Model output discussion - is the beast awakening?

[Weather of Mass Disruption]

1 hour ago, Pennine Ten Foot Drifts said:

So, not wanting to be Mr Grumpy, but having been on here model watching for 16 (!) years:

FI = anything beyond T180, and what Operational models are showing is the slight favourite amongst a wide range of possible outcomes. no point viewing these for any local detail, or really even with any great confidence.

T144 - T180 = most likely broad synoptic pattern i.e. likely to be warmer / colder / wetter / drier than average, but in terms of local detail, barely more reliable than FI.

T72 - T144 = broad synoptic pattern likely to be accurate (but not 'nailed on'!). Detail starting to be defined, but for a small area such as the UK, in a predominantly maritime influenced region, confidence in accuracy of detail is still not high. And it mustn't be forgotten that what are actually relatively minor changes to the broader pattern can still have significant changes for UK localities, so even at this range, for 'my location' confidence in just how much warmer / colder / wetter / drier than average is not going to be very high at all.

T36 - T72 = confidence in broad synoptic pattern is high, confidence in local forecast is moderate to high dependent on the volatility of the forecast pattern i.e. a forecast large high pressure can give pretty high confidence of at least dry weather locally (although, for example, cloud amounts even at this range cannot be forecast with absolute certainty), whereas what we're looking at now i.e. highly volatile synoptics, means even at this range confidence of local weather conditions is no better than moderate (and in this case probably lower than that).

T12 - T36 = broad synoptic pattern highly likely to have been resolved, fairly high confidence in local detail, but again, as for T36 - 72, dependent on the type of synoptics being forecast, changes can happen.

T0 - T12 = radar watching!

So, for the upcoming 10 days, trying to predict where snow may fall next weekend is at this juncture pretty futile, (and even now, it's quite possible the synoptics will change such that nowhere outside the usual northern upland suspects see any at all). I'd say, assuming the currently modelled synoptics play out broadly as forecast, the soonest we'll be able to confidently start anticipating widespread lowland snow will be Wednesday.

Great post  and I couldn’t agree more. My feet are firmly on the ground, I’ll only start to get excited at the prospect of an Easterly if it is still showing at T12- T36, even then I’ll still be twitching. Seen too many near misses over the years, which have led to much disappointment 

[bluearmy]

Can we change the name of the thread - since we opened this on Friday things have got progressively less beast like !

[Bermuda High]

24 minutes ago, sunnijim said:

To continue my obsession with the balance of probability, would love to know what the mogreps,decider,M.O outlook and our  other friends on the free to view models were calling for a that time?

Molegrips and nodecider failed epically in winter 2018,2019 especially February 2019.

[tight isobar]

The members gfs - ensembles...are cracking tbh.

 

 

..and are certainly beginning a reaembilistic look of those of 2018!!!!...onto the 12z....✌

Edited January 31, 2021 by tight isobar

[Methuselah]

4 minutes ago, bluearmy said:

Can we change the name of the thread - since we opened this on Friday things have got progressively less beast like !

Whimper Watch?

[Chasbrown]

6 minutes ago, bluearmy said:

Can we change the name of the thread - since we opened this on Friday things have got progressively less beast like !

How about The Beast Is Dead?! 

[tight isobar]

21 minutes ago, northwestsnow said:

On a brighter note I doubt we will have to wait until 6.30 pm to know whether its hoorah Henry or downbeat Doris 

UKMO will be out for 4pm.

That will reveal all.

I agree..the ukmo raw on a BIG stage this afternoon...

[Vikos]

9 minutes ago, Chasbrown said:

How about The Beast Is Dead?! 

The Beast 2.0 - It never happens (again!)

[cyclonic happiness]

"The Least From The East"?

[sheikhy]

How about "ecm the return of the king"!!!

Edited January 31, 2021 by sheikhy

[Battleground Snow]

23 minutes ago, bluearmy said:

Can we change the name of the thread - since we opened this on Friday things have got progressively less beast like !

What do we define as the beast?

 At least -10 uppers and a feed from the east with low heights over UK? Granted it's only the GFS and maybe gem showing this ATM

[Garthvader]

Interesting ......sharp rise again last 12hrs!

[That ECM]

25 minutes ago, bluearmy said:

Can we change the name of the thread - since we opened this on Friday things have got progressively less beast like !

Bet the mods are glad you asked

 

t96 for comparison as the 12z’s come out.

[birdman]

40 minutes ago, Snowman. said:

Usually it just ends up with one thread completely dead and the other extremely active. It has been semi-tried with one thready being model discussion and another being a cold chase.

Who would dictate where FI starts? Too many logistics to work out, FI is still model discussion and the regionals are for weather closer to the current day. Current thread is fine you dont have to read every post you can just skip them.

Fair points. Just seems to me they're as useful as a chocolate fireguard but as you say, they're valid charts nonetheless 

I suppose at the moment FI starts in 5 days time! 

[BlueHedgehog074]

If the evidence increases over the next few days for the models to put the beast to sleep, I guess we could make a few tweaks to the thread title

[Vikos]

Op in the smallest cluster But yet we go crazy over it...

[Doctor96]

BLUE ARMY 

 

here in the north east of England i am looking forward to the beast from the east which is just about there with the GFS . 

[tight isobar]

29 minutes ago, DiagonalRedLine said:

If the evidence increases over the next few days for the models to put the beast to sleep, I guess we could make a few tweaks to the thread title

Not gonna happen pal...there will be an-easterly flow by late next week...the scrutiny should only be how established.=prologned she becomes!!!...see ya @the 12z suites.✌

 

Edited January 31, 2021 by tight isobar

[phil nw.]

The differences in the way the UK low complex is modeled is certainly keeping everyone focused.I guess the forum will be very busy soon.Anyway here's the latest fax at t84

We can't really deduce from that what will eventually happen but it does underline the sharp boundary between the mild and cold.I think Scotland and the n.Isles especially have been seeing that cold arctic feed for some time with snow showers ongoing.

I do often use the ensembles, as do many others i realise, and usually they are a decent guide to any upcoming setup  as they can be quite useful in showing outliers in a macro 500 hPa pattern and upper air temperatures etc.

In this case however, where we are looking at quite short range for a resolution on a particular feature, you would normally favour the higher resolution of the operational runs.The movement of the low complex could go either way or indeed stall,It's impossible to make a confident judgement at the moment i think.

If by chance the ECM op is the one that evolves all is not lost imo. The basic HN pattern still looks primed  for further cold chances with the cold block to the north continuing to hold just waiting for a kick further south.There is plenty of signs further ridging will be available across the Atlantic.

It would be great if the UKMO raw charts prove correct so we could all see the cold come right down to the channel by the weekend.

Hopefully the 12z runs give coldies a big lift this evening.

Edited January 31, 2021 by phil nw.

[BlackburnChris]

Don't know why everybody is so downbeat this afternoon, The Beast is still there on several models and ensembles ...

WWW.METEOCIEL.FR

---

Meteociel propose des cartes de prévisions du modèle americain GFS

 

[Catacol]

There are signs in the pacific of a substantive increase in AAM. Never easy to predict exactly how this indicator will develop, but let’s take a stab. Mountain torque has spiked significantly

and we have a rise in relative tendency already in the bank

. 

The GWO orbit has begin the rise from the more Niña orbit that took hold in mid January

and if Ventrice’s GFS based predictor is anything close to accurate we may be about to see a quite significant rise into a higher orbit

What does all this gobbledygook mean? Putting it simply, westerlies at the equator are predicted to increase as the MJO moves into that key 7/8/1 zone which lies in the western Pacific. Westerlies here will help suppress the sub tropical ridges that are mostly responsible for +NAO patterns in our sector, and the downstream wave pattern produced by a surge in these westerlies strongly favours northern blocking.

 Putting this into a broader big winter context, the distressed vortex and dislocation to Asia through January was able to override the tropospheric signal which at that point had convection in the Indian Ocean and a downstream forcing which would have usually promoted a +NAO signature. See the seasonals for the impact. But seasonals do not predict SSW events well at all, and we have come to know that a SSW event is our golden trump card - never guaranteed to bring in Siberia, but guaranteed to throw the hemispheric pattern into chaos. We have reaped the benefits of this despite the disappointing failure to split, and the northern part of the country has seen cold and a lot of snow....and the south has seen some too. And now....with the vortex still in distress and currently undergoing another hit to its strength we have the troposphere coming to our aid.

So...unless reasonable interpretation of what’s happening in the Pacific is way off we can expect back to back cold months this season, and maybe in February we can tap into a period of sustained and severe cold. January was a real rollercoaster for weather lovers. So much happened....so much potential and excitement and twists and turns. February will be no different I suspect. 

 

 

 

 

Edited January 31, 2021 by Catacol

[bluearmy]

18 minutes ago, Doctor96 said:

BLUE ARMY 

 

here in the north east of England i am looking forward to the beast from the east which is just about there with the GFS . 

It’s cold on Gfs ( poss deep cold for a time ) but it isn’t a beast doc 

[supernova]

46 minutes ago, birdman said:

Fair points. Just seems to me they're as useful as a chocolate fireguard but as you say, they're valid charts nonetheless 

I suppose at the moment FI starts in 5 days time! 

Much less I reckon, @birdman, probably more like 3 although the broad journey toward cold snap rather than cold spell (as it stands) remains likely. The earlier post by @Pennine Ten Foot Drifts nailed it perfectly actually. 

[Eskimo]

If I hadn't looked at the output for a few days, I'd be forgiven for thinking the outlook had suddenly switched from an easterly to a b******t unanimously across all the models. I would think at that point, "yeah, fair enough, that's pretty disappointing!"

Most of us are chasing nirvana, and yeah it doesn't look as fantastic as it did a few days ago, but the outlook looks far from 'home'. 

[Man With Beard]

Are there any precedents for how the models handle these situations? One of my loves is working out what a model is likely to do in a given situation, whether it is likely to correct north or south, etc. depending on past actions.

Many years ago, I took it as a given than an easterly would correct south between T144 and T72, but in recent years that error has disappeared. The ECM did pretty well at T144 in Feb 2018 and also in the recent easterly at the start of the month - almost bang on precision with what occurred come T0.

However, there is a precedent for the ECM making a mess of a low at T144 causing it to mistakenly miss an easterly, and the other models (inc ensembles) outfoxing it. The second "beast" of March 2018: Look below how the ECM was way off at T144 and T168, yet the GFS and UKMO, and even the ECM ensembles had it pretty close at this range:

Actuals: 17th & 18th March:

    

GFS at T144 / T168

    

UKMO (first attempts at each date, T144)

    

ECM ensemble mean at T144 / T168

    

And now the ECM op at T144/T168

  

Will history repeat itself!