danthetan
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Posts posted by danthetan
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1 hour ago, bradythemole said:
I know all the talk at the moment is about the SSW and the potential impacts starting to now enter the model timeframes, but this has been covered well already today by other superb posts as always.
Just wanted to highlight a wintry Sunday for some coming up and just how cold the air is that has been coming from the west at the moment.
We have -10/-11c 850 temps from an Atlantic modified air mass on Sunday which is pretty impressive. Wet bulb down to below 100 for whole UK. Thickness also very low. For the majority this setup doesn’t deliver what we all crave the most and it will just be dry and cold. But Ireland and parts of the west could do well on Sunday but regardless these really are some chilly air masses hitting us from the west at the moment considering the modification. ❄️
Im with you all the way I don't bother looking at charts past 120hrs imo no point. With Sunday in mind Monday night into Tuesday is looking interesting as a weather front moves into cold air and as winds fall light behind it becoming slow moving, so over Wales scotland & Northern England so potential for heavy snow. Also Wednesday morning after a frosty night, a system moving up from the south into cold air with SE winds wrapping cold air into the mixes it pushes up the western side of UK so more snow again for a time.
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Had Snow showers on and off all afternoon to wet to stick but showers getting going again and have a covering here, hopefully the dangler gets going again tonight and drops the hammer
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light snow covering all surfaces here
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13 minutes ago, andymusic said:
Seems a bit more intense on the euro 4 12Z possibly picking up moisture off the Irish sea as it crosses? Looks like the showers are going to pile after the weather front so 2 bites at the cherry tomorrow that doesn't happen often.
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GFS showing frontal snow and then snow showers affecting Pembs Tuesday into Wednesday. Pembrokeshire dangler will be in full swing with a keen North wind blowing down the Irish sea.
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2 minutes ago, Allseasons-si said:
who lives in NE Scotland to SW england
still cold though
and there is no way out of this cold spell if it goes to plan.
Thats where the front has stalled and dumping all the snow
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3 minutes ago, igloo said:
Yes it would be a nice change western scotland has had a real pasteing this season from snow but looking at the 18z run we will need a new snow shovel well i will i broke mine last week trying to shovel 14 inches of snow from my pad two weeks of hard frosts and sun would cheer us all up
To be fair you western scots have an absolute tuning from every weather apart from sunshine. so you'll save a bit on sunglasses this year for a new shovel
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31 minutes ago, ICE COLD said:
Because everyone loves to chase cold snowy charts at 240hrs ?. To be fair John the reason the most of us are chasing them is because in the next 5 to 7 days it standard boring weather . What is there to discuss ?? We all want proper winter weather for once . Like tonight's ECM .
Last time I checked this isn't a roulette table or some sort disconnect from real life that people come to discuss weather it still needs some degree of normality to steer it away from charts in the 10 day range to keep sanity.. its like walking into a job tomorrow and the boss telling you in 10 years time you will leave here a millionaire
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14 minutes ago, blizzard81 said:
All looks too topplerish for my liking. Yes, it won't be mild but this just will not deliver for most.
Im sure this post is regarding the eastern US. Although I would like to think he means europe
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High pressure slap bang over the UK is always a good starting block to get winds in from the north or east, *IF* it retrogresses north you will always draw winds from a cold source. Trying to get a high pressure building from the east seems very rare these days and always ends up close but no cigar.
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Here we had a light horizontal snow shower and now a covering of hail
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5 minutes ago, Allseasons-si said:
To my untrained eye,it looks like -ve heights disrupting SE into Europe,it does look like an undercut to me.
if i am wrong then i stand corrected
I think what John is getting at is the green lines indicate the flow and the blue and red indicate anomaly heights.
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1 hour ago, ribster said:
Not sure that makes any sense, I wouldn't expect it to look the same. A more informative analysis would be to compare it to the next 6z run...
The point being that the GFS has no consistency as far out as 96 Hrs so what chance has anything beyond that got of being correct. It was an observation.
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6 minutes ago, tight isobar said:
Gfs 6z going down ecm ooz route for the same time.
The ridge having better designs run to run...and output-to output...
Could be some top modeling coming up...if its colder your looking for...we shall see!??
Noted that the GFS 6Z was completely different @96hr to its 00Z run with the placing of low pressure systems so charts @ 8-10day cant hold much credence
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Crymych seems to snowing @200M so Preseli's should have lying snow by now
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On 19/12/2017 at 14:48, danthetan said:
Why people are focusing on charts way out in the ontha and not in the semi reliable time frame 144hr is beyond me. The Alaskan ridge surging into the pole on the last few runs is going to play havoc within the models not worth looking past that timeframe.
Refering back to my post yesterday regarding the model volatility and alaskan ridge taking todays 12Z UKMO it seems to be advertising with the idea of building heights towards Greenland which sends the jet south and low pressure systems with it this keeping us in colder air. Taking the GFS 12Z you notice the deep low pressure systems are much less apparent compared with a few days ago, but is less keen on building heights into Greenland. We shall have to wait and see if this becomes the trend.
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49 minutes ago, Frosty. said:
The answer is simple, there is no interesting weather forecast until next week when it could become disturbed / stormy..whereas the reliable / semi-reliable timeframe..i.e this week, the weekend into the start of next week is..putting it mildly.. a yawn fest!
I take your point about the uk weather being boring in the semi reliable time frame. But I'm not looking at whats happening in the uk at 144hr my focus is on the alaskan ridge heading into the pole and what effects that has.
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Why people are focusing on charts way out in the ontha and not in the semi reliable time frame 144hr is beyond me. The Alaskan ridge surging into the pole on the last few runs is going to play havoc within the models not worth looking past that timeframe.
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42 minutes ago, ArHu3 said:
You can't compare ecm 0z runs with 12z runs because there is only 1 frame per 24h for ecm, so there is a 12h difference between those frames. If you want to compare you have to compare with yesterday's 0z
I understand that, but I could only find a 12z chart from yesterday in the thread. From memory if I did post yesterdays 0z it would show an even bigger adjustment south according to the ECM.
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ECM 12Z yesterday on the left and ECM 0Z looks likes trended south overnight
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A few members were discussing the Pembrokeshire Dangler earlier. Living here, I have witnessed it in action, so I managed to find in the archives the chart which produced 10 inch's of snow at sea level back in 2004. The conditions look right for the Dangler to form weds night and Thursday but wether it will be cold enough to turn to snow we will have to wait. Although we have hills @500M so lying snow up there isn't out of the question.
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One thing I've noticed over the years of model watching is a correction south of low pressure systems coming up against an area of high pressure by the models. It seems the heights to the north are developing rather than established as the low pressure systems are moving across the Atlantic, so this might not be the case but we shall see.
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1 hour ago, knocker said:
The term was coined by Jon O’Rourke, a regular contributor to USW. It is used to describe a line of showery precipitation which forms in a NNW to NNE airflow, typically from Pembroke to Cornwall. This often results in frequent showers, or even more persistent rain, in quite a narrow band. When this occurs a narrow strip can receive quite a high rainfall total, whilst the rest of the south west is virtually dry.
It is by no means an unusual phenomenon, occurring several times a year, particularly in autumn and winter. The long fetch across ‘warm’ water from the Irish Sea to Cornwall, provides the right conditions for showers to form. The shape of the Pembrokeshire Peninsula has the effect of concentrating this unstable northerly flow, in the same way as an obstruction in a stream would concentrate the flow around it. The resultant line of often heavy showers is a convergence zone.
The long and narrow Cornish peninsula protrudes into this line of precipitation, and often has the affect of intensifying it further. Below are just 2 examples from 2008.
Absolute snow machines in the right conditions. Ive seen them pull the temperature down 5 degrees and over 8 inches of snow in a very short space of time in pembs.
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The GFS has continued to show slight adjustment West with both the high pressure to the north of the UK and the deep low to the NE Scandinavia if this continues in the next few days and that trough can drop south into europe surley this will aid retrogression towards Greenland.
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Wales/Cymru Regional Weather Discussion
in Regional
Posted
Attached charts show 1982 blizzard, the weather fronts coming from the W/SW rather than South it did stall and head back south it was fine margins mind.