"Joe Hunt" wrote in message
...

"Waghorn" wrote in message
...
535.9 J/kg of energy waiting to be released already at 12Z at Watnall,
if
the cap suppressing convection at 800hPa is overcome. If this was to
happen we'd have at least 1000J/kg of CAPE. However, as has been the
case
the last few days, all the ingredients are there for thunderstorms but
nothing to trigger it. The higher ground around Yorkshire did this last
night.
ATB, Joe
Looks rather dry below 500hPa tho Joe.The Basel model-
http://www.unibas.ch/geo/mcr/3d/meteo/
(thanks Martin )
suggests the CAPE is concentrated just south of the Wash in E Anglia.But
maybe along the Cottesmore
ridge or Lincoln Edge and south of there wld provide updrafts ?VIS
imagery suggests the notional
cold front mvg east,surface wind veer cld be the trigger.

Anyway,looks like the main breakdown is gonna be low key as the upper
forcing arrives too late to
phase with the Theta w plume.(I won't mention the M**s ;-))

--
regards,
david
(add 17 to waghorne to reply)

Hi Bernard and David,

You're right Bernard, I am now totally lost as to what triggered the
storms. Do you have any ideas ?

Thanks David (and Martin) for that link, most useful. It's gone very cool
here in Manchester after the passage of the cold front, with a keen breeze
off the Irish Sea.

ATB, Joe



The high level storms last night were most likely triggered by differential
thermal advection, continued warm advection at 850mb accompanied by cooling
of cloud tops and slight cooling aloft would have destabilised the
conditionally unstable mid levels, thus convection was allowed to develop
and rise through the mid levels.

This afternoons storms would have been more widespread should there have
been more moisture. No doubt convergence played a key part in the
development across Lincs and Humberside this evening, with just enough
moisture around to allow the convection to rise and develop, something
missing from most other areas today. I am not entirely conviced the "death
cap" scenario is the correct path to follow, given the temp and dew point
across many parts of Eastern England, boundary layer therodynamics were
certainly supportive of strong thunderstorm development (Note 12Z Watnall
Ascent)

The low -mid levels were far too dry across the vast majority of E&Wales.
Thus the high dewpoint air mass was lifted and mixed with the dry air aloft
before decent convection could occur, thus ensuring there was hardly any
*convective* cloud forming across large parts today. Clearly towards the end
of the day sufficient moisture was found to allow convection to develop
rapidly across the areas mentioned. Had more moisture been around then n no
doubt despite the lack of upper level forcing there would have been more
storms around across Eastern England.

Regards
Paul