"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
--

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

On Monday, 6 August 2012 11:12:01 UTC+1, wrote:
"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

--



http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm

Will Hand (Haytor, Devon, 1017 feet asl)

---------------------------------------------

Hi Will.
Will be on storm watch in the Thames Valley if super cells form.
Regards Richard Bailey Marlow

"Dartmoor Will" wrote in message
...

"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.


The event is now almost here and the MetO FAX chart sequence at
http://www.wetterzentrale.de/topkarten/fsfaxsem.html
illustrate the possibilities. The solid black lines indicate the main plume
of very warm and moist low-level air and where thunderstorm activity could
be most intense.

This is my last update now, bring it on!

Will
--