Short range model discussion - into 2018

[knocker]

Clear skies for all this evening but during the night the wind will back easterly, still quite breezy along the south coast, and the front in the North Sea will track east and bring cloud to eastern regions and gradually further west with scattered showers. Feeling quite chilly especially in some sheltered spots in the south west

 

Edited November 18, 2018 by knocker

[phil nw.]

A snapshot of the colder regime on Tuesday pm from NWxtra.with the easterly well established.

Cloud and showers moving in on a brisk wind although at this stage any snowfall risk looks small and would be confined to high levels above circ.500M..Feeling raw though with daytime temperatures around 3/6C..

[knocker]

Frequent rain showers around on Tuesday with more concentrated precipitation in the Channel along the convergence zone but according to the ecm a tad too warm for snow, with dew points 32-34F at 1200, except possible on the higher ground

Edited November 18, 2018 by knocker

[knocker]

And whilst on the subject of snow and what parameters to look for, a good way to start is by having a shufty at what a man who was a senior forecaster for many years has to say on the subject

https://www.netweather.tv/forum/topic/27989-how-to-try-and-forecast-snow/

 

[knocker]

Outlook - colder, showers

The NH profile and surface analysis for midnight and the 0300 WV image

Cloud with some showers have been spreading west during the night so the cooler start to the day is in the west with some patchy frost. During the day the showers will become more widespread, interspersed with plenty of sunshine, but feeling a lot cooler in the fresh wind.

A similar story this evening and overnight with the showers pepping up with a convergence zone along the Channel. Feeling cold as the wind increases a tad, particularly along the south coast with again some patchy frost.

By now general developments of the pattern are taking place which have been addressed in greater detail in previous posts, so suffice it to say low pressure is becoming active in the south and pushing north which not only peps up the showers with perhaps some more concentrated periods of rain, but also introduces colder air into the south. Some of these showers will be wintry with sleet and snow on the hgher ground and possibly a bit lower

Over Tuesday night and through Wednesday the pattern continues to evolve and the low pressure becomes more influential which veers and abates the easterly wind but heavy showers continue with just about everything in the mix and another cold day with temps below average.

The next couple of days is essentially about the energy flows promoting troughs in the western Atlantic and another plunging south in eastern Europe, and almost by default the low adjacent to the UK, all of which pressurizes and distorts the high cell. Resulting in the showers becoming less frequent and perhaps temps warming a tad from Wednesday but still quite cold in the south on Thursday. Some widespread frosts, particularly on Thursday morning.

And the NH profile at T120

 

 

Edited November 19, 2018 by knocker

[knocker]

As expected quite cloudy over the UK on the 1120 MODIS and also in the southern quadrant of the high cell

[knocker]

Some nice lee waves on the 1399 sat image

[knocker]

Despite CAA in the boundary layer the UK is still in the warmer airmas, Different story tomorrow

 

[knocker]

Showers in eastern regions will continue this evening and overnight and in the strong easterly wind they will spread further inland, particularly in the north east where they may become more concentrated. Further west frost quite likely, particularly in rural areas.

[knocker]

Outlook - breezy, cold with frequent wintry showers. Becoming less so by the weekend.

The NH profile and surface analysis for midnight

Currently frequent showers north of a line North wales to the Wash. mainly in the eastern half but not exclusively so, Further south and west where it is clearer a touch of frost in places. During the day the showers will become more widespread and frequent, particularly in the north, in the strong easterly wind so wind chill will need to e factored in to the low temps.

During this evening and overnight the low pressure over France begins to move north and this backs the easterly wind a tad at first and with an occlusion draped across the north of England showers pep up and become more intense here and the Midlands  with snow on the high ground and this will include north wales. But the movement of the low also drags some colder air north into the south west, central southern England and Wales so snow showers distinctly possible on Dartmoor and other similar areas

The wind now starts to veer and abate though Wednesday as the low drifts west, apart from the north east, and thus the showers become more concentrated in western regions of England and Wales and the north. Still feeling very cold.

Over Wednesday night and through Thursday the low continues to drift west and the showers are  now concentrated in the north, including N. Ireland, but particularly so along the NE coast. Warming up a tad

By now we have reached the position discussed previously with, over the next couple of days, the twin energy flows exiting North America facilitating the development of intense upper lows in the western Atlantic and eastern Europe which pressurizes the high cell and nudges it west whilst leaving the low pressure adjacent to the UK and just to the west. Thus the UK remaining in a south easterly/easterly wind, albeit not as strong, with showers tending to confined to the NE and SW Temps now quite near average.

So to the NH profile at T120

Edited November 20, 2018 by knocker

[knocker]

Not a bad morning here with some Ci/ A bit nippy with a Tg of 1C

The 0600 Synops

http://www.met.reading.ac.uk/~brugge/06.html

[knocker]

Deleted wrong thread

 

Edited November 20, 2018 by knocker

[knocker]

I suspect the front/trough is bringing more persistent rain to the east Midlands and the south east than aticipated

[knocker]

still a lot of rain over much of England and Wales with temps quite depressed which about decsribes the day as well, although it's not been a gad day in these parts except cold in the wind

 

[Sky Full]

Quite stormy conditions for some on Wednesday - especially the further west you are....wind gusts at T+72hr as predicted  by the  1) WRF,  2) ARPEGE,  3) ICON,  4) GFS:

1)      2) 

3)      4)  

There is also quite a bit of rain associated with this system.  The exact track and speed of this deep Atlantic low pressure has yet to be determined but let's hope it stays as far to the west as possible.  At least it seems to zip by fairly quickly next week.

[Sky Full]

Moving on to Thursday (+96h) the main models see the north and west still being battered by the imminent Atlantic system but at least it has stayed in the Atlantic so the worst conditions confined to the west coast of Ireland, probably.....

1)  UKMO;  2) ECM;  3) GFS;  4) GEM....

1)     2) 

3)     4) 

The location and strength of the maximum wind gusts expected over the next 96 hours as predicted by the ICON and ARPEGE models:

  

The Midlands and south east England escaping the worst of the stormy conditions this week at least.

 

 

Edited November 26, 2018 by Sky Full

[snefnug]

Where is Knocker?  Is he ok?

[Sky Full]

33 minutes ago, snefnug said:

Where is Knocker?  Is he ok?

Not seen Knocker for the past few days - hoping he will give us an update soon.  His analysis is second to none.

[Sky Full]

Everyone can expect to get wet in the next few days....except maybe the far north east of Scotland.... Accumulated rainfall totals for the next 72 hours as predicted by the WRF, Arpege and ICON:

 

Dartmoor and the Brecons taking a soaking there.

[Sky Full]

A graphic colour enhanced satellite image of the circulation in storm Diana just off the west coast of Ireland at around 9:00 am this morning:

 

The total accumulated rainfall for the next 72 hours now not looking as bad as first predicted a couple of days ago -

[knocker]

The complex area of low pressure to the west of Ireland will become more organized and deepen to 949mb slap bang over the position of the old OWS station 'India' this evening and overnight. But the fronts, and heavy rain, associated with this will quickly clear northern England and Scotland early this evening. Still quite windy but by midnight the frontal wave, currently forming away to the south west, will being heavy rain and strengthening winds to the south west which will spread north east and effect most of England and Wales by morning.

[phil nw.]

The mean track of the jetstream across our shores over the coming few days continuing to bring spells of wet and windy weather.

Sunday's charts pretty typical of what is on the horizon.

A common pattern at this time of year with the boundary between the 2 air masses cutting across the UK with polar air encroaching from the north at times so snowfall quite likely over the higher levels especially in Scotland.

Good to see you back Malcolm.

[knocker]

Cheers Phil. The PC is up and running again and hopefully will remain that way.

[Sky Full]

1 hour ago, knocker said:

The complex area of low pressure to the west of Ireland will become more organized and deepen to 949mb slap bang over the position of the old OWS station 'India' this evening and overnight. But the fronts, and heavy rain, associated with this will quickly clear northern England and Scotland early this evening. Still quite windy but by midnight the frontal wave, currently forming away to the south west, will being heavy rain and strengthening winds to the south west which will spread north east and effect most of England and Wales by morning.

Great to see you back again and glad it was just an IT problem!   I'm hoping the worst of the gales are over for SW Wales for the time being at least - it's been howling round my roof all afternoon!  The next couple of days should see calmer conditions but it looks like we can all expect further rain leading up to the weekend...

[knocker]

Outlook - unsettled with periods of rain and strong winds at times.

The NH profile and surface analysis at midnight.

it's the forecasters nightmare scenario at the moment attempting to assess how much, and how quickly, the developing wave will deepen as it swings north on the jet.

This would appear to be be the situation at 0400 with moderate rain over much of southern England and Wales.

The rain will quickly track NNE through the morning, with quite strong winds over England and Wales. and clearing all areas by early afternoon leaving in it's wake frequent showers in the fresh south westerly wind. Very Mild.

This evening and tonight the main low and associated occlusion is quite close to Scotland thus very windy here with frequent heavy showers which may well merge into longer periods of rain. Some showers also in western areas further south

By Friday the low has moved away to the north leaving the UK in a breezy westerly with frequent showers, particularly over Scotland where hail and thunder could well be in the mix with the east and south east remaining fairly dry and temps around average.

There is little respite, particularly over England and Wales through Saturday as another frontal system rushes through on the strong westerly flow bringing more rain. Very mild in the south.

A not dissimilar story on Sunday as another system brings some rain and showers to England and Wales as the upper trough in the Atlantic digs further south under pressure from some transient ridging of the high pressure zones. Again very mild in the south with temps way above average

Come Monday a complex area of low pressure covers the UK thus sunny intervals and showers with a marked latitudinal temp variation whilst away to the south west another low has formed at the base of the trough

And the NH profile at T120

Edited November 29, 2018 by knocker