Bernard Burton wrote:

"Tudor Hughes" wrote in message
... A marked
thunderstorm starting 1332Z with many c-g discharges, one or two quite close
(about half a mile). More interestingly, the precipitation was mostly large
snow pellets, up to 20 mm, quite lumpy and hard but certainly not hail.
Outside it was like being pelted with white fudge. The total amount was not
large but enough to almost completely whiten the short grass in my back
garden. The temperature fell from 90C to 60C. The sky was yellowish (and
still is) with haze and had a distinctly summery look but other factors soon
gave the lie to that. A combination of late March sunshine a cold pool (524
dam) must be what set it off. I notice that showers broke out widely over
southern England and the Midlands from from about 10 a.m. onwards. Do I
call this snow? If so, that is 2 consecutive days in March with snow but
none in "winter".

Tudor Hughes, Warlingham, NE Surrey, 556 ft.



You raise an interesting point, Tudor. I have always been of two minds when
logging snow pellets. Officially, snow pellets come under the category of
'ice meteors', and are logged as such with small hail (ice pellets), snow
grains and diamond dust, hail itself being reserved for hail stones of 5mm
dia or more.

I made a note in my Observer's Handbook back in the 1970s against the
definition of snow pellets; 'snow or hail depending on size', and later in
the early 1980s; 'classed as hail provided that the hail pad is marked,
otherwise snow'. These definitions are not, I think, official, but just for
my own benefit, so that I do not have to agonise over how to classify them on
the rare occasions that they occur.

We recently had a fall of snow pellets on the 23rd, and these were up to
appx. 6 mm dia. At the time I thought I would call them snow, especially as
they produced a temporary covering on the roads etc. But when I returned
home, I found they had marked the hail pad well, thus changed my mind to
enter them under the 'small hail/ice' category.


The stuff that we had in Tideswell at about 1230z was very similar to what
Tudor described. I could best describe it as an agglomeration of frozen stuff
something like very big snowflakes but with a hardish centre. I didn't measure
it but Tudor's estimate of up to 20 mm sounds about right. The stuff came down
faster than snowflakes and slower than hail. On hitting the ground each
agglomeration disintegrated and instantly melted, not at all like hail. What
was striking was that there didn't seem to be any liquid water present even
though the temperature was over 6 deg. I've called it snow pellets though that
doesn't really describe it properly

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org