The Weather Outlook

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GezM
  • GezM
  • Advanced Member
20 January 2021 11:58:59

I think cold fans in the snow starved S.E need to look at the near future rather than long term, which is frankly hopeless at the moment based on the 006z GFS Ensembles (London). But his weekend is of interest now, The 850hPa still hits a low of-6.5C air temps forecast to be around 3C and DP's lower than last weekend at -3C maybe at times. Now in range of the fax charts there is a little low coming up from France which may provide the precipitation. As in the majority of cases this century it will probably marginal and not more than 1-2cm but likely to be our best bet till February is well under way,

Originally Posted by: fairweather 

So often these types of lows end up missing England and skirting along the channel. If they do hit, they bring milder air with them and so we get rain. Could be wrong this time though!?

There is also an occluded front pushing east across the south on Sunday. So perhaps we get 2 bites of the cherry ....


Living in St Albans, Herts (116m asl)

Working at Luton Airport, Beds (160m asl)

tallyho_83
20 January 2021 12:09:19

Really not much sign of any support for the Parallel solution on the GEFS, it is out on its own with the Scandi high.

Originally Posted by: Rob K 

Yes also no -10c uppers in FI like in previous runs:


Home Location - Vixen Tor Close, Okehampton, Devon (221m ASL)

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Sean Moon

Magical Moon

www.magical-moon.com

Rob K
20 January 2021 12:36:34

 

Yes also no -10c uppers in FI like in previous runs:

Originally Posted by: tallyho_83 

P27 does bring in the -10C air, and is most similar to the parallel solution. Not much support though!


Yateley, NE Hampshire, 73m asl

"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome

doctormog
20 January 2021 12:37:46

 

Yes also no -10c uppers in FI like in previous runs:

Originally Posted by: tallyho_83 

I think there are 16 ensemble members dropping below -10°C here on the 06z suite. No doubt what will eventually transpire in reality will be more cold rain.


tallyho_83
20 January 2021 12:53:17

 

P27 does bring in the -10C air, and is most similar to the parallel solution. Not much support though!

Originally Posted by: Rob K 

That's my point - it's an outlier so not worth taking note of until it has some support from other ENS members.


Home Location - Vixen Tor Close, Okehampton, Devon (221m ASL)

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Sean Moon

Magical Moon

www.magical-moon.com

Brian Gaze
20 January 2021 13:02:42

Yesterday we were talking about model resolution. Here's an example of a GFS 6z op chart plotted at 0.02deg instead of 0.25deg. The resolution is SO high that I've had to make the plot bigger and skip grid points to make it readable. Of course it all matters not a bean to the forecast accuracy and that is the point often lost on people. Factors determining that are: model input data, model physics, internal model resolution which is different thing


Brian Gaze

Berkhamsted

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Jeff
  • Jeff
  • Advanced Member
20 January 2021 13:55:47

 

That's 3 GFS parallel runs in the trot with evolution to a Scandi high in FI. Unusual consistency so far out. Looking through the ENS there does appear to be some support. It all seems to depend on the extent of the Iberian high ridging North. 

Given it's FI, all very possible that the evolution could disappear in the next run, but interesting all the same. 

Originally Posted by: Arbroath 1320 

 

I make it four. Such consistency across one model is normally reserved for the 3-5 day range, not 10-12. Something up, or could it just be random, like throwing four sixes with four rolls of the dice ? Even if it disappears - which is surely must do even if it turned out to be an actual evolution in 10 days time - it has to be of interest? Does the Para lose half its resolution after 192hrs as per the Op?  I had a quick look for the Para's verification stats but couldn't locate 


On the East/West Sussex Border

70m ASL

UncleAlbert
20 January 2021 14:01:16
Sure the parallel is an outlier but it is not a one off is it? That scenario has been shown a few times now and something similar popped up in the op yesterday.

Many times disappointed but never dismissive!

Surrey John
20 January 2021 15:14:00

 

Yes also no -10c uppers in FI like in previous runs:

Originally Posted by: tallyho_83 

 

What is most noticeable, is have another 4 day milder (less cold, not mild) spell similar to current one, with the trend (mean) then reverting to about 4c below long term norm.

 

Whilst they may not be that interesting, there is something unusual in that we keep reverting to the bit colder than normal, nothing that could remotely be described as a warm plume.

 

What is frustrating is that for much of the country it just brings more cold rain, or sleet.  Not what most people consider as a proper winter. But a potential for a long winter (and a wet one)

 


Bradford on Avon, Wiltshire

35m ASL

DPower
20 January 2021 16:06:17

All eyes down for the 12z. Icon first out of the blocks and t180 as far out as the model runs, looks to be going the same way as the gfs para runs. Pressure remains high to the north with troughs disrupting west to east across the UK and very cold air to the the n/e pushing south. With cold pooling to our east.

Great start to this afternoons runs.

CField
20 January 2021 16:11:19

 

 

What is most noticeable, is have another 4 day milder (less cold, not mild) spell similar to current one, with the trend (mean) then reverting to about 4c below long term norm.

 

Whilst they may not be that interesting, there is something unusual in that we keep reverting to the bit colder than normal, nothing that could remotely be described as a warm plume.

 

What is frustrating is that for much of the country it just brings more cold rain, or sleet.  Not what most people consider as a proper winter. But a potential for a long winter (and a wet one)

 

Originally Posted by: Surrey John 

Amazing that this winter looks like being a below average winter CET.

Does a consistantly below average winter from Dec - April be classed as a classic without a proper snowfall ?

 


Favourite snowstorm

Famous channel low

Dec 31st 1978

Hastings East Sussex

Foot of level snow severe drifting

Next day max temp -4 degrees Celsius

Snow Hoper
20 January 2021 16:42:05
Think the Para will need to pull a rabbit out of the hat to save this one!
Going to war over religion is like killing each other to see who has the better imaginary friend.

Home : Mid Suffolk.

48m Asl

Snow Hoper
20 January 2021 17:11:08

Think the Para will need to pull a rabbit out of the hat to save this one!

Originally Posted by: Snow Hoper 

It did find something with ears and a fluffy tail about 100hrs later😉🤡


Going to war over religion is like killing each other to see who has the better imaginary friend.

Home : Mid Suffolk.

48m Asl

tallyho_83
20 January 2021 17:30:36

Think the Para will need to pull a rabbit out of the hat to save this one!

Originally Posted by: Snow Hoper 

Operational has southerly tracking lows which follow the 12z Para. I wonder how this Op run will sit in the ENS!?


Home Location - Vixen Tor Close, Okehampton, Devon (221m ASL)

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Sean Moon

Magical Moon

www.magical-moon.com

Rob K
20 January 2021 17:30:36

Parallel goes for a northerly rather than easterly but still cold, and the GFS op run follows suit.

GEM also close to an easterly towards the end.

 

And P10 of the GEFS throws a curveball, binning the mild incursion altogether with a frigid blast from the north


Yateley, NE Hampshire, 73m asl

"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome

ballamar
20 January 2021 17:41:18
Few more ENS members flirting with a Scandi high in 11 days
fairweather
20 January 2021 18:36:23

Amazing that this winter looks like being a below average winter CET.

Does a consistantly below average winter from Dec - April be classed as a classic without a proper snowfall ?

 

Originally Posted by: CField 

One of the problems with the CET is in winter it favours an area of the Country that is relatively good for snowfall and frosts. We have had very few frosts and virtually no snowfall this winter. I bet my mean temp is higher than the CET.


S.Essex, 42m ASL
fairweather
20 January 2021 18:45:48

Short term 12z 850's down again to -6.8C mean on 25th. Snow row up to 20 (All London data)


S.Essex, 42m ASL
Rob K
20 January 2021 18:54:24

 

Trend for a renewed cooldown in early Feb is growing IMHO.

Hopefully we will start to see that come into range of the ECM within a day or two.


Yateley, NE Hampshire, 73m asl

"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome

Zubzero
20 January 2021 18:55:22

 

One of the problems with the CET is in winter it favours an area of the Country that is relatively good for snowfall and frosts. We have had very few frosts and virtually no snowfall this winter. I bet my mean temp is higher than the CET.

Originally Posted by: fairweather 

Imby I'm below the CET as had quite a few days with fog or cloudy with cold rain keeping the temp low but no snow

https://www.cl.cam.ac.uk/research/dtg/weather/period-text.cgi?2021-01 

ballamar
20 January 2021 19:01:06
ECM looks primed for a NE /E outbreak
Ally Pally Snowman
20 January 2021 19:01:52

Fascinating ECM plenty of snow interest even for the south upto 144h . Then goes very mild.

Has snow event on Sunday  for the South and EA. Plenty of snow up north especially for Scotland.


Bishop's Stortford 85m ASL.
doctormog
20 January 2021 19:02:01
Mild rain or cold rain. Take your pick.
Zubzero
20 January 2021 19:04:00

 

Back to the drawing board if ECM on the right track!

Hippydave
20 January 2021 19:37:44

Mild rain or cold rain. Take your pick.

Originally Posted by: doctormog 

No need to pick I'll be able to enjoy both varieties

Some interesting signals still in the longer range output and GFS still reasonably confident of a cooldown post the milder few days in the middle of the run.

GEM ended on an intriguing note with a rather amusing contrast of -10 850s from the East/North East and +10 850s (few higher splodges) coming in from the SW.

ECM is an odd run - T168 to T192 the Atlantic seems to reverse and then  T216 it wanders a LP through and in to Scandi with no issues. The T240 chart is I would say 'poised' in that it could lead to cold or very mild quite easily. 

All good fun

I think the outlook up to the 30th Jan is being modelled consistently enough to have a reasonable degree of confidence in it verifying (down south, chilly/cold for 5/6 days, then mild/very mild for 3/4 days but I'll reserve judgement on the longer term outlook for the time being. Decent chance of cold is there but some very mild stuff is possible too. I guess we might be really unlucky and be on the boundary of both airmasses and just get even more rain

 


Home: Tunbridge Wells

Work: Tonbridge

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