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phil nw.

Model Output Discussions 06z 04/11/16

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The deep depression that is forecast along the east coast of N. America, it has tracked there from the central states is sure dragging in some cold air from Canada around the New England/Canada border. And just as interesting the energy from this system helps push the Atlantic ridge NE and also find a southerly feed to the trough to our SW/S Oh what a web we weave.

gfs_z500a_noram_10.pnggfs_thickness_noram_10.pnggfs_z500a_natl_28.png

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1 minute ago, CreweCold said:

All a bit of a mess....

gfsnh-0-228.png?12

From this, you'd think an easterly was likely with the troughing advecting the cold air under the block eventually. However, as we've heard from bluearmy earlier today, this idea is not even on the table as far as the EC goes

Certainly is a bit of a mess with this run. I don't see a cold easterly forming either to be honest maybe a slack flow in the mid term not to be to technical but it all looks a bit flabby on this run. Something tells me the 18z will be produce a complete outlier with stunning charts which will be on the coldest end of the ensembles then should hopefully go back to something a bit more realistic on the 0z run producing a MLB block.

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This GFS run is a serious mess - it's like it can't decide what it wants to do, you can't blame it with how complicated a set up like this.

My personal opinion is I see high pressure situated over the UK, shortwave energy off the south of Greenland and around Iceland always seems to cause us serious headaches in these situations, and even if we do get lucky there's no cold to tap into JUST YET so I think it could be worth waiting.

Will be interesting to examine the ensembles, I can imagine there's going to be a very large array of different outcomes.

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6 minutes ago, CreweCold said:

Cluster 3 is the one we're after....Otherwise we'd all have to descend upon the eastern tip of Kent to get a sniff of a snow chance!

Not much wrong with cluster 2 ?

Judging by the mean,  that's the op and not the cooler para 

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I should take back what I said about the models not showing anything mild. The Gfs 12z actually shows temperatures recovering to 11/13c across the south for most of next week.

ukmaxtemp.png

ukmaxtemp (1).png

ukmaxtemp (2).png

ukmaxtemp (3).png

h850t850eu.png

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3 minutes ago, bluearmy said:

Not much wrong with cluster 2 ?

Judging by the mean,  that's the op and not the cooler para 

I read cluster 2 as more wet than white...would be dependent on depth of LPs and just how much any weak blocking to the N deflects/disrupts them to our advantage. A high risk,potential high reward scenario. Cluster 3 is a banker for cold.

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Just one of the many possible solutions given the complex nature of the setup nothing can be ruled out.

Hopefully it's an outlier mind you and it's not picked up on a new signal as the end of that run is utter dross!

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The Gfs 12z ends with a dartboard low bringing severe gales and heavy rain, it doesn't have much in common with the majority of the run which is actually quite benign.

h850t850eu.png

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I know its madness to even talk the FI but just a few more frames on and we would be looking at one huge undercut to the HP to our east. I still favour a crazy 18z display tonight before GFS realises its been a little off today and goes back to something a little more reasonable :)

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With respect to the posters here. I don't think models can be 'off' (or at least any given run), nor can they be wrong because they aren't showing us want 'we' want. The GFS can be right, it can show dross weather for weeks...it has happened before in the Winter, and I'm sure it will happen again. It's just a prediction, so there's absolutely no way we can say, "it's wrong, it will revert back to bla bla!"

Regardless of the fact that that this is 16 days away, how can we be sure it will be wrong?

gfs-0-372.png?12

Edited by PerfectStorm

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16 minutes ago, CreweCold said:

If we can't get cold I guess I'll have to settle for having my roof blown off :unknw:

gfs-0-372.png?12

If it ain't going to cold let it be stormy instead I say. 80 mph gusts bring it on dear Deep Fi

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16 minutes ago, PerfectStorm said:

With respect to the posters here. I don't think models can be 'off' (or at least any given run), nor can they be wrong because they aren't showing us want 'we' want. The GFS can be right, it can show dross weather for weeks...it has happened before in the Winter, and I'm sure it will happen again. It's just a prediction, so there's absolutely no way we can say, "it's wrong, it will revert back to bla bla!"

Regardless of the fact that that this is 16 days away, how can we be sure it will be wrong?

gfs-0-372.png?12

I'm not sure anybody has said GFS is wrong? It is just about probabilistic forecasting at these longer ranges and which outcome we believe to be more likely.

An armageddon storm on Dec 4th, 100/1

But really it is about general upper air patterns rather than forecasting in any detail, that just can't be done.

 

Edit.

Just to add the Op does have good support within its ensembles for the high to sink SE rather than get squeezed West.

That goes against other long range mean anomalies.

Which is right? 

It is just a case of seeing if the long range models change or GFS finds some consistency and other models and their ensembles support it.

Certainly can't be ruled out but still the less likely scenario IMO.

Edited by Mucka

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9 minutes ago, PerfectStorm said:

With respect to the posters here. I don't think models can be 'off' (or at least any given run), nor can they be wrong because they aren't showing us want 'we' want. The GFS can be right, it can show dross weather for weeks...it has happened before in the Winter, and I'm sure it will happen again. It's just a prediction, so there's absolutely no way we can say, "it's wrong, it will revert back to bla bla!"

Regardless of the fact that it's 16 days away, how can we be sure it will be wrong?

gfs-0-372.png?12

My reference to being "off" is nothing to do with wanting cold its more to do with the fact its been all over the place today with regards to positioning of the HPs. Once the 2 LPs over the next 4 days have passed through the models will then in my opinion show something more realisitic. The models trying to forecast deep LPs and blocking at the same will never be accurate to be honest.

So I stand by my the models have been a bit off today and by off I mean they are struggling to get grips with both scenarios although tomorrows low is probably on track now

Edited by ShaftsburySnow

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All I will say about todays Gfs 12z is I preferred yesterday's Gfs 12z.:D

12_384_mslp850.png.fa2601105dd663cdfb68ec077ce46654.png

12_384_preciptype.png.8dc49c619fc25cdfe123ee7359556d13.png

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Orange is my favourite colour.

image.jpg

GFS continuing to show strat warming in FI

Edited by Spah1

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GFS ensembles a real mixed bag in FI.

Some fairly flat Atlantic driven runs, some mild, some cold zonal, others with decent blocking and cold shots. No real signal overall and with the Op lurching around hard to take anything from it good or bad TBH.

graphe3_1000_256_106___.gif

Edited by Mucka

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4 hours ago, Nouska said:

Yes, from an E. European weather agency so focus on their region.

 

You'll be struggling to find an analogue for this year - so many anomalous factors.

I've been through old charts and nothing similar to current N. America/Arctic/Siberian anomalies.

Just to expand on this - below is the 925mb temp anomaly for the first fifteen days of November - all the negative anomalies are outwith the arctic circle and mostly in the eastern arc of the NH - nothing* of this pronounced nature in the modern ESRL record going back to 1948.

114859d0cc748c1c4f96ff7239dc73e3.gif

 * Only one other year with a similar, but weaker, profile.

compday.jdDpz_UZlV.gif

What about 83/84? Similar looking weak La Nina and Eurasia cold.

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2 minutes ago, Mucka said:

GFS ensembles a real mixed bag in FI.

Some fairly flat Atlantic driven runs, some mild, some cold zonal, others with decent blocking and cold shots. No real signal overall and with the Op lurching around hard to take anything from it good or bad TBH.

Yep   all over the shop ..........not a good sign me thinks

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The GFS 12hrs run tries but fails and any blocking doesn't last long. If we do see a block it needs to be aligned with the jet cutting back towards the Low Countries not angled se'wards.

That way you direct the colder air into the UK rather than to the east. In terms of both the GFS and UKMO they have failed miserably over the last few days and came up short upstream with their handling of low pressure there.

The ECM has wiped the floor with both and so has repaired its recent damaged reputation for the time being.

 

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Brutal warmth hits southern Europe. Sales of factor 20 soar.

gefs_t2ma_5d_eur_37.png

Mitigated by some retrogression of the HP and a trough running south

gefs_z500a_5d_nh_61.png

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4 minutes ago, Banbury said:

Yep   all over the shop ..........not a good sign me thinks

Still 12 days of autumn left after today, a few so so op runs is no cause for concern.

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Too busy to post charts, but l think the GFS ensemble mean still indicates blocking to the NW

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Sounds good to me. Correct me if I'm wrong. 

 

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1 hour ago, bluearmy said:

Is that what I said?

uppers are also below average throughout apart from a couple of days around day 20 and after xmas

 And any west based NAO becomes less likely after week 3 as height anomolys rise more notably around Greenland. Weekly Mean anomolys are not too details at his range though 

Just like to apologise for my comment, it was worded badly, I take cold uppers as uppers likely to produce heavy convective snowfall, ie - at this time of year -8c to -10c, but I would imagine the average for Nov is around -2c. so anything -5c is classed as cold.

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