9 - Weather photographs
Sea Breeze Convergence  - August 2004

This photo was taken at Godrevy at the eastern end of St Ives Bay looking back inland over Hayle towans. There was a nice line of cumulus along the sea breeze convergence zone,  but it is the reflection in the sand that really makes the picture.
Coastal Clouds
9 - Weather photographs
Coastal Clouds
Sea Fog being brought in by the sea
breeze running up the Camel estuary.

Daymer Bay, opposite Padstow
The Sea-Breeze Effect

Down in Penzance, at the tip of Cornwall, the surrounding sea clearly has a marked influence on the weather.

In particular, due to the sea breeze effect, the coasts are much sunnier than inland . When the air is rather unstable the effect can be dramatic. Cloudless on the beaches, billowing cumulus just a mile inland.

The top photo is taken from Porthleven, looking south towards the Lizard point. In this case the gradient wind was north, blowing the cloud along the spine of the Lizard, and off the southern point.
The peninsula in west Cornwall is so narrow, the sea breezes from the north & south coasts commonly converge in the middle.

In most cases this gives a distinct line of cumulus / strato-cumulus as in the 2nd photo, which was taken just north of Penzance looking NE towards Camborne.

At other times this convergence can give rise to heavy showers or thunderstorms, the 19th March 2013 saw one such event. The day started out with plenty of strong sunshine, little wind & excellent visibility. This, together with a slack area of low pressure and the associated very unstable air, resulted in the rapid development of Cb clouds in the centre of the Penwith peninsula.
The north coast of Cornwall is particularly prone to severe thunder storms as the sea breeze sets in. An example being a the storm of the 29th June 2005 over St. Merryn (just west of Padstow). Many properties in St Merryn, and villages just to the south, were flooded. Full details of the storm are on the Major Local Weather Events page.
Sea Breeze and Sea Fog

Sometimes the sea breeze will bring in sea fog. In this photo the fog is drifting into Mount’s Bay, and around St. Michael’s Mount.
The 1st photograph (below) was taken at  10:15, the 2nd at 10:30, by which time heavy rain was falling a couple of miles inland.
Sea Fog drifts around St. Michael’s Mount
When the sea breeze is coming in against an off-shore wind it struggles to reach the coast.  The picture to the right was taken at Sennen Cove, looking north towards Cape Cornwall.  

The sea breeze brought sea fog in to within a few  hundred metres at one point. The fog at the top of the cliff was moving back westwards under the gradient  wind, whilst at sea level it was moving towards the beach. Open Atlantic to the left, beach to the right.