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Model Output Discussion - Stormy Period Inbound...


Paul

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Posted
  • Location: Glasgow, Scotland (Charing Cross, 40m asl)
  • Weather Preferences: cold and snowy in winter, a good mix of weather the rest of the time
  • Location: Glasgow, Scotland (Charing Cross, 40m asl)

Neither GFS, UKMO or GFSp have downgraded next weeks potential storm this morning unfortunately, starting to look a little ominous but thankfully enough time for something less destructive to be modelled yet.

 

gfs-0-156.png?0gfs-0-144.pnggfs-0-162.png?0

 

Yes the UK is under there somewhere. Let's hope it gets significantly downgraded.

 

This is now three of the last four winters where we've been hit by severe storms, and it's safe to say charts like this don't fill me with much joy:

156-289PUK.GIF?09-0

 

 

In the interim there's some decent snow potential at least but really there's no need for any more wind!

57-780PUK.GIF?09-0 132-780PUK.GIF?09-0

 

UKMO looks the least worst in terms of destruction and at least there's a northerly and some blocking at the end of the tunnel too on the GFS P:

gfs-0-210.png?0

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

This is now three of the last four winters where we've been hit by severe storms, and it's safe to say charts like this don't fill me with much joy:

156-289PUK.GIF?09-0

 

 

In the interim there's some decent snow potential at least but really there's no need for any more wind!

57-780PUK.GIF?09-0 132-780PUK.GIF?09-0

 

UKMO looks the least worst in terms of destruction and at least there's a northerly and some blocking at the end of the tunnel too on the GFS P:

gfs-0-210.png?0

 

 

Good morning

 

UKMO maybe slightly less frightening but it is a little further West and still deepening so it would be worse by the time it crossed the UK. I guess it doesn't matter right now as it will change every run and fingers crossed it downgrades.

 

As you say GFSp makes a reasonable first of an Atlantic ridge whereas GFS Op remains unsettled with lows running NW/SE.

Edited by Mucka
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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

I wish GEM were a more reliable model as that makes less of the storm and has low pressure sliding West of the UK later. I mentioned the other models were hinting at this scenario a couple of days ago but they seem to have dropped it now.

 

gemnh-0-204.png?00gemnh-0-240.png?00

 

ECM's take on the storm,  not off the chart as GFS.

 

ECH1-144.GIF

Edited by Mucka
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Posted
  • Location: st albans
  • Location: st albans

in broad terms the back end of PTRB 17 on the 12z gefs is a representation of where I think the NH pattern is going. Within two weeks would be a bit quick though.

post-6981-0-44503100-1420786360_thumb.jp

Edited by bluearmy
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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

The ECM, GFS(P) carve out low heights over Iberia by day 9/10, that could be seen as a positive trend.

GFS(P)

gfs-0-240.png?0

ECM

ECM1-240.GIF?09-12

Can we see enough amplification to deposit an area of heights over Scandinavia after the initial toppling northerly.

Next week looks pretty normal in terms of temperatures, with a mix of milder days (Monday and Thursday) along with cooler ones (Tuesday, Wednesday and Friday). Still the risk of heavy rain and strong winds at times, especially Thursday.

Edited by Captain shortwave
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Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset

Seen enough output in recent days to believe it's a case of all roads lead to cold. The 00z reaffirms this. The nature and degree of the cold is the only thing up for grabs.

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Posted
  • Location: Yatton, South of Bristol
  • Location: Yatton, South of Bristol

Quite conceivably. MOGREPS is particularly strong on the colder NW'ly signal towards same period and agreement on a generally colder theme is consistent across all output. How long this phase lasts is another matter, however (especially judging from yesterday's EC Monthly suite, but I've not yet seen if GloSea offers consensus).

Thanks for the update. Are the models seeing 'cold' Ian or a 'cooler' period? 

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Posted
  • Location: st albans
  • Location: st albans

in broad terms the back end of PTRB 17 on the 12z gefs is a representation of where I think the NH pattern is going. Within two weeks would be a bit quick though.

attachicon.gifimage.jpg

I'm more noting the pattern elsewhere rather than nw Europe. Asian and Canadian vortices split with the Asian master. Asian vortex elongated. The blocking on the other side of the NH probably overdone but less relevant anyway.

The strength etc of Atlantic and euro heights dictate nw Europe

But given the mobility in the system, achieving this profile in 2 weeks would be rather fast.

Edited by bluearmy
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Posted
  • Location: North Somerset, UK
  • Location: North Somerset, UK

Thanks for the update. Are the models seeing 'cold' Ian or a 'cooler' period?

"Generally colder", unsettled but with a wide spread of EPS solutions (yesterday's clusters showed very equal and rather indecisive spread), as UKMO characterise the latter stages of trend period (the 00z EC EPS still awaited over next hour). Edited by fergieweather
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Posted
  • Location: Yatton, South of Bristol
  • Location: Yatton, South of Bristol

"Generally colder", unsettled but with a wide spread of EPS solutions (yesterday's clusters showed very equal and rather indecisive spread), as UKMO characterise the latter stages of trend period (the 00z EC EPS still awaited over next hour).

Thank you :)

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

You can tell things may be getting more interesting when you look at the snow chances for London for the next 16 days:

post-14819-0-67042200-1420788890_thumb.g

Although still nothing to get excited about but with several 20% chances and 12 days in a row where at least one member sees snow is rare for us Londeners.

To be honest anything after D6 (Wednesday) looks uncertain cross model with the potential storm showing different tracks and intensity. The following ridge looks like likely as heights out of the US build on top of the Azores. The GFS P and C show both ends of the scale:

post-14819-0-87541200-1420789241_thumb.p post-14819-0-24713000-1420789242_thumb.p

The Control has a shortwave spoiler whilst the P gets some WAA and builds for a nice toppler. The latter not dissimilar to the late December one. The good news is that the mean 850s stays negative from D5 to D16 in London so the further NW/N that should be even more significant.

Looking at the GEFS the Atlantic heights after D9 are not sustainable, the PV remains too strong for longevity. The second attempt is around D13 when we get another potential Atlantic ridge. At the moment at D16 that looks more solid especially with the PV looking a lot less organised than currently. So there is a chance, without any delays for the last week of January to maybe get colder. However this may be a repeating pattern so for snow a synoptic that is more likely to favour the north.

The MJO if it is a driver continues to trend on the CFS into phase 7 and also it now gets through phase 8:

post-14819-0-48709000-1420790482_thumb.p

The CFS bar one blip has consistently lent towards keeping it going. That could help with the second attempt at ridging (D13).

So again the main interest are the storms, but after D8 these should become less dominant as the zonal flow slows. This will allow for lower heights/trough to disrupt, with associated height rises, and in the colder upper flow the north may see wintry potential and the south should be more seasonal.

Edited by i'm dreaming of...
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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

The latest update from Dr Cohen suggests that the current Minor SSW is not closely coupled with the trop and he expects up to 3 weeks for the main  effect (-AO) to be felt on the surface:  http://www.aer.com/science-research/climate-weather/arctic-oscillation

 

Over all for the rest of Jan he is suggesting a westerly regime with alternating TM and PM flows from after week 2. The GFS can be read that way.

Edited by i'm dreaming of...
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Morning all

 

Todays outputs are a good example of how northern and southern jet stream interaction upstream can be the determining factor at least for the medium term.

 

You'll see the GFS is basically pants because it has the southern stream dominant and does not phase those two streams over the ne USA.

 

The GFS P has the northern stream dominant and phases this with a shortwave running ne from the Gulf of Mexico, the ECM does phase but isn't quite as good upstream at that point.

 

Regardless of those differences it looks like this first attempt at cold might not last too long unless that is after any toppling of the ridge the next low cuts se to the west of the UK and we see sufficient pressure rises to the ne.

 

So for those hoping for at least the GFS P to verify you need favourable upstream phasing and sufficient amplitude, you'll note comments from NCEP this morning:

 

 THE FULL
MODEL/ENSEMBLE ENVELOPE FOR PSBL SFC LOW PRESSURE FROM THE GULF
COAST INTO THE WRN ATLC BECOMES QUITE BROAD... INDICATING THE
DIFFICULTY OF THE FCST BY WED-FRI.

 

 SFC EVOLUTION WILL BE
HIGHLY DEPENDENT ON STREAM INTERACTION DETAILS THAT ARE TYPICALLY
NOT WELL RESOLVED 5-7 DAYS OUT IN TIME.

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

ECM ens

EDH1-144.GIF?09-12

EDH1-192.GIF?09-12

EDH1-240.GIF?09-12

Out to day 10, no real sign of a significant or prolonged cold spell, just a brief north/north westerly on the 18th/19th before the next surge of westerlies come across the Atlantic with the Greenland lobe still being the dominant segment of the polar vortex. Beyond this there is enough scope for another cold plunge around the 23rd onwards perhaps going by the GFS.

Still room perhaps for an area of heights to build to our north east as the lowest heights clear off towards Siberia around day 10.

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK

Morning, the models for the next 5 days here in Central Europe and much of mainland West Europe certainly remain benign with some amazingly widespread high temperatures for this time in the season expected tomorrow. The wet and windy weather further north seems a million miles away as another cloudless day dawns here. Hopefully, after day 5 some cold can be imported more widely. This winter, thus so far, following on from the warmest year ever is certainly in the very mild list.

 C

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

in broad terms the back end of PTRB 17 on the 12z gefs is a representation of where I think the NH pattern is going. Within two weeks would be a bit quick though.

attachicon.gifimage.jpg

That's broadly how I see end of Jan and mainly Feb setting up.  Nice chart.  I too think any showing of deep cold synoptics setting in over next 10-12 days is too soon and westerly dominance of some form to remain.  I also think the 15th isn't the last of any storms and any ridge behind the 15th one will be transient.....we'll see anyway......but for me nothing really to get excited about nationwide until months end re deep/lengthy cold prospects....but plenty of local issues to overcome.  

 

BFTP

Edited by BLAST FROM THE PAST
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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

Morning, the models for the next 5 days here in Central Europe and much of mainland West Europe certainly remain benign with some amazingly widespread high temperatures for this time in the season expected tomorrow. The wet and windy weather further north seems a million miles away as another cloudless day dawns here. Hopefully, after day 5 some cold can be imported more widely. This winter, thus so far, following on from the warmest year ever is certainly in the very mild list.

 C

I think a completely different second half and extended winter beckons, signs are there for improvement in 7-10 days

 

BFTP

Edited by BLAST FROM THE PAST
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Posted
  • Location: North East London (E4) 147ft
  • Location: North East London (E4) 147ft

Highly unlikely that the killer GFS storm verifies at this range, certainly not with such a southern track, IMO. This model has a habit for overdoing depressions at this range so I would be very surprised to see people's garden fences in London taking to the skies next week but I stand to be corrected of course and prepare for a trip to B&Q.

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK

I think a completely different second half and extended winter beckons, signs are there for improvement in 7-10 days

 

BFTP

Lets hope a prolonged cold spell, but no indications of that presently. This is the worst type of winter weather over here, stuck under a mild high, week in , week out.

 C

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