"Waghorn" wrote in message
oups.com...
http://weather.uwyo.edu/cgi-bin/soun...000&STNM=03882

shows the warm,dry air in depth.Tropopause at ~170hPa, and thickness
565.
Does anybody know how unusual this is for early July?

[ assumed early June ]

.... as regards the total thickness (500-1000 hPa) value, 5655gpm,
looking at the list that Jon O'Rourke & I put together (see:-
http://homepage.ntlworld.com/booty.weather/tthkxtrm.htm ), and doing a
very rough linear interpolation between May & June, then for the period
these data cover (1945-1993), values close to 570dam wouldn't
necessarily seem to be out of place. The whole-May value of ~567dam must
be 'off' the 'extreme maxima' for early June I suppose, so 565 would, I
*guess* be within the top 5 % or so of high thickness values in this
corner of England using that dataset. Based on experience of plotting,
then analysing, these charts over 35yr, I would say that 565 in this
region was 'interesting' in the first third of June, without being
dramatic.

However, it may be that such occasions are becoming more common & the
45-93 record may not now be representative; I have kept a log of
thickness anomalies for a point notionally within the CET 'triangle'
since 1971.

Relating to the 1961-1990 long-term means, and just looking at *Junes*
in that series, during the 1970's & 1980's, above-average thicknesses
(by about 3dam or more, i.e. a reasonably 'significant' amount),
occurred once or twice in each of those decades.

In the 1990's though, anomalies =3dam occurred 5 times (1992, 1993,
1994, 1995, 1996), and so far, for the 2000's, we have had two (2003,
2005).

I suspect therefore that such high thickness values are becoming more
common, without having access to detailed records on the point.

Martin.


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