492 Dam Air

[Snowyowl9]

I recall that a rough method of calculating the DAM figures from the hPa charts is as follows:

Height (dam) = hPA + (0.8*(sea-level pressure-1000))

I think it was Steve Murr who originally suggested that formula.

The 11th January 1993 was actually quite a cold day over Scotland with heavy blizzards, but a warm one in the south- the low hPa values were mainly a consequence of the very low pressure.

January 1993 could of been just as good Jan 1984,only for that high to the SE and therefore only giving SW-lys.

http://www.wetterzentrale.de/archive/ra/1984/Rrea00219840115.gif

http://www.wetterzentrale.de/archive/ra/1993/Rrea00219930111.gif

[johnholmes]

January 1993 could of been just as good Jan 1984,only for that high to the SE and therefore only giving SW-lys.

http://www.wetterzen...00219840115.gif

http://www.wetterzen...00219930111.gif

how about we stick to the title folks?

please?

[londonsnow]

out of interest what dam air is a classification lower than 492?

[SMU]

probably one for mr data, but i just wondered if 492 air has ever reached our shores. i think almost certainly not, as lets face it 510 air is a rarity these days. just a passing query. LS

quote UK Sci

As to extremes, for the UK mainland only, the highest I could find came out around 575dam in July over southeast Kent (SE England), and the lowest around 495dam on the extreme tip of NE Scotland in January. However, for the British Isles, we have a low value of 491dam over Shetland, and values below 500dam can be recorded in exceptionally cold easterly types as far south as East Anglia & SE England; for example, in January 1987, total thickness values in these latter areas were certainly below 498dam, and probably briefly around 495dam. (Record low UK day-maxima on the 12th January, 1987

Steve

Edited November 12, 2009 by Steve Murr

[johnholmes]

out of interest what dam air is a classification lower than 492?

486DM

they are measured in units of 6DM

[londonsnow]

thanks john. 486dm must be mighty chilly!