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Posts posted by alexisj9
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45 minutes ago, WYorksWeather said:
Very, very unlikely to be anything like that cold. That specific ensemble was record-breaking at 850hPa but around 10C at the surface, with very low diurnal range, so probably fog and cloud, but definitely not freezing fog! Quite a few ensembles getting into the mid-teens.
This morning, the warmer options are continuing to gain traction. ECM mean is at 5C at 850hPa, GFS not quite that high, but on balance probably starting to move in that direction.
In terms of surface conditions, the ECMs 00z P09 shows surface temperatures peaking at 15C in London on January 23rd at midday. Historically these are underestimates, don't account for afternoon heating since it jumps from 12z to 18z, and of course that is a spot temperature for London which may not be the warmest location, so 17C is quite possible somewhere.
As an example of what this might look like, here's the chart for P9:
Can only get a detailed view for the south using Meteociel's France view, but that's widespread 12C at mid-day from London and the SE up through East Anglia, parts of the Midlands, even into Yorkshire. The darker yellow colour is 14C for the SE and East Anglia. And in practice, usually the ECM under-reads the spot maxima, so add 1-2C is a safe bet for the UK-wide daily maximum.
Of course, this is only one scenario, but even the mean has a maximum of 11C in London, and very widespread double figures (the cream colour):
Still a few days away, but as long as those exceptionally mild options remain in the ensemble, I'd be loathe to dismiss them, since quite often mild gets upgrades and cold gets downgrades.
Yep with the iso bars I can see why, the winds mix the air and bring the warmth down.
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16 minutes ago, Kent Blizzard said:
So we are finally at Sunday and the start of this next Cold spell.
So as things stand for the week ahead..
Cold ☑ Frost ☑ Snow 20% Wednesday for the SE.
I'm hoping by this time tomorrow the % can get to 30% for Wednesday depending on how the outputs show the low positioning.
Today is an interesting day as to how the models compare to the events being played out up North today in real time.
In terms of a significant snow event for the SE I'd say we are currently at 10% with plenty of twists and turns to come still. When you look at some of the temperatures modelled for Thursday and Friday that tells me they've considered snow cover on the ground?
Enjoy the ride!
Us it only just starting, yesterday was freezing here, and developed fog even before night fall.
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53 minutes ago, Froze were the Days said:
That actually looks like more than a chance. That one coming down seems to be where the snow line on the icon was going up to. Perhaps we'll see Wednesday either way, but if low stays south, I don't think it matters looking at that fax chart. Just a little worrying where the dam line is, above us. But I'm not sure that'll be a problem.
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2 hours ago, WYorksWeather said:
Has to be said that once again we're now seeing some absurd, probably near record-breaking, mild ensemble members. Not what we want to see, but still interesting to me as someone who keeps an eye on all things records!
This ensemble member gets the 850hPa temperatures to 14C in the far SE corner. Absolutely extraordinary. Perhaps more remarkable is that it isn't the only one, there is a mini cluster of about 10% of the ensemble that supports this idea.
Still unlikely to verify, but worth keeping an eye on.
What's the 2m temps, as that looks like a high, might be freezing at ground level, or might not, all depends on cloud amounts. Freezing fog lasting all day is possible if it's slack under that, if it's windy could be warmer however.
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4 minutes ago, blizzard81 said:
The 18z Icon really does set the cat amongst the pigeons.
I suppose it's possible that it's taking GFS place re the pub run, but let's hope not, I'm intrigued what the 0z might show in the morning.
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6 minutes ago, Don said:
I think now that a mild return is inevitable, all eyes are on February for the next chance of cold potential.
Wow, seriously, how about letting this cold spell play out, and I'm not so sure about the warm up, icon might be showing the way, we will see later in the week. I'm not looking for the next spell just yet.
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1 hour ago, Met4Cast said:
Really?
This week has been largely below average with blocking. High pressure is now shifting NW towards Greenland ushering in much colder air for this coming week. That’s 2 weeks of below average & blocked conditions which has been well advertised within the GSDM/teleconnections.
Is it widespread snow? No, perhaps but, but that wasn’t really advertised or promised. What was advertised is an increased likelihood of blocking & colder weather and in fairness that’s exactly what we’ve seen.
Teleconnections can give a broad sense of the larger patterns but will never be able to tell you if X will see snow.
Hasn't really warmed up all week here, though not as cold as during Mondays snow
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1 hour ago, throwoff said:
Kent really in firing line on todays models. Maybe even a few flakes Sunday night as well
Just as long as I can get to Canterbury and back on Monday using public transport I don't mind.
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53 minutes ago, knocker said:
The rapid cyclogenesis on this evening's gfs worth a mention as the low tracks NE south of Iceland down to 924mb by 00 Saturday
Not really paying attention to it yet, GFS is probably playing it's normal game at that distance. I think it will be weaker, hopefully much weaker, and do something completely different, but I guess we'll see
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1 hour ago, CoventryWeather said:
Another 200 miles north and we'll be happier in the mids. The south don't need another snow event - had plenty last December.
Lol not down here, but I don't mind it going a little further north as long as I don't get rain while everyone else has snow again pmsl. The models today are really keeping us on our toes.
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2 hours ago, Methuselah said:
I think there's an outbreak of confirmation bias infecting the MAD thread?
Yep as usual the models were right at day seven, things have changed a little but now the models are just as right at day seven. We'll see next weekend I guess. In the mean time cold week beckons.
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5 hours ago, Polaris said:
Absolutely no surprise the snow risk has faded for our region next week.
As with the beginning of last December, with the LOW going into France, it does look quite a dry cold spell. At least we get another week with the ground to dry out.
Nothing dry about last December's cold, many places in the se got snow.
5 hours ago, snowblind said:Looks like the operational runs for all the models are pretty dry but there seem to be quite a few of the ensemble members that have more precipitation around so sending the low pressure further north. All is not lost quite yet perhaps.
Like you say, keep an eye on the met office updates and we'll know what the pros are thinking but still looks like quite a bit of uncertainty with the track of the low next week.
This the ensemble graph for the latest ECM run. You can see the precipitation spikes around the 17th along the bottom. Some ensemble members must take the low pretty for north as they introduce milder air as well
Well we certainly don't want the latter, but north enough for snow would be nice.
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6 hours ago, Tom Quintavalle said:
Much thanks, Vortex3929.
Just a P.S. to my explanation. The "Channel Low" that resulted in the Snowstorm that struck our Region on the Evening of 30th December 1978, was pretty unusual with regard to its shape. Its centre was elongated and managed to maintain that shape, as it moved, along the English Channel:
Therefore, the flow remained in the East, from a frigid Continent.
I collected Newspaper cuttings of many severe Wintry outbreaks over our Region, and maximum temperatures in Cities and Towns the other side of the North Sea, were well below freezing on the preceding Friday and a few hours, before the Snowstorm struck.
What tends to happen when an area of Low Pressure approaches from the S.W. and engages bitter air on its Northern flank, the Ppn may start off as Snow but if the Low Pressure has more of a "Bowling Ball" shape, the flow will veer more to a S.E. or S.
This will result in Southern areas of the U.K., obviously including our Region, being infiltrated by milder air from the English Channel.
And like Anne Elk below, that's the theory anyway, ahem!!
Lows approaching from the S.W. are normally round and NOT thin and elongated, like the Channel Low of 30th December, 1978.
Meanwhile, the Low Forecast for next Week and possibly cause some disruptive Weather, just to prove me wrong has developed that elongated shape but has gone all "shy" on us, and disappeared over France:
Therefore, it could well remain mainly dry but cold next Week, until a possible warm up next Weekend.
Regards,
Tom Q.
Just to mention cold has definitely not gone on those charts, so basically people are moaning cause it's gonna be cold and sunny. Strange people as that's actually good weather for winter.
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8 hours ago, Vortex3929 said:
Does anyone actually know why the M4 is such a definitive feature in weather? Is it something to do with concerte/cement/asphalt etc retaining a temperature as opposed to surrounding locations and therefore acting as a "barrier", as I would make an uneducated guess at..?
Or is there a more defined and accepted reason? Really puzzling how it becomes such a defined feature when it comes to weather.. any opinions would be greatly appreciated
It's just the road which is closest to the line cold doesn't want to pass sometimes.
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2 hours ago, The Beast From The East said:
Last night's ecm
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42 minutes ago, Kasim Awan said:
I don't think there was any such streamer in early 2009.
There was a famous one, but it came from the east and literally shut SE London down for three days.
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1 hour ago, winterof79 said:
Thank god someone else reads it like that.We were doing post mortems earlier and looking to February.Very cold next week and impossible to predict snowfall yet.
And slack does NOT mean no snow with very cold air off the Irish sea
No it doesn't, in fact slack often means there's room for a trough to form.
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1 hour ago, Lord Grogon said:
Geez. Keep that one away from the Daily Express.
Going by there article today, already to late, they must have seen this somewhere lol
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4 hours ago, lassie23 said:
yes if ever there was such thing as pointless snow we had it yesterday
There is no such thing , days like yesterday I call safe snow, you watch the beauty of it falling, and temporary coverings, then don't slip e everywhere afterwards.
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58 minutes ago, Gazse9 said:
Yeah..has definitely got bigger in last 30mins...keeping an eye on it
Just had a proper look on sat, it coming all the way up from the Mediterranean sea.
Model Output Discussion - Colder but how cold and for how long?
in Forecast Model Discussion
Posted
Omg I've missed a whole month somewhere, what happened to the rest of January, and beginning of Feb. Knew I was tired but must have slept a long time.