A new Meteorology
 

Met. Office spokesperson today:

Air masses are defined by the temperature and humidity in a layer 1.5km up in atmosphere.

Sheer gobbledygook. I honestly have no idea what this means, and if I did understand it I expect I would disagree. Mind you, climate change might just have altered the basics.
Climate change, Covid, BoJo and Brexit are responsible for just about every misfortune and murrain.

Bring back the old seaweed hung on the washing line huh ;)

It always bugged me when some pretty piece would talk about 'spits and spots of rain'.

The only weather girl that I trust is Laura Tobin, formerly of Brize Met office. Not only did she give an epic met brief but she always looked stunning while delivering it.

Little known fact: she always coordinated her stilettos with her top. The usual question from the crew on return to the Planning Room was "What did she say the weather was again? I wasn't listening."

Go on, I'll bite. How would you describe an airmass in a way that the general public can understand?

I am sure that they failed to understand the tripe offered.

I shall work on an answer!

As an ex seafarer I aways look at the Atlantic Weather charts to make my own mind up about the Wx Forecast.I also worked in Port Operations for many years where the Wx was just as important.We also paid for our own forecast and wind warnings.Forecasting a small area is much more accurate.

https://cimg1.ibsrv.net/gimg/pprune....b705112fb.jpeg

A version of a good hohoho seen all over. We even had our "Weather Dog Katy" at B o Bs and Shows in the 1980s, with suitable canine amendments.

As to recognising an "air mass" in practical terms useful to Met. and the aviation customer, the dew point temperature plotted on the station circles of a synoptic chart is a fairly conservative property give or take a degree or two, and a day or two.

I remember I used to know about things like that.

Not terribly useful in an Easterly, but each to his/ her/ their own.

Hmm. Not that far apart so far.

So what is a LAYER 1.5km UP?

A layer has a bottom and a top.

Temperature has a huge diurnal variation so is useless for a definition.

Far far apart.

Maybe the bottom of the layer is at the surface (or just above the boundary layer) I don't know what he actually said nor meant, although I would have thought it unwise to define the depth of the layer too closely.
I thought that air temperature has a huge diurnal variation only close to the surface of the earth and temperature combined with dew point give a measure of humidity, which, in the station circle, is only represented at the surface? As you imply surface observation could require several days observations and skill to identify the horizontal boundaries of an air mass and only with difficulty describe the depth of it. Perhaps the definition of and method of detection of air masses has changed since you retired.
Having described how you would find an air mass, how would you define an air mass?

Langley, serious, but maybe dumb, question. It seems to me, a layman, that a lot of the places where 40deg.was exceeded are subject to non meteorological influences making it seem hotter. I am aware that thermometers are contained in louvered boxes but when these boxes are sited on a large concrete/tarmac area with hot jet exhaust coming from aircraft movements, Coningsby/Heathrow for example, this is going to make things seem hotter or is it my imagination?

They are not sited on large.concrete or tarmac areas. Heathrow weather station is N of the runway and I imagine Congingsby will be on the grass near the tower.
See section on siting in
https://en.wikipedia.org/wiki/Stevenson_screen

In a very few words, yes, many a measurement is made in less than 100% correct exposure.

There is often some tension between where the S Met O would like his instruments, and the operational needs. The "old fashioned" but essential kit in a grassed enclosure must usually be attended every hour/ six hours/ 24 hours by the observer so has to be handy [I once lost an observer in fog but that is another story]. What has happened at many airfields is that the instrument enclosure, initially ideally situated from a purist point of view, has been encroached upon by essential operational priorities. Jet efflux fortunately is not a major villain as taxiways have to be minimum distances from obstructions. Acres of tarmac ............ even car parks are known to exaggerate temperature readings. For some known problems there are empirical adjustments that can be made, most cannot.

Once a year S Met O's boss is/ was supposed to visit and do a detailed inspection ....... often brings his/ her/ their own expert observer along. Many howlers over the years: anemometer on a dwarfish mast, anemometer too near disturbances to free flow due to a new-build hangar, louvred screen fitted back to front, screen not screwed in position.

And then there is the light-hearted Ho Ho Ho! of passing folk passing water into the rain gauge.

One thing you can be sure of: the quality control people at HQ put any new claims for records through the ringer before accepting them

Shurely an air mass is where the faithful kneel and pray for rain / sunshine ?

Thanks Langley.

I would assume all equipment in a Stephenson Screen does go through the annual calibration cycle that all measuring equipment should be subjected to (certainly not to groats but defined standards) to confirm their accuracy. I now live up in the north east (I was working on a jet powered craft with the designation of K7 last weekend, what an honour!) but watched the news from my last homeland. The Met man mentioned why a place was constantly one of the highest temperature areas. It wasn't just due to the air above, but the heat releasing properties of the land below and moisture bearing properties of it. Sandy soil that threw out energy as fast as it could take it in. Doesn't that go in one direction?

An interesting item on BBC, showing virtually no difference between temperatures measured at London Airport and at Kew Gardens: https://www.bbc.co.uk/news/uk-44980493

Second Thoughts.

My diatribe on who does what, where and when, was based on established practice and the worthy pursuit of excellence "in my day".

For all I know, the push for fewer and fewer bodies on the ground and more and more automation, may have got rid of the enclosure and the observer.

It is a long time since 1997, when I last knew what I was talking about.

Apart from establishing records of slight value to man or beast, perhaps the arbitrary accuracies sought are meaningless: what is a couple of knots, a 3 degree wind veer/back, a decimal point of a degree C., a tenth of a millibar [or whatever they are called] in the scheme of things?

A latter day heretic wonders out loud.