"Richard Dixon" wrote ...
I've gone back to my thickness study I stuck on here last month -
top 10
lowest thicknesses I could find from the NCEP reanalysis (which I
realise
will have its errors, and I've only looked from 1960-2000) is - and
these
are daily mean thickness for a gridpoint in west/central England:
Date TT500
22/11/1965 517.2
19/11/1971 519.2
19/11/1962 519.4
21/11/1993 519.4
29/11/1969 519.7
23/11/1993 520.7
28/11/1985 520.8
22/11/1993 520.8
28/11/1980 521.2
25/11/1978 521.3
Richard


.... have just looked at the soundings from yesterday (27th November,
nominal time 12Z), and at Lerwick [Shetland] the total thickness
(500-1000 hPa) was 507 dam, and at Albermarle [Northumberland] it was
511 dam. Using the data published in the FAQ (reference elsewhere in
the thread) then these would appear to fall *outside* the minimum
values implied from that series for November (but note caveats
regarding period used etc.).

Following Richard's post (above), although we don't have an explicit
value for 'west/central' England (somewhere like the old Aughton), I
reckon we've gone below even the lowest value he quoted (517 dam
November 1965), with Watnall/Nottingham (east Midlands) 517 dam at
27/00Z and 513 dam at 28/00Z; the coldest air would have passed over
them late yesterday.

I made a comment that reality doesn't always accord with model at the
range of the forecast ( roughly a week ahead ). I am very happy to
note that the model (GFS in this case) played a blinder & I should
have had more faith!

A superb indication on the 'depth' of the cold air (in terms of how
cold) and where the cold air would be.

Martin.


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