Model output discussion - mid-winter

[Weather-history]

1 hour ago, CreweCold said:

I'm a storm lover but these runners can be a whole different beast due to their RACY nature. If it hits just at the right time you'll catch it whilst it's bombing...mixed in with the fact that the conditions it has bred in are ripe for severe weather (gradient between HP and LP), it would not be a storm to be messed with. It wouldn't be your typical autumn blow. We're talking over land gusts of 90mph...something rarely ever seen.

If you look back through the archives, these runner type lows in tight pressure gradients have historically brought the UK some of its most severe storms and resultant devastation.

The burns night storm started in a similar way...

That happened in a period of cold zonality, The day before we had an unexpected snowfall across north Wales, north Midlands, southern parts of NW England caused by a small trough in the flow. Something to watch out for in this type of flow. 

Edited January 13, 2018 by Weather-history

[Banbury]

1 minute ago, Rocheydub said:

Some confusion here. If that low tracks further north, it will introduce milder air making the storm a rain event mostly, before and after would be snow mind you. If it’s snow you’re after, you want this storm to track further south by about 300 /400 miles and be a much shallower affair. Lots of posters also saying they see this as actually being further south than being modeled. That to me is pure hopecasting!!! One thing is for sure, if it stays as programmed , it’s going to be a wild one!

Not too sure it’s hopecasting , historically as time goes on the models push the LP further South 

[MR EXTREMES]

As I suggested a couple days ago upgrades are very likely and more to come.

Excellent cold wintry charts.

[georgiedre]

29 minutes ago, Man With Beard said:

Up to 90mph even inland through the Sheffield/Leeds area

I live 7 miles from bangor and its safe to say they wont get that much wind. Maybe snowdon might get that

[supernova]

To my eye ARPEGE has snow only for higher elevations in the NW next week. Dew points and uppers certainly marginal. Hope that’s not the case.

[nick sussex]

As CC rightly said these types of low pressures are by far the worst compared to those bigger systems.

I detest these fast developing lows which run east at the base of the trough. They’re much more difficult to track and often have higher winds than larger systems.

I’ve had two major storms here in sw France over the nearly ten years I’ve been here and they were these small lows.

The first was an absolute horror show  , power out for 5 days and I was lucky no major damage. Areas further north fared even worse , the Landes forest area was decimated and sadly there was loss of life.

Having said this the current one modeled could just as easily be downgraded , if not I hope people don’t take any chances.

 

[Man With Beard]

6 minutes ago, georgiedre said:

I live 7 miles from bangor and its safe to say they wont get that much wind. Maybe snowdon might get that

Probably, but I wouldn't bet on it. Lots of even worse options in the ECM ensembles, and some in the GEFS too.

Overall the trend has been to keep this low running through midlands/north, snow risk will always be to the north of the centre of the low (and maybe the rap-around after but this won't be much on such a fast moving low).

[shaky]

14 minutes ago, Man With Beard said:

Probably, but I wouldn't bet on it. Lots of even worse options in the ECM ensembles, and some in the GEFS too.

Overall the trend has been to keep this low running through midlands/north, snow risk will always be to the north of the centre of the low (and maybe the rap-around after but this won't be much on such a fast moving low).

Its crazy though how u mentioned yesterday a lot more of the ensembles had it running further south on the ecm and ensembles but today they have flipped and the op takes it further north!!gfs probably better at this type of stuff maybe cos its to do with the atlantic and normally handles things better out there?

[OfficialKevWX]

I’d expect a mix between GFS and UKMO outputs wrt the runner on Thursday

[MR EXTREMES]

I think perhaps forget marginal and wait until we see as systems move on.

Definitely a plunging ao index and very possibly a neg nao.

The heights to the north of Greenland still there and moving forward in its timeframe.

Could well have mid latitude block perhaps linking with the north Greenland heights.

One thing noticeable is the ever more disrupted jet stream.

Over all cold wet windy for the south but surprises likely towards end of the week.

West and north and Northwest is best Midlands as well, Ireland going to get there well deserved snowfall to.

But wintry outlook is definitely the outlook.

[andymusic]

let's see where the barrelling destructive low runs now on the gfs 6z - north/south - hurricane with blizzards, trees flattened etc, or low further south with more snowy ops

[Summer Sun]

13 hours ago, Summer Sun said:

UKMO extended appears to be heading towards a northerly

And here it is

[snowfish1]

32 minutes ago, nick sussex said:

As CC rightly said these types of low pressures are by far the worst compared to those bigger systems.

I detest these fast developing lows which run east at the base of the trough. They’re much more difficult to track and often have higher winds than larger systems.

I’ve had two major storms here in sw France over the nearly ten years I’ve been here and they were these small lows.

The first was an absolute horror show  , power out for 5 days and I was lucky no major damage. Areas further north fared even worse , the Landes forest area was decimated and sadly there was loss of life.

Having said this the current one modeled could just as easily be downgraded , if not I hope people don’t take any chances.

 

No "horror show" on gfs this morning Nick I always laugh when u use that catchphrase 

[feb1991blizzard]

This storm is going to bring a mild sector in anyway so any snow Tuesday is likely to melt, I'm starting to hope this storm tracks right through me, potential for a sting jet - those are the best storms.

[Captain Shortwave]

Regarding that low Wednesday night, you can either have a snow event or a wind event, in this case you can't really have both. If that low deepens it willtravel slower and move further north and willbring milder air ahead of it so the snow people would have would melt and the preicipitation will be of rain. The shallower the system, the less mild air gets mixed in so ideally we want the low to be tracking as far south as possible and as shallow as possible, in the end for snow this will probably hit the Midland south (Shallow feautre) or not produce any snow at all (Further north and deeper).

Beforehand, the risk of showers just about anywhere with western areas favoured most but there could be shower trains and streamers which could penetrate further inland, one in particular looks like running from the Mersey/Dee ESE through the North Midlands and into Norfolk and Suffolk. Also as Steve mentions there is a wave whichruns through Scotland Tuesday night.

Edited January 13, 2018 by Captain Shortwave

[shaky]

Looks like gfs has picked up a new trend and this 06z run is so far the same as the 00z run in its track!!expect ukmo to come in line later!!

[SMU]

06z T90

very obvious trough over SE Scotland extending SE out through Ireland moving SE....

That will bring more organised snow with embedded -8s

[snowice]

108 key time frame look for the low North of Ireland. 

[Banbury]

2 minutes ago, shaky said:

Looks like gfs has picked up a new trend and this 06z run is so far the same as the 00z run in its track!!expect ukmo to come in line later!!

Far too early to say 

[northwestsnow]

3 minutes ago, Steve Murr said:

06z T90

very obvious trough over SE Scotland extending SE out through Ireland moving SE....

That will bring more organised snow with embedded -8s

Hi steve...any thoughts as to why there seems to be a complete lack of mention of snow in the tv forecasts?

Seems odd given the models..

[bluearmy]

just checking out the 48 hour trend on the eps days 10 to 8 shows the scandi trough sharpening and edging west whilst the mid atlantic ridge, not surprisingly also sharpens. There may be a littlest further to go on this yet and the upstream pattern that follows Is firming up - coldies require more ridging/wedging  around griceland , and the next system to slide. A broad repeat of Dec 11 weekend 

[shaky]

Storm slightly less deep on this run by 5mb!!

[Day 10]

Similar track to last run not quite as intense.

[snowice]

Looks like snow to rain than back to snow from the West on 6z.

Edited January 13, 2018 by snowice

[bluearmy]

9 minutes ago, shaky said:

Looks like gfs has picked up a new trend and this 06z run is so far the same as the 00z run in its track!!expect ukmo to come in line later!!

Does the gfs pick up the trend first because it comes out first?  On that basis, we will be paying homage to the icon more often than not! 

Edited January 13, 2018 by bluearmy