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Model Output Discussion 31/03/14 onwards.


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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

GFS is showing some quite Wintry synoptic's further into the run..

 

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Edited by Polar Maritime
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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

GFS op runs are rather erratic at the moment, probably due to the uncertainty. Yesterday's cold 12z replaced this morning by a more settled HP dominated FI. However really no change from the ensembles, a Scandi trough remains the most likely initial development from the lower pressure system coming at the end of the week, about 50% support this morning at D10, though this is trending down. The Azores High continues to influence the remaining members, some are like the op, some have the AH just to the west and some messy charts with a mix of LP/HP.

 

The GEFS at D10: post-14819-0-27702600-1398058588_thumb.p  No solidity to that mean either way yet.

 

GEM are now closer to last night's ECM at D10:  post-14819-0-24053800-1398058691_thumb.p And there is support in the GEFS for this.

 

Last night's ECM mean suggests a slack trough somewhere close to the UK: post-14819-0-73821900-1398058810_thumb.g

 

With a HP cell close to the UK, hence D10-15 temp variance (50/50?): post-14819-0-64642700-1398059808_thumb.g

 

And of course we have this morning ECM as quite similar to last night's cold GFS:

 

T216: post-14819-0-63156000-1398063059_thumb.g T240: post-14819-0-93927600-1398063468_thumb.g post-14819-0-08418500-1398063104_thumb.g

 

As you would expect with this uncertainty in the 7-10 days range,  the GEFS further out are less helpful than normal. However a meridional pattern is dominant with an Atlantic trough at T300 showing some credence, so a ridge close to the UK follows on most of these. The Scandi trough is also still prevalent, but again any trough look a slack affair.

 

When the block takes hold we could have an extended period of HP as per the 0z op (T252-T384+) and control (also T252-T384+), the op being cooler whilst the control much milder, or we could be in a showery trough:

 

Control in distant FI: post-14819-0-11094200-1398059710_thumb.p

 

The long wave pattern appears to be nailed, its just where the UK sits when the music stops (around D11), but more signs that we might return to more settled conditions, though 50/50 from the GEFS this morning, and my thoughts still remain along the ECM op line.

 

 

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Only 2 models which are close this morning and thats GFS and GEM at t144 all the rest offer different solutions for the low on Sunday

 

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Temperature wise its as you were for the 2m temperatures with them staying above normal for all but some south western parts

 

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Quite wet up to the 29th but significantly drier from the 29th to May 7th

 

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

The anomaly charts, in spite of differences in emphasis, continue to show in the 6-15 day period, a rather cool and unsettled pattern at 500mb, so no sign of any hot spell for sure.

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Posted
  • Location: Camborne
  • Location: Camborne

No wish to repeat what others have been saying but quick look at the ECM suggests a dodgy week culminating in a wet weekend. And later supporting what JH said above which of course is not surprising.

post-12275-0-40724700-1398072347_thumb.p

post-12275-0-13773100-1398072359_thumb.p

post-12275-0-98517200-1398072371_thumb.p

post-12275-0-92740900-1398072391_thumb.p

Edited by knocker
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Posted
  • Location: Maltby, Rotherham - 150m ASL
  • Weather Preferences: Snow and Cold! Winter :)
  • Location: Maltby, Rotherham - 150m ASL

Can I ask which model is best at longer range? I know GFS seems to swing about a lot, but thats because it has more runs.

 

However, we have some posts on here showing the UK above average all the time every day, and countering that, posts showing the UK well below average all the time every day. I think you can guess the posts but I dont want to mention any names.

Im not getting at anybody, but for a learner like me its very confusing lol! Which is it?

 

Seems to be the GFS crew against the ECM crew lol

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Posted
  • Location: Bristol
  • Location: Bristol

To echo the growing consensus, ECM Ens & GEFS both trending cooler into mid term, with a negative anomaly for the UK shown into days 7-12.

 

 

Posted ImagePosted Image

ext ecm & gefs temp anom days 7-12

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Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

Can I ask which model is best at longer range? I know GFS seems to swing about a lot, but thats because it has more runs.

 

However, we have some posts on here showing the UK above average all the time every day, and countering that, posts showing the UK well below average all the time every day. I think you can guess the posts but I dont want to mention any names.

Im not getting at anybody, but for a learner like me its very confusing lol! Which is it?

 

Seems to be the GFS crew against the ECM crew lol

 

You need to be comparing like with like - some anomaly charts (the GFS one Gavin posted above) are based on individual operational runs at many days ahead - absolutely useless, it will change many times over the four daily runs.

The ECM anomaly charts are ensemble mean and have a better chance of being nearer the outcome.

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Interestingly UKMO doesn't look as unsettled by Sunday compared to the 00z run

 

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The uncertainties continue

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

ECM continues with its cooler outlook for next week.....

 

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Edited by Summer Sun
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Posted
  • Location: Maltby, Rotherham - 150m ASL
  • Weather Preferences: Snow and Cold! Winter :)
  • Location: Maltby, Rotherham - 150m ASL

Yep, it doesnt look warm...

 

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What kind of surface temps would tonights ECM bring for the 30th? Looks to be -6 to -8 air over us.

 

I asked in winter and was told the rule is add 7 to get the temperature but im guessing thats not the case for the last day of April?

 

This wont obviously be -6 + 7 = 1C surely!!!!!

 

Would we be looking at maybe 10C, or lower? Wintry showers a possiblity?

 

I hope it comes off, a lovely northerly blast so we can feel like winter one last time before having to wait probably 6 months until next time...

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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

I hope it comes off, a lovely northerly blast so we can feel like winter one last time before having to wait probably 6 months until next time...

 

Do mean for the first time since last March.. :rofl:

 

Posted Image

Edited by Polar Maritime
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

How does the control look tonight gavin?

 

Next week looks quite unsettled though in brighter spells it should feel warm away from windward coasts

 

Ensembles show hints of something slightly more settled into early may, pressure looks like it will be at its lowest between the 27th and 2th

 

Posted ImagePosted ImagePosted Image

Edited by Summer Sun
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Posted
  • Location: Evesham/ Tewkesbury
  • Weather Preferences: Enjoy the weather, you can't take it with you 😎
  • Location: Evesham/ Tewkesbury

Hiyer folks , ecm at day ten and yes I know an unreliable timeframe but gives us glimmers of hope of some dry conditions albeit with some frosts too and of course sparkling sunshine for most.... :closedeyes:

post-6830-0-68205900-1398110035_thumb.pn

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

Hmm there seems to be good consensus of heights building close to Greenland in the semi-reliable time frame, in fact I would say that it will happen. But will it bring cool or even cold weather? It all depends on the strength of this high and of course how quickly and effectively heights to our north east break down. ECM and GEM though with differences towards Greenland do offer falling heights and a developing Scandi trough. UKMO on the other hand shows a much more resilient high and much weaker heights to the north west. This would likely result in low heights in the Atlantic squeezing through and pushing north east towards the UK, but with more average conditions compared to the cool and wet conditions shown by other models.

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Posted
  • Location: South Essex
  • Location: South Essex

Yep, it doesnt look warm...

 

Posted Image

 

What kind of surface temps would tonights ECM bring for the 30th? Looks to be -6 to -8 air over us.

 

I asked in winter and was told the rule is add 7 to get the temperature but im guessing thats not the case for the last day of April?

 

This wont obviously be -6 + 7 = 1C surely!!!!!

 

Would we be looking at maybe 10C, or lower? Wintry showers a possiblity?

 

I hope it comes off, a lovely northerly blast so we can feel like winter one last time before having to wait probably 6 months until next time...

 

 

hmm, hideously complex this one! :excl:

 

+7c works pretty well in Dec / Jan / early Feb as a base line with an adjustment up if Atlantic based and downwards if continental based. Therefore if its a northwesterly +9C would be a better benchmark, whereas an early Jan easterly you might get away with adding 5c (or less) to the 850 temps.

 

As you already comment this technique doesn't really work outside the winter months as the strength of the sun over rides the 850s at this time of year. Your guess of 10c would be a decent guess IMO. The trouble is that by mid April surface conditions will swing wildly with cloud cover / sunshine / rain. If the weather is calm with strong sunshine +14 would be possible in the south, under a heavy shower +3C wouldn't be surprising. Nightmare to forecast and we might see national forecasts showing plus 10c but also indicating wet snow. In essence all four seasons in a couple of hours :lol:

 

In summary, its impossible to predict as the actual ground temps will depend on weather its sunny or not. GFS temp charts for next weekend will about as reliable as Putin assuring us that there are no Russian troops in eastern Ukraine! They are simply militia.. honest :ninja:  :rofl:

 

Hope this helps

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Posted
  • Location: Camborne
  • Location: Camborne

The ECM ens remains pretty grim for the week and weekend. The upper air set up still is looking at an unsettled period into May.

post-12275-0-69969800-1398114406_thumb.p

post-12275-0-46895700-1398114414_thumb.p

post-12275-0-39117200-1398114422_thumb.p

post-12275-0-66797100-1398114433_thumb.p

post-12275-0-42099000-1398114442_thumb.p

Edited by knocker
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Posted
  • Location: Maltby, Rotherham - 150m ASL
  • Weather Preferences: Snow and Cold! Winter :)
  • Location: Maltby, Rotherham - 150m ASL

hmm, hideously complex this one! :excl:

 

+7c works pretty well in Dec / Jan / early Feb as a base line with an adjustment up if Atlantic based and downwards if continental based. Therefore if its a northwesterly +9C would be a better benchmark, whereas an early Jan easterly you might get away with adding 5c (or less) to the 850 temps.

 

As you already comment this technique doesn't really work outside the winter months as the strength of the sun over rides the 850s at this time of year. Your guess of 10c would be a decent guess IMO. The trouble is that by mid April surface conditions will swing wildly with cloud cover / sunshine / rain. If the weather is calm with strong sunshine +14 would be possible in the south, under a heavy shower +3C wouldn't be surprising. Nightmare to forecast and we might see national forecasts showing plus 10c but also indicating wet snow. In essence all four seasons in a couple of hours :lol:

 

In summary, its impossible to predict as the actual ground temps will depend on weather its sunny or not. GFS temp charts for next weekend will about as reliable as Putin assuring us that there are no Russian troops in eastern Ukraine! They are simply militia.. honest :ninja:  :rofl:

 

Hope this helps

 

Hi Jason

 

Thanks very much for your response and time to reply :)Learning all the time, its realy interesting!!

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

The LP system makes landfall this Saturday morning (T96) and fills in situ till T288, becoming the base of the trough, waxing and waning depending on the feed from the trough:

 

This morning's GFS: post-14819-0-62600600-1398147866_thumb.p post-14819-0-79220800-1398147877_thumb.p

 

The GFS op does not drag down the very cold uppers, but still relatively cool and unsettled period forecast on this run. The Control is similar though the far south loses the low a day earlier as heights build from the SE. However the GEFS indicate that the C & OP are close to worse case scenarios though the mean does go for about a 7 day fall in pressure, for London:

 

post-14819-0-77387900-1398148151_thumb.g  post-14819-0-00185500-1398148233_thumb.g

 

The ECM ensemble (12z from yesterday) temp mean (above) also hints at a 7-8 day cooling down before temps (pressure) rise again.

 

However still some uncertainty as GEM at T126 sends the low into Continental Europe rather than the GFS UK position:

 

post-14819-0-22018700-1398148398_thumb.p

 

Consequently the associated trough is centred further east and although still influential to us is less active:

 

T180: post-14819-0-90009100-1398148486_thumb.p  T240: post-14819-0-50791200-1398148513_thumb.p

 

ECM is closer to GFS at T168: post-14819-0-87684400-1398148736_thumb.g 

But the trough is again further east allowing ridging to encroach at T240: post-14819-0-87070700-1398149904_thumb.g

 

This tallies with the ECM mean from last night at T240: post-14819-0-41407900-1398149949_thumb.g

 

So looking at ECM and GFS we are looking at about a minimum of 6-7 days of a cooler more unsettled trough regime, with GEM also cool, probably the coldest of the runs with temps well below seasonal averages, but maybe less unsettled initially.

Edited by i'm dreaming of...
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Those orange colours get very close to southern parts of England from the 30th to 8th

 

Posted Image

 

Based on the 00z its pretty wet through out

 

Posted Image

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