In article
,
Colin Youngs writes:
On 12 déc, 22:32, John Hall wrote:
In article
,

Colin Youngs writes:
Brussels Uccle 6.0°C - overnight minimum -1.1°C.
Brussels Airport 3.3°C - overnight minimum -0.9°C.

That's a big difference in maxima over a shortish distance. Any idea of
the likely cause?

Yes, John, I noticed that too. Uccle is in the southern outer
suburbs of Brussels. Brussels Airport is just outside the city to
the NE.

In a stable winter situation as on Wednesday - with a very gentle
drift from the NE - Uccle tends to be slightly warmer than the Airport
because it is downwind of the city "heat island".

On Wednesday Brussels was on the western edge of a large area of low
cloud and mist covering most of the eastern half of Belgium. Where I
work in the "European" area of Brussels - a couple of miles east of
the centre - most of Wednesday morning was fairly clear and sunny.
Towards the end of the morning the broken edge of the stratocumulus
layer moved over from the east. By 2 p.m. the sky was completely
overcast with increasingly poor visibility.

Perhaps the Airport was covered by the low cloud much sooner so that
the morning rise in temperature stopped at around 3°C. There may
also have been a drift of colder air from the east over the Airport
area, inhibiting the rise in temperature. At Uccle the sunshine will
have persisted until noon or so - perhaps long enough for the
temperature to rise nearly 3 deg. C higher.

Some combination of factors like this is the only explanation I can
think of. I agree, though, that the difference is surprisingly
large.

Thanks, Colin.
--
John Hall
"Honest criticism is hard to take,
particularly from a relative, a friend,
an acquaintance, or a stranger." Franklin P Jones