Model Output Discussion - cold spell to end Autumn

[radiohead]

Looking very stormy indeed here.

Edit: could get a transition from rain to blizzards as the deep low wraps colder air down. 

Edited November 30, 2017 by radiohead

[Day 10]

Such a fine line between wet & windy or blizzards! It's just another option on the table, very interesting viewing.

[festivalking]

 

Some tasty winds round that system!!!

 

[tight isobar]

The system is off the scale...

But look at the air coming in'..

In-regards to it!!!

[A.J]

2 minutes ago, Dean E said:

Think you might be right with that one, does appear to slowly form off that Low towards Newfoundland. Clearly tired eyes!

I think it's more a case the phrase 'shortwave' gets used an awful lot in the model thread, and often incorrectly IMHO.....I'm no expert but it's a bit like describing a 'light shower' and a 'thunderstorm' as the same thing.......just a pet peev, I'll go back to grumbling to myself under my breath 

[Dean E]

Just now, ajpoolshark said:

I think it's more a case the phrase 'shortwave' gets used an awful lot in the model thread, and often incorrectly IMHO.....I'm no expert but it's a bit like describing a 'light shower' and a 'thunderstorm' as the same thing.......just a pet peev, I'll go back to grumbling to myself under my breath 

Agreed! To be honest, right now shortwave is the last thing I'd like to hear 

[MattTarrant]

The Jet Stream profile is notably different on this run. The 6z run has more energy going into the southern arm, the 12z has more going into northern arm combining with a higher latitude based northern arm jet. The net result is the low pressure traversing a more northerly route in contrast to that of the 6z. 

[Methuselah]

14 minutes ago, ajpoolshark said:

surely they're secondary low pressure centers and not 'shortwaves'?.......look at the pressure contours..................the low pressure to the west of the azores,  now that has a shortwave trough on it, to the east of the LP center

You are not alone in being less than enthusiastic, as far a 'shortwaves' are concerned, aj...What's wrong with 'frontal wave', 'wave depression', 'secondary low', 'minor low' or even 'kink in the isobars'?

Edited November 30, 2017 by Ed Stone

[IDO]

The EPO ridge modeled stronger on 12z, similar to 0z. That will just fire up the jet and power through off US trough flattening downstream longwave pattern, UK included and killing any HLB:

 

If the Eastern Pacific Ridge continues to be forecast I think we will miss out on this chance. No surprise these lows are blowing up with so much energy in the jet, and they will wash out the cold uppers.

Still time for upstream LW corrections but there is now inter-model support for the E Pacific wave and that has been a pain in recent times for UK cold.

Edited November 30, 2017 by IDO

[Derecho]

Poor 12z's so far if its sustained cold you are looking for, GFS has a brief northerly and NW'ly but again too far out. The Greenland high isn't strong enough earlier on.

UKMO also doesn't look good at all TBH.

Lets hope we see a turnaround, as mentioned earlier this is very finely poised hence the huge scatter in the ensembles. The SLP ensembles for the Greenland area will be interesting.

Edited November 30, 2017 by Quicksilver1989

[bluearmy]

Gem and gfs heading the same way days 8/10 with jet heading in a nw/se axis - fits in with eps 

 

[radiohead]

A significant wind event on the 12Z GFS.

[northwestsnow]

5 minutes ago, IDO said:

The EPO ridge modeled stronger on 12z, similar to 0z. That will just fire up the jet and power through off US trough flattening upstream longwave pattern, UK included and killing any HLB:

 

If the Eastern Pacific Ridge continues to be forecast I think we will miss out on this chance. No surprise these lows are blowing up with so much energy in the jet, and they will wash out the cold uppers.

Still time for upstream LW corrections but there is now inter-model support for the E Pacific wave and that has been a pain in recent times for UK cold.

We could be looking down the barrel of a very disturbed period of weather if GFS is correct- added to that according to the strat thread the GFS is also forecasting an uptick in zonal winds and a stronger PV..

[SizzlingHeat]

So another couple of cold days followed by a milder weekend and then a mild week followed by perhaps a stormy beginning to next weekend. Not much cold showing up now anymore.

[frosty ground]

2 minutes ago, radiohead said:

A significant wind event on the 12Z GFS.

Gone by the 18Z back by the 0z.........
 

[knocker]

49 minutes ago, Dean E said:

Short wave at +102hrs already modeled weaker on the 12z, compared to the 06z at the same time (4th Dec)

06z +96                                                   12z +102hrs

 

It's one of a series of frontal waves that form, and disappear, on the active front. It's the boundary between the cold and warm air

Edited November 30, 2017 by knocker

[Djdazzle]

Interesting that people were saying the other day that the Atlantic looks dead and the one thing that won’t happen is a return to zonality!

 Very poor output now if you are looking for cold.

[Frosty.]

Must admit I'm liking the run up to mid December on the Gfs 12z...Bank!!☺????

[Summer Sun]

4 minutes ago, Djdazzle said:

Interesting that people were saying the other day that the Atlantic looks dead and the one thing that won’t happen is a return to zonality!

 Very poor output now if you are looking for cold.

 

It was but now the models are picking up on the major cold outbreak for eastern America this will fire up the Jetstream we could still end up on the cold side of it yet though

 

[johnholmes]

26 minutes ago, Ed Stone said:

You are not alone in being less than enthusiastic, as far a 'shortwaves' are concerned, aj...What's wrong with 'frontal wave', 'wave depression', 'secondary low', 'minor low' or even 'kink in the isobars'?

It sounds clever is the main reason, the US forecasters use it, usually in the more meteorological sense.

[East_England_Stormchaser91]

11 minutes ago, Djdazzle said:

Interesting that people were saying the other day that the Atlantic looks dead and the one thing that won’t happen is a return to zonality!

 Very poor output now if you are looking for cold.

Still a lot that could happen. 120 hours is a very long time in model output. Look how much has changed over the last day and a half.. 

[Frosty.]

3 minutes ago, johnholmes said:

It sounds clever is the main reason, the US forecasters use it, usually in the more meteorological sense.

I've always wanted to hunker down as the Americans call it when a blizzard hits..if the Gfs 6z verifies i will get my wish!☺?????

[Methuselah]

1 minute ago, Frosty. said:

I've always wanted to hunker down as the Americans call it when a blizzard hits..if the Gfs 6z verifies i will get my wish!☺?????

You'll need to hunker down in your 'frame-supported tension structure' then?

[Djdazzle]

2 minutes ago, East_England_Stormchaser91 said:

Still a lot that could happen. 120 hours is a very long time in model output. Look how much has changed over the last day and a half.. 

True, but very unlikely if the ECM shows cross model agreement later.

[Johnp]

I must be looking at another GFS run to everybody else?

Looks cold and potentially snowy to me.