Thursday, 12 January 2006
BRACKNELL (TAWFIELD)
0900 S F2-3 25km - 7/CI COTRA T025D017
RMK: the wind very variable in speed; within space of 10 mins or so,
dropped to near-calm and perked up to F4 for a short time - the
temperature rising sharply as a result with hoar frost melting.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: -00.1 grass min: -02.5 precipitation: tr [24hr total: tr
mm]
other data: significant hoar frost deposits, not only on the 'usual'
roof/grass surfaces, but all pavements and minor roads - quite
slippery. ]=

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W

Thursday, 12 January 2006
BRACKNELL (TAWFIELD)
0900 S F2-3 25km - 7/CI COTRA T025D017
RMK: the wind very variable in speed; within space of 10 mins or so,
dropped to near-calm and perked up to F4 for a short time - the
temperature rising sharply as a result with hoar frost melting.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: -00.1 grass min: -02.5 precipitation: tr [24hr total: tr
mm]
other data: significant hoar frost deposits, not only on the 'usual'
roof/grass surfaces, but all pavements and minor roads - quite
slippery. ]=

0930 SSE F2 4000 BR 8/ST T028D023
RMK: The aviation forecaster's nightmare! Post-dawn stirring leading to
extensive ST~004, and reducing the visibility markedly. Lots of sorties
abandoned!=

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W

"Martin Rowley" wrote in message
...

0930 SSE F2 4000 BR 8/ST T028D023
RMK: The aviation forecaster's nightmare! Post-dawn stirring leading to
extensive ST~004, and reducing the visibility markedly. Lots of sorties
abandoned!=

Fog and low cloud drifting NW from the continent has been modelled well by
the mesoscale model and shows up well on the 0915Z MSG image from Bernard's
site -
http://www.btinternet.com/~wokingham...g-0915-eu.html

I didn't manage to see the earlier short TAFs, I was still in bed, but let's
hope not many were caught out.

Joe

Thursday, 12 January 2006
BRACKNELL (TAWFIELD)
0900 S F2-3 25km - 7/CI COTRA T025D017
RMK: the wind very variable in speed; within space of 10 mins or so,
dropped to near-calm and perked up to F4 for a short time - the
temperature rising sharply as a result with hoar frost melting.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: -00.1 grass min: -02.5 precipitation: tr [24hr total: tr
mm]
other data: significant hoar frost deposits, not only on the 'usual'
roof/grass surfaces, but all pavements and minor roads - quite
slippery. ]=

0930 SSE F2 4000 BR 8/ST T028D023
RMK: The aviation forecaster's nightmare! Post-dawn stirring leading to
extensive ST~004, and reducing the visibility markedly. Lots of sorties
abandoned!=

1030 SSE F2 20km - 1/SC 7/CI T040D030
RMK: Last of the St cleared by 1010Z - fine/bright now.

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W

Thursday, 12 January 2006
BRACKNELL (TAWFIELD)
0900 S F2-3 25km - 7/CI COTRA T025D017
RMK: the wind very variable in speed; within space of 10 mins or so,
dropped to near-calm and perked up to F4 for a short time - the
temperature rising sharply as a result with hoar frost melting.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: -00.1 grass min: -02.5 precipitation: tr [24hr total: tr
mm]
other data: significant hoar frost deposits, not only on the 'usual'
roof/grass surfaces, but all pavements and minor roads - quite
slippery. ]=

0930 SSE F2 4000 BR 8/ST T028D023
RMK: The aviation forecaster's nightmare! Post-dawn stirring leading to
extensive ST~004, and reducing the visibility markedly. Lots of sorties
abandoned!=

1030 SSE F2 20km - 1/SC 7/CI T040D030
RMK: Last of the St cleared by 1010Z - fine/bright now.

1800 S F3 30km - 7/SC T056D032
RMK: There is something above the Sc, but nothing significant enough to
block out the position of the moon.
[ DAYTIME DATA (09Z - 18Z):
screen max: 05.8 precipitation: NIL ]=

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W

Interesting your comments about the fluctuations in ff this morning as
the strong inversion was breaking down this morning, Martin.

As I left to drive to work in Bracknell at 0730, my anemometer was
barely stirring - the mean for the hour ending 0800 was only 0.3 kn,
and quite variable. Yet Reading's new wind farm turbine on Green Park,
alongside the M4, was spinning quite merrily at about 35 m above ground
level and obviously in the free air above the inversion.

It's only been there for six weeks, so I'm still getting a feel for the
'calibration' of turbine spin vs surface wind speeds, but it looked as
though it was a good 10 kn up there.

I'm going to try to find out if they have a recording anemometer on the
turbine and try to get hold of the readings, they'll make an
interesting comparison with mine (at 11 m AGL) about 7 km SSW.

Air min here much lower at -4.1°C, grass min -8.4°C. Surprised to see
I was colder than Benson for a change (-4.0°C).

Stephen

Well, I underestimated the height of the thing. According to
http://www.ecotricity.co.uk/projects...greenpark.html the turbine is
85 m tall, no wonder it was spinning so well above the surface
inversion!