Model Output Discussion - Into Autumn 2019.

[Methuselah]

A couple of snapshots from today's GFS 00Z:

   

   

[Summer Sun]

Looking at the ens the unsettled spell could just be a blip maybe something better developing during next week?

[weirpig]

Maybe only brief   but single digits  for many on this chart  colder in Scotland  with some glens  only getting to around 2-4c   certainly  different as we start a new month 

[Frosty.]

The chance of an Arctic shot is there again, this time on the Gfs 6z operational with snow on northern hills / mountains, ice and frosts at the end of sept / start of oct..Boom?!!.❄❄

In the meantime, enjoy this week's rain, for some it's very much welcome..South / Southeast / East Anglia!!!!!!

 

Edited September 23, 2019 by JON SNOW

[Methuselah]

Aye karl, a rather unpleasant four days, should the GEFS 06Z prove correct.

   

 

   

Now to see if it gets into the reliable?

[knocker]

The filling low will edge closer to the west coast of Ireland through this evening and overnight as the associated fronts continue to track north east up the country

By 1700 the main moderate rain band will be Isle of Man > west Midlands > Sussex on it's journey north east but by around 0100 rain with embedded heavy thundery outbreaks is encroaching the south west and this will also move north east through the early hours of tomorrow morning and then spread further afield as Tuesday morning gets underway. Apart from all of this a very mild night

 

Edited September 23, 2019 by knocker

[ARW WeatherMan]

5 hours ago, Summer Sun said:

Looking at the ens the unsettled spell could just be a blip maybe something better developing during next week?

If the 850 temps were to reach almost 20oC what temperature should we expect on ground level at this time of year? 26/27oC? 

[booferking]

Ukmo looks tasty for late sep.

[Zak M]

Tomorrow looks like an interesting day with the arrival of Ex-Humberto. By Tuesday morning some showers are likely over parts of Wales, the SW and southern England. Some of these showers could produce embedded lightning and could merge into longer spells of rain, causing problems on the roads with flooding likely in other parts of the UK. When these heavy showers or longer spells of rain clear away and start moving NE, some more heavy, perhaps thundery showers could develop in the south.The temperatures on Tuesday could range from 14-21c in the south, and 12-19c in the north. So, for the rest of the week? Well, for the next 5 days, it's just a case of weather fronts bringing heavy rain to the British Isles.

 

[feb1991blizzard]

We don't want this to verify, poor Arctic profile which would return a positive OPI value, not what you wan't this early in October.

[knocker]

The evolution from the gfs over the weekend is pretty much as already discussed so the charts Sat > Monday should suffice without further waffle Basically a continuation of likely unsettled weather this week

 

Edited September 23, 2019 by knocker

[Frosty.]

I'm liking these charts the Gfs keeps churning out, timeframe doesn't matter in this case, there have been similar charts in high res today and recently!!! 

 

[Radiating Dendrite]

55 minutes ago, feb1991blizzard said:

We don't want this to verify, poor Arctic profile which would return a positive OPI value, not what you wan't this early in October.

Not the OPI - I thought that was proven to be a busted flush circa 2015? I really don't think the pressure patterns in October will determine whether we get a chilly spell in February. 

[Methuselah]

So, the tail-end of the GFS 12Z looks interesting, in a moot kinda way:

   

And, anywho, as the GEFS 12Zs clearly demonstrate, the 'interest' has more to do with scatter than trends:

   

   

And, as for all the 'indexes'? One may as well enter a raffle, in order to win a chocolate teapot!?

[knocker]

The ecm continuing unsettled over the weekend and beginning of next week as systems track east under the Greenland/Iceland block, albeit complicated to some extent by the two energy flows around it, before an intervention by some more amplification of the subtropical high later but that's getting ahead of ourselves

Edited September 23, 2019 by knocker

[MATTWOLVES 3]

2 hours ago, JON SNOW said:

I'm liking these charts the Gfs keeps churning out, timeframe doesn't matter in this case, there have been similar charts in high res today and recently!!! 

 

Hey Karl... No half measures for me! Snow over the higher mountains of Scotland and cool rain elsewhere doesn't really float my yacht at this time of the year. Back to earth with a bang, and we have an encouraging mean to finish off the night.... High pressure perhaps building with an upturn in those temps to boot!! Winter for me can wait till the appropriate time.

[knocker]

The North Atlantic 500mb and surface analysis for midnight

At the moment there is still some showery rain over Scotland from yesterday's frontal system which will clear this morning. But the main area of rain, with thundery outbreaks, is tracking northeast and is currently over central SW England and east Wales.and this will effect most of England and southern and central Scotland through the day. There could well be some significant rainfall in some places. Showers will follow in the wake of main rain area but by lunchtime another area of heavy showery rain will encroach the south west and move east. Note the convergence zone on the analysis.

Through this evening and overnight the centre of the filling low moves into the southern Irish Sea and the bands of showery rain will continue to travel around in the circulation mainly effecting the north and south of the country. Cloudy and murky elsewhere

Wednesday the low is over East Anglia so still some heavy showers around in the east, and to some extent Scotland also. whilst elsewhere tending cloudy but dry. But to the west a new trough has arrived on the scene

Over Weds night and through Thursday fronts associated with the new low will sweep across the country bringing rain and quite strong winds to most with showers following on once the fronts clear to the east

On Friday the country is in the circulation of the low now centred to the WNW of Ireland so a day of sunshine and showers with perhaps some longer spells of rain in western areas courtesy of the wrap around occlusion

By Saturday we are reaching the point in the evolution that has previously been discussed with the block setting up in the Greenland/Iceland area and the two energy flows around it. Which essentially translates to windy showery day with another frontal system approaching from the south west.

 

Edited September 24, 2019 by knocker

[knocker]

According to the gfs this is the NH profile for midday Sunday and the new wave mentioned above is tracking across the south

Over the next couple of days the Atlantic/trough conduit continues so remaining unsettled but by Wednesday the subtropical high is stirring and interrupts this. Note TS Lorenzo has latched on to the base of the Atlantic trough

[Timmytour]

There's a big question mark in that last map though Knocker.....

[knocker]

The ecm makes rather more of the low on Sunday than the gfs but it too amplifies the subtropical high next week with a trough swinging south in the northerly flow early Tuesday It is but a transient ridge

[Frosty.]

On balance the GEFS 0z mean is trending more settled / benign as we go further into early october, at least across southern uk.

[coldwinter]

14 hours ago, Radiating Dendrite said:

Not the OPI - I thought that was proven to be a busted flush circa 2015? I really don't think the pressure patterns in October will determine whether we get a chilly spell in February. 

The OPI was linked in with the snow cover advance theory, as well as pressure patterns across the hemisphere,  a predictor of the winter time AO. But people took it as a gospel for a cold winter, i feel it still has some merit wrt strength of the Siberian high, strength of the PV going into October, and possibly further 'attacks' on the PV through November into December. I certainly don't think its amazing, but there does definitely  seem to be a link between October pressure patterns and the wintertime AO. 

[mb018538]

1 hour ago, JON SNOW said:

On balance the GEFS 0z mean is trending more settled / benign as we go further into early october, at least across southern uk.

It certainly is Karl:



Not quite nailed on yet as there are still quite a few unsettled members lurking in the ensembles. The mean is only 1020mb too - I always feel you like to see a mean of 1025-1030mb to have a true high pressure settled spell, 1020mb tends to be a weaker and more transient high.

[knocker]

Through this evening and overnight the UK will reside under the umbrella of quite a complex upper trough that dominates the eastern Atlantic. Thus a myriad of fronts/troughs and low centers running around in the circulation resulting in a lot of showery and at times heavy rain in some areas and strong winds along the south west and south coastal regions of England

By late afternoon the main rain band will be roughly down central and southern Scotland to north east England with some showery activity SW Wales and England, Through this evening and overnight the rain in the north will be mainly concentrated over eastern Scotland and north east England whilst another area of rain will track east from the south west effecting an area south of a line north Wales > the Wash which could well contain some heavy pulses. The main band should clear the south east by dawn

 

Edited September 24, 2019 by knocker

[CheesepuffScott]

Next Thursday into Friday, GFS brings the the remanants of TS / Hurricane(?) Lorenzo approach the British Isles, tracking north east towards Ireland before weakening, this brings some warm air for a time after it.

Then by the new week, we have a deep low over Southern England... fantasy island of course.

 

Edited September 24, 2019 by CheesepuffScott