regions from 1300 onwards

The front and belt of rain will move south through the night as windy and showery conditions again effect N. Ireland Scotland

The front more or less comes to a halt across the south on Wednesday so still rain/drizzle here but quite inclement in Scotland where it is still windy with frequent heavy showers with thunder, hail and snow in the mix

By Thursday changes are taking place that have been well documented previously so I'll merely illustrate them. Regarding the UK still showery in the north and the ever present front still giving some rain in the south with some very varied temps across the country

Friday the ridge continues to build NE whilst the front is still close to the south coast so still some rain here. Just few showers elsewhere

Strong amplification continues on Saturday but things get a tad complex when an upper trough associated with a lobe of the tpv to the north west deconstructs west of Ireland, effectively isolating the high cell to the north east. The rain from the front at last moving to SW Ireland

[knocker]

According to the gfs over the first half of next week the high cell is established to the east resulting in a south easterly flow across the UK. To the west the battle between the energy running south of the trough and further amplification from the subtropical high to the south west continues