Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!


Paul

Recommended Posts

Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

I know people want a definitive answer to whether they're likely to see some snow but I think this is likely to be a situation where you probably won't know whats going to happen until the day itself.

 

This isn't a clear cold undercut scenario with low pulling in some very cold drier air from the Continent as it slides in.Much depends on the heaviness of the precip aswell as evaporative cooling, in that respect because of the slack flow this could help.

 

Elevation could be quite important just to tip things the right way however in terms of dew points that could be imparted from the continent although not desperately cold they are likely to feed into the flow as the low pulls se into France.

 

Further on the models seem less bullish now about another slider on Friday however theres still some uncertainty upstream with the low exiting the eastern USA regarding speed and amplitude, this impacts the sharpness of the next possible slider.

 

Thereafter there does seem now a strong signal to bring the Atlantic in although timing wise still some uncertainty there.

 

A further problem re the snow situation for the first slider is the lack of agreement between the major models which doesn't help matters , hopefully we can get that this evening.

Edited by nick sussex
  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

The complex situation hasn't happened yet and they have been all over the place.The rest of the week looks cold with fronts at the end of the week looking to try and push in.

As for using the M62 as a snow line IDO,forget it.It's not like using the M4 as there are the pennines which run down through Derbyshire and South Yorkshire.

Hi yes. I am talking about for sea level. Obviously hills and mountains are a total different situation and I think the general consensus is that is taken as higher chance of snow.

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire

The complex situation hasn't happened yet and they have been all over the place.The rest of the week looks cold with fronts at the end of the week looking to try and push in.

As for using the M62 as a snow line IDO,forget it.It's not like using the M4 as there are the pennines which run down through Derbyshire and South Yorkshire.

The models handled the general synoptical theme well for this week (give or take 50-100 miles)

There will be snow for some - some of which will be nowcasting (marginality)

Everything is wrongly positioned synoptically for significnat cold (Stubborn PV Greenland & Azores High)

Russian High does not have the associated energy to flex it's muscles

As I stated though - for some a wintry week with snow and cold minima - nothing unusual though

Fingers crossed for February

Edited by Jonathan Evans
  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

The models have thus far handled this complex situation very well - and all have been signalling the return of W/SW regime for some time. We need a reset which takes us into February. More than likely looking towards mid February for another shot at cold.

I think a look at late December 1978 shows how quickly things COULD change....not saying they will mind...

FROM DEC 25

Rrea00119781225.gif

To DEC 31

Rrea00119781231.gif

Different synoptics already in place at the start of that 5 day period for sure.....but perhaps.....(not withstanding my earlier post) the seeds of something similar are already in place regarding the strat

Link to comment
Share on other sites

Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire

I think a look at late December 1978 shows how quickly things COULD change....not saying they will mind...

FROM DEC 25

Rrea00119781225.gif

To DEC 31

Rrea00119781231.gif

Different synoptics already in place at the start of that 5 day period for sure.....but perhaps.....(not withstanding my earlier post) the seeds of something similar are already in place regarding the strat

Look at the HLB on the 25th December 1978 chart though - not a sign of that emerging for us any time soon

  • Like 3
Link to comment
Share on other sites

Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

I think a look at late December 1978 shows how quickly things COULD change....not saying they will mind...

FROM DEC 25

Rrea00119781225.gif

To DEC 31

Rrea00119781231.gif

Different synoptics already in place at the start of that 5 day period for sure.....but perhaps.....(not withstanding my earlier post) the seeds of something similar are already in place regarding the strat

Not a great example imo, as if we didn't get cold and snow set up from Dec 25th chart I'd be very disappointed....that already shows where we should be heading?  Synoptics can switch quickly though, agreed

 

BFTP

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Kippax (Leeds) 63m
  • Location: Kippax (Leeds) 63m

Thought I would compare todays 06Z with yesterdays!

 

1035mb high over Scandi

http://modeles.meteociel.fr/modeles/gfs/archives/gfs-2015011806-0-240.png?6

 

Today a 975mb low pressure over Scandi

http://modeles.meteociel.fr/modeles/gfs/runs/2015011906/gfs-0-216.png?6

 

Whilst I believe a W,lys is likely, such a switch in 24hrs makes me want to view more runs before being certain.

 

 

Only yesterday you was predicting another easterly  :mellow:

  • Like 6
Link to comment
Share on other sites

Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Its a shame we don't get to see what the control run does on the ECM De Bilt ensembles, that looked interesting. It obviously has a slider of sorts because we have got the T120hrs postage stamp, then the flow veers rapidly to the north then quickly ne then sw then se.

 

I think perhaps what happens here is that theres a second slider, ridge topples over then the upstream pattern is a bit more amplified as another low moves in which helps to turn the flow back towards the se.

 

The fact that the control and operational run look similar at day 5 over Europe means its differences over the west Atlantic which then go onto see them go in different directions.

 

Anyway I'm rambling, which happens when we're in that waiting time between outputs!

Edited by nick sussex
  • Like 2
Link to comment
Share on other sites

Posted
  • Location: West/East/Sussex Surrey border
  • Location: West/East/Sussex Surrey border

Hi Tamara, could you possibly say whether you believe a ssw will take place leading to colder conditions across the UK? I understand that a ssw isn't the only contributing factor.

In simple terms ...... ??

Edited by steveinsussex
Link to comment
Share on other sites

Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

Not a great example imo, as if we didn't get cold and snow set up from Dec 25th chart I'd be very disappointed....that already shows where we should be heading?  Synoptics can switch quickly though, agreed

 

BFTP

True,,,but we got to the 25th DEC 78 from here a week earlier...

Rrea00119781218.gif

That's not a million miles away from where the models are taking us next week and if we get the SSW that did seem on the cards for a few runs it's not inconceiveable that we could end up with a good start to February.

That said, it's a long shot, but I can certainly see no point in writing off any further opportunities till mid Feb like some (not you I hasten to add!) have said

EDIT...just realised I had Jan not DEC!

 

Edited by Timmytour
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

Its a shame we don't get to see what the control run does on the ECM De Bilt ensembles, that looked interesting. It obviously has a slider of sorts because we have got the T120hrs postage stamp, then the flow veers rapidly to the north then quickly ne then sw then se.

 

I think perhaps what happens here is that theres a second slider, ridge topples over then the upstream pattern is a bit more amplified as another low moves in which helps to turn the flow back towards the se.

 

The fact that the control and operational run look similar at day 5 over Europe means its differences over the west Atlantic which then go onto see them go in different directions.

 

Anyway I'm rambling, which happens when we're in that waiting time between outputs!

Don't get excited nick

Trough disrupts to our East followed by General Azores ridge which becomes a euro ridge. Eventually we come under the forecast Atlantic trough and the run ends well with upstream Atlantic block but that's pie in the sky at this range

Edited by bluearmy
  • Like 1
Link to comment
Share on other sites

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

The models show a return to normal UK winter weather by Sunday as rain spills in off the Atlantic, whilst the last few days there has been a lot of uncertainty, the smoke is now clearing and the outlook is for a return to a mobile broadly westerly regime with milder wet and breezy / windy spells interspersed with colder & showery interludes, much like we had previously.

  • Like 3
Link to comment
Share on other sites

Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Don't get excited nick

Trough disrupts to our East followed by General Azores ridge which becomes a euro ridge. Eventually we come under the forecast Atlantic trough and the run ends well with upstream Atlantic block but that's pie in the sky at this range

Thanks BA, at least the end is interesting although too far out to have much confidence in.

Link to comment
Share on other sites

Posted
  • Location: Hemingfield, South Yorkshire (49m / 160ft ASL)
  • Weather Preferences: Summer Sunshine / Winter Snow
  • Location: Hemingfield, South Yorkshire (49m / 160ft ASL)

Looks like they think only South West Scotland will be in the firing line for this 'event'.....

 

http://www.metoffice...nings/#?tab=map

However, the higher resolution model (Euro4?) does seem to suggest that the above area will be in the firing line before places like Northern England so maybe further warnings will be issued after the 12z runs?

Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

trying to get some trends from the back end of the ecm eps mean and anomolys and there is no reason to think that we are locked into some never ending zonal mildfest. i think more time under pm than tm. i am also keen to see the ec 32 in the morning as week 3 could show more interest for cold than it usually does (assuming there is a correlation between the ec ens and ec 32 run).

 

one thing catching my attention is the vortex split is largely retained out to the end. the n of alaska ridge desperatley trying to get through.

 

need more suites to see if we can get some continuity back into the extended period

  • Like 6
Link to comment
Share on other sites

Posted
  • Location: Windsor
  • Weather Preferences: Snow and cold
  • Location: Windsor

Looks like they think only South West Scotland will be in the firing line for this 'event'.....

 

http://www.metoffice...nings/#?tab=map

However, the higher resolution model (Euro4?) does seem to suggest that the above area will be in the firing line before places like Northern England so maybe further warnings will be issued after the 12z runs?

Maybe the precipitation is likely to fizzle out as it approaches Eastern parts ?

Link to comment
Share on other sites

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

It will surprise me if more areas don't see snow this week considering how cold the nights will be, for example, last night saw the coldest night of this winter so far with almost minus 13 Celsius in the highlands and tonight it will be close to minus 8 to minus 10 c across most of England and Wales. Anyway, we have 3 bands if wintry precipitation to cross the uk from west to east this week so some of us will see a covering, even if it's only a temporary wet and slushy one, overnight it will freeze before our pattern flattens out by the end of next weekend onwards.

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

I've just been looking at the upstream pattern in relation to the possibilities of another possible slider low on Friday.

 

This is effected by the speed and amplitude of a low exiting the eastern USA at around T90hrs, theres also the issue of a shortwave over Norway but just dealing with the pattern over in the eastern USA.

 

Preferably we want this low slowing down and not phasing with the one near the UK for as long as possible.we also need it to be more amplified so as to promote a better Azores ridge.

 

In terms of this the latest SREF has made a correction westwards comparing its 03hrs with 09hrs with a more negative tilt, the original 03hrs was similar to the trend of the GFS 06hrs.

 

The SREF is the short term mesoscale ensemble forecast system for the USA model so I don't want to get hopes up here too much but a possibility that the SREF might be seeing a slightly more favourable upstream pattern which might increase the chances for the next slider.

 

Theres still a spread of solutions for that low but the mean certainly looks better upstream than both its earlier run aswell as the GFS 06hrs.

Edited by nick sussex
  • Like 4
Link to comment
Share on other sites

Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Further to my previous post heres the comparison between the SREF ;

 

So 03hrs run to T87hrs:

 

post-1206-0-65743200-1421678402_thumb.gi

 

Then the 09hrs run to T81hrs:

 

post-1206-0-99512700-1421678414_thumb.gi

 

 

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Hastings (Seafront)
  • Weather Preferences: Snow and Thunderstorms
  • Location: Hastings (Seafront)

Hope you don't mind, just going to pop in charts from this time last week for today, today, and for next Monday based on today's outputs. UKMO doesn't go to 168 so emitted from this. Plus on Meteociel the charts are all over the place still! So just the GFS, ECM & GEM for now. So let's see which of these has been most accurate, bearing in mind these charts were issued prior to the stormy period we had on Weds/Thurs.

 

T-168(ish), T0 and T+168(ish).

 

GFS

 

gfs-0-174.png?6?6gfs-0-6.png?6gfs-0-174.png?6

 

ECM

 

ECM1-168.GIF?19-00ECM1-0.GIF?19-12ECM1-168.GIF?19-12

 

GEM

 

gem-0-174.png?00gem-0-6.png?00gem-0-174.png?00

 

 

Anyone want to analyse these for me? I've got to dash out for a few hours in 1 minute, cutting it fine! 

 

I'll try to do this again next Monday to see how well the models have done again.

Edited by GUWeather
  • Like 2
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

Hope you don't mind, just going to pop in charts from this time last week for today, today, and for next Monday based on today's outputs. UKMO doesn't go to 168 so emitted from this. Plus on Meteociel the charts are all over the place still! So just the GFS, ECM & GEM for now. So let's see which of these has been most accurate, bearing in mind these charts were issued prior to the stormy period we had on Weds/Thurs.

T-168(ish), T0 and T+168(ish).

GFS

gfs-0-174.png?6?6gfs-0-6.png?6gfs-0-174.png?6

ECM

ECM1-168.GIF?19-00ECM1-0.GIF?19-12ECM1-168.GIF?19-12

GEM

gem-0-174.png?00gem-0-6.png?00gem-0-174.png?00

Anyone want to analyse these for me? I've got to dash out for a few hours in 1 minute, cutting it fine!

I'll try to do this again next Monday to see how well the models have done again.

Interesting post GU - maybe if I post the ecm mean anomoly for that point

post-6981-0-48359500-1421680531_thumb.jp

Ecm saw the disruption and had done for a while but never saw the weak Scandi ridging. The Gfs brothers were hot on that.

Edited by bluearmy
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness
  • Weather Preferences: Winter: Snow>Freezing Fog; Summer: Sun>Daytime Storms
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness

Maybe the precipitation is likely to fizzle out as it approaches Eastern parts ?

Not according to the latest NMM (6z), where there is still snow forecast for southern areas from the small hours of Wednesday until that evening (and has been on each of the previous 4 runs): http://www.meteociel.fr/modeles/wrfnmm.php?ech=3&mode=1&map=5

 

EDIT - for easier comparison with Karlos' Euro4 screenshot below for the same time period:

post-992-0-34142000-1421681741_thumb.png

 

Not as much detail, but you can see the same pattern emerging on the HIRLAM model:

post-992-0-82168700-1421682177_thumb.png

Edited by The Enforcer
  • Like 2
Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
  • UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-29 07:13:16 Valid: 29/03/2024 0600 - 30/03/2024 0600 THUNDERSTORM WATCH - FRI 29 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather

    Difficult travel conditions as the Easter break begins

    Low Nelson is throwing wind and rain at the UK before it impacts mainland Spain at Easter. Wild condtions in the English Channel, and more rain and lightning here on Thursday. Read the full update here

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather

    UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-28 09:16:06 Valid: 28/03/2024 0800 - 29/03/2024 0600 SEVERE THUNDERSTORM WATCH - THURS 28 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather
×
×
  • Create New...