Models, teleconnections and nowcasting

[knocker]

Not much to add to previous comments regarding this evening's ext mean EPS

[knocker]

Given the propensity for posting single charts at t384 in this forum I'm a tad surprised, or perhaps not, that nobody has thought fit to mention. en passant. the ecm take on the beginning of next week

It drops a fragment of the vortex down the west coast of Greenland which then undergoes some very rapid cyclogenisis resulting in a surface low of 933mb which is low even by Atlantic standards. Of course it probably will not pan out quite like this but in this baroclinic environment rapid cyclogenisis is a distinct possibility

When people say the weather is totally boring at the moment, what they actually mean is to them it's totally boring. They are not entitled to speak for the rest of us

Edited January 6, 2020 by knocker

[Jordan S]

47 minutes ago, knocker said:

When people say the weather is totally boring at the moment, what they actually mean is to them it's totally boring. They are not entitled to speak for the rest of us

Mentioned this the other day.

Anyway Here's the Gfs on that storm system early next week.. Gfs shows Lowest Central pressure in this storm to be 936 milibars. 

Edited January 6, 2020 by jordan smith

[BlueHedgehog074]

Looking at the various operational models at 144 hours, and there’s good agreement regarding the overall pattern we’re likely to continue heading in:

06Z GFS

00Z ECMWF

00Z GEM

00Z UKMO

 

Stretchy areas of High Pressure situated to the South and South-East of the UK. This combined with some strong areas of low heights to the North of the UK (the dark blues and purples). Helping to keep the pattern quite flat and mobile bringing West or South-Westerly winds over the UK. The 06Z GFS does have a bit more of a direct, cooler, Westerly flow over a wider area of the UK around that time-frame. But otherwise all the operational models above look broadly very similar. 

The most disturbed conditions towards North-Western parts of the UK. South-Eastern areas a little bit less disturbed, though some rain likely to affect these parts at times too. The fairly suppressed European High probably could get close enough to provide one or two more brighter, less unsettled breaks. But more likely that South and Eastern areas seeing the most influence from this. 

The NOAA 500mb anomaly chart in its 8 to 14 range going for some kind of ridging towards the East of the UK. Ridging still present towards the Pacific area and perhaps a chance for troughing to dig fairly far South in the mid-Atlantic at times (maybe a possible chance models, such as the GFS, are currently being a touch too flat with the pattern in both the Atlantic area and over the nearby continent).

An upper flow over the UK from the South-West. Probably remaining quite mild. Especially for South-Eastern UK.

Climate Prediction Center - 8-14 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

Again, not really any expert with these mean upper charts. However, for those wanting to board the Polar Express to a cold and snowy paradise, the charts don’t seem to be offering the tickets for that train at the moment.

[knocker]

Following on from earlier posts by myself and Jordan the gfs this evening has troughs swirling around the vortex and down the west coast of Greenland into mid Atlantic with a surface low undergoing rapid cyclogenisis

This would have been a joy on the the old OWS station 'India'

[knocker]

The 5-10 gfs det output illustrates very well the intense east pacific ridge and the associated cold plunge into north west North America and. heat in the south east US with, apparently, an eastward shift of the tpv

 

Edited January 6, 2020 by knocker

[knocker]

The intense ridge in the eastern Pacific and the cold trough over north west America, accompanied by some restructuring of the vortex and associated trough extension east, all tends to suggest a continuation of cyclogenisis in the beroclinic zone that is the  north west Atlantic.at the moment. And with the subtropical high being quite resilient the track of any subsequent depressions will be north easterly whilst warmer air is advected into Europe, particularly in the east

Edited January 6, 2020 by knocker

[knocker]

[Jordan S]

The developing storm that has its centre move across Iceland today will continue intensifying gradually throughout today into tonight with the Gfs showing pressure dropping to a very low 934 milibars as it moves close by or over the Norwegian sea with this comes a second swathe of very strong winds which will effect Shetland tomorrow with gusts of 60-70mph before easing tomorrow afternoon. 

Icon has it at 938 milibars you can see the extent of those very strong winds just to the north of Scotland well by tomorrow morning. 

Edited January 7, 2020 by jordan smith

[knocker]

The ext EPS mean anomalies this morning appear to be indicating a general slackening of the NH pattern, particularly upstream where the is now a more differences two centred (just) vortex, but importantly still with the trough extension aligned into the north west Atlantic. Thus still a strong westerly upper flow exiting the eastern seaboard, but backing and abating a tad in the east courtesy of some remaining influence from the subtropical high/ Perhaps a tad less unsettled in this period than the forthcoming one

[BlueHedgehog074]

1 hour ago, knocker said:

Certainly seems to be more tendency there for both the North Atlantic Oscillation and the Arctic Oscillation to stay more into the positive territory on those current extended ensemble forecasts. 

[BlueHedgehog074]

3 hours ago, jordan smith said:

Morning.

A wet evening and night to come for England and Wales some heavy bursts of rain at times from a developing low and as this pushes into northern England and perhaps southern Scotland then a risk of some mainly hill snow later tonight. some of this rain may push into northern Ireland, Turning windy for England and Wales with a risk of gales in exposure. 

After this area of rain clears into the north sea tomorrow morning another spell of heavy rain likely to move across the south during tomorrow evening. 

10-20mm widely falling altogether throughout this period perhaps upto 30mm in parts of the south. 

The trend for the next week to 10 days has not changed much since yesterday or indeed the last few day's next week starts stormy for all and Very wet then continuing unsettled thereafter possibly into next weekend, remaining mostly mild although with colder air in the Northwest at times the possibility of some snow mainly for Scotland and over hills but with a very mobile set up there will be drier and calmer interludes between low pressure systems.

Thought it was worth quoting this post by @jordan smith in this thread as it contains some useful informations regarding the energetic weather the models are showing for the next few days. Plus, it’s become too quiet in here lol

[Jordan S]

Aswell as being very wet in places through tonight especially for central and northern areas of England and Wales its also likely to become very windy for many parts of England and Wales tonight with a risk of gales in a few places, gusts widely inland of 35-45mph are likely with the chance of locally 50-55mph in exposed areas especially in coastal areas, the strongest winds transferring to Eastern England by tomorrow mid morning along with the main area of heavy rain and mostly hill snow a chance of this falling to lower levels for a time for the far north of England possibly southern Scotland. 

A big temperature contrast between northern England and the rest of central and southern England by the end of the night with 11 or 12c tonight with 1-4c for the north. 

Edited January 8, 2020 by jordan smith

[Dorsetbred]

Apologies if wrong thread, so MODS feel free to move. I notice in various threads how people are considering the signs of the Jet Stream moving south as a +ve move for a change to the current situation. Looking at both the North Atlantic & the US jet models, whilst they both suggest a southerly trend, for the start of next week, they both return to seemingly volatile more northerly trend the week after. Of course that always takes into account the further out they go, the less reliable they become in their analysis, but the "trend" of southerly movement appears short lived. Any thoughts?

[knocker]

36 minutes ago, Dorsetbred said:

Apologies if wrong thread, so MODS feel free to move. I notice in various threads how people are considering the signs of the Jet Stream moving south as a +ve move for a change to the current situation. Looking at both the North Atlantic & the US jet models, whilst they both suggest a southerly trend, for the start of next week, they both return to seemingly volatile more northerly trend the week after. Of course that always takes into account the further out they go, the less reliable they become in their analysis, but the "trend" of southerly movement appears short lived. Any thoughts?

For what it's worth Dorset. The Ext EPS is indicating retrogression of the Atlantic trough and the European subtropical high which will negate any southward movement of the jet. I do not have access to the 300mb wind field in the ext period but the 500mb illustrates what I mean. All good news for a less unsettled and drier period

 

Edited January 9, 2020 by knocker

[knocker]

Something to keep an eye on with this morning's ecm. It develops another low at the base of the upper trough at t120 which then undergoes rapid cyclogenisis as it tracks north east

[knocker]

A further look at the possibility of some very windy and wet weather beginning and middle of next week with the 06 gfs

[Jordan S]

54 minutes ago, knocker said:

A further look at the possibility of some very windy and wet weather beginning and middle of next week with the 06 gfs

Here's the Ukmo, Gem and Icon on the system for tuesday.. 

Icon.. 

Ukmo.. 

Gem.. 

They are clearly all In good agreement atm with that potential deep low. Ofcourse the main low that moves across the Atlantic on Monday develops into an intense storm system which we have previously discussed and although the centre now is shown to stay to the west its associated weather fronts ensure a very windy and wet start to next week for all. 

Edited January 9, 2020 by jordan smith

[knocker]

The front just through here

[knocker]

This will be updated later but a quick glance at the increasing wind in the north Friday/Sat as the frontal system moves through and the sharp drop behind the waving cold front

[knocker]

Interesting sat image showing the two centers close to the UK and the intense system to the west

 

[knocker]

By Monday midnight the cold front has whipped through the UK as the trough dominates the eastern Atlantic with another low (as we have seen) forming in it's southern quadrant (and spare a thought for Iceland)

Over the next 24 hours it undergoes rapid cyclogenisis as it tracks north east. Needs watching as this could bring some very nasty weather to N. Ireland and Scotland

[knocker]

The salient features of the ext mean GEFS anomaly are the strong Aleutian ridge and the two vortex lobes with the trough extensions to the one over northern Canada. A strong westerly upper flow exiting the eastern seaboard across the Atlantic. which is uninterrupted as the subtropical high has lost amplification and is exerting little influence

Pretty much ties in with the lower Strat

 

[knocker]

The ecm next week

[Dorsetbred]

2 minutes ago, knocker said:

The ecm next week

That last image with the two deep low to the north of Scotland looks really interesting. Suggesting they are that low in pressure, apart from the obvious windy spell, would you expect to see any knock on effect, because that creates a potential huge area of low pressure and so deep?