Focussed Model Discussion

[knocker]

The Aleutian ridge/American trough axis initiating amplification of the Bermuda high and ejection south of the Atlantic trough seems to be the form horse this evening. But according to the EPS as the ridge subsides the energy pathway is reestablished across the Atlantic which drives, the now negatively trough east and facilitates the firmly established European high cell to amplify north west into eastern Greenland. This is at odds with the det run which is keen to keep the strong ridge in the western Atlantic and high amplification

It is difficult to see a route to cold air with the ecm evolution.

[knocker]

Outlook - becoming more settled with some crisp mornings next week

The NH 500mb profile for midnight and the European surface chart and WV image for 0300

Still very windy, particularly in the north, but the wind will abate during the day although still strong over the north of Scotland,  And currently still a batch of rain across the north associated with Erik and the occlusion which will move away to the north east quite quickly this morning leaving sunny intervals over most of the country with squally showers in western regions, Temps a tad above average but not feeling so in the wind

But whilst Erik fills and slips away towards Norway a couple of cheeky waves have formed to the south west of Cornwall and they track north east to bring cloud and rain to Cornwall by 1800 today, perhaps snow on the high ground, which will then spread across the southern half of the country through tonight and tomorrow. Precisely how far north this will get is still up for grabs. At the other end of the country another wave has formed on an occlusion and this is tracking south with patchy rain, again snow on the high ground in Scotland, and introducing much colder air in it's wake.

The occlusion will track south over over Sunday night through Monday with some patchy rain which fizzles out as the front weakens courtesy of subtropical high ridging from the south west so a much calmer and drier day further south but a colder day generally after a frosty start

We are now entering familiar territory with the strongly amplifying subtropical high battling the energy exiting the eastern seaboard across the Atlantic and on Tuesday a couple of fronts manage to ingress the north west with some patchy rain but generally a dry and quite mild day

But the high is very resilient and becoming more influential so by Wednesday any wet and windy weather is confined to the far north whilst elsewhere will be dry with temps generally above average.

Edited February 9, 2019 by knocker

[knocker]

To continue briefly with the gfs. By Friday the ridge is still under immense pressure and a front is lying across N. Ireland and Scotland bringing some patchy rain but it goes no further and fizzles out. A simlar scenario on on Sunday vis the front but some changes are afoot to the west with the Bermuda subtropical high amplifying strongly which forces the Atlantic trough to unravel and as the ridge nudges east, fronts do manage to to traverse the country from the NW on Tuesday/

[Mizzle]

@knocker A huge thank you for your updates and forecasts - immensely helpful to those, like me, who are learning. It's so good to see the charts with a full commentary, so thank you so much.

[knocker]

The ecm has the Atlantic trough deconstructing on Friday and then a repeat performance with the next one on the scene on Sunday  All of this means that, with a lot of energy flowing around the top of the high cell; cut off upper lows are tending to phase/meet from the south west of the UK into western Europe, All of this  leaves the UK in a settled and dry environment with temps varying around the average but with some cold early mornings with widespread frosts

Edited February 9, 2019 by knocker

[knocker]

The EPS gradually loses amplification in the Atlantic (the Bermuda ridge) and at t252 causally drops a lobe of the votes into the NW Atlantic. It then expands this and has the deep upper trough dominating the Atlantic by t330 with a negative tilt which facilitates the European high to ridge north west into Greenland. The key transition appears to be around t240.  Ergo a continuation of generally dry weather with temps varying around the average

[knocker]

The midday analysis, and forecast for 0600 tomorrow, with the 1300 Sat image and Camborne midday sounding

We have Cs lowering to As here now as indicated on the sounding from the frontal wave rapidly approaching from the west.and, a further complication another from the south west  The rain will arrive shortly and spread north east this evening and though the night becoming heavier later midnight The wind finally easing over northern Scotland through this evening

[knocker]

Now if the evolution from this point ran along the lines of the Alaskan and Bermuda ridges combining to create a high cell over Greenland, with the European cell nudged east, there would be a conduit for an Arctic plunge from the vortex lobe over Franz Joseph south over the UK

Edited February 9, 2019 by knocker

[knocker]

A typical illustration of the current pattern. At t156 the ecm has the ridge coming under immense pressure with a lot of energy running around the top of it and down through central Europe to North Africa where it joins the subtropical jet. And over Morocco there is a cut off upper low from a previous trough deconstruction in the Atlantic, Then follows renewed amplification of the subtropical highs forcing another trough to deconstruct and further adjustment of the energy flows. The question is will this cycle continue?

 

Edited February 9, 2019 by knocker

[knocker]

The answer apparently is not long. At t240 the det run has an offshoot ejected from the chunk of the vortex that has plunged down western North America over Newfoundland. Taking this on another 24 hours with the EPS it has developed and deepened int the western Atlantic suppressing the amplification and initiating a south westerly flow over the UK  Moving on further a new pattern starts to emerge with the  intense trough now  dominating the Atlantis and the European high beginning to ridge weakly NW into Greenland  We shall see

Edited February 9, 2019 by knocker

[knocker]

NOAA perhaps trending to this

[Singularity]

Seems the Nina-like interference isn’t being broken quite soon enough for the MJO P7 crossing to be able to suppress the mid-lay westerlies enough to keep the Atlantic maritime airmasses from continuing to flow across the UK later next week. So yet another example of that interfering force preventing the usual response from fully taking shape (it does a bit; the very strong high inflating across Europe is the response but it’s shunted S by the too-strong polar jet; it’s the weakening of that which is not looking to occur as much as normal).

So what about the MJO P8 response? Well this should come after the immense WWB shatters the Nina interference - but after being keen yesterday the models have become less clear on the matter today. We’ll have to wait and see in this truly unique season of conflicting ocean-atmosphere states.

[knocker]

Outlook - this week should herald a quieter and drier period for most as high pressure becomes more influential

For a change the NH temp distribution and surface analysis at midnight and the 0300 WV image

The frontal waves duly brought rain to the southern half of the country during the night and this will slowly clear to the east by early afternoon leaving wintry showers in its wake. Meanwhile another wave has been forming on another front that has been giving continuous rain over Orkney This feature will track south east during the afternoon and evening to bring rain to N. Ireland ,Wales, some snow on the high ground, and eventually the south of England whilst slowly dragging the front south over Scotland which is the gateway for cooler air and wintry showers

Through early Monday the weakening occlusion  will bring some patchy rain as it moves south but it fizzles out as the ridge builds from the south west so after a frosty start a fairly pleasant day. Dome cloud and rain will effect the north west late on as a warm front associated with a complex low pressure system to the west pushes north east.

Through Monday night the warm front clears to the east but the waving cold front, associated with a low 975mb over Iceland, will bring further patchy rain and quite strong winds to the north on Tuesday with the the rest of the country remaining dry. Generally mild with temps a tad above average

As can be seen by Wednesday the Atlantic is dominated by an upper trough with a myriad of surface systems littered about but the ridge is very resilient and frontal systems are being forced ENE and any fronts that do stagger across the country are quickly weakened so another dry and mild day on Wednesday

A similar scenario on Thursday but with the ridge adjusting a tad east perhaps i bit breezier in the north west, but another dry day with temps still above average in the south westerly drift

Edited February 10, 2019 by knocker

[knocker]

To continue with the gfs. By Saturday midday the ridge, under pressure, has become positively tilted to the east of the UK and the energy flow around it is advecting colder air into Egypt and points south of there. In the meantime front(s) continue to stall across the north west of the country with temps way above average in the strengthening south westerly wind.The front(s) do eventually traverse the country as the subtropical high in the Atlantic once more amplifies and yet another cycle unfolds

Edited February 10, 2019 by knocker

[knocker]

A lot of rain around south of a line North Wales to the Humber on the 0600 chart. Moderate rain here at the moment

[knocker]

The ecm has a front across N. Ireland and Scotland midday on Saturday  with renewed amplification getting underway to the west which brings a more active front across the same area over the next 24 hours  And by midnight Tuesday with the trough deconstructing a low and associated fronts brings rain and quite strong winds to the north

[knocker]

A glance at the 0600 analysis shows the trough compromising the clearance down here which is a tad annoying

[knocker]

The EPS much the same as last night with a trough ejected from the vortex plunge down western America and intensifying in the Atlantic

Edited February 10, 2019 by knocker

[bluearmy]

35 minutes ago, knocker said:

The EPS much the same as last night with a trough ejected from the vortex plunge down western America and intensifying in the Atlantic

In true Eric morecambe style ....it’s playing all the right notes, just not in the right order ! 

Very frustrating for coldies but pretty typical for uk winters in reality .......

[johnholmes]

I suggested uncertainty with regard to just where the upper high might end up over the next 2 weeks in a post 24 hours ago. The latest set of charts from the 3 anomaly sets I use do now look like it will be somewhere over central/northern Europe. So a fairly mild overall outlook for 2 weeks and pretty changeable, even unsettled might sum the overall pattern up. To me, there is no sign of any major cold outbreak in the next 2 weeks.

https://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

[TEITS]

Have to say John  I disagree with your analysis.

I agree with the mild outlook but pressure is likely to remain high. So settled for most except maybe Scotland who may see more in the way of unsettled weather. The SLP mean for Cambs remains above 1020mb.

Possible colder for the last week of Feb?

Edited February 10, 2019 by TEITS

[phil nw.]

Certainly the eps clusters have backed off Greenland heights compared to 36 hrs ago when i last looked when around 40% was the main cluster for that trend. 

Latest for days 10 and 15

Plenty of support for an on going Euro/UK high but only around 20% support for any ridging gaining enough traction north or north west to create any possible cold interest.

 

 

[knocker]

The high res. MODIS at midday illustrating the frontal wave and the retreating occlusion very well

[winterof79]

28 minutes ago, winterof79 said:

UKMO at 144z with high pressure to our E/NE as per METO forecast and GFSV3 nearest match at 144.Cold pool sneaking around the flank more evident on UKMO

Thereafter confidence dwains so no point looking in any further detail. 

Waste  of effort in the other thread.

[WhiteFox]

10 minutes ago, winterof79 said:

Waste  of effort in the other thread.

Indeed. If you're not pointing out a route to bitter cold you might as well whistle in the wind...

For quite a while it's looked like high pressure builds over or just to east of UK. Chance of some surface cold with a chilly continental flow, or a warmer southerly flow with a chance of an Atlantic incursion. Could even be frost and some fog. What does not look likely is a bitter cold outbreak!