Yes as everybody says Will ,great stuff with your clear assesment,which
reminds me to bring up the question of freezing levels again,apart from
yourself freezing levels are seldom mentioned in any weather forecasts
especially from the Met Office .
Snow levels are now being mentioned more frequently on the Beeb ,but not
freezing levels ,which if they were it would give everybody an idea of how
they would be likely affected when the snows come .
I know the great British Public are not generally believed to handle deep
scientific data ,but the inclusion of forecast freezing levels shouldn't be
too difficult to handle ....
I think I will make this my own private campaign until our betters concur

RonB



"Eskimo Will" wrote in message
...
Wow is all I can say, this is why I love winter with all its drama.

The deep low set to come over or close to northern Scotland is not even on
the charts yet but it will develop explosively as a shallow wave is
excited on the low-level baroclinic zone in the North Atlantic. This then
phase locks with an upper trough and high PV coming south from west of
Greenland and rapidly deepens late Wednesday into Thursday and is then
steered by the jet towards Scotland. The depression looks like being warm
cored meaning that close to the centre wet-bulb freezing levels will be up
around 400 metres or so asl but deep cold air will be tucking in round it.
Winds could well exceed 70 knots (hurricane force in northern Scotland)
and as the cold air tucks in, blizzards (heavy snow and severe gales) are
likely on hills above 200 metres asl bringing white-out conditions in the
mountains. Given the warm core as part of the seclusion process the snow
is likely to be of the wet sticky variety and hence poses a significant
risk of ice accretion on power lines, especially Thursday evening when
some truly horrific conditions are likely in northern Scotland and the
northern Isles (possibly with power cuts). The winds will also generate a
surge down the North Sea which is being discussed elsewhere. The London
barrier will be raised no doubt and Holland should worry.

Now the cold front will sweep SEwards on Thursday, the main feature being
a rapid fall of temperature with possibly a short spell of sleet/snow on
its back edge, even on low ground in England. Before then though the air
in the warm sector is quite mild and may give rise to temporary snow-melt
in some upland areas. Then we have a frosty ridge on Friday.

Meanwhile the very cold (exceptionally cold?) air over Greenland will
continue to leak south lowering North Atlantic SSTs even more and push the
baroclinic zone a notch further south meaning that the next rapidly
deepening Atlantic low could slam further south into the UK early next
week after some respite over the weekend (rain and hill snow but just
normal wind). Further ahead I cannot see any end to this cold westerly
zonality which will tend to get even colder with time due to lowering SSTs
and the time of year!

Phew, I think that's enough from me!

Exciting cheers,

Will
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