Altocumulus

9.45 am, looking east, wind from south-west, 19°C: This altocumulus cloud has formed as a layer, so it is classified as stratiformis. The ripples mean that it’s also undulatus and, finally, because the sun is visible through the cloud, it’s translucidus.

10.30 am: Three-quarters of an hour later the sky has filled with stratocumulus. We don’t get thunderstorms but there are a few rain showers later in the day.

As you might have guessed, my current bedtime reading is Clouds by Eric M. Wilcox.