"Len Watts" wrote in message
...
The other thing I would like to know is why was it snowing here with a
temperature of +3c when had it have been January, it would have been rain
at that temperatuure.

I have noted this on a number of occasions, in other words it never seems
to have to be so cold for spring snow as it does for winter snow. Anyone
out there know the reasons why?

Regards.
Len.

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I'm not sure that for a few Januaries now we've had the coincidence of a
cold upper pool of air at the same time as the 850 hPa's were around -8C for
a while, as we did today in the S.E . Or maybe not at the same time as low
pressure with reasonable precipitation. I think today's synops would have
given snow in most winter months. Also, on some occasions it would be
because the sea temp could be 3C lower at this time of year than in January,
although I don't think this was a major factor today. I know that the
formula that Will once gave me of adding the dew point to temperature and
looking on a table for the percentage chance of snow worked well again for
me today. The dew point was relatively low and the two added together
remained below zero so high percent chance of snow. Perhaps "spring" snow is
more associated with heavy showers so the dew point might be lower and there
might be more evaporative cooling if the showers are heavy although the air
temp is higher either side of the showers.The experts may be able to
elaborate or add other reasons.
Dave