On Jul 15, 12:11*pm, "peter clarke" wrote:
Following *Keith's earlier thread, *more evidence has accumulated. The late
Colin Finch- one of the founder members of COL , and the only person I have
ever met who spent Saturdays *in the 1960s and 1970s plotting a northern
hemisphere chart from morse code transmissions on a shortwave radio -
produced a formula for predicting late summer temperatures. Briefly, if the
second week of July( 7-14th) failed to produce at least 2 days *with the
temperature *reaching at least 24c in his part of Surrey, then there
wouldn't be many more in the weeks leading up to the end of August. I'm sure
he wrote this up for a COL bulletin *in the 1970s; no doubt someone here
will have a copy.

I find myself checking *the daily max temperatures every year at this time
of July. There were NO days with 24c here * between the 7th and 14th, and
there were none last year or in 2007. *We all know how the late summers
turned out. Going back through my temperature records since 1970, I found
that there were 12 years when 24c failed to *be reached in the critical
week. The 6 weeks which followed produced an average of 9 days with at least
24c.. By contrast, in the years when 24c was achieved on at least 3 days
between the 7 and 14th, *the next 6 weeks produced an average of *21 such
days.

In 5 years there were 7days *above 24c in the critical week ( 1976, 1983,
1995, 1997, 1999) . The average number of similar days in the following 6
weeks was 29.

Peter Clarke
Ewell,Epsom

Very interesting - and certainly not impossible, as an established
pattern is more likely to continue than to stop and this pattern has
now been with us for over a week. but 6 weeks is a long time in
forecasting UK summer weather! It would be great to see further
research on periods well before 1970 and it will be interesting to see
if we get a possibly less likely warmer "Finch" late summer, or a more
likely cooler "Finch" late summer this year! The outlook over the next
10 days is unsetlled, but the 06z raises the possibility of some very
warm weather in Surrey (and other areas) early next week, in a plume,
though it is only a possibility ATM.