"Jon O'Rourke" wrote in message
...

There was indeed an upper trough expected to drive east on Monday
leading to
destabilisation and a scattering of showers. Yesterday's mesoscale
runs
continued this theme and were also indicating a more organised
dynamically
generated feature in the far SE, although admittedly not of the
intensity of
this morning's radar returns.


.... always the risk at this time of year of disrupted portions of upper
troughs (puddles of colder air wandering around with a life of their own
at / above 700 mbar), and with the potentially strong heating as spring
advances .... poof! Up they go. I'm always surprised the models do so
well as they do, particularly with fewer routine upper air ascents
nowadays to keep them on track. The models in the past always warmed
such features a little too fast - modern iterations are better, but
because it is such a fine balance (between surface heating / trigger and
mid-tropospheric thermal & humidity structure), the potential for things
going awry is huge!

Martin.

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