Model output discussion 02/02/20

[nick sussex]

16 minutes ago, feb1991blizzard said:

Yes true - the aforementioned problem is usually more prevalent with an Easterly rather than a WNW flow, the late Feb 2018 Easterly would have delivered me an even bigger dumping if the isobars were less tightly packed IMO.

Mind you its not that unstable.

I tend to steer clear of GFS predictions both in terms of that Cape Index and it’s snow forecasts . 

[Anthony Burden]

ECM 240hrs looking very interesting looking eastward ,some very cold air also not that warm to our west .

perhaps a pincer movement.

[Mapantz]

I wouldn't worry about CAPE predictions, particularly surface-based ones. Lapse rates look good and with very cold air aloft, so they'll be plenty going on!

[mushymanrob]

Im just a bit bewhildered.... most of the big name sites (metcheck, accuweather, bbc etc) arent going for snow showers and many are predicting dry for monday and tuesday. Yet the GFS and other suites do show snow showers penetrating inland. (im referring to areas away from northwest coastal regions)

 

[PiscesStar]

1 hour ago, Mapantz said:

I wouldn't worry about CAPE predictions, particularly surface-based ones. Lapse rates look good and with very cold air aloft, so they'll be plenty going on!

From a novice point of view, is that conducive to hail lightning and thunder snow? They are fantastic when they form? 

[northwestsnow]

30 minutes ago, mushymanrob said:

Im just a bit bewhildered.... most of the big name sites (metcheck, accuweather, bbc etc) arent going for snow showers and many are predicting dry for monday and tuesday. Yet the GFS and other suites do show snow showers penetrating inland. (im referring to areas away from northwest coastal regions)

 

BBC /METO raw have rain sleet locally and that for 300m asl...

EC has uppers of -7 but im not sure that will be enough when one factors in the Irish sea..

Edited February 6, 2020 by northwestsnow

[tight isobar]

2 minutes ago, northwestsnow said:

BBC /METO raw have rain sleet locally and that for 300m asl...

EC has uppers of -7 but im not sure that will be enough when ine factors in the Irish sea..

thermo gradient. .is not absorbed  yet!!..

we'll  await  the incuring flow. ..thenter perhaps  eye the overheads. ..a fickle  situation. .and 1 that could develop  a few now cast /rapid  response! !!

interesting nonetheless! !..

and something to keep our interest. ...

in disturbed  weather 'overall '!

[weirpig]

Icon for early sunday morning  10am  showing 65-70mph winds across most of the middle of England  closer to 80mph on the coasts of  England,Wales    Very high winds  still into the afternoon  Infact the high winds are still there into the evening.  Quite a duration  to be exposed to those gusts

Edited February 6, 2020 by weirpig

[SqueakheartLW]

This looks initially like a monster low on the GFS 6z run at +342hrs

That central pressure is below 920mb

However the predicted wind gusts with it are actually lower than what they are saying with storm Ciara on Sunday

Storm Ciara gusts

Gusts with this predicted low that probably won't verify like this

[Jordan S]

13 minutes ago, SqueakheartLW said:

This looks initially like a monster low on the GFS 6z run at +342hrs

That central pressure is below 920mb

However the predicted wind gusts with it are actually lower than what they are saying with storm Ciara on Sunday

Storm Ciara gusts

Gusts with this predicted low that probably won't verify like this

Those seemingly less strong winds are just in association with the frontal system of that storm the main core of strongest winds is further to the Northwest on the image.

Edited February 6, 2020 by jordan smith

[Dennis]

something seen.for coldies... i know its a long way but maybe more of you have the feeling its at the horizon.....

 

.

Edited February 6, 2020 by Dennis

[IDO]

So the 06z suppressing the euro heights and sinking the jet further south is followed on the 12z with a continuation of that theme:

D8: 

Uppers are warmed out but potential more wind and cold rain. If this repeats as on the 06z FI then the colder uppers should show up later in the run. Not quite a trend yet, but a possible development?

[SMU]

Just worth noting the GEFS have made a subtle shift in track ( not all ) on the low at 144 - the ECM built that significant high behind it so it tracked ESE over the UK

The GEFS arent building that high yet but have moved the track to a more NW > SE angle hence the cold hangs on longer & perhaps a higher risk of a snow event over the North drifts a little further south-

Heres a typical example

 

** PTB 17 is the only ECM lookalike by 192 **

Edited February 6, 2020 by Steve Murr

[BlueHedgehog074]

Not always a huge fan on commenting on charts deep into FI as it’s always liable to change. However, the GFS does seem to get some chillier polar Westerly air into the mix quite far into its run. 

The week after next would see some further chilly and wintry conditions at times (especially again towards Northern and Western UK), should the 12Z GFS be near to the mark. This model does seem to have been making the European heights somewhat less troublesome, while the ECMWF been laying out the garden path of trying to get High Pressure to the North-East of the UK.

Next week does still look to be windy, very windy, at times with a dolly mixture of wintry showers as the charts show some strong Lows to the North of the UK bringing in some chilly Polar Maritime air through the UK. No kitchen sinks likely to fall from the showers, but some white stuff, more especially on high ground, is very possible.

[shaky]

12 minutes ago, Steve Murr said:

Just worth noting the GEFS have made a subtle shift in track ( not all ) on the low at 144 - the ECM built that significant high behind it so it tracked ESE over the UK

The GEFS arent building that high yet but have moved the track to a more NW > SE angle hence the cold hangs on longer & perhaps a higher risk of a snow event over the North drifts a little further south-

Heres a typical example

 

** PTB 17 is the only ECM lookalike by 192 **

If anything like the above happened am sure the thread would defo come alive then!!lets see where ecm takes us!!!i be surprised if it looks the same as this mornings 00z between 168 and 240 hours!!

[Interitus]

Greenland tip jet forming -

Extending downstream -

Detaches, heads towards UK -

 

[nick sussex]

The UKMO is once again the flattest solution by day 6 .

No ridging between the low to the west of the UK and the one leaving Newfoundland.  

Upstream there are differences at day 6 across the models over the USA and Canada with shortwave energy .

One thing we certainly don’t want though is that UKMO output !

[stodge]

Afternoon all

Colour me none the wiser once again - the 12Z GFS OP is unstintingly disturbed all next week and indeed well into the following week before the Azores HP attempts to ridge NE in FI.

Control heads in a very different direction into FI with an intense mid-latitude HP over central Europe.

That kind of variation suggests there's no strong signal as to how the coming period of intensely disturbed weather will end. 

12Z GFS OP keeps the HP suppressed well to the SW and the trough has a slight negative tilt whereas UKMO is the more traditional "sine wave" with the HP a lot closer.

[northwestsnow]

Tues looks the day when some folk will see snow showers , uppers -7/dews negative, PM flow..

Altitude going to be needed for sure,question being how much altitude.

Edited February 6, 2020 by northwestsnow

[Mike Poole]

Well, after over two months of winter, we are now talking about a weather event or events...first the strength of the winds from storm Ciara over the weekend, and then possibilities of snow for some and further storms over the course of next week.

I like a probabilistic take on things, so here's something on the uncertainty about the strength of wind gusts, highest up to including Sunday, to T90 from the 6z ARPEGE ensembles.  The 5 plots below show the minimum, 25%, median, 75% and maximum over the distribution of uncertainty:

While the max looks over egged, there is clearly potential for damaging wind over pretty much most of the country, which is why the MO warning is widespread.  Hopefully this can be firmed up over the next day or so...

Edited February 6, 2020 by Mike Poole

[Ravelin]

Could you get more different at T192? 

 

 

[nick sussex]

The ECM is pretty similar upto day 7 with its 00 hrs runs before the wheels come off .

There are differences upstream between all the models and their handling of shortwave energy over the USA and Canada at day 6 however these aren’t really a game changer at the moment .

As we can see from the ECM op , it’s really just bailing out the water before the lifeboat eventually sinks anyway .

 

[SqueakheartLW]

The GFS 12z is bad in terms of zonality for any hopes of sustained cold but the best we get are a few cold zonality shots at times during the run

There appears to be nothing that can disrupt the polar vortex it would seem and this run shows just that from the moment the latest warming finally subsides at around +180 hours

10hpa          30hpa

And again no disruption to the vortex at any point after this right out to 384 hours. Just a nice tightly rounded ball on both charts

10hpa          30hpa

If this chart is also to be believed then the zonal winds are going almost off the scale again in the anomalies really throughout the time period but especially later on.

This other chart from weather is cool is just a sight of horror if you want anything cold. Seems like zonal winds could be setting some new records again later this month based on the mean of the GFS members and some of the CFS runs too.

All of this just translates to the expected pattern with zonal from start to finish and the two following charts are snapshots of the surface pattern at the same +180 hours and +384 hours timeslots

+180hrs          +384hrs

As can be seen, nothing but zonal but the best chance of anything wintry is within the colder sectors between systems and this will most likely be higher ground or in the far north.

[IDO]

The GFS op is in a small cluster of about 20%, so possible that it has spotted a new trend. The rest similar to the ECM op, to varying degrees, as you would expect. So the choices appear to be between, settled milder SW flow or a cool zonal wet at times westerly veering NW'ly later. Hard to get excited either way post-D8. ***No shock the amplified ECM 0z D10 fails again, probably 20+ in a row now.

So really make the most of this upcoming seasonal spell, though snow at a premium for most. Then back to the drawing board with no signal for the final warming to a more pliable tPV. Certainly not seeing any tropical forcing, any blocking is the status quo of this winter, mid-lat blocks over the Pacific, UK and Russia, and useless so far 2019/20. D16 GEFS FWIW: 

 

The spread highlighting the main two regions of doubt, UK and Pacific, as it is most of the FI period. A sorry bunch as a whole, so no change there...

[MATTWOLVES 3]

Shocking end to the ECM mean, the set up just remains all wrong, and it warms up... Its doing my grapefruit in now. This winter ship looks like its about to sink now, so it's either get a bigger boat, or man overboard... Roll on March. 

And to sum it all up, that's one hell of a purple blob of doom to the NW... Mehhh

Edited February 6, 2020 by Mattwolves