Model output discussion-mid Autumn and beyond

[damianslaw]

In a year in the main that has seen a very inactive atlantic, perhaps a tall order to expect it to continue in similiar vein now we enter the time of year when it should ramp into overload - alas, not the case.. this is turning into an abnormal year in this respect.

For the foreseeable we have a very dry pattern setting in after some showery outbreaks of rain early on in the week, with the atlantic running out of steam yet again, with a major block forming to our east and inch by inch ridging into the UK and quite possible retrogressing to the NW in time, ushering in an eventual much colder set up (see GFS evolution which is very plausible.

The coming days will bring very benign weather - some of the plants might be lulled into thinking its spring, and I won't be surprised to see some coming into flower, helped by some abundant sunshine at times.

Temperatures look like peaking Thursday, then gradually falling day by day, dropping down to average levels in a weeks time, with colder nights and likely frost and fog, as we import dry continental air and dry lapse rates.

In the days ahead, keep an eye on developments to our NE, looks like some colder air will begin to pool over NW russia, and into east europe nothing desperately cold for November though. Longer term we could see a classic scandi trough slice through the east side of heights propelling the ridge towards Greenland with a flock of a switch, but not until the very latter part of the month - before then some lovely late autumnal frosty days could envelop the country.

[knocker]

A very dry period with high pressure in charge with surface temps a little below average for the second half

Edited November 11, 2018 by knocker

[tinybill]

jets see what f1 comes with  over  night!

[Mucka]

I'm really looking forward to what should be a warm and sunny weekend next weekend.

The weekend after looks sure to be much more seasonable - the one after that?

[knocker]

Following on from the other post the theme from the gfs in the reasonable time frame is the continuing battle between the energy trying to get east and the very strong high cell which ends with a compromise. The high drifts from being NE of the UK to the NW as two energy flows are established  resulting in the cut off lows south of the high cell being brought into the action and colder air being asdvected into Europe around the eastern flank of the high. Some minor adjustments would significantly alter this scenario

Edited November 12, 2018 by knocker

[knocker]

A mentioned above, a slight variation in the energy distribution can make significant differences in the detail

[Summer Sun]

Two trends that stand out 

1 - A fall back in the 850's from around the 19th probably going a bit below average towards the end of the month

2 - Very little rain over the next 2 weeks

[knocker]

In the pattern that is very much likely to emerge in the medium the 850mb temps will be a very poor guide to the surface temps as the temp profile in the boundary layer could be modified by a number of factors.

Edited November 12, 2018 by knocker

[knocker]

A good example of how, with two energy flows, much the analysis can change in just six hours as you get past  day 5

 

Edited November 12, 2018 by knocker

[BlueHedgehog074]

Using the 144 hour samples from various operational models, and they do all seem to shake there hands with each other regarding a more settled picture developing. High Pressure influencing the U.K from the East vanquishing the evil powers of the Atlantic Lows! 

00Z UKMO

00Z ECMWF

00Z GEM

06Z GFS

00Z ICON

Some do have the Scandinavian/European High Pressure a little further East than others, especially the GFS and ICON. Essentially, however, an outlook free of the wet stuff! With the flow looking to be between the South and East, probably quite sunny at times in places too with a flow over a short(ish) sea track off the nearby continent. And helping to raise the temperatures to some mild levels during the day.

An example from the 06Z GFS for next Saturday and Sunday daytime.

But nights likely to be chilly.

And providing the flow is free from much windy conditions (does look as though the flow will be quite slack at times with the isobars fairly spaced out), then mist and fog is possible for places. 

There’s always chances that the Eastern UK block could end up getting knocked away further East as it tries to ridge Northwards from the South-East of the U.K in the next few days, but this seems unlikely. Support for the European block to settle things down for the U.K is high! 

Sorry Atlantic (and your wind and rain), but it looks like you’re gonna lose!

For those areas, such as parts of Wales and some North-Western UK spots that have had particular problems with flooding, it will provide a relieved break! 

Edited November 12, 2018 by DiagonalRedLine
Accidentally attached 2 Max temperature charts for Sunday

[gottolovethisweather]

36 minutes ago, DiagonalRedLine said:

There’s always chances that the Eastern UK block could end up getting knocked away further East as it tries to ridge Northwards from the South-East of the U.K in the next few days, but this seems unlikely. Support for the European block to settle things down for the U.K is high! 

Sorry Atlantic (and your wind and rain), but it looks like you’re gonna lose!

For those areas, such as parts of Wales and some North-Western UK spots that have had particular problems with flooding, it will provide a relieved break! 

1

4

Is this a Brexit exit post? Speaking of the Eastern block and perhaps the best is NorthWest Europe. Beware the release of the Beast, come late November into December? Hopefully, the long-range uncertainty will be sorted by then in the models and in political circles.

Edited November 12, 2018 by gottolovethisweather

[BlueHedgehog074]

36 minutes ago, gottolovethisweather said:

Is this a Brexit exit post? Speaking of the Eastern block and perhaps the best is NorthWest Europe. Beware the release of the Beast, come late November into December? Hopefully, the long-range uncertainty will be sorted by then in the models and in political circles.

Yeah, the North-Western Europe area would say seems the favourite place for now for the High Pressure. The models do appear to hint at that. It’s possible that Beast may not be too far away! Guess it will depend for sure how that block behaves. 

And I guess you could say that, lol. Not just an exit from Brexit, but the models would have us believe we’ll be leaving the Atlantic! (At least for the time being ).

Edited November 12, 2018 by DiagonalRedLine

[knocker]

I'm not sure I go along with many comments I've  read dismissing the Atlantic. Of course raging zonal is way off the table and has been for a while but the two energy flows exiting North America, the Polar and Subtropical jets, which diverge on hitting the block in mid Atlantic still have an important role to play in determining the position and orientation of our high cell imo, And on this a lot of detail vis the our regional weather next week depends

[booferking]

CFS looking not to shabby..

[BlueHedgehog074]

Some pretty nice CFS runs their! 

If the Atlantic was to make more of an influence and that (some of the) models might be under-estimating it, may the Atlantic just pay a brief visit. On a personal level anyway (but I appreciate some may want it to be more of dominant force).

Suppose really, there’s no guarantees how long any blocking we have will last. Clearly it’s not impossible it could be more of a shorter-lived affair than what it first seems.

Still likely, at least, this week will become more settled for places, especially for Eastern parts, with a build of Pressure to the East of the U.K.

[I remember Atlantic 252]

GFS 12Z, vile FI, horrid from around 20th, chilly feel, windy and rain at 6 degrees, can I have this weeks mild back

[johnholmes]

1 minute ago, I remember Atlantic 252 said:

GFS 12Z, vile FI, horrid from around 20th, chilly feel, windy and rain at 6 degrees, can I have this weeks mild back

why not ask in the other thread for an answer?

[knocker]

Regarding the two energy flows, The ecm has the northern arm that swings around north of the high pressure starting to engage with the subtropical jet at T150 and by T180 they are engaged and are promoting the low south of the UK with the high cell now negatively tilted.

Because of the negative tilt energy travels along the Southern arm which by t240 has created an upper trough over the UK with further ridging taking place in the west from the Atlantic subtropical high. All very interesting but I can't see it being replicated

 

[knocker]

I posted this in the wrong thread last evening (yet another senior moment)

In hemispheric terms there is pretty good agreement between the GEFS, EPS and NOAA mean anomalies this evening. The only major difference , even if one can call it that, is the treatment of the ridge/high cell adjacent to the UK. Otherwise twin vortex lobes with the main one over N. Russia and associated trough eastern Europe and with the other relevant trough aligned south east from the Canadian lobe into the north Atlantic

There is a lot of energy exiting North America, probably connected to the two jets, which diverge in mid Atlantic, one running around the ridge/high pressure and the other south east with a conduit to the European trough. The tricky detail vis the weather for the UK is down to the det. runs but the percentage play at the moment is for the UK to remain under the auspices of high pressure with little or no rain and temps a tad below average.

[knocker]

Last evening's EC46 not too bad. Generally surface temps western Europe staying below average for the rest of November (after this warm spell) with the colder air in south east Europe. But getting a tad warmer through December, albeit surface temps still a tad below average, but the 850mb temps trending above which suggests a not particular cold anticyclonic airmass supported by a very low precipitation anomaly.

[knocker]

Moving on to the evolution next week from the gfs and the latest interpretation of the two energy flows and the adjustment of the orientation and position of the high cell. It essentially means remaining dry  but with the surface wind backing to a freshening easterly component possible some rain showers in eastern regions of England with temps not far off average

[knocker]

Wrong again Knocker. The ecm continues to promote low pressure to the south of the UK courtesy of the influence of two energy flows

All of which initiates a strong easterly flow over the UK with copious rain showers, perhaps even sleet or snow in the far south as a shallow surface low drifts north.

And then this scenario at the end. All of which is of course subject to change given the likely pattern

Edited November 13, 2018 by knocker

[knocker]

What is quite striking with the ecm is the displacement of the Canadian vortex and the two jets, Polar and Subtropical, exiting north America  It is how these 'combine' downstream that pushes the high cell NW

[knocker]

Not too bad

[jvenge]

1 hour ago, knocker said:

Not too bad

Yep. EPS not really with the op this morning. EPS not keen on the high shifting to Iceland and then onwards, rather keeping it north east of the UK.