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Model Output Discussion - 23rd Jan - 12z onwards


Paul

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Posted
  • Location: Gillingham, Kent
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Gillingham, Kent

Sorry if off topic

 

can i ask a question, i have searched but not found what i am looking for and there are alot of knowledgable posters on here!

 

I have heard that the rainfall radars we all look at are not live but a prediction based on the model runs and current observations, it was mentioned on few posts recently, is that correct? Or is the precipitation radar live but wether its rain, sleet or snow is what the prediction factor is?

 

Thanks

 

The precipitation on the radar is live, but the precipitation type is based off of the GFS I believe - So if the GFS doesn't show supportive temperatures for snowfall, the precip type radar might be showing rain/sleet when in reality it could be snow.

 

Or, like last night the precip radar was showing snow but many areas were seeing sleet/rain instead. In marginal setups it isn't a very helpful tool

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Posted
  • Location: Aviemore
  • Location: Aviemore

That doesn't explain why last night the radar showed snow going over me in bands yet it was bone dry on the ground.

 

We're getting miles off topic here, but as snow tends to blow a long way it could well have been that - more info on the radar systems and what can cause it to show phantom prec, or miss prec here:

 

http://www.metoffice.gov.uk/media/pdf/j/h/Fact_sheet_No._15.pdf

 

Best we get backto the models now though please - can answer more radar questions if there are any over in the help section, or the learners area..

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Posted
  • Location: Wirral, Merseyside
  • Weather Preferences: Snow & Thunderstorms
  • Location: Wirral, Merseyside

First output of the evening the GME brings in an easterly, not one of the major models but still nice to see:

 

SLP:

 

attachicon.gifgmenh-0-132.png

 

850's:

 

attachicon.gifgmenh-1-132.png

 

The deepish low in northern Italy helps to drive the cold air westwards along the southern flank of the high.There is some sub -10 850's waiting to moving westwards and if they arrive the set up is more condusive to the convective type easterly, the question at this stage is really how long that strong easterly can last. I think theres a decent chance of an easterly flow but longevity and cold pool to tap into still quite uncertain.

GFS at 132

post-23289-0-85209900-1422634555_thumb.p

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby

If that was a snipe at my comment "Breakdown, what breakdown?" which I expect it was, this is my response.  :closedeyes:

 

Not that anyone called an Easterly as you suggest but I'm curious, what one unsupported run was it that this non existent forecast was based on?

Do you mean the JMA or GFS or the majority of GFS ensembles or the cluster in the extended ECM ensembles from last night?  :cc_confused:

Maybe you can quote a post of a member who forecast an easterly based on this one run? 

 

I take it from your comment though you are now saying an Easterly is off the table, which run do you base that on exactly?

Wouldn't talking so definitively on one set of output be the mugs game to which you accuse others of playing?

 

Clearly the cold has slowly been extended out several days since early this week as has has been discussed and last nights ensembles, GFS in particular, showed a big move toward extending the cold still further with the large majority showing an Easterly flow at end of high res. That was a big flip toward an Easterly from previous runs.

Have they flipped back this morning?

 

Yesterdays 12z

 

graphe3_1000_280_115___.gif

 

Todays 06z

 

graphe3_1000_280_115___.gif

 

They are not as impressive as last nights 18z by any means but clearly there is still a big improvement from previous runs with any breakdown being put back several days from around the 5th to the 9th.

So yeah, breakdown, what breakdown? (And a breakdown is not high pressure and cold surface conditions)

There is a breakdown almost perpetually modelled in FI unless there is an extremely strong signal for blocking.

In last nights post I pointed out how GFS had trended right through the day and wanted further improvement on this mornings run before deciding if we were truly onto something Easterly wise which didn't come unfortunately, but is it going the same way today? 

 

 

It looks about 50/50 to me whether we will see a breakdown later next weekend or an Easterly type or perhaps just high pressure over the UK maintaining the cold.

This mornings output is a bit disappointing after last nights JMA,GFS and ensembles no doubt but to suggest saying the breakdown has been put off was unsupported, when the overall output which still shows exactly that, seems rather churlish to me.

 

At least you are not here to win any popularity contests Mushy, I can respect that even if I completely disagree with your "unsupported" version of how things have unfolded. 

 

Clearly there is scope for change either way, especially the crucial period between 72h and 120h where the Atlantic pushes in against the ridge.

It is very finely balanced as to how much the low will disrupt and energy push through the Southern tip of Greenland over the ridge and the upstream keeps chopping and changing. Also downstream is important to see if we can get a decent ridge pushing back NW through Scandi for any potential link up.

 

Because the time-frame is quite near this should all be resolved quite quickly (At least if the breakdown proper with an Atlantic influence really is going to occur next weekend)

We do need to see improvements upstream being modelled soon but all to play for this evening and let's remind ourselves the breakdown was being solidly modelled for next Tuesday not so long ago, we didn't even have a ticket to the raffle.  :hi:

 

no it certainly wasnt a snipe aimed at you, i missed your comment .

last night afew people cherry picked charts showing an easterly, i dont know who they were and i certainly didnt want to single anybody out...hence the broad statement . i think it was the jma that showed them, i dont know i dont view it. imho there can be too much information at hand and its easy to cherry pick which data anyone can use in order to promote an agenda.

i viewed my usual charts this morning, and posted them, showing no easterly, and my last line made it perfectly clear that my post referred to fi charts that could change...so no, of course its not a done deal.

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Posted
  • Location: Waltham Abbey, West Essex 144ft a.s.l.
  • Weather Preferences: snow, thunderstorms
  • Location: Waltham Abbey, West Essex 144ft a.s.l.

Nice UKMO

Yep, definitely signs of a more north easterly developing

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Nice UKMO

That is a lovely looking chart I must say. Much better ridging than the GFS and surely a much better chance of a more potent 

easterly. I noticed on the GFS run the low started to track east much earlier at t72 if this is a new trend then could we be looking 

at a channel low. Also the low is much deeper on this run which would help sustain better heights to the north.

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Posted
  • Location: Wirral, Merseyside
  • Weather Preferences: Snow & Thunderstorms
  • Location: Wirral, Merseyside

Yep, definitely signs of a more north easterly developing

120 :)

post-23289-0-34065600-1422634728_thumb.g

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

UKMO at T120, and GFS at T150, both desperately close to producing an easterly. Heights building towards Scandi linking with a cold High off the coast of north Russia. Its a 50/50 call at the moment. Perhaps 60/40 for a 2 or 3 day easterly at the end of next week regardless of what happens after.

UKMO T144 really close, a weakish easterly looking a good bet actually.

Edited by rjbw
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Posted
  • Location: leicester
  • Location: leicester

Improvements on both the ukmo and gfs!! Could actually see some more meaning snowfall early next week with colder temps and dew points so should stick around for longer!!

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

The UKMO is an improvement on its 00hrs run but the high is still too far south. A northwards correction and with that deep low over northern Italy and it could be very interesting as that looks like a decent convective easterly set up.

 

This is often the problem to get these highs sufficiently north. Still time for changes we wait to see what the ECM does.

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Posted
  • Location: near dalmellington E ayrshire 302m asl
  • Weather Preferences: mediterranean summer
  • Location: near dalmellington E ayrshire 302m asl

the UKMO for sure is better this evening than the GFS which tryes its best to send everything over the top at +144h then sinks everthing one thing i have learned over the years is the euro models by quite a fair bit are better at +144h mark

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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'm quite sure the relatively brief slack Easterly flow and high pressure shown on GFS isn't what coldies are hoping for but it at least proper winter fare and cold at the surface with some possible ice days and it does bring in some very cold air (coldest for a long time) from the continent for a while.

 

gfs-1-162.png?12

 

UKMO 144 likewise is not the sort of thing that excites but again it is a cold chart and at least going the right way. Can we squeeze out the extra amplification needed for an easterly feed proper? 

In the longer term things don't look too bad even if the Atlantic pushes in as the Azores high will likely be displaced West once more giving a reload of the current set up after a short interlude.

ECM hasn't been buying an Easterly at all really so interesting to see what it comes up with this evening.

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Posted
  • Location: Locksbottom, NW Kent 92m asl(310ft)
  • Weather Preferences: Warm summers but not too hot and colder winters with frost and snow
  • Location: Locksbottom, NW Kent 92m asl(310ft)

This seems like Groundhog Day again. The last few days the mornings runs bring disappointment from a coldies perspective, then the afternoon runs see an improvement, but the frustrating part is that yet again there is no real sign of a Scandi High or GH.As has been said before by others although background signals are positive we haven't seen trends of Heights all winter and it would be great to see a trend start but yet again the Met Office(with the help of so much more data than us) refuse to see this as a strong option which is fair enough and until this changes I think this will be a disappointing cold spell(especially for Southerners in terms of snowfall). That said, it  wouldn't  take much for things to fall in place and bring the NE or E element which the Eastern side of UK require in terms of potential snowfall. 

 

It will be another Interesting viewing of the Models again this afternoon and evening and lets hope a trend starts for HLB either to NW or NE(more likely imho)

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

Am i missing something here....?

The METO have had mention of winds veering on shore for a while on their website and now have a warning out.So no kudos to a model depicting an easterly fetch in my book.Hardly a beasterly but could produce heavy convective showers for a day or so.

UW120-21.GIF?30-17

 

gfs-0-138.png?12

 

What i must add is that the air from  Saturday onward as, Mucka posted, is very cold and with that comes instability and the formation at close range of convective showers/features..... and nowcasting for snow.

gfs-1-162.png?12

Edited by winterof79
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I'm quite sure the relatively brief slack Easterly flow and high pressure shown on GFS isn't what coldies are hoping for but it at least proper winter fare and cold at the surface with some possible ice days and it does bring in some very cold air (coldest for a long time) from the continent for a while.

 

gfs-1-162.png?12

 

UKMO 144 likewise is not the sort of thing that excites but again it is a cold chart and at least going the right way. Can we squeeze out the extra amplification needed for an easterly feed proper? 

In the longer term things don't look too bad even if the Atlantic pushes in as the Azores high will likely be displaced West once more giving a reload of the current set up after a short interlude.

ECM hasn't been buying an Easterly at all really so interesting to see what it comes up with this evening.

Agreed. We really want to see a strong easterly flow with instability mixed in leading to plenty of snow showers feeding in off the 

north sea. Alas this is not been shown at the moment. Why we nearly always have this problem with the high to far south sending 

the coldest and snowiest weather into southern Europe. Still plenty of time for the output to change to our way of thinking perhaps.

I think the track of the low moving south at t72 is still far from settled yet and this could have a big bearing on what follows depending 

on track and depth. 

Still not buying into the the dominance of the low heights to the north in the mid to long range just yet either.

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Posted
  • Location: Boar's Hill, Oxon
  • Weather Preferences: Interesting weather
  • Location: Boar's Hill, Oxon

Much more stretched out and elongated, is the next step going to be for it to move over to Siberia, or will it divide in two and high pressure will develop in the middle?

post-22381-0-91703100-1422638090_thumb.p

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

Agreed. We really want to see a strong easterly flow with instability mixed in leading to plenty of snow showers feeding in off the 

north sea. Alas this is not been shown at the moment. Why we nearly always have this problem with the high to far south sending 

the coldest and snowiest weather into southern Europe. Still plenty of time for the output to change to our way of thinking perhaps.

I think the track of the low moving south at t72 is still far from settled yet and this could have a big bearing on what follows depending 

on track and depth. 

Still not buying into the the dominance of the low heights to the north in the mid to long range just yet either.

The flow does not need to be strong for convective showers to penetrate well in land and mid-week onward looks tasty for the East

Rtavn1388.gif

Rtavn1382.gif

 

Rtavn13817.gif

Rtavn1562.gif

Rtavn1504.gif

Rtavn1508.gif

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Posted
  • Location: Home near Sellindge, 80m/250feet, 5miles from Coast
  • Weather Preferences: Severe Storms and Snow
  • Location: Home near Sellindge, 80m/250feet, 5miles from Coast

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Posted
  • Location: Camborne
  • Location: Camborne

The ECM isn't going for an easterly flow. At T156 there is a light NE from the extended Azores ridge By T192 this has extended further bringing mainly westerlies and then the HP slips south allowing the Atlantic in through the front door and increasing temperatures.

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