"Will Wilkinson" wrote:
Philip Eden writes
"Philip Eden" philipATweatherHYPHENukDOTcom wrote :
"Philip Eden" philipATweatherHYPHENukDOTcom wrote:

0850z W F3 25km 3Cu018 16.6/11.8 1012.6
RMK: Cu med/con to the S and SE, otherwise hum and fra

1150z SW F3 35km 5Cu030 18.6/10.6 1012.6
RMK Cu mostly med; tr Ac; tr Ci
A good example of the CS sunshine recorder's greatest
weakness ... burn spread. The card has a continuous trace
since 0530z, whereas during the last couple of hours I doubt
whether the sun has been shining much more than 50% of
the time

1750z Var/ESE F1 25km VCSH RETS 3Cu020 6Ci200
13.2/12.4
1013.4
RMK: Ci Cbgen. Several heavy/violent showers between
1450 and 1710. Thunderstorm with several close discharges
between 1625 and 1705. Rainfall to date 8.4mm, bringing
the total for the last two weeks to 77mm. As I write, at
1805, it's raining again.

Drove through the TS on my way from St. Albans to Bletchley - very heavy
at times, but quite localised. In the heaviest bits I'd have estimated the
rainfall rate at around 100mm/hour, there was significant flooding on some
of the back roads round Potter's Crouch with one section of Appspond Lane
under around 9" of water. Much less intense through Hemel Hempstead but
then a HUGE downpour, with some significant hail (5mm hailstones for
around 30 seconds at the start) around Horton. By the time I got to the
Leighton Buzzard bypass it was dry with no sign of recent precipitation.

Thunderstorm with hail at Luton ... 12h rainfall total there 17.8mm,
most of which fell inside one hour

pe