Curvature shown by the clouds on this suggest that this is a
mesocyclone.
Moving over IOW and Dorset.
http://www.sat24.com/en/gb

Origins?
Inititiated by SST air temp difference possibly. Shallow Cu clouds.

Len Wood

On Fri, 14 Oct 2011 06:54:00 -0700 (PDT), Len Wood
wrote:
Curvature shown by the clouds on this suggest that this is a
mesocyclone.

Not sure I agree with your assertion that it's a mesocyclone. True
the cloud bands are curved, but there isn't any rotation evident in
the system - it is just translating west-north-westward. Probably
attained its original shape from the humidity distribution and
small-scale variations in SST and low-level stability, but I don't
think we are looking at anything other than chance distribution of
cloud.

--
Freddie
Bayston Hill
Shropshire
102m AMSL
http://www.hosiene.co.uk/weather/cumulus/

Ruined my charge from the P.V. Interestingly, yesterday we had a classic late season sea breeze. Easterly off shore converging south easterly along the Eastern Solent. Even had a band of convergence cloud cross the Island. This with only a 2 degrees difference between the sea and land temperature.

Mike McMillan

IOW

On Oct 14, 3:59*pm, Freddie wrote:
On Fri, 14 Oct 2011 06:54:00 -0700 (PDT), Len Wood

wrote:
Curvature shown by the clouds on this suggest that this is a
mesocyclone.

Not sure I agree with your assertion that it's a mesocyclone. True
the cloud bands are curved, but there isn't any rotation evident in
the system - it is just translating west-north-westward. Probably
attained its original shape from the humidity distribution and
small-scale variations in SST and low-level stability, but I don't
think we are looking at anything other than chance distribution of
cloud.

--
Freddie
Bayston Hill
Shropshire
102m AMSLhttp://www.hosiene.co.uk/weather/cumulus/
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Admittedly the use of the term mesocyclone is a bit OTT, but usually
the cloud streets are pretty straight in an easterly down the channel.
It would be difficult to be sure of any rotation as there are no
surface or boundary layer top obs at this resolution.
I was wondering if the Normandy peninsula played any role, but there
seems curvature before it reaches this region.

Len

On Fri, 14 Oct 2011 08:25:12 -0700 (PDT), Len Wood
wrote:
usually the cloud streets are pretty straight in an easterly down
the channel.
Yeah, they would be in a more homogeneous airstream than that which
we have today.

It would be difficult to be sure of any rotation as there are no
surface or boundary layer top obs at this resolution.
I did have a brief look at surface obs, but as you say the placing
between them was a bit too wide to pick up any signs. I paid far more
attention, though, to the hi-res visible satellite picture sequence.
The timestep in the sequence was 15 min, which I think is fine enough
to enable rotation to be observed. I couldn't see any.

I was wondering if the Normandy peninsula played any role, but there
seems curvature before it reaches this region.
Yes, I agree, the shape of the coastline probably influenced the
shape of the cloud - or, more accurately, influenced the low-level
humidity distribution.

--
Freddie
Bayston Hill
Shropshire
102m AMSL
http://www.hosiene.co.uk/weather/cumulus/

On Oct 14, 2:54*pm, Len Wood wrote:
Curvature shown by the clouds on this suggest that this is a
mesocyclone.
Moving over IOW and Dorset.http://www.sat24.com/en/gb

Origins?
Inititiated by SST air temp difference possibly. Shallow Cu clouds.

Len Wood

The cloud was the result of an upper low/cold pool which was
indentifiable up to around the 700mb level on the Met Office NAE model
products.

Dick Lovett

On Oct 15, 9:15*am, Dick wrote:
On Oct 14, 2:54*pm, Len Wood wrote:

Curvature shown by the clouds on this suggest that this is a
mesocyclone.
Moving over IOW and Dorset.http://www.sat24.com/en/gb

Origins?
Inititiated by SST air temp difference possibly. Shallow Cu clouds.

Len Wood

The cloud was the result of an upper low/cold pool which was
indentifiable up to around the 700mb level on the Met Office NAE model
products.

Dick Lovett

Thanks for info Dick.

On Oct 14, 2:54 pm, Len Wood wrote:
Curvature shown by the clouds on this suggest that this is a
mesocyclone.
Moving over IOW and Dorset.http://www.sat24.com/en/gb

Origins?
Inititiated by SST air temp difference possibly. Shallow Cu clouds.

[and]
"Dick" wrote ...

The cloud was the result of an upper low/cold pool which was
indentifiable up to around the 700mb level on the Met Office NAE
model
products.

Dick Lovett


.... indeed Dick: that puddle of colder air really spoilt the day
(Friday/14th) hereabouts; a cracking start and promised a fine day to
come, but rapidly after 09Z, Sc spread across from the east, and at
the same time, because the land had been warming strongly before-hand,
shallow Cu developed, which on other occasions would probably have not
been of any consequence, 'fed' the moist layer above 4000 ft and for a
time late morning/early afternoon, we had 8 oktas cloud, with dark
bases - wouldn't have been surprised to feel a few droplets of rain -
but in the end the afternoon was dry, though cloudy, with the cloud
gradually thinning/weakly breaking. Around dusk, the cloud melted away
to give us a chilly evening & night.

Martin.


--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

On Sat, 15 Oct 2011 01:15:31 -0700 (PDT), Dick
wrote:
The cloud was the result of an upper low/cold pool which was

I presume the pva associated with this upper feature locally deepened
the underlying boundary layer such that convection was possible in a
limited area.

--
Freddie
Bayston Hill
Shropshire
102m AMSL
http://www.hosiene.co.uk/weather/cumulus/