.... So that you can compare with the current event, I've tried to pick
out, from the 'Wetterzentrale' (ex. NCEP re-analysis) archive, what
the typical 850T and Total Thickness (TTHK) values were in early June
1975.

** At Albermarle (NE England), the 850T from 31/0000Z May to 04/0000Z
June (midnight data only) were varying between -2 & -4°C.

** At Crawley/Herstmonceux (SE England), same data/period (but also
using the WxLog ex RMetSoc 12Z data), they were generally -2 or -3°C
(-1°C at 02/0000Z).

Picking a point roughly in the middle of the CET domain, the total
thickness (500-1000hPa) values [00Z charts only] were between 531 &
536 dam over this same period - lowest value (531) 03/00Z; note
however that these are very approximate, based on 'eyeballing' the
500hPa & mslp (crude conversion to 1000hPa) data. I suspect that the
TTHK would have fallen below 530dam late 2nd/early 3rd somewhere over
central England.

This time around, over *England* the values don't seem to be expected
to be quite so low, at least based on latest GFS output.

After 4th of course, there was a dramatic rise in
temperature/thickness as the southerly took over: at Crawley for
example, the 850T at 04/12Z was -2; just 24hours later, the
temperature was +7°C. IIRC, it was stated at the time that the
'switchover' from the cold-to-warm event was one of 3 or 4 most
notable such events in at least 80 years.


Martin.




--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

Martin Rowley wrote:

... So that you can compare with the current event, I've tried to pick
out, from the 'Wetterzentrale' (ex. NCEP re-analysis) archive, what
the typical 850T and Total Thickness (TTHK) values were in early June
1975.

** At Albermarle (NE England), the 850T from 31/0000Z May to 04/0000Z
June (midnight data only) were varying between -2 & -4°C.

** At Crawley/Herstmonceux (SE England), same data/period (but also
using the WxLog ex RMetSoc 12Z data), they were generally -2 or -3°C
(-1°C at 02/0000Z).

Picking a point roughly in the middle of the CET domain, the total
thickness (500-1000hPa) values [00Z charts only] were between 531 &
536 dam over this same period - lowest value (531) 03/00Z; note
however that these are very approximate, based on 'eyeballing' the
500hPa & mslp (crude conversion to 1000hPa) data. I suspect that the
TTHK would have fallen below 530dam late 2nd/early 3rd somewhere over
central England.

This time around, over *England* the values don't seem to be expected
to be quite so low, at least based on latest GFS output.

After 4th of course, there was a dramatic rise in
temperature/thickness as the southerly took over: at Crawley for
example, the 850T at 04/12Z was -2; just 24hours later, the
temperature was +7°C. IIRC, it was stated at the time that the
'switchover' from the cold-to-warm event was one of 3 or 4 most
notable such events in at least 80 years.


As I remember it, Monday and Tuesday were both cold with temperatures
maxing at 7-8C. My recollection has been that a sudden warming occurred on
Thursday afternoon but, thinking back on it, the shift pattern I would
have been on makes that impossible so it must have been Wednesday. I was
in the Abbey Gardens at Bury St Edmunds during the afternoon when I
noticed it suddenly felt warmer. There was no other visible change - no
change of cloud and I didn't notice a change of wind direction - it just
suddenly got muggy.

--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."