"Dartmoor Will" wrote in message news:...
I have just issued a "heads up" for this event at
http://www.lyneside.demon.co.uk/weeklydiscussions.htm


Still looking threatening and ominous.

Here is a rundown of the synoptics:
High pressure builds mid-week as the deep upper trough to the west disrupts
establishing a hot and dry SE'ly bringing hot prolonged sunshine to SE'ern
areas in particular. Meanwhile very hot air becomes established over Spain
(post 582 DAM thickness) with the southern low portion of the disrupting
trough nudging east encouraging formation of SSW'ly jet. Not quite classic
Spanish plume but getting there. On Friday the left exit of jet will
encourage a pressure fall to the SW and advection of the elevated hot air
from Spain northwards de-stabilising the atmosphere probably producing a lot
of floccus cloud in the SW on Friday. Then later Friday into Saturday things
get going with a warm plume encouraging deep convection nudging slowly NE.
During Saturday into Sunday the hot air from the SE gets pulled into the mix
and we have the ingredients for some violent storms in the Midlands
northwards possibly on a line. Vertical wind shear will be strong and this
could encourage formation of propagating mesoscale convective systems
giving potential for widespread torrential rain. Obviously this is all
possibilities, we need to await the fine detail, but an exciting weekend
weather-wise is in prospect for some areas.

A word of caution: global NWP is notoriously poor at handling the details of
disrupting upper troughs so there will be a lot of variability in the models
leading up to this possible event. Ensembles will give the best guide and
look for how the 500 hPa contours evolve.

Will
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http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
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