Thanks for the responses so far.

I have got reports from several balloonists and microlight pilots who were
flying around the same time last night.

It seems there was an area of strong winds to around 5000ft in the area
northeast of and bounded by bdefordshire, running north to Yorkshire.

The odd think is that the wind was reported as being steady throughout the
flight, no real shear to it, apart from initially at the surface.

Simon

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"Waghorn" wrote in message
...
I was thinking along similar lines but there are some conditions lacking
to
confirm it is. With a nocturnal LLJ, unlike one induced by a mid-latitude
cyclone, the cooling aloft (900-850hPa) can only occur through land at a
higher elevation. For example, the Great Plains is often used in examples
from papers I have read. However, is it possible that the urban heat from
London could have triggered an effect, such that there was a thermal
gradient between Bedford and London even to that height ?

But 30 Kt ?
http://weather.ou.edu/~oscarvdv/maps...hetae_eur6.png
shws a surface convergence zone fed by Slies/SElies, presumably a heat low
which wld make a
gradient.
Sdgs for Watnall and Herstmonceux 0Z have strong inversions but no low
level jet.

And another, Blackardar (1957), Boundary Layer Wind Maxima and Their
Significance for the Growth of Nocturnal Inversions,
http://twister.caps.ou.edu/MM2004/Bl...ar1957BAMS.pdf (14.3MB)

Have you read the latter ?Joe
Now,I like 'obscure' papers ,but that one has evaded me!
;-)

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