"John Whitby" wrote in
:

Paul Hudson the forecaster on 'Look North' admitted he got it wrong.
The snow arrived in the Yorkshire area in the late morning, 6 hours
earlier than forecast yesterday. I suspect it may have been a wave on
the warm front - which can be very nasty in these siuations. In York
we had about 2-3cm of snow only, but road conditions became bad from
early afternoon. Conditions in areas to the east have been (and still
are) very bad, especially over the Moors and the East Riding.

There was also a very interesting N-S line of heavier snow that you could
track from western Scotland shifting eastward to the Wash from 6am to about
3pm. Not seen something like in a while - initially I thought it was a
radar artefact but it's definitely there. A hallmark of conditional
symmetric instability (essentially thunderstorm-style convective
instability but oriented along the shallow frontal surface in the absence
of the traditional thunderstorm-style upright convective instability), I
reckon !

Richard