This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK. This front is likely to be accompanied by
strong pre-frontal wind gusts and, at the frontal passage, severe
gusts,wind shear and veer with tornadoes, intense precipitation
including small hail. The frontal passage is so sharp 5 minute AWS
observations are unlikely to capture key features of the front.
Therefore, can I ask AWS owners to turn on high resolution recording
for this evening eg 18Z onwards. It is possible that 'network'
observations and opportune observations by 'amateur' AWSs may be of
scientific value in helping elucidate the nature of damaging winds at
this type of cold front.
A paper detailing observations and simulations of the 24 September
2007 cold front is under review (provisionally accepted)at QJRMS-
Morphology and evolution of cold-frontal misocyclones, D.J. Smart and
K.A. Browning (Emeritus Professor University of Reading & University
of Leeds, UK).
I am particularly interested in reports of extreme wind gusts (25 m/
s, 49 kt) coincident with wind veer and reports of damage in the
locality.

Please post observations here or to me at
davidDOTwaghornATgmailDOTcom,
with thanks,
David Smart ('Waghorn')

Very lively as the front passed through Lands End 1710 wind S'ly gust to
78mph.
1715 wind WSW 6-7 gust 40mph
1720 wind W'ly 6-7 gustiness gone
John

www.landsendweather.info



"Waghorn" wrote in message
...
This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK. This front is likely to be accompanied by
strong pre-frontal wind gusts and, at the frontal passage, severe
gusts,wind shear and veer with tornadoes, intense precipitation
including small hail. The frontal passage is so sharp 5 minute AWS
observations are unlikely to capture key features of the front.

A number of sferics now showing on the front due west of Cornwall
http://andvari.vedur.is/athuganir/el...ics/today.html

Jon.

Waghorn wrote:

This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK. This front is likely to be accompanied by
strong pre-frontal wind gusts and, at the frontal passage, severe
gusts,wind shear and veer with tornadoes, intense precipitation
including small hail. The frontal passage is so sharp 5 minute AWS
observations are unlikely to capture key features of the front.
Therefore, can I ask AWS owners to turn on high resolution recording
for this evening eg 18Z onwards. It is possible that 'network'
observations and opportune observations by 'amateur' AWSs may be of
scientific value in helping elucidate the nature of damaging winds at
this type of cold front.
A paper detailing observations and simulations of the 24 September
2007 cold front is under review (provisionally accepted)at QJRMS-
Morphology and evolution of cold-frontal misocyclones, D.J. Smart and
K.A. Browning (Emeritus Professor University of Reading & University
of Leeds, UK).
I am particularly interested in reports of extreme wind gusts (25 m/
s, 49 kt) coincident with wind veer and reports of damage in the
locality.

Please post observations here or to me at
davidDOTwaghornATgmailDOTcom,
with thanks,
David Smart ('Waghorn')


Nothing of any note in Chalfont St Giles. Max gust was 24 knots at
2118z, some time before the front. Around the time of the wind veer the
max gusts were 22 knots at 2249 and 2250z. The rain stopped about half
an hour before the wind veer.

Norman
--
Norman Lynagh
Chalfont St Giles, Buckinghamshire
85m a.s.l.
(remove "thisbit" twice to e-mail)

Waghorn wrote in news:9fb68cca-adad-4eb6-
:

This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK.

Anything of note, David?

Cheers
Richard

"Richard Dixon" wrote in message
53...
Waghorn wrote in
news:9fb68cca-adad-4eb6-
:

This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK.

Anything of note, David?


.... activity late yesterday evening seemed to have spawned a tornado
in Ireland:

http://www.rte.ie/news/2008/1108/waterford.html

Martin.


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

On 9 Nov, 01:04, Richard Dixon wrote:
Waghorn wrote in news:9fb68cca-adad-4eb6-
:

This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK.

Anything of note, David?

Cheers
Richard

Dunno where my initial post has gone, anyway...
as Martin has posted there was a tornado (?) in southern Ireland about
0330Z. This appears to be associated with the northern end of a line
segment producing sferics, but radar coverage in the area is sketchy.
Elsewhere there were reports of gusts to ~60 mph (eg Little
Rissington.). From radar there is evidence for transient LEWP
structures, at least one between Cardiff and Bristol has strong
'broken S' structure implying presence of miso-/mesocyclone. We did
not get the extensive line convection and pressure jump as on 24
September 07, probably because the trough was diffluent type rather
than convergent (thanks to Nigel Bolton). front was overun by dry air,
with strong PVA . an extensive gravity current was not able to form.
I thank people for sending data. I'm still interested in reports with
gusts 25 m/s, wind veer and esp any localised damage. IMO it's
valuable to make the effort to collect the data as one day one of
these gap structures is going to go right over an AWS. Bernard Burton
collected i min data in Dec 2006 located close to a 'broken-S'
structure associated with possible tornadic damage,
David

On 9 Nov, 09:37, Waghorn wrote:
On 9 Nov, 01:04, Richard Dixon wrote:

Waghorn wrote in news:9fb68cca-adad-4eb6-
:

This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK.

Anything of note, David?

Cheers
Richard

Dunno where my initial post has gone, anyway...
as Martin has posted there was a tornado (?) in southern Ireland about
0330Z. This appears to be associated with the northern end of a line
segment producing sferics, but radar coverage in the area is sketchy.
Elsewhere there were reports *of gusts to ~60 mph (eg Little
Rissington.). From radar there is evidence for transient LEWP
structures, at least one between Cardiff and Bristol has strong
'broken S' structure implying presence of miso-/mesocyclone. We did
not get the extensive line convection and pressure jump as on 24
September 07, probably because the trough was diffluent type rather
than convergent

I mean't to write 'confluent',
D

On 9 Nov, 09:49, Waghorn wrote:
On 9 Nov, 09:37, Waghorn wrote:



On 9 Nov, 01:04, Richard Dixon wrote:

Waghorn wrote in news:9fb68cca-adad-4eb6-
:

This evening an intense ana-cold front is expected to move rapidly
eastwards across the UK.

Anything of note, David?

Cheers
Richard

Dunno where my initial post has gone, anyway...
as Martin has posted there was a tornado (?) in southern Ireland about
0330Z. This appears to be associated with the northern end of a line
segment producing sferics, but radar coverage in the area is sketchy.
Elsewhere there were reports *of gusts to ~60 mph (eg Little
Rissington.). From radar there is evidence for transient LEWP
structures, at least one between Cardiff and Bristol has strong
'broken S' structure implying presence of miso-/mesocyclone. We did
not get the extensive line convection and pressure jump as on 24
September 07, probably because the trough was diffluent type rather
than convergent

I mean't to write 'confluent',
D

Another cold front, associated with a developing wave, is forecast to
cross Sunday evening into Monday. This time the trough is forecast to
a more confluent type. A TORRO tornado watch and Estofex Level1 have
been issued,
D

On 9 Nov, 09:49, Waghorn wrote:

snip

Here a sharp gust 37 kn at 2203 from 212° associated with short,
briefly heavy shower, and quite a bit of minor tree damage resulting.
A fence in my garden was blown down. An hour before there were some
interesting barometer antics - two falls of 0.7 mbar within 1 min at
2051, 2057. Selected 1 min data for the period of the barometer antics
and the highest gust is given below - if you'd like more, please e-
mail me.

Time MSLP TT C T
dew C ff kn dd deg ff gust kn gust Z Rain
8 Nov 2008 2050 1002.3 11.6 10.2 13.9 195 25.0 2049 -
8 Nov 2008 2051 1001.6 11.6 10.2 9.7 173 15.9 2050 -
8 Nov 2008 2052 1001.6 11.6 10.1 15.0 182 24.3 2051 -
8 Nov 2008 2053 1001.4 11.6 10.2 17.8 175 28.2 2052 -
8 Nov 2008 2054 1001.5 11.5 10.1 18.6 180 26.2 2053 0.2
8 Nov 2008 2055 1001.5 11.6 10.1 17.1 176 22.1 2054 -
8 Nov 2008 2056 1001.4 11.6 10.1 13.0 182 21.8 2055 -
8 Nov 2008 2057 1001.0 11.6 10.1 9.7 167 14.3 2056 -
8 Nov 2008 2058 1000.9 11.6 10.1 11.3 167 22.4 2057 -
8 Nov 2008 2059 1000.9 11.5 10.1 13.1 173 20.6 2058 -
8 Nov 2008 2100 1001.1 11.5 10.1 13.6 163 19.6 2059 -

8 Nov 2008 2200 1001.0 11.7 10.4 15.0 215 25.2 2159 -
8 Nov 2008 2201 1000.9 11.8 10.4 17.6 214 31.3 2200 -
8 Nov 2008 2202 1001.1 11.8 10.4 15.6 211 21.8 2201 -
8 Nov 2008 2203 1000.7 11.9 10.4 16.1 214 29.1 2202 -
8 Nov 2008 2204 1001.2 11.9 10.4 21.1 212 37.3 2203 0.2
8 Nov 2008 2205 1000.9 11.9 10.4 10.3 209 15.0 2204 0.2
8 Nov 2008 2206 1000.8 11.9 10.4 20.7 212 32.8 2205 -
8 Nov 2008 2207 1001.1 11.9 10.3 15.9 212 25.5 2206 -
8 Nov 2008 2208 1001.1 11.9 10.3 14.6 211 22.7 2207 -
8 Nov 2008 2209 1001.2 11.9 10.3 22.1 218 30.4 2208 -
8 Nov 2008 2210 1001.4 12.0 10.3 18.8 219 25.0 2209 -

Campbell Scientific AWS, sampling 1 Hz, logging at 1 min intervals.

--
Stephen Burt
Stratfield Mortimer, Berkshire