On Thursday, 27 March 2014 19:35:38 UTC, Norman wrote:
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

The precipitation we had here was similarly snowy but harder and more coherent than an agglomeration of snowflakes. Only the largest were 20 mm, the bulk of it 10-12 mm. It fell somewhat slower than raindrops but much faster than snowflakes and remained as coherent balls on landing. I picked a few of the larger ones apart to see if they had a hard hail-like nucleus but they didn't and could be crushed completely though it took some force, more than a loose little snowball would. There didn't appear to be any liquid water content until they started melting on the ground, which took some time, over 15 minutes. On the road after a few minutes it resembled slush and cars made quite a noise ploughing through it.

Tudor Hughes, Warlingham, NE Surrey, 556 ft.