On Tue, 27 Jul 2004 22:27:37 +0300, Yannis wrote in


There are hills to the upwind side of Faro - NW and N - so perhaps there
is
a föhn effect. That might also explain the extremely low RH - 6% at
12.00
UTC today - unless the instrument is faulty. Notice also the reports of
"smoke" - brush fires perhaps ?

So, can there be a Foehn effect without clouds over the hills? I thought the
Foehn effect was due to the descending air (downwind side of the hills)
being heated at the dry adiabatic rate, rather than the moist one, at which
it cools while ascending at the windprone side of the hill.

HiYannis

Yes, that is often the text book explantion of the Foehn, but it can happen
in entirely clear air. One way would be if dry/warm air above an inversion
(somewhere near mountain top height) is brought down to low levels on the
lee side.

--
Mike 55.13°N 6.69°W Coleraine posted to uk.sci.weather 27/07/2004 20:01:02 UTC