full_frontal_occlusion

And the nominations for this winters Forecasting-Oscars are: Best LR evolution: BFTP for 'Eastie Beasties', TEITS for 'Some like it hot but not a lot', Nick Sussex for 'Me too' And the winner is.......? But as they say in the business 'It ain't over till the fat lady sings.' ffO

I've watched the model thread since it began and although I'm no weather guru, I do have signficant interest in the science and maths behind the models and in particuar lrf techniques. It strikes me though that precious few NW posters use rigorous methods and experience (or even know how) to correctly predict with better than 50:50 chance, medium range and beyond. Even fewer are prepared to stick their necks out and make lr predictions (whatever method they use)and then stick by them. The ones that do are brave souls and have my respect. Let's face it, models (and seagulls) are indicators only and are nowhere near the point where proven experience can be replaced. ffO.

Interested to know why you are confident the AO will shift? Is it just because the indexes are predicting a shift or is there something else that's causing your optimism? Thanks. ffO.

You know the old adage - if it looks too good to be true it probably is. ffO

Quite. The missile was a failed submarine launched Bulava ICBM. Here's the advance notice of intended launch: ZCZC FA79 031230 UTC DEC 09 COASTAL WARNING ARKHANGELSK 94 SOUTHERN PART WHITE SEA 1.ROCKET LAUNCHING 2300 07 DEC TO 0600 08 DEC 09 DC 0200 TO 0900 10 DEC 0100 TO 0900 NAVIGATION PROHIBITED IN AREA 65-12.6N 036-37.0E 65-37.2N 036-26.0E 66-12.3N 037-19.0E 66-04.0N 037-47.0E 66-03.0N 038-38.0E 66-06.5N 038-55.0E 65-11.0N 037-28.0E 65-12.1N 036-49.5E THEN COASTAL LINE 65-12.2N 036-47.6E 2. CANCEL THIS MESSAGE 101000 DEC= NNNN ffO.

Latest generation models use ensembles as a way of representing the probability density function of errors for each run. In simple terms 'spread'. This depicts spatial (3D) distributions by introducing a random element - the so called Monte-Carlo type 'seeding' which itself introduces error. Next generation NWP use 4D-Kalman filtering (a variant on the filters used extensively in missile guidance algorithms). Ensemble Kalman filters EnKF uses predictive algorithms to plot spatial trajectory as a function of time. i.e. Spatial error as a funtion of time is computed from actual synoptics vs the previous predicted spatial distribution. This generates a spatial compensation function. Feedback loops try to reduce the error to zero. As you may imagine, this type of algorithm imposes very significant demands on processing power! ffO.

Has any one taken a look outside recently? I'm in Hertfordshire this afternoon (just outside Stevenage) and erm - it's snowing. Very fine but quite a moderate flow with larger flakes interspersed. Not showing up on any of the radars. ffO.

Good morning all. Unfortunately that band of ppn crossing the North Sea is driven by the high pressure system to our NE. That means the track will back away clockwise from SE England. We've also lost the -10 850hpa's. Any ppn for this region looks increasingy marginal. Not to worry, plenty of opportunity still to come thos winter. It is after all not yet the middle of January! ffO.

Wind Chill A few figures for you: ..0C air temp, 5mph wind feels like -3C .-5C air temp, 10mph wind feels like -11C -10C air temp, 15mph wind feels like -18C -15C air temp, 20mph wind feels like -26C -20C air temp, 25mph wind feels like -34C -25C air temp, 30mph wind feels like -42C 'Raw' and 'bone chilling' are inadequate adjectives to describe the effects of wind-chill. Low temperatures coupled with even moderate winds create another danger for the unprepared. Expect to hear more talk of wind-chill in the media over the coming days. ffO

Indeed. The main ppn proged for this afternoon and into tonight looks to consequently shift WSW by 75 miles or so. ffO

And long may that balance continue John. Judging from the Meteogroup radar ppn images, it looks very much like a fast moving closed circulation is forming just SW of Aberporth out in Cardigan Bay. ffO.

Perfectly normal. That is after all, the location of the Atlas mountains rising to 4150m (14,000'). Winter sports are common and snow lasts until late spring. ffO

ffO

Just an observation, but, do any of you guy's ever check the reality state of the models with actual weather? There is already snow falling in Lincolnshire and East Anglia. Eumetsat time lapsed images show the air now over the south east, originated in the far north east of Greenland, well inside the Arctic Circle. Carol Kirkwood stated 1 - 3cm today, with 5 - 10cm by tomorrow night (Thursday). Must have watched a different Carol to some ffO.

Article here The problem of predicting the start of solar cycles with a good degree of accuracy seems within grasp. The trigger event is linked to a heliosphere jetstream 7000km below the surface, which forms at the solar poles and migrates towards the equator - following the 11 year cycle pattern. Whan it gets to 22 degress, sunspots begin forming at the surface and then continue migration on the same track as the jetstream sinks towards the equator. Now it strikes me that there are many similarities with our own jetreams, Ferrell, Hadley and Polar cells: I would postulate solar rotation to cause some form of thermal and electromagnetic cyclogenesis at the poles within the hot ionised hydrogen at the surface and helium fusion products from within the solar mass. i.e. where centrifugal forces are at a minimum. At the equator, centrifugal forces are at maximum causing an equatorial bulge. Thus, a thermal / electromagnetic imbalance is set up between the equator and poles caused by the attractive gravitational forces, and repulsive electromagnetic and rotational forces. 22 degrees latitude seems to be the point where some kind of equilibrium between these forces is breached and triggers the formation of sunspots. Of course it is most probably hugely more complicated than this. ffO.

July '07 sounds spot on. I made a mental note after noticing 'unusual' clouds whilst driving through Hampshire on my way to the International Air Tatoo. That was on Sunday, July 15. Rain held off mercifully, but I believe the Midlands took a pasting. Might be worth looking at the synoptic archives for that day. ffO.

We could aways start a new conspiracy theory: "Space faring nations scramble to colonise moon before asterod impact wipes out life on earth." If you read the above, you must e-mail it to at least ten of your friends or else something terribly bad will happen to you in 2036. Lets see how fast this one can take hold. ffO.

Near Earth Asteroid designated 2004 MN4 will pass within 20,000 miles in 2029 with the possibility of impact in 2036. For a brief period after discovery, the asteroid reached Torino Impact Scale 4 - the highest ever recorded for a NEO. (i.e. a 1% or greater chance of collision capable of regional devastation.) The asteroid is estimated to be between 350 - 450 metres diameter with an energy release 5 times that of Krakatoa and equivalent to a 900 megaton nuclear bomb. ffO.

I often contemplate Spoonerisms. i.e. Sit and think. :o

At 0330 GMT today, NASA announced the new node will be called Tranquility - joining the other nodes Harmony and Unity. Colbert does get his name and face on the stations new exercise treadmill though. http://www.space.com/news/090414-colbert-s...ation-node.html ffO.

NASA are in a bt of a pickle over the name of a new module due to be installed on the International Space Station. The new module executes human waste re-cycling and environmental conditioning, electrical power distribution and a panoramic earth observation window. A NASA organised on-line public voting competition to name the new node ended in March. However, a US TV comedian (Colbert) conducted a compaign through his weekely television show, urging his viewers to vote for his own name and hence win the competition to name the module after him. The voting concluded with Colbert wining 230,000 votes (19%) and Serenity the next name coming in with 190,000 votes (16%). Over 1,200,000 votes were cast for all entries. Question is: should NASA honour Colbert as the outright winner even though its arguably not the spirit or intent of the competition? Bear in mind that clause 4 of the published competition rules states, NASA is not bound by the vote outcome to use the vote winning name (presumably to prevent an inappropriate name). On the other hand, Colbert has given publicity for the ISS and perhaps reached a section of the public that previously had no knowledge or concept of the ISS. And what does it say for the power of celebrity to manipulate an outcome through ego? NASA is due to make an announcement on the Colbert show tonight. ffO

I lived at home with my parents in Harrow north west London at the time and remember the event vividly. I watched from my bedroom window as the snow came down, whilst listening ironically to the Rain Song by Led Zeppelin! Later that year Genesis released Wind and Wuthering with the line 'when the evil of a snowflake in June, could still be a source of relief' from the track Mad Man Moon. Halcyon days. ffO.

Interesting observation GP. My scientific background is in electronics and aerospace application not meteorology, but the maths for wave propagation is pretty much identical Haigh and Blackburn (8/06, Space Science Reviews V125, N1-4, Pgs 331-334) used an AGCM to investigate the response of the troposhere to thermal perturbations in the stratosphere. They found heating weakens the sub-tropical jets and the tropospheric mean meridional circulations. The distribution of stratospheric heating directly impacted the scale of Hadley cells and the positioning of the jets with uniform heating displacing them towards the equator. They found stability at the tropopause is initially reduced by eddy (Foucault) flux convergence in this region within 12 days. A vertical transfer of the momentum follows forcing anomalous mean circulation to the surface and they concude by suggesting thermal stratospheric changes is a key mechanism affecting Rossby wave propagation. All of this bears striking similarities for eddy currents within electromagnetic domains and much can be read across. Within these systems intial perturbations result in magnetic field disruption almost instantaneously (propagation velocity dependent on dielectric medium) followed by sustained vortices with preserved momentum dissipating over a much longer time frame. Boundary features now play an important role in energy dissipation. The analogue to tropospheric weather can clearly be seen with the set up of eddy's from stratospheric forcing having an initial effect and then unrelated surface height rises within the troposphere protruding into the stratosphere subsequently causing the major lagged energy dissipation back into the troposphere. A sort of transmission reflection effect. I can feel a paper coming on! ffO.

BBC website and iPlayer. The Countryfile forecast should be available to download in a few hours. ffO.

Do you not think this is perhaps a response to the demographic shift of the UK population in that there are now more pensioners than 16 year olds? I'm pretty sure there will be far more of the older generation interested in the weather during the winter months, not least because of soaring energy and heating costs. Like any service provider, one has to 'keep the customer satisfied' - playing to a minority of weather enthusiasts is simply not a priority. ffO.