.... in another thread Hugh (Evershot) was wondering about my rainfall
total for the month, and I have had a reminder (off list) that we need
to clarify which recording period is being used for rainfall returns,
given that some interesting totals are going to pop up for November
2009.

I use the 'standard' climatological period 09 - 09 GMT, which means
that for this month about to end, the 'November' rainfall will run
from 0900 GMT on the 1st November to 0900 GMT on the 1st December.

Specifically this month, the period up to 0900 GMT on the 1st was wet
hereabouts, and that rain has been credited to October. For my
station, this amounts to 13.5 mm.

If anyone is looking at Hurn data, then that record has been
compromised. I estimate (and it is that please note), that for the
period 12th - 14th inclusive, ~45 mm was 'lost' from that record and
again on the 28th, their total looked about 20 mm too light.

I only have the SYNOP data to monitor this station, so it's possible
that the NCMs (based on 09Z timing) may / will show different data,
but allowing for the differences on the 1st and the 'lost' rainfall
above, I reckon Hurn total for this month should be around 170 mm.
This wouldn't be a record (in the 1957 onwards dataset), as there was
234.6 mm recorded in November 2002, and there have been four Novembers
[ 1963/192mm, 1970/217mm, 1997/169mm & 2000/202mm ] which came close
or exceeded my estimated value.
[ date ex. Met Office historical data site ]

Martin.


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