On 05/05/2020 16:31, Bernard Burton wrote:
"Nigel Paice" wrote in message
...
1500Z: 08019KT 30KM 2AC100 3AS170 7CS200 13.3/5.7 QFF 1018.6 irregular
slow fall
SYNOP: 42980 70819 10133 20057 40186 56001 84078 333 82360 83467 87270
90710 91130=
Beaufort letters (1400-1500Z): c

Medium and upper cloud layers have thinned considerably during the
afternoon, enough for the sun to cast distinct shadows. More definite blue
sky is visible away to the north.
A curious pressure jump of 3mb occurred inside one hour this morning,
coincident with the passage of an equally curious arc of Ac castellanus
from the SE and wind increase (gust to 39kt). About half a dozen large
spots of rain fell from this feature, otherwise a dry day.
RH 60%. Good visibility. Max temp so far today 13.3

Nigel (Niton, Isle of Wight)
101m amsl

Hello Nigel. Your post about a curious pressure jump reminded me that we
also had an interesting jump (more like a surge) yesterday evening. Not sure
if there was any cloud changes associated with it. There is a link to my AWS
graphs for yesterday here, scroll down for the pressure, and click on
thumbnails to enlarge.

http://www.woksat.info/cs/ejsgr200504.gif

Hello Bernard,

That's fascinating; a similar large pressure rise, yet more than
12 hours apart which would suggest in all probability, that the
two events were purely coincidental and not linked to the same
cause.