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phil nw.

Model Output Discussions 06z 04/11/16

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I don't think developing a deep trop Polar Vortex over E Canada is necessarily a bad thing, shifting the low heights away from our north into Canada may open up the Norwegian and Barents Seas to allow high pressure to be drawn north and northeast. Our stubborn block ain't going nowhere fast and if we get a PV lobe over NE Canada it may strengthen WAA northeastwards to our north to draw the block north - so long as some jet energy goes under towards SW Europe too.

There seems little impetus to shift the pattern over the N Atlantic for a while, particularly the block. MJO signal is weak, so no atmospheric waves to work through to drastically change the pattern for now. Though the Aleutian high may push on the poles enough to affect the mslp over the arctic region.

Edited by Nick F

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1 minute ago, gottolovethisweather said:

And those less old hands as well, don't forget. Quite a rare event I imagine Frosty, yes. My question from yesterday remains unanswered. What often pointers should we looking for in the models other than the 850s should we be considering when looking for cold?

Just look at the 2 meter temperatures. I don't know about UKMO, but ECM and GFS both have charts available for this.

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1 minute ago, jvenge said:

Just look at the 2 meter temperatures. I don't know about UKMO, but ECM and GFS both have charts available for this.

Ok jvenge, Thanks. Anyone got an example they can show me and all others remaining confused by this important topic?

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16 hours ago, nick sussex said:

Tonights UKMO is a cold pattern lock in compared to the dire GFS slow descent into crud. For those that followed my earlier obsession with the Iberian shortwave tonights divergence in outputs shows what a massive difference this can make.Its all about the handling of that and that small piece of shortwave energy which the GFS takes nw towards Ireland.

The GFS 12hrs run has though trended in its earlier stages to the UKMO but you can see with the latter that we manage to get the Scandi shortwave under the high.

If you want to avoid the GFS crud start praying the UKMO is correct!

Not the picture I was hoping for this morning, especially after yesterday UKMO runs. Here the latest ECM at 168h shows a similar picture as the extended UKMO for the same time. On the face of it appears to sink the high into the WWcontinent and throw out a strong ridge way out into SW Europe. So a snow starved first week of winter for much of Western/ Central Europe/UK, staying dry and mostly cold for many. On the bright side no sign of zonal train and the warm advection flow  in the Eastern Atlantic should maintain heights around the British Isles and who knows a relocation to a more favourable position to advect colder temperatures can still easily occur.

 C

ECMOPEU00_168_1.png

Edited by carinthian

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5 minutes ago, gottolovethisweather said:

And those less old hands as well, don't forget. Quite a rare event I imagine Frosty, yes. My question from yesterday remains unanswered. What often pointers should we looking for in the models other than the 850s should we be considering when looking for cold?

Dew point forecasts normally good indicator that temps will get cold at the surface under clear skies

dewp.png

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1 minute ago, Glacier Point said:

TRANSWM.jpg

Worth noting that we have a tropical storm (FOUR) in the Indian Ocean forecast to track across southern India and westwards. This is confusing the MJO signal (sending it back to phase 1) and also likely behind GFS dropping angular momentum. A likely pointer to model meh at present.

The broader analysis continues to suggest upper level velocity potential heading into the Maritimes and eastward, which would assist in reamplifying the pattern. GEFS continue to show around 7-8 members per run going for the expected mid Atlantic amplification.

Just hope the sun doesn't get in on the act right now.

GP, I thought phases 1 and 8 of the MJO were supportive of height rises in the Greenland area in Winter time?

Would a return of the MJO to sector 1 not be a good thing?

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3 minutes ago, Glacier Point said:

TRANSWM.jpg

Worth noting that we have a tropical storm (FOUR) in the Indian Ocean forecast to track across southern India and westwards. This is confusing the MJO signal (sending it back to phase 1) and also likely behind GFS dropping angular momentum. A likely pointer to model meh at present.

The broader analysis continues to suggest upper level velocity potential heading into the Maritimes and eastward, which would assist in reamplifying the pattern. GEFS continue to show around 7-8 members per run going for the expected mid Atlantic amplification.

Just hope the sun doesn't get in on the act right now.

Not sure what you mean by your last line GP? There is an increased risk of flare activity this morning so are your thoughts that this could impact patterns going forward?

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5 minutes ago, Glacier Point said:

TRANSWM.jpg

Worth noting that we have a tropical storm (FOUR) in the Indian Ocean forecast to track across southern India and westwards. This is confusing the MJO signal (sending it back to phase 1) and also likely behind GFS dropping angular momentum. A likely pointer to model meh at present.

The broader analysis continues to suggest upper level velocity potential heading into the Maritimes and eastward, which would assist in reamplifying the pattern. GEFS continue to show around 7-8 members per run going for the expected mid Atlantic amplification.

Just hope the sun doesn't get in on the act right now.

Sunspot activity is virtually zero gp.Where do you see things going mid dec??? Thanks in advance

 

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37 minutes ago, Frosty. said:

All this talk of faux cold vs real cold, I imagine minus 9 celsius in parts of the south with severe frost and freezing fog this morning feels pretty real!:cold-emoji::D

And with this set up!

0_mslp850uk.png

I can assure you, it felt expletively cold whilst I was waiting for my car to defrost at 6am

Edited by karlos1983

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7 minutes ago, Glacier Point said:

TRANSWM.jpg

Worth noting that we have a tropical storm (FOUR) in the Indian Ocean forecast to track across southern India and westwards. This is confusing the MJO signal (sending it back to phase 1) and also likely behind GFS dropping angular momentum. A likely pointer to model meh at present.

The broader analysis continues to suggest upper level velocity potential heading into the Maritimes and eastward, which would assist in reamplifying the pattern. GEFS continue to show around 7-8 members per run going for the expected mid Atlantic amplification.

Just hope the sun doesn't get in on the act right now.

Sadly GP you may be right re The Sun , we had a M Class flare yesterday , cant remember the last time we had one as the sun has been quite over last 6 weeks , sods law just as we get the jigsaw parts coming together at this crucial conjucture and the Sun starts to yawn , be interesting to see what effect this has over next few days

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13 minutes ago, mountain shadow said:

GP, I thought phases 1 and 8 of the MJO were supportive of height rises in the Greenland area in Winter time?

Would a return of the MJO to sector 1 not be a good thing?

Sorry for trending on GPs toes, but worth pointing out that any movement to phase 1 is shown as a weak signal on model forecasts - hence little impetus to change much in the model outputs. Need a more coherent movement of MJO in P1, i.e. orbiting further out.

ECMF_phase_51m_full.gif

Lets hope GP is right re: more amplification later across the Atlantic, as the models are indeed meh for snow lovers for now!

Edited by Nick F

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2 minutes ago, southbank said:

Sadly GP you may be right re The Sun , we had a M Class flare yesterday , cant remember the last time we had one as the sun has been quite over last 6 weeks , sods law just as we get the jigsaw parts coming together at this crucial conjucture and the Sun starts to yawn , be interesting to see what effect this has over next few days

Yea the sun has picked up its action recently.

http://spaceweather.com/

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2 minutes ago, booferking said:

Yea the sun has picked up its action recently.

http://spaceweather.com/

Although to quote from that site, referencing the flare yesterday. "This was a relatively minor event, notable mainly because of the quiet that preceded it. NOAA forecasters estimate a 10% chance of additional M-flares on Nov. 30th." This was an M1 so at the bottom of the linear scale for M Class flares, an M2 being twice as powerful as an M1 and so on. 

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I know slightly off topic but worth putting it into the discussion.  If you check the Met Office monthly summaries for 1962/3, you can clearly see that the Aurora was visible in Scotland approx 15 days each month.  I have seen it twice and i live in Scotland and i am 33. 

The discussion above is about the Suns possible interaction...

What are the general view points on sun activity?  Would it be safe to say that the more active the sun, the possibility of colder weather increases as per the monthly summaries? 

Met Office Monthly Summaries 1960's

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15 minutes ago, gottolovethisweather said:

And those old hands as well, don't forget, Pete. Quite a rare event I imagine Frosty, yes. My question from yesterday remains unanswered. What other pointers should we looking for in the models other than the 850s should we be considering when looking for cold?

The forecast 1000mb-850mb thickness chart will give an idea of the temp of the boundary layer without being specific to surface temps and the 1000mb-500mb thickness can be used for airmass mean temperature in general thus in situations like now it will actually be quite high as the airmass is quite warm apart from the lower layer.

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1 minute ago, Seasonality said:

Although to quote from that site, referencing the flare yesterday. "This was a relatively minor event, notable mainly because of the quiet that preceded it. NOAA forecasters estimate a 10% chance of additional M-flares on Nov. 30th." This was an M1 so at the bottom of the linear scale for M Class flares, an M2 being twice as powerful as an M1 and so on. 

Yes i agree but the sunspots have been growing day by day, hopefully it will have no effect and we see them decline again.

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Thanks for your help, guys. I see tonight is predicted to be a night of generally less severe frosts. According to the Beeb forecasts I've seen, this GFS t+21hrs (7am December 1st) chart from the 6z showing relevant 2m Temperatures should be somewhat accurate.

 

This is obviously what I should have been looking for, before getting confused with my 850s and inversion issues. You live and learn. I will also keep an eye out for dew point charts in conjunction with the forecasted 850 charts, thanks Nick F. Simply proves to me, we shouldn't take everything at face value and need to account for several parameters at once when second guessing what the model predictions are indicating at any one time. :)

 

GFS charts - 30th November 2016 06z UK 2m Temperatures t+21hrs.gif

Edited by gottolovethisweather

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Here we go, wheels starting to fall off. You have to laugh really!

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Just now, booferking said:

On a brighter note the pacific high looks to be rather strong this time playing ball.

gfsnh-0-174.png

Pacific side it's better, our side it's decidedly worse with pressure sinking

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