On 22/04/2018 18:08, Norman Lynagh wrote:
Graham P Davis wrote:

On 21/04/18 23:23, N_Cook wrote:
So about 28mm in 55 minutes with a peak rate of 200mm/hr

Reminded of some crap we were taught on the assistants' course in
1962, one of several piles dumped on us. We were told never to report
a violent shower as we never get that in this country, it only occurs
in the tropics. I thought it was nonsense at the time and have been
proven right on many occasions.

For the record, a violent shower is classified in my "notes for
scientific assistants" as having an intensity of "greater than about
50mm (2 inches) per hour". ["Greater than about"? what?]

Heaviest rain I witnessed brought visibility down to 200m, which is
not often seen in snow let alone rain. Don't know the rainfall rate
(I was sitting in my stalled car outside the tower waiting for it to
ease off) but the observer said the tipping-bucket-rain-gauge counter
"sounded like a machine gun". That was on a cold front.

Just after 1630z this afternoon we had a shower in Tideswell with a max
rate briefly of 57 mm/hr. It really did hammer down for a minute or so.
Not particularly unusual, though.


About 08:00 29 Dec 2017, on the same St Denys, Southampton rain gauge
230mm/hr peak rain rate.

On 21/04/2018 17:21, Norman Lynagh wrote:
The current Severe Weather Warning predicts that the thunderstorms will
develop over North Wales late this afternoon and will become widespread
over Norther England this evening. The present activity is much further
south than that with sferics showing an increasing amount of thundery
activity over Devon. There's nothing happening over North Wales yet.



Here in Northampton, over the last 24 hours we have had:
NO thunder
NO lightning
2.1mm of rain (between midnight and 4am).

So much for last evenings' local "doom and gloom" forecast of torrential
rain and thunderstorms (stressing the strong possibility of a sleepless
night for most of us) expected in the early hours of the morning.

Had a look at the lightning radar at 1am, and Dorset and Hampshire were
getting a right old hammering.

jim, Northampton