Model Output Discussions 06z 04/11/16

[Nick F]

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 November 30, 2016 by Nick F

[jvenge]

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.

[gottolovethisweather]

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?

[Glacier Point]

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.

[carinthian]

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

Edited November 30, 2016 by carinthian

[Nick F]

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

[mountain shadow]

1 minute ago, Glacier Point said:

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?

[jonboy]

3 minutes ago, Glacier Point said:

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?

[swfc-ocs]

5 minutes ago, Glacier Point said:

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

 

[karlos1983]

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!

And with this set up!

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

Edited November 30, 2016 by karlos1983

[southbank]

7 minutes ago, Glacier Point said:

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

[Nick F]

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.

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

Edited November 30, 2016 by Nick F

[booferking]

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/

[Glacier Point]

I think broad scale we are still on track. Some oddities with the Indian Ocean right now, which are precluding the cast iron signal one would want. The phase 1 progression not in itself important, more it means we have to go back through phases 2-3, but noted the upper level signal may be ahead of this in the Maritimes. This conflicts with the Global Synoptic Dynamical Model which suggests that following a very positive frictional torque we should see positive mountain torque event with associated extension and retraction of the Asian Jet. Possible indication of this around the 8th-10th December, which is where our amplification would stem from.

Two (very low level) M class flares in the last 24 hrs observed. Again not in itself important, but need to keep an eye on this to make sure it's not a sign of increased activity phase.

Edited November 30, 2016 by Glacier Point

[karlos1983]

3 minutes ago, booferking said:

Yea the sun has picked up its action recently.

http://spaceweather.com/

You have got to be kidding me 

[Seasonality]

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. 

[JRMcLeod]

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

[knocker]

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.

[booferking]

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.

[gottolovethisweather]

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. 

 

Edited November 30, 2016 by gottolovethisweather

[blizzard81]

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

[Methuselah]

This we snippet might help a few peeps get their heads around temperature inversions, as it concerns the very simplest example: http://www.bbc.co.uk/weather/feeds/31200198

[booferking]

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

[Weathizard]

Just now, booferking said:

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

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

[Man With Beard]

1 hour ago, warrenb said:

Quite amusing, when all the agencies with Long Range forecasting tools have all been stating there will be a temporary warm up before blocking reasserts itself.

The models show exactly this, and the place is in depression. Patience is required, as I said yesterday, remarkable similarities to 1962, and we all know what happened then.

Reality check, go a look at the charts for early to mid December 1962.

I don't want to kill anyone's joy and I'm sure the 1962 analogy will come off one day, but for the sake our sanities I must add:

- Every single year, we get to a point where the daily chart is compared to  a chart from 1947 / 1962 (even 2010 now).

- The synoptic pattern for early December 1962 is comparable to probably 30% of winters in the past 50 years.