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Model discussion - Warm spell ending as Spring begins


Paul

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

Look at how rapidly this low deepens, if this verified then for once the Daily Express definition of 'Weatherbomb' would actually be at least somewhere near the truth.

image.thumb.png.2e6f06b6a05a87016f8371cf4fed18fb.png

image.thumb.png.5b5e830d3cd9b7bfafadeb5a72fdba89.pngimage.thumb.png.bca0e2f9d1f8c718841657803163fa6c.pngimage.thumb.png.0635fed7c180e991930cbed55f36b362.png

 

Edited by feb1991blizzard
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Posted
  • Location: oldham
  • Location: oldham

GFSOPUK06_144_53.pngGFSOPUK06_147_53.pngGFSOPUK06_150_53.png

That's a pretty nasty rain event for North Wales, snow possible on the northern extent but the big picture would be flooding

Snow around the northern and western flank as the system pulls away

Edited by frosty ground
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Posted
  • Location: Reading/New York/Chicago
  • Location: Reading/New York/Chicago
50 minutes ago, feb1991blizzard said:

Your never going to be that accurate that far out - its a strongly +AO / NAO setup which it got right.

Yes. It's often said, but look at the overall pattern: the 500mb forecast was largely correct, but it's incredibly difficult to forecast exact conditions closer to the surface at a longer range. Given the range involved, it's pretty good. If you'd looked at the 500mb forecasts you'd have said that the likelihood for the weather in ten days time was unsettled with a high probability of rain at times. And so it transpires.

Edited by WhiteFox
Typo
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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

Potential for 2 snow events across the north, between Sunday and mid-next week, if GFS is to believed.

Both GFS and EC flagging up potential for some snow across N. Ireland, N England and S Scotland on the northern flank of a wave low moving east on Sunday, as colder air wraps in from the NW combines with heavy ppn lowering freezing level. 00z EC below:

ECMWF_096_GB_SFC_fr-FR_fr.thumb.png.0bec4a1dbfc50892311cd133f8ea41d6.pngECMWF_102_GB_SFC_fr-FR_fr.thumb.png.167f7fe01a6a46b311a249788b7de55e.png

Again another northern flank of low snow event for the north on the 06z gfs for Tuesday, gales/severe gales and heavy rain to the south, but pinch of salt required, models keep trying to spin up these deep lows, had one for Sunday but now a wave, so we'll see if it's on to something

gfs_ptype_slp_uk2_25.thumb.png.17d309632f4718a63b5fece503ef07b8.pnggfs_ptype_slp_uk2_26.thumb.png.ff5f7f26be94ee28d3520b136a393bac.png

Winter bites back for the north in particular. For the south, cold rain and gales at times interspersed with milder spells looks the form horse for now.

Extended 00z EPS z500 mean keeps mean trough over N Europe, the axis just east of the UK/N Sea - so a continuation of colder but zonal flow from the W and NW, perhaps occasionally from the N too. So further opportunities for snow, mainly the N, as we head towards and past mid-month.

eps_z500a_5d_nh_61.thumb.png.cd06143db31df645309f4f6c0a2c02d8.png

Edited by Nick F
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2 hours ago, West is Best said:

GFS ... I love it but it's propensity either to wildly over-bake Atlantic storms and then ignore the ones which actually do occur (eg Freya) makes it so erratic.

Here's a classic example. Last night's 18z for Sunday:

206964901_ScreenShot2019-03-06at07_49_52.thumb.png.3858b2136bbd7c362120fbd050e5c0f9.png

= a deep and potent storm over southern Britain.

Six hours later on the 0z run? It's completely vanished!!!!

426994489_ScreenShot2019-03-06at07_50_04.thumb.png.5b2f3dfbff0d1f4a8f8a961a2dc0cd58.png

 

 

Unreliable model madness will kill positive debate if things don't improve in the future ,what images shows is what I've been saying all winter ,anything on the models beyond 120 hours can't be relied on is now sometimes down to 96 hours which makes the forecasters job a nightmare ,I look forward to the day when the model performance improve s

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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level

Models seem to be struggling to get a handle on the situation at present, even so the 6z yet again throws up a bit of delight! It could be a fair amount... On the other hand!!!!! 

gfs-0-180.png

gfs-0-168.png

06_108_preciptype.png

06_114_preciptype.png

06_150_preciptype.png

cf120cfa3cec61f8c545538069f90be3.jpg

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

After reading some of the earlier comments one would think the cold and snow potential is dead but far from it, winter could bite back..soon..hopefully!

Edited by Frosty.
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Posted
  • Location: Reading/New York/Chicago
  • Location: Reading/New York/Chicago
32 minutes ago, Eastnorthwest said:

Unreliable model madness will kill positive debate if things don't improve in the future ,what images shows is what I've been saying all winter ,anything on the models beyond 120 hours can't be relied on is now sometimes down to 96 hours which makes the forecasters job a nightmare ,I look forward to the day when the model performance improve s

I disagree! What you need to do is tune out the noise. The longwave pattern is identical in the two charts that @West is Best posted. The surface analysis is different because it always will be at that range; smaller scale features are enormously complex to forecast.

As far as forecasting goes, IMHO, you can only reliably predict PPN amounts and temperature within a range that broadens as you move further out in time (yes, there are times when the range narrows or widens, generally when a pattern change is occurring). Beyond that, you are simply looking at likelihoods and probabilities; no scientific forecaster will be willing to say if it will rain and what the temperature will be at a particular time on a date more than six days in the future. They may forecast above or below average conditions in a range of categories for a period of time, but I don't think that models going past 6 days were ever intended to be taken literally, but rather as a guide.

Forecasts do bust, with this winter being a prime example. But, on the whole, NWP models are pretty good when it comes to forecasting PPN (not type!), wind direction and overall conditions out to the six or seven day range. Going further out, I only consider a forecast to be a bust if a predicted pattern change hasn't happened or an unforeseen change did happen (e.g. mobile to blocked) and anything beyond day 10 is simply a possibility rather than a likelihood.

A forecast hasn't failed just because a secondary low appeared on one operational output and then does not on the next: that is what I mean by noise.

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Posted
  • Location: Fenland Fylde.The same village as Duncan Iceglide.
  • Weather Preferences: LP - Horizontal Drizzle - Nice Blizzards
  • Location: Fenland Fylde.The same village as Duncan Iceglide.

BANK

One to watch Reliable? FI or is it not FI?

06Z

T+147 12-3-19

uksnowrisk.thumb.png.5e79e9c2ea35abbcfbde358095c93907.png

 

 

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Posted
  • Location: Fenland Fylde.The same village as Duncan Iceglide.
  • Weather Preferences: LP - Horizontal Drizzle - Nice Blizzards
  • Location: Fenland Fylde.The same village as Duncan Iceglide.
1 hour ago, Eastnorthwest said:

Unreliable model madness will kill positive debate if things don't improve in the future ,what images shows is what I've been saying all winter ,anything on the models beyond 120 hours can't be relied on is now sometimes down to 96 hours which makes the forecasters job a nightmare ,I look forward to the day when the model performance improve s

Yes - at what timeframe do we say FI is FI?

T+120 as you say?

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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level
18 minutes ago, Man With Beard said:

Had a good look at the mid-term for the first time in a while ... I finally broke in mid-February after a year of non-stop weather chasing - the Beast from the East, then the Spring heatwave, then the Summer heatwave, then the early cold snap in autumn, then the agonising snow hunt from mid-December until the start of February - I hadn't had a rest from model watching in all that time. So I'm clearly not as hardcore as people like @frosty 

Anyway ... 

ec-ens_nat_z500scenarios_2019030600_192.  ec-ens_nat_z500scenarios_2019030600_240.  ec-ens_nat_z500scenarios_2019030600_300.

in a nutshell, it looks like conditions won't be far from normal overall, but certainly some openings for Atlantic height rises in the next two weeks which could lead to a couple of snow windows - especially considering northerly sourced air stays colder for longer into March than easterly sourced (usually!) does. But sustained cold looks tricky from the charts we have this morning. 

Winter chase not quite over!

Hope you have recovered from your model fatigue MWB. A good summary as always, good to see you posting again, as for frosty, I think he must be taking some kind of super vitamins for his fatigue, as he just keeps on bouncing back!!

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Posted
  • Location: Solihull, Midlands. (Formerly DRL)
  • Weather Preferences: Sunshine, thunder, hail & heavy snow
  • Location: Solihull, Midlands. (Formerly DRL)

Would have to agree that the last few months has been rather fatiguing for chasing our favourite setups, especially of the cold and snow kind in the models. Just hope  next Winter will be less frustrating lol. And that this Spring produces something for everyone. 

While a repeat of some warmer sunnier conditions would be welcomed (just like what happened in late February), not really any signs of this in the models at the moment. At least the next week or 2. Looks like a mostly cool and unsettled, at times, setup with a general Westerly flow. Some chance of some possible colder shots from the North-West or North behind the frontal bands of rain, but these colder shots might as well be potent enough to produce the cold and snow enthusiasts with another shot of the white stuff. A proper unstable cold Northerly flow would be nice for some widespread beefy snow showers (stronger sun help to produce some wintry showers inland), or perhaps longer spells of sleet or snow should disturbances occur with these possible colder flows. It becomes the time of year when I start looking forward to warmer weather. However, admittedly some snow with at least a 2cm plus convering would be great after the disappointment of the last few months. Or if not, just seeing some falling! I suppose I imagine some others in here feeling the same too. Besides, snow is still certainly possible in March - in fact, sometimes more likely than December - and even April too. Not necessarily just for Northern high-ground. 

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

I'm not happy with the current resolution out in FI?

When I see the Azores high plumping up I do not expect to see it battered away by a succession of lows ( over recent months you understand?) but rather see it push north and guide the lows to our North?

Over winter we have seen some pretty juicy FI charts all but go by 5 days out and so I will wait until next week to see if what the GFS wants to see happens pans out or my 'return to H.P. dominance does?

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

The GEFS 6z postage stamps are certainly not without considerable interest for snow starved coldies still reeling from the abysmal winter..to me there's a good chance or indeed several chances of snow in the short to mid range!❄️

snow_78_ps_slp.png

snow_102_ps_slp.png

snow_150_ps_slp.png

snow_174_ps_slp.png

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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level
3 minutes ago, feb1991blizzard said:

No GFS!

Not at all, or delayed Feb?? 

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
Just now, Mattwolves said:

Not at all, or delayed Feb?? 

Delayed - they will always come out no matter what, i bet they still came out even on sept 11th, they have back up computers etc, i have never known a major run not come out at all, although i have known them to come out so late that they are practically redundant - ie - when the next run is just about to come out anyway!

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Posted
  • Location: leicester
  • Location: leicester
3 minutes ago, karyo said:

The UKMO has updated and it looks better (colder) than its earlier output.

Yup and 96 hour chart looks interesting for the midlands as well as the 144 hour chart!!could be some snowfall over the next week anywhere!!

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
3 minutes ago, karyo said:

The UKMO has updated and it looks better (colder) than its earlier output.

Yes, although looks a midlands event rather than N England event on that run, i predicted that yesterday but since then the runs have actually bucked their normal southwards correction and have trended the other way.

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Posted
  • Location: Sedgley 175metres above sea level
  • Weather Preferences: Any kind of extremes. But the more snow the better.
  • Location: Sedgley 175metres above sea level
9 minutes ago, feb1991blizzard said:

Yes, although looks a midlands event rather than N England event on that run, i predicted that yesterday but since then the runs have actually bucked their normal southwards correction and have trended the other way.

Gerrin excited now!! Perhaps the gfs is delayed due to the overwhelming weight of snow charts its carrying on its shoulders!,

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
Just now, Mattwolves said:

Gerrin excited now!! Perhaps the gfs is delayed due to the overwhelming weight of snow charts its carrying on its shoulders!,

Its just started now.

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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)
1 minute ago, Mattwolves said:

Gerrin excited now!! Perhaps the gfs is delayed due to the overwhelming weight of snow charts its carrying on its shoulders!,

Yes, wet snow is much heavier! 

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